Documentation: Make kernel-ABI.txt 80 columns wide
Note that this only has line-wrapping and white-space changes.
No text was changed at all.
Signed-Off-By: Horms <horms@verge.net.au>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
My patch to add brief documentation of the nomca boot parameter
added it out of alphabetical order.
Signed-Off-By: Horms <horms@verge.net.au>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
this changes if() BUG(); constructs to BUG_ON() which is
cleaner, contains unlikely() and can better optimized away.
Signed-off-by: Eric Sesterhenn <snakebyte@gmx.de>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
this changes if() BUG(); constructs to BUG_ON() which is
cleaner, contains unlikely() and can better optimized away.
Signed-off-by: Eric Sesterhenn <snakebyte@gmx.de>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
this changes if() BUG(); constructs to BUG_ON() which is
cleaner, contains unlikely() and can better optimized away.
Signed-off-by: Eric Sesterhenn <snakebyte@gmx.de>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
this changes if() BUG(); constructs to BUG_ON() which is
cleaner, contains unlikely() and can better optimized away.
Signed-off-by: Eric Sesterhenn <snakebyte@gmx.de>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
this changes if() BUG(); constructs to BUG_ON() which is
cleaner, contains unlikely() and can better optimized away.
Signed-off-by: Eric Sesterhenn <snakebyte@gmx.de>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
this changes if() BUG(); constructs to BUG_ON() which is
cleaner, contains unlikely() and can better optimized away.
Signed-off-by: Eric Sesterhenn <snakebyte@gmx.de>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
this changes if() BUG(); constructs to BUG_ON() which is
cleaner, contains unlikely() and can better optimized away.
Signed-off-by: Eric Sesterhenn <snakebyte@gmx.de>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
this changes if() BUG(); constructs to BUG_ON() which is
cleaner, contains unlikely() and can better optimized away.
Signed-off-by: Eric Sesterhenn <snakebyte@gmx.de>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
this changes if() BUG(); constructs to BUG_ON() which is
cleaner, contains unlikely() and can better optimized away.
Signed-off-by: Eric Sesterhenn <snakebyte@gmx.de>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
this changes if() BUG(); constructs to BUG_ON() which is
cleaner, contains unlikely() and can better optimized away.
Signed-off-by: Eric Sesterhenn <snakebyte@gmx.de>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
this changes if() BUG(); constructs to BUG_ON() which is
cleaner, contains unlikely() and can better optimized away.
Signed-off-by: Eric Sesterhenn <snakebyte@gmx.de>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
this changes if() BUG(); constructs to BUG_ON() which is
cleaner and can better optimized away
Signed-off-by: Eric Sesterhenn <snakebyte@gmx.de>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
this changes if() BUG(); constructs to BUG_ON() which is
cleaner and can better optimized away
Signed-off-by: Eric Sesterhenn <snakebyte@gmx.de>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
this changes if() BUG(); constructs to BUG_ON() which is
cleaner and can better optimized away
Signed-off-by: Eric Sesterhenn <snakebyte@gmx.de>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
this changes if() BUG(); constructs to BUG_ON() which is
cleaner and can better optimized away
Signed-off-by: Eric Sesterhenn <snakebyte@gmx.de>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
The note that SOFTWARE_SUSPEND doesn't need APM is helpful, but nowadays
the information that it doesn't need ACPI, too, is even more helpful.
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Remove the obsolete Kconfig options MTD_CFI_AMDSTD_RETRY
and MTD_CFI_AMDSTD_RETRY_MAX
The code that depended on these was removed in early 2004, but
Kconfig was not updated accordingly.
Signed-off-by: Anders Larsen <al@alarsen.net>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Commit 70674f95c0a2ea694d5c39f4e514f538a09be36f:
[PATCH] Optimize select/poll by putting small data sets on the stack
resulted in the poll stack being 4-byte aligned on 64-bit architectures,
causing misaligned accesses to elements in the array.
This patch fixes