This concludes the main part of the system call rework for 64-bit time_t,
which has spread over most of year 2018, the last six system calls being
- ppoll
- pselect6
- io_pgetevents
- recvmmsg
- futex
- rt_sigtimedwait
As before, nothing changes for 64-bit architectures, while 32-bit
architectures gain another entry point that differs only in the layout
of the timespec structure. Hopefully in the next release we can wire up
all 22 of those system calls on all 32-bit architectures, which gives
us a baseline version for glibc to start using them.
This does not include the clock_adjtime, getrusage/waitid, and
getitimer/setitimer system calls. I still plan to have new versions
of those as well, but they are not required for correct operation of
the C library since they can be emulated using the old 32-bit time_t
based system calls.
Aside from the system calls, there are also a few cleanups here,
removing old kernel internal interfaces that have become unused after
all references got removed. The arch/sh cleanups are part of this,
there were posted several times over the past year without a reaction
from the maintainers, while the corresponding changes made it into all
other architectures.
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Merge tag 'y2038-for-4.21' of ssh://gitolite.kernel.org:/pub/scm/linux/kernel/git/arnd/playground
Pull y2038 updates from Arnd Bergmann:
"More syscalls and cleanups
This concludes the main part of the system call rework for 64-bit
time_t, which has spread over most of year 2018, the last six system
calls being
- ppoll
- pselect6
- io_pgetevents
- recvmmsg
- futex
- rt_sigtimedwait
As before, nothing changes for 64-bit architectures, while 32-bit
architectures gain another entry point that differs only in the layout
of the timespec structure. Hopefully in the next release we can wire
up all 22 of those system calls on all 32-bit architectures, which
gives us a baseline version for glibc to start using them.
This does not include the clock_adjtime, getrusage/waitid, and
getitimer/setitimer system calls. I still plan to have new versions of
those as well, but they are not required for correct operation of the
C library since they can be emulated using the old 32-bit time_t based
system calls.
Aside from the system calls, there are also a few cleanups here,
removing old kernel internal interfaces that have become unused after
all references got removed. The arch/sh cleanups are part of this,
there were posted several times over the past year without a reaction
from the maintainers, while the corresponding changes made it into all
other architectures"
* tag 'y2038-for-4.21' of ssh://gitolite.kernel.org:/pub/scm/linux/kernel/git/arnd/playground:
timekeeping: remove obsolete time accessors
vfs: replace current_kernel_time64 with ktime equivalent
timekeeping: remove timespec_add/timespec_del
timekeeping: remove unused {read,update}_persistent_clock
sh: remove board_time_init() callback
sh: remove unused rtc_sh_get/set_time infrastructure
sh: sh03: rtc: push down rtc class ops into driver
sh: dreamcast: rtc: push down rtc class ops into driver
y2038: signal: Add compat_sys_rt_sigtimedwait_time64
y2038: signal: Add sys_rt_sigtimedwait_time32
y2038: socket: Add compat_sys_recvmmsg_time64
y2038: futex: Add support for __kernel_timespec
y2038: futex: Move compat implementation into futex.c
io_pgetevents: use __kernel_timespec
pselect6: use __kernel_timespec
ppoll: use __kernel_timespec
signal: Add restore_user_sigmask()
signal: Add set_user_sigmask()
All callers of migrate_page_move_mapping() now pass NULL for 'head'
argument. Drop it.
Link: http://lkml.kernel.org/r/20181211172143.7358-7-jack@suse.cz
Signed-off-by: Jan Kara <jack@suse.cz>
Acked-by: Mel Gorman <mgorman@suse.de>
Cc: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In preparation of handing in iocbs in a different fashion as well. Also
make it clear that the iocb being passed in isn't modified, by marking
it const throughout.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Replace the percpu_ref_put() + kmem_cache_free() with a call to
iocb_put() instead.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Plugging is meant to optimize submission of a string of IOs, if we don't
have more than 2 being submitted, don't bother setting up a plug.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
It's 192 bytes, fairly substantial. Most items don't need to be cleared,
especially not upfront. Clear the ones we do need to clear, and leave
the other ones for setup when the iocb is prepared and submitted.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This is in preparation for certain types of IO not needing a ring
reserveration.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We know this is a read/write request, but in preparation for
having different kinds of those, ensure that we call the assigned
handler instead of assuming it's aio_complete_rq().
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
* for-4.21/block: (351 commits)
blk-mq: enable IO poll if .nr_queues of type poll > 0
blk-mq: change blk_mq_queue_busy() to blk_mq_queue_inflight()
blk-mq: skip zero-queue maps in blk_mq_map_swqueue
block: fix blk-iolatency accounting underflow
blk-mq: fix dispatch from sw queue
block: mq-deadline: Fix write completion handling
nvme-pci: don't share queue maps
blk-mq: only dispatch to non-defauly queue maps if they have queues
blk-mq: export hctx->type in debugfs instead of sysfs
blk-mq: fix allocation for queue mapping table
blk-wbt: export internal state via debugfs
blk-mq-debugfs: support rq_qos
block: update sysfs documentation
block: loop: check error using IS_ERR instead of IS_ERR_OR_NULL in loop_add()
aoe: add __exit annotation
block: clear REQ_HIPRI if polling is not supported
blk-mq: replace and kill blk_mq_request_issue_directly
blk-mq: issue directly with bypass 'false' in blk_mq_sched_insert_requests
blk-mq: refactor the code of issue request directly
block: remove the bio_integrity_advance export
...
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Merge tag 'for-linus-20181214' of git://git.kernel.dk/linux-block
Pull block fixes from Jens Axboe:
"Three small fixes for this week. contains:
- spectre indexing fix for aio (Jeff)
- fix for the previous zeroing bio fix, we don't need it for user
mapped pages, and in fact it breaks some applications if we do
(Keith)
- allocation failure fix for null_blk with zoned (Shin'ichiro)"
* tag 'for-linus-20181214' of git://git.kernel.dk/linux-block:
block: Fix null_blk_zoned creation failure with small number of zones
aio: fix spectre gadget in lookup_ioctx
block/bio: Do not zero user pages
Matthew pointed out that the ioctx_table is susceptible to spectre v1,
because the index can be controlled by an attacker. The below patch
should mitigate the attack for all of the aio system calls.
Cc: stable@vger.kernel.org
Reported-by: Matthew Wilcox <willy@infradead.org>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
struct timespec is not y2038 safe.
struct __kernel_timespec is the new y2038 safe structure for all
syscalls that are using struct timespec.
Update io_pgetevents interfaces to use struct __kernel_timespec.
sigset_t also has different representations on 32 bit and 64 bit
architectures. Hence, we need to support the following different
syscalls:
New y2038 safe syscalls:
(Controlled by CONFIG_64BIT_TIME for 32 bit ABIs)
Native 64 bit(unchanged) and native 32 bit : sys_io_pgetevents
Compat : compat_sys_io_pgetevents_time64
Older y2038 unsafe syscalls:
(Controlled by CONFIG_32BIT_COMPAT_TIME for 32 bit ABIs)
Native 32 bit : sys_io_pgetevents_time32
Compat : compat_sys_io_pgetevents
Note that io_getevents syscalls do not have a y2038 safe solution.
Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Refactor the logic to restore the sigmask before the syscall
returns into an api.
This is useful for versions of syscalls that pass in the
sigmask and expect the current->sigmask to be changed during
the execution and restored after the execution of the syscall.
With the advent of new y2038 syscalls in the subsequent patches,
we add two more new versions of the syscalls (for pselect, ppoll
and io_pgetevents) in addition to the existing native and compat
versions. Adding such an api reduces the logic that would need to
be replicated otherwise.
Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Refactor reading sigset from userspace and updating sigmask
into an api.
This is useful for versions of syscalls that pass in the
sigmask and expect the current->sigmask to be changed during,
and restored after, the execution of the syscall.
With the advent of new y2038 syscalls in the subsequent patches,
we add two more new versions of the syscalls (for pselect, ppoll,
and io_pgetevents) in addition to the existing native and compat
versions. Adding such an api reduces the logic that would need to
be replicated otherwise.
Note that the calls to sigprocmask() ignored the return value
from the api as the function only returns an error on an invalid
first argument that is hardcoded at these call sites.
The updated logic uses set_current_blocked() instead.
Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
No one is going to poll for aio (yet), so we must clear the HIPRI
flag, as we would otherwise send it down the poll queues, where no
one will be polling for completions.
Signed-off-by: Christoph Hellwig <hch@lst.de>
IOCB_HIPRI, not RWF_HIPRI.
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Merge tag 'v4.20-rc5' into for-4.21/block
Pull in v4.20-rc5, solving a conflict we'll otherwise get in aio.c and
also getting the merge fix that went into mainline that users are
hitting testing for-4.21/block and/or for-next.
* tag 'v4.20-rc5': (664 commits)
Linux 4.20-rc5
PCI: Fix incorrect value returned from pcie_get_speed_cap()
MAINTAINERS: Update linux-mips mailing list address
ocfs2: fix potential use after free
mm/khugepaged: fix the xas_create_range() error path
mm/khugepaged: collapse_shmem() do not crash on Compound
mm/khugepaged: collapse_shmem() without freezing new_page
mm/khugepaged: minor reorderings in collapse_shmem()
mm/khugepaged: collapse_shmem() remember to clear holes
mm/khugepaged: fix crashes due to misaccounted holes
mm/khugepaged: collapse_shmem() stop if punched or truncated
mm/huge_memory: fix lockdep complaint on 32-bit i_size_read()
mm/huge_memory: splitting set mapping+index before unfreeze
mm/huge_memory: rename freeze_page() to unmap_page()
initramfs: clean old path before creating a hardlink
kernel/kcov.c: mark funcs in __sanitizer_cov_trace_pc() as notrace
psi: make disabling/enabling easier for vendor kernels
proc: fixup map_files test on arm
debugobjects: avoid recursive calls with kmemleak
userfaultfd: shmem: UFFDIO_COPY: set the page dirty if VM_WRITE is not set
...
For cases when the application does not specify aio_reqprio for an aio,
fallback to use get_current_ioprio() to obtain the task I/O priority
last set using ioprio_set() rather than the hardcoded IOPRIO_CLASS_NONE
value.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Adam Manzanares <adam.manzanares@wdc.com>
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
If the ioprio capability check fails, we return without putting
the file pointer.
Fixes: d9a08a9e61 ("fs: Add aio iopriority support")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Christoph Hellwig suggested a slightly different path for handling
backwards compatibility with the 32-bit time_t based system calls:
Rather than simply reusing the compat_sys_* entry points on 32-bit
architectures unchanged, we get rid of those entry points and the
compat_time types by renaming them to something that makes more sense
on 32-bit architectures (which don't have a compat mode otherwise),
and then share the entry points under the new name with the 64-bit
architectures that use them for implementing the compatibility.
The following types and interfaces are renamed here, and moved
from linux/compat_time.h to linux/time32.h:
old new
--- ---
compat_time_t old_time32_t
struct compat_timeval struct old_timeval32
struct compat_timespec struct old_timespec32
struct compat_itimerspec struct old_itimerspec32
ns_to_compat_timeval() ns_to_old_timeval32()
get_compat_itimerspec64() get_old_itimerspec32()
put_compat_itimerspec64() put_old_itimerspec32()
compat_get_timespec64() get_old_timespec32()
compat_put_timespec64() put_old_timespec32()
As we already have aliases in place, this patch addresses only the
instances that are relevant to the system call interface in particular,
not those that occur in device drivers and other modules. Those
will get handled separately, while providing the 64-bit version
of the respective interfaces.
I'm not renaming the timex, rusage and itimerval structures, as we are
still debating what the new interface will look like, and whether we
will need a replacement at all.
This also doesn't change the names of the syscall entry points, which can
be done more easily when we actually switch over the 32-bit architectures
to use them, at that point we need to change COMPAT_SYSCALL_DEFINEx to
SYSCALL_DEFINEx with a new name, e.g. with a _time32 suffix.
Suggested-by: Christoph Hellwig <hch@infradead.org>
Link: https://lore.kernel.org/lkml/20180705222110.GA5698@infradead.org/
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Pull vfs aio updates from Al Viro:
"Christoph's aio poll, saner this time around.
This time it's pretty much local to fs/aio.c. Hopefully race-free..."
* 'work.aio' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
aio: allow direct aio poll comletions for keyed wakeups
aio: implement IOCB_CMD_POLL
aio: add a iocb refcount
timerfd: add support for keyed wakeups
Pull vfs open-related updates from Al Viro:
- "do we need fput() or put_filp()" rules are gone - it's always fput()
now. We keep track of that state where it belongs - in ->f_mode.
- int *opened mess killed - in finish_open(), in ->atomic_open()
instances and in fs/namei.c code around do_last()/lookup_open()/atomic_open().
- alloc_file() wrappers with saner calling conventions are introduced
(alloc_file_clone() and alloc_file_pseudo()); callers converted, with
much simplification.
- while we are at it, saner calling conventions for path_init() and
link_path_walk(), simplifying things inside fs/namei.c (both on
open-related paths and elsewhere).
* 'work.open3' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (40 commits)
few more cleanups of link_path_walk() callers
allow link_path_walk() to take ERR_PTR()
make path_init() unconditionally paired with terminate_walk()
document alloc_file() changes
make alloc_file() static
do_shmat(): grab shp->shm_file earlier, switch to alloc_file_clone()
new helper: alloc_file_clone()
create_pipe_files(): switch the first allocation to alloc_file_pseudo()
anon_inode_getfile(): switch to alloc_file_pseudo()
hugetlb_file_setup(): switch to alloc_file_pseudo()
ocxlflash_getfile(): switch to alloc_file_pseudo()
cxl_getfile(): switch to alloc_file_pseudo()
... and switch shmem_file_setup() to alloc_file_pseudo()
__shmem_file_setup(): reorder allocations
new wrapper: alloc_file_pseudo()
kill FILE_{CREATED,OPENED}
switch atomic_open() and lookup_open() to returning 0 in all success cases
document ->atomic_open() changes
->atomic_open(): return 0 in all success cases
get rid of 'opened' in path_openat() and the helpers downstream
...
If we get a keyed wakeup for a aio poll waitqueue and wake can acquire the
ctx_lock without spinning we can just complete the iocb straight from the
wakeup callback to avoid a context switch.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Avi Kivity <avi@scylladb.com>
Simple one-shot poll through the io_submit() interface. To poll for
a file descriptor the application should submit an iocb of type
IOCB_CMD_POLL. It will poll the fd for the events specified in the
the first 32 bits of the aio_buf field of the iocb.
Unlike poll or epoll without EPOLLONESHOT this interface always works
in one shot mode, that is once the iocb is completed, it will have to be
resubmitted.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Avi Kivity <avi@scylladb.com>
This is needed to prevent races caused by the way the ->poll API works.
To avoid introducing overhead for other users of the iocbs we initialize
it to zero and only do refcount operations if it is non-zero in the
completion path.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Avi Kivity <avi@scylladb.com>
Pull vfs fixes from Al Viro:
"Fix several places that screw up cleanups after failures halfway
through opening a file (one open-coding filp_clone_open() and getting
it wrong, two misusing alloc_file()). That part is -stable fodder from
the 'work.open' branch.
And Christoph's regression fix for uapi breakage in aio series;
include/uapi/linux/aio_abi.h shouldn't be pulling in the kernel
definition of sigset_t, the reason for doing so in the first place had
been bogus - there's no need to expose struct __aio_sigset in
aio_abi.h at all"
* 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
aio: don't expose __aio_sigset in uapi
ocxlflash_getfile(): fix double-iput() on alloc_file() failures
cxl_getfile(): fix double-iput() on alloc_file() failures
drm_mode_create_lease_ioctl(): fix open-coded filp_clone_open()
glibc uses a different defintion of sigset_t than the kernel does,
and the current version would pull in both. To fix this just do not
expose the type at all - this somewhat mirrors pselect() where we
do not even have a type for the magic sigmask argument, but just
use pointer arithmetics.
Fixes: 7a074e96 ("aio: implement io_pgetevents")
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reported-by: Adrian Reber <adrian@lisas.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
takes inode, vfsmount, name, O_... flags and file_operations and
either returns a new struct file (in which case inode reference we
held is consumed) or returns ERR_PTR(), in which case no refcounts
are altered.
converted aio_private_file() and sock_alloc_file() to it
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
... so that it could set both ->f_flags and ->f_mode, without callers
having to set ->f_flags manually.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
The poll() changes were not well thought out, and completely
unexplained. They also caused a huge performance regression, because
"->poll()" was no longer a trivial file operation that just called down
to the underlying file operations, but instead did at least two indirect
calls.
Indirect calls are sadly slow now with the Spectre mitigation, but the
performance problem could at least be largely mitigated by changing the
"->get_poll_head()" operation to just have a per-file-descriptor pointer
to the poll head instead. That gets rid of one of the new indirections.
But that doesn't fix the new complexity that is completely unwarranted
for the regular case. The (undocumented) reason for the poll() changes
was some alleged AIO poll race fixing, but we don't make the common case
slower and more complex for some uncommon special case, so this all
really needs way more explanations and most likely a fundamental
redesign.
[ This revert is a revert of about 30 different commits, not reverted
individually because that would just be unnecessarily messy - Linus ]
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The ->poll_mask() operation has a mask of events that the caller
is interested in, but not all implementations might take it into
account. Mask the return value to only the requested events,
similar to what the poll and epoll code does.
Reported-by: Avi Kivity <avi@scylladb.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This is the per-I/O equivalent of the ioprio_set system call.
When IOCB_FLAG_IOPRIO is set on the iocb aio_flags field, then we set the
newly added kiocb ki_ioprio field to the value in the iocb aio_reqprio field.
This patch depends on block: add ioprio_check_cap function.
Signed-off-by: Adam Manzanares <adam.manzanares@wdc.com>
Reviewed-by: Jeff Moyer <jmoyer@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
In order to avoid kiocb bloat for per command iopriority support, rw_hint
is converted from enum to a u16. Added a guard around ki_hint assignment.
Signed-off-by: Adam Manzanares <adam.manzanares@wdc.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
as it is, the logics in native io_submit(2) is "if asked for
more than LONG_MAX/sizeof(pointer) iocbs to submit, don't
bother with more than LONG_MAX/sizeof(pointer)" (i.e.
512M requests on 32bit and 1E requests on 64bit) while
compat io_submit(2) goes with "stop after the first
PAGE_SIZE/sizeof(pointer) iocbs", i.e. 1K or so. Which is
* inconsistent
* *way* too much in native case
* possibly too little in compat one
and
* wrong anyway, since the natural point where we
ought to stop bothering is ctx->nr_events
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
get rid of insane "copy array of 32bit pointers into an array of
native ones" glue.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
The logics for 'avail' is
* not past the tail of cyclic buffer
* no more than asked
* not past the end of buffer
* not past the end of a page
Unobfuscate the last part.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
... so just make them return 0 when caller does not need to destroy iocb
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
If we can acquire ctx_lock without spinning we can just remove our
iocb from the active_reqs list, and thus complete the iocbs from the
wakeup context.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Simple one-shot poll through the io_submit() interface. To poll for
a file descriptor the application should submit an iocb of type
IOCB_CMD_POLL. It will poll the fd for the events specified in the
the first 32 bits of the aio_buf field of the iocb.
Unlike poll or epoll without EPOLLONESHOT this interface always works
in one shot mode, that is once the iocb is completed, it will have to be
resubmitted.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
With the current aio code there is no need for the magic KIOCB_CANCELLED
value, as a cancelation just kicks the driver to queue the completion
ASAP, with all actual completion handling done in another thread. Given
that both the completion path and cancelation take the context lock there
is no need for magic cmpxchg loops either. If we remove iocbs from the
active list after calling ->ki_cancel (but with ctx_lock still held), we
can also rely on the invariant thay anything found on the list has a
->ki_cancel callback and can be cancelled, further simplifing the code.
Signed-off-by: Christoph Hellwig <hch@lst.de>
No need to pass the key field to lookup_iocb to compare it with KIOCB_KEY,
as we can do that right after retrieving it from userspace. Also move the
KIOCB_KEY definition to aio.c as it is an internal value not used by any
other place in the kernel.
Signed-off-by: Christoph Hellwig <hch@lst.de>
If io_destroy() gets to cancelling everything that can be cancelled and
gets to kiocb_cancel() calling the function driver has left in ->ki_cancel,
it becomes vulnerable to a race with IO completion. At that point req
is already taken off the list and aio_complete() does *NOT* spin until
we (in free_ioctx_users()) releases ->ctx_lock. As the result, it proceeds
to kiocb_free(), freing req just it gets passed to ->ki_cancel().
Fix is simple - remove from the list after the call of kiocb_cancel(). All
instances of ->ki_cancel() already have to cope with the being called with
iocb still on list - that's what happens in io_cancel(2).
Cc: stable@kernel.org
Fixes: 0460fef2a9 "aio: use cancellation list lazily"
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
kill_ioctx() used to have an explicit RCU delay between removing the
reference from ->ioctx_table and percpu_ref_kill() dropping the refcount.
At some point that delay had been removed, on the theory that
percpu_ref_kill() itself contained an RCU delay. Unfortunately, that was
the wrong kind of RCU delay and it didn't care about rcu_read_lock() used
by lookup_ioctx(). As the result, we could get ctx freed right under
lookup_ioctx(). Tejun has fixed that in a6d7cff472 ("fs/aio: Add explicit
RCU grace period when freeing kioctx"); however, that fix is not enough.
Suppose io_destroy() from one thread races with e.g. io_setup() from another;
CPU1 removes the reference from current->mm->ioctx_table[...] just as CPU2
has picked it (under rcu_read_lock()). Then CPU1 proceeds to drop the
refcount, getting it to 0 and triggering a call of free_ioctx_users(),
which proceeds to drop the secondary refcount and once that reaches zero
calls free_ioctx_reqs(). That does
INIT_RCU_WORK(&ctx->free_rwork, free_ioctx);
queue_rcu_work(system_wq, &ctx->free_rwork);
and schedules freeing the whole thing after RCU delay.
In the meanwhile CPU2 has gotten around to percpu_ref_get(), bumping the
refcount from 0 to 1 and returned the reference to io_setup().
Tejun's fix (that queue_rcu_work() in there) guarantees that ctx won't get
freed until after percpu_ref_get(). Sure, we'd increment the counter before
ctx can be freed. Now we are out of rcu_read_lock() and there's nothing to
stop freeing of the whole thing. Unfortunately, CPU2 assumes that since it
has grabbed the reference, ctx is *NOT* going away until it gets around to
dropping that reference.
The fix is obvious - use percpu_ref_tryget_live() and treat failure as miss.
It's not costlier than what we currently do in normal case, it's safe to
call since freeing *is* delayed and it closes the race window - either
lookup_ioctx() comes before percpu_ref_kill() (in which case ctx->users
won't reach 0 until the caller of lookup_ioctx() drops it) or lookup_ioctx()
fails, ctx->users is unaffected and caller of lookup_ioctx() doesn't see
the object in question at all.
Cc: stable@kernel.org
Fixes: a6d7cff472 "fs/aio: Add explicit RCU grace period when freeing kioctx"
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This is the io_getevents equivalent of ppoll/pselect and allows to
properly mix signals and aio completions (especially with IOCB_CMD_POLL)
and atomically executes the following sequence:
sigset_t origmask;
pthread_sigmask(SIG_SETMASK, &sigmask, &origmask);
ret = io_getevents(ctx, min_nr, nr, events, timeout);
pthread_sigmask(SIG_SETMASK, &origmask, NULL);
Note that unlike many other signal related calls we do not pass a sigmask
size, as that would get us to 7 arguments, which aren't easily supported
by the syscall infrastructure. It seems a lot less painful to just add a
new syscall variant in the unlikely case we're going to increase the
sigset size.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Simple workqueue offload for now, but prepared for adding a real aio_fsync
method if the need arises. Based on an earlier patch from Dave Chinner.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Don't reference the kiocb structure from the common aio code, and move
any use of it into helper specific to the read/write path. This is in
preparation for aio_poll support that wants to use the space for different
fields.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Jeff Moyer <jmoyer@redhat.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
If we release the lockdep write protection token before calling into
->write_iter and thus never access the file pointer after an -EIOCBQUEUED
return from ->write_iter or ->read_iter we don't need this extra
reference.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Instead of handcoded non-null checks always initialize ki_list to an
empty list and use list_empty / list_empty_careful on it. While we're
at it also error out on a double call to kiocb_set_cancel_fn instead
of ignoring it.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Jeff Moyer <jmoyer@redhat.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
These days we don't treat sync iocbs special in the aio completion code as
they never use it. Remove the old comment and BUG_ON given that the
current definition of is_sync_kiocb makes it impossible to hit.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
The page size is in no way related to the aio code, and printing it in
the (debug) dmesg at every boot serves no purpose.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Jeff Moyer <jmoyer@redhat.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
While converting ioctx index from a list to a table, db446a08c2
("aio: convert the ioctx list to table lookup v3") missed tagging
kioctx_table->table[] as an array of RCU pointers and using the
appropriate RCU accessors. This introduces a small window in the
lookup path where init and access may race.
Mark kioctx_table->table[] with __rcu and use the approriate RCU
accessors when using the field.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Jann Horn <jannh@google.com>
Fixes: db446a08c2 ("aio: convert the ioctx list to table lookup v3")
Cc: Benjamin LaHaise <bcrl@kvack.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: stable@vger.kernel.org # v3.12+
While fixing refcounting, e34ecee2ae ("aio: Fix a trinity splat")
incorrectly removed explicit RCU grace period before freeing kioctx.
The intention seems to be depending on the internal RCU grace periods
of percpu_ref; however, percpu_ref uses a different flavor of RCU,
sched-RCU. This can lead to kioctx being freed while RCU read
protected dereferences are still in progress.
Fix it by updating free_ioctx() to go through call_rcu() explicitly.
v2: Comment added to explain double bouncing.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Jann Horn <jannh@google.com>
Fixes: e34ecee2ae ("aio: Fix a trinity splat")
Cc: Kent Overstreet <kent.overstreet@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: stable@vger.kernel.org # v3.13+
Pull compat and uaccess updates from Al Viro:
- {get,put}_compat_sigset() series
- assorted compat ioctl stuff
- more set_fs() elimination
- a few more timespec64 conversions
- several removals of pointless access_ok() in places where it was
followed only by non-__ variants of primitives
* 'misc.compat' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (24 commits)
coredump: call do_unlinkat directly instead of sys_unlink
fs: expose do_unlinkat for built-in callers
ext4: take handling of EXT4_IOC_GROUP_ADD into a helper, get rid of set_fs()
ipmi: get rid of pointless access_ok()
pi433: sanitize ioctl
cxlflash: get rid of pointless access_ok()
mtdchar: get rid of pointless access_ok()
r128: switch compat ioctls to drm_ioctl_kernel()
selection: get rid of field-by-field copyin
VT_RESIZEX: get rid of field-by-field copyin
i2c compat ioctls: move to ->compat_ioctl()
sched_rr_get_interval(): move compat to native, get rid of set_fs()
mips: switch to {get,put}_compat_sigset()
sparc: switch to {get,put}_compat_sigset()
s390: switch to {get,put}_compat_sigset()
ppc: switch to {get,put}_compat_sigset()
parisc: switch to {get,put}_compat_sigset()
get_compat_sigset()
get rid of {get,put}_compat_itimerspec()
io_getevents: Use timespec64 to represent timeouts
...
Please do not apply this to mainline directly, instead please re-run the
coccinelle script shown below and apply its output.
For several reasons, it is desirable to use {READ,WRITE}_ONCE() in
preference to ACCESS_ONCE(), and new code is expected to use one of the
former. So far, there's been no reason to change most existing uses of
ACCESS_ONCE(), as these aren't harmful, and changing them results in
churn.
However, for some features, the read/write distinction is critical to
correct operation. To distinguish these cases, separate read/write
accessors must be used. This patch migrates (most) remaining
ACCESS_ONCE() instances to {READ,WRITE}_ONCE(), using the following
coccinelle script:
----
// Convert trivial ACCESS_ONCE() uses to equivalent READ_ONCE() and
// WRITE_ONCE()
// $ make coccicheck COCCI=/home/mark/once.cocci SPFLAGS="--include-headers" MODE=patch
virtual patch
@ depends on patch @
expression E1, E2;
@@
- ACCESS_ONCE(E1) = E2
+ WRITE_ONCE(E1, E2)
@ depends on patch @
expression E;
@@
- ACCESS_ONCE(E)
+ READ_ONCE(E)
----
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: davem@davemloft.net
Cc: linux-arch@vger.kernel.org
Cc: mpe@ellerman.id.au
Cc: shuah@kernel.org
Cc: snitzer@redhat.com
Cc: thor.thayer@linux.intel.com
Cc: tj@kernel.org
Cc: viro@zeniv.linux.org.uk
Cc: will.deacon@arm.com
Link: http://lkml.kernel.org/r/1508792849-3115-19-git-send-email-paulmck@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
struct timespec is not y2038 safe. Use y2038 safe
struct timespec64 to represent timeouts.
The system call interface itself will be changed as
part of different series.
Timeouts will not really need more than 32 bits.
But, replacing these with timespec64 helps verification
of a y2038 safe kernel by getting rid of timespec
internally.
Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com>
Cc: linux-aio@kvack.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Pull nowait read support from Al Viro:
"Support IOCB_NOWAIT for buffered reads and block devices"
* 'work.read_write' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
block_dev: support RFW_NOWAIT on block device nodes
fs: support RWF_NOWAIT for buffered reads
fs: support IOCB_NOWAIT in generic_file_buffered_read
fs: pass iocb to do_generic_file_read
Introduce a new migration mode that allow to offload the copy to a device
DMA engine. This changes the workflow of migration and not all
address_space migratepage callback can support this.
This is intended to be use by migrate_vma() which itself is use for thing
like HMM (see include/linux/hmm.h).
No additional per-filesystem migratepage testing is needed. I disables
MIGRATE_SYNC_NO_COPY in all problematic migratepage() callback and i
added comment in those to explain why (part of this patch). The commit
message is unclear it should say that any callback that wish to support
this new mode need to be aware of the difference in the migration flow
from other mode.
Some of these callbacks do extra locking while copying (aio, zsmalloc,
balloon, ...) and for DMA to be effective you want to copy multiple
pages in one DMA operations. But in the problematic case you can not
easily hold the extra lock accross multiple call to this callback.
Usual flow is:
For each page {
1 - lock page
2 - call migratepage() callback
3 - (extra locking in some migratepage() callback)
4 - migrate page state (freeze refcount, update page cache, buffer
head, ...)
5 - copy page
6 - (unlock any extra lock of migratepage() callback)
7 - return from migratepage() callback
8 - unlock page
}
The new mode MIGRATE_SYNC_NO_COPY:
1 - lock multiple pages
For each page {
2 - call migratepage() callback
3 - abort in all problematic migratepage() callback
4 - migrate page state (freeze refcount, update page cache, buffer
head, ...)
} // finished all calls to migratepage() callback
5 - DMA copy multiple pages
6 - unlock all the pages
To support MIGRATE_SYNC_NO_COPY in the problematic case we would need a
new callback migratepages() (for instance) that deals with multiple
pages in one transaction.
Because the problematic cases are not important for current usage I did
not wanted to complexify this patchset even more for no good reason.
Link: http://lkml.kernel.org/r/20170817000548.32038-14-jglisse@redhat.com
Signed-off-by: Jérôme Glisse <jglisse@redhat.com>
Cc: Aneesh Kumar <aneesh.kumar@linux.vnet.ibm.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: David Nellans <dnellans@nvidia.com>
Cc: Evgeny Baskakov <ebaskakov@nvidia.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Mark Hairgrove <mhairgrove@nvidia.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Sherry Cheung <SCheung@nvidia.com>
Cc: Subhash Gutti <sgutti@nvidia.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Bob Liu <liubo95@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently, aio-nr is incremented in steps of 'num_possible_cpus() * 8'
for io_setup(nr_events, ..) with 'nr_events < num_possible_cpus() * 4':
ioctx_alloc()
...
nr_events = max(nr_events, num_possible_cpus() * 4);
nr_events *= 2;
...
ctx->max_reqs = nr_events;
...
aio_nr += ctx->max_reqs;
....
This limits the number of aio contexts actually available to much less
than aio-max-nr, and is increasingly worse with greater number of CPUs.
For example, with 64 CPUs, only 256 aio contexts are actually available
(with aio-max-nr = 65536) because the increment is 512 in that scenario.
Note: 65536 [max aio contexts] / (64*4*2) [increment per aio context]
is 128, but make it 256 (double) as counting against 'aio-max-nr * 2':
ioctx_alloc()
...
if (aio_nr + nr_events > (aio_max_nr * 2UL) ||
...
goto err_ctx;
...
This patch uses the original value of nr_events (from userspace) to
increment aio-nr and count against aio-max-nr, which resolves those.
Signed-off-by: Mauricio Faria de Oliveira <mauricfo@linux.vnet.ibm.com>
Reported-by: Lekshmi C. Pillai <lekshmi.cpillai@in.ibm.com>
Tested-by: Lekshmi C. Pillai <lekshmi.cpillai@in.ibm.com>
Tested-by: Paul Nguyen <nguyenp@us.ibm.com>
Reviewed-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Benjamin LaHaise <bcrl@kvack.org>
This is based on the old idea and code from Milosz Tanski. With the aio
nowait code it becomes mostly trivial now. Buffered writes continue to
return -EOPNOTSUPP if RWF_NOWAIT is passed.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Reviewed-by: Andreas Dilger <adilger@dilger.ca>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
RWF_NOWAIT informs kernel to bail out if an AIO request will block
for reasons such as file allocations, or a writeback triggered,
or would block while allocating requests while performing
direct I/O.
RWF_NOWAIT is translated to IOCB_NOWAIT for iocb->ki_flags.
FMODE_AIO_NOWAIT is a flag which identifies the file opened is capable
of returning -EAGAIN if the AIO call will block. This must be set by
supporting filesystems in the ->open() call.
Filesystems xfs, btrfs and ext4 would be supported in the following patches.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
aio_rw_flags is introduced in struct iocb (using aio_reserved1) which will
carry the RWF_* flags. We cannot use aio_flags because they are not
checked for validity which may break existing applications.
Note, the only place RWF_HIPRI comes in effect is dio_await_one().
All the rest of the locations, aio code return -EIOCBQUEUED before the
checks for RWF_HIPRI.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Pull sched.h split-up from Ingo Molnar:
"The point of these changes is to significantly reduce the
<linux/sched.h> header footprint, to speed up the kernel build and to
have a cleaner header structure.
After these changes the new <linux/sched.h>'s typical preprocessed
size goes down from a previous ~0.68 MB (~22K lines) to ~0.45 MB (~15K
lines), which is around 40% faster to build on typical configs.
Not much changed from the last version (-v2) posted three weeks ago: I
eliminated quirks, backmerged fixes plus I rebased it to an upstream
SHA1 from yesterday that includes most changes queued up in -next plus
all sched.h changes that were pending from Andrew.
I've re-tested the series both on x86 and on cross-arch defconfigs,
and did a bisectability test at a number of random points.
I tried to test as many build configurations as possible, but some
build breakage is probably still left - but it should be mostly
limited to architectures that have no cross-compiler binaries
available on kernel.org, and non-default configurations"
* 'WIP.sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (146 commits)
sched/headers: Clean up <linux/sched.h>
sched/headers: Remove #ifdefs from <linux/sched.h>
sched/headers: Remove the <linux/topology.h> include from <linux/sched.h>
sched/headers, hrtimer: Remove the <linux/wait.h> include from <linux/hrtimer.h>
sched/headers, x86/apic: Remove the <linux/pm.h> header inclusion from <asm/apic.h>
sched/headers, timers: Remove the <linux/sysctl.h> include from <linux/timer.h>
sched/headers: Remove <linux/magic.h> from <linux/sched/task_stack.h>
sched/headers: Remove <linux/sched.h> from <linux/sched/init.h>
sched/core: Remove unused prefetch_stack()
sched/headers: Remove <linux/rculist.h> from <linux/sched.h>
sched/headers: Remove the 'init_pid_ns' prototype from <linux/sched.h>
sched/headers: Remove <linux/signal.h> from <linux/sched.h>
sched/headers: Remove <linux/rwsem.h> from <linux/sched.h>
sched/headers: Remove the runqueue_is_locked() prototype
sched/headers: Remove <linux/sched.h> from <linux/sched/hotplug.h>
sched/headers: Remove <linux/sched.h> from <linux/sched/debug.h>
sched/headers: Remove <linux/sched.h> from <linux/sched/nohz.h>
sched/headers: Remove <linux/sched.h> from <linux/sched/stat.h>
sched/headers: Remove the <linux/gfp.h> include from <linux/sched.h>
sched/headers: Remove <linux/rtmutex.h> from <linux/sched.h>
...
Pull vfs pile two from Al Viro:
- orangefs fix
- series of fs/namei.c cleanups from me
- VFS stuff coming from overlayfs tree
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
orangefs: Use RCU for destroy_inode
vfs: use helper for calling f_op->fsync()
mm: use helper for calling f_op->mmap()
vfs: use helpers for calling f_op->{read,write}_iter()
vfs: pass type instead of fn to do_{loop,iter}_readv_writev()
vfs: extract common parts of {compat_,}do_readv_writev()
vfs: wrap write f_ops with file_{start,end}_write()
vfs: deny copy_file_range() for non regular files
vfs: deny fallocate() on directory
vfs: create vfs helper vfs_tmpfile()
namei.c: split unlazy_walk()
namei.c: fold the check for DCACHE_OP_REVALIDATE into d_revalidate()
lookup_fast(): clean up the logics around the fallback to non-rcu mode
namei: fold unlazy_link() into its sole caller
Fix up affected files that include this signal functionality via sched.h.
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
When a non-cooperative userfaultfd monitor copies pages in the
background, it may encounter regions that were already unmapped.
Addition of UFFD_EVENT_UNMAP allows the uffd monitor to track precisely
changes in the virtual memory layout.
Since there might be different uffd contexts for the affected VMAs, we
first should create a temporary representation for the unmap event for
each uffd context and then notify them one by one to the appropriate
userfault file descriptors.
The event notification occurs after the mmap_sem has been released.
[arnd@arndb.de: fix nommu build]
Link: http://lkml.kernel.org/r/20170203165141.3665284-1-arnd@arndb.de
[mhocko@suse.com: fix nommu build]
Link: http://lkml.kernel.org/r/20170202091503.GA22823@dhcp22.suse.cz
Link: http://lkml.kernel.org/r/1485542673-24387-3-git-send-email-rppt@linux.vnet.ibm.com
Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Signed-off-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Hillf Danton <hillf.zj@alibaba-inc.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Pavel Emelyanov <xemul@virtuozzo.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
ktime is a union because the initial implementation stored the time in
scalar nanoseconds on 64 bit machine and in a endianess optimized timespec
variant for 32bit machines. The Y2038 cleanup removed the timespec variant
and switched everything to scalar nanoseconds. The union remained, but
become completely pointless.
Get rid of the union and just keep ktime_t as simple typedef of type s64.
The conversion was done with coccinelle and some manual mopping up.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
This was entirely automated, using the script by Al:
PATT='^[[:blank:]]*#[[:blank:]]*include[[:blank:]]*<asm/uaccess.h>'
sed -i -e "s!$PATT!#include <linux/uaccess.h>!" \
$(git grep -l "$PATT"|grep -v ^include/linux/uaccess.h)
to do the replacement at the end of the merge window.
Requested-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
... and fix the minor buglet in compat io_submit() - native one
kills ioctx as cleanup when put_user() fails. Get rid of
bogus compat_... in !CONFIG_AIO case, while we are at it - they
should simply fail with ENOSYS, same as for native counterparts.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Currently we dropped freeze protection of aio writes just after IO was
submitted. Thus aio write could be in flight while the filesystem was
frozen and that could result in unexpected situation like aio completion
wanting to convert extent type on frozen filesystem. Testcase from
Dmitry triggering this is like:
for ((i=0;i<60;i++));do fsfreeze -f /mnt ;sleep 1;fsfreeze -u /mnt;done &
fio --bs=4k --ioengine=libaio --iodepth=128 --size=1g --direct=1 \
--runtime=60 --filename=/mnt/file --name=rand-write --rw=randwrite
Fix the problem by dropping freeze protection only once IO is completed
in aio_complete().
Reported-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: Jan Kara <jack@suse.cz>
[hch: forward ported on top of various VFS and aio changes]
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Pass the ABI iocb structure to aio_setup_rw and let it handle the
non-vectored I/O case as well. With that and a new helper for the AIO
return value handling we can now define new aio_read and aio_write
helpers that implement reads and writes in a self-contained way without
duplicating too much code.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Otherwise we might dereference an already freed file and/or inode
when aio_complete is called before we return from the read_iter or
write_iter method.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Using a local variable we can prevent gcc from reloading
aio_ring_file->f_inode->i_mapping twice, eliminating 2x2 dependent
loads.
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This ensures that do_mmap() won't implicitly make AIO memory mappings
executable if the READ_IMPLIES_EXEC personality flag is set. Such
behavior is problematic because the security_mmap_file LSM hook doesn't
catch this case, potentially permitting an attacker to bypass a W^X
policy enforced by SELinux.
I have tested the patch on my machine.
To test the behavior, compile and run this:
#define _GNU_SOURCE
#include <unistd.h>
#include <sys/personality.h>
#include <linux/aio_abi.h>
#include <err.h>
#include <stdlib.h>
#include <stdio.h>
#include <sys/syscall.h>
int main(void) {
personality(READ_IMPLIES_EXEC);
aio_context_t ctx = 0;
if (syscall(__NR_io_setup, 1, &ctx))
err(1, "io_setup");
char cmd[1000];
sprintf(cmd, "cat /proc/%d/maps | grep -F '/[aio]'",
(int)getpid());
system(cmd);
return 0;
}
In the output, "rw-s" is good, "rwxs" is bad.
Signed-off-by: Jann Horn <jann@thejh.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
aio_setup_ring waits for mmap_sem in writable mode. If the waiting task
gets killed by the oom killer it would block oom_reaper from
asynchronous address space reclaim and reduce the chances of timely OOM
resolving. Wait for the lock in the killable mode and return with EINTR
if the task got killed while waiting. This will also expedite the
return to the userspace and do_exit.
Signed-off-by: Michal Hocko <mhocko@suse.com>
Acked-by: Jeff Moyer <jmoyer@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Benamin LaHaise <bcrl@kvack.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
vma->vm_ops->mremap() looks more natural and clean in move_vma(), and this
way ->mremap() can have more users. Say, vdso.
While at it, s/aio_ring_remap/aio_ring_mremap/.
Note: this is the minimal change before ->mremap() finds another user in
file_operations; this method should have more arguments, and it can be
used to kill arch_remap().
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Pavel Emelyanov <xemul@parallels.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Benjamin LaHaise <bcrl@kvack.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jeff Moyer <jmoyer@redhat.com>
Cc: Laurent Dufour <ldufour@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull third hunk of vfs changes from Al Viro:
"This contains the ->direct_IO() changes from Omar + saner
generic_write_checks() + dealing with fcntl()/{read,write}() races
(mirroring O_APPEND/O_DIRECT into iocb->ki_flags and instead of
repeatedly looking at ->f_flags, which can be changed by fcntl(2),
check ->ki_flags - which cannot) + infrastructure bits for dhowells'
d_inode annotations + Christophs switch of /dev/loop to
vfs_iter_write()"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (30 commits)
block: loop: switch to VFS ITER_BVEC
configfs: Fix inconsistent use of file_inode() vs file->f_path.dentry->d_inode
VFS: Make pathwalk use d_is_reg() rather than S_ISREG()
VFS: Fix up debugfs to use d_is_dir() in place of S_ISDIR()
VFS: Combine inode checks with d_is_negative() and d_is_positive() in pathwalk
NFS: Don't use d_inode as a variable name
VFS: Impose ordering on accesses of d_inode and d_flags
VFS: Add owner-filesystem positive/negative dentry checks
nfs: generic_write_checks() shouldn't be done on swapout...
ocfs2: use __generic_file_write_iter()
mirror O_APPEND and O_DIRECT into iocb->ki_flags
switch generic_write_checks() to iocb and iter
ocfs2: move generic_write_checks() before the alignment checks
ocfs2_file_write_iter: stop messing with ppos
udf_file_write_iter: reorder and simplify
fuse: ->direct_IO() doesn't need generic_write_checks()
ext4_file_write_iter: move generic_write_checks() up
xfs_file_aio_write_checks: switch to iocb/iov_iter
generic_write_checks(): drop isblk argument
blkdev_write_iter: expand generic_file_checks() call in there
...
Pull block layer core bits from Jens Axboe:
"This is the core pull request for 4.1. Not a lot of stuff in here for
this round, mostly little fixes or optimizations. This pull request
contains:
- An optimization that speeds up queue runs on blk-mq, especially for
the case where there's a large difference between nr_cpu_ids and
the actual mapped software queues on a hardware queue. From Chong
Yuan.
- Honor node local allocations for requests on legacy devices. From
David Rientjes.
- Cleanup of blk_mq_rq_to_pdu() from me.
- exit_aio() fixup from me, greatly speeding up exiting multiple IO
contexts off exit_group(). For my particular test case, fio exit
took ~6 seconds. A typical case of both exposing RCU grace periods
to user space, and serializing exit of them.
- Make blk_mq_queue_enter() honor the gfp mask passed in, so we only
wait if __GFP_WAIT is set. From Keith Busch.
- blk-mq exports and two added helpers from Mike Snitzer, which will
be used by the dm-mq code.
- Cleanups of blk-mq queue init from Wei Fang and Xiaoguang Wang"
* 'for-4.1/core' of git://git.kernel.dk/linux-block:
blk-mq: reduce unnecessary software queue looping
aio: fix serial draining in exit_aio()
blk-mq: cleanup blk_mq_rq_to_pdu()
blk-mq: put blk_queue_rq_timeout together in blk_mq_init_queue()
block: remove redundant check about 'set->nr_hw_queues' in blk_mq_alloc_tag_set()
block: allocate request memory local to request queue
blk-mq: don't wait in blk_mq_queue_enter() if __GFP_WAIT isn't set
blk-mq: export blk_mq_run_hw_queues
blk-mq: add blk_mq_init_allocated_queue and export blk_mq_register_disk
Pull second vfs update from Al Viro:
"Now that net-next went in... Here's the next big chunk - killing
->aio_read() and ->aio_write().
There'll be one more pile today (direct_IO changes and
generic_write_checks() cleanups/fixes), but I'd prefer to keep that
one separate"
* 'for-linus-2' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (37 commits)
->aio_read and ->aio_write removed
pcm: another weird API abuse
infinibad: weird APIs switched to ->write_iter()
kill do_sync_read/do_sync_write
fuse: use iov_iter_get_pages() for non-splice path
fuse: switch to ->read_iter/->write_iter
switch drivers/char/mem.c to ->read_iter/->write_iter
make new_sync_{read,write}() static
coredump: accept any write method
switch /dev/loop to vfs_iter_write()
serial2002: switch to __vfs_read/__vfs_write
ashmem: use __vfs_read()
export __vfs_read()
autofs: switch to __vfs_write()
new helper: __vfs_write()
switch hugetlbfs to ->read_iter()
coda: switch to ->read_iter/->write_iter
ncpfs: switch to ->read_iter/->write_iter
net/9p: remove (now-)unused helpers
p9_client_attach(): set fid->uid correctly
...
exit_aio() currently serializes killing io contexts. Each context
killing ends up having to do percpu_ref_kill(), which in turns has
to wait for an RCU grace period. This can take a long time, depending
on the number of contexts. And there's no point in doing them serially,
when we could be waiting for all of them in one fell swoop.
This patches makes my fio thread offload test case exit 0.2s instead
of almost 6s.
Reviewed-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Pull vfs update from Al Viro:
"Part one:
- struct filename-related cleanups
- saner iov_iter_init() replacements (and switching the syscalls to
use of those)
- ntfs switch to ->write_iter() (Anton)
- aio cleanups and splitting iocb into common and async parts
(Christoph)
- assorted fixes (me, bfields, Andrew Elble)
There's a lot more, including the completion of switchover to
->{read,write}_iter(), d_inode/d_backing_inode annotations, f_flags
race fixes, etc, but that goes after #for-davem merge. David has
pulled it, and once it's in I'll send the next vfs pull request"
* 'for-linus-1' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (35 commits)
sg_start_req(): use import_iovec()
sg_start_req(): make sure that there's not too many elements in iovec
blk_rq_map_user(): use import_single_range()
sg_io(): use import_iovec()
process_vm_access: switch to {compat_,}import_iovec()
switch keyctl_instantiate_key_common() to iov_iter
switch {compat_,}do_readv_writev() to {compat_,}import_iovec()
aio_setup_vectored_rw(): switch to {compat_,}import_iovec()
vmsplice_to_user(): switch to import_iovec()
kill aio_setup_single_vector()
aio: simplify arguments of aio_setup_..._rw()
aio: lift iov_iter_init() into aio_setup_..._rw()
lift iov_iter into {compat_,}do_readv_writev()
NFS: fix BUG() crash in notify_change() with patch to chown_common()
dcache: return -ESTALE not -EBUSY on distributed fs race
NTFS: Version 2.1.32 - Update file write from aio_write to write_iter.
VFS: Add iov_iter_fault_in_multipages_readable()
drop bogus check in file_open_root()
switch security_inode_getattr() to struct path *
constify tomoyo_realpath_from_path()
...
We check if ->ki_pos is positive. However, by that point we have
already done rw_verify_area(), which would have rejected such
unless the file had been one of /dev/mem, /dev/kmem and /proc/kcore.
All of which do not have vectored rw methods, so we would've bailed
out even earlier.
This check had been introduced before rw_verify_area() had been added there
- in fact, it was a subset of checks done on sync paths by rw_verify_area()
(back then the /dev/mem exception didn't exist at all). The rest of checks
(mandatory locking, etc.) hadn't been added until later. Unfortunately,
by the time the call of rw_verify_area() got added, the /dev/mem exception
had already appeared, so it wasn't obvious that the older explicit check
downstream had become dead code. It *is* a dead code, though, since the few
files for which the exception applies do not have ->aio_{read,write}() or
->{read,write}_iter() and for them we won't reach that check anyway.
What's more, even if we ever introduce vectored methods for /dev/mem
and friends, they'll have to cope with negative positions anyway, since
readv(2) and writev(2) are using the same checks as read(2) and write(2) -
i.e. rw_verify_area().
Let's bury it.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Way, way back kiocb used to be picked from arrays, so ioctx_alloc()
checked for multiplication overflow when calculating the size of
such array. By the time fs/aio.c went into the tree (in 2002) they
were already allocated one-by-one by kmem_cache_alloc(), so that
check had already become pointless. Let's bury it...
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Linus Torvalds
Jan Kara
Jens Axboe
Christoph Hellwig
Jeff Moyer
Deepa Dinamani
Damien Le Moal
Arnd Bergmann
Al Viro
Adam Manzanares
Tejun Heo
Mark Rutland
Jérôme Glisse
Mauricio Faria de Oliveira
Goldwyn Rodrigues
Ingo Molnar
Mike Rapoport
Miklos Szeredi
Shaohua Li
Thomas Gleixner
Rasmus Villemoes
Jann Horn
Michal Hocko
Oleg Nesterov
Jens Axboe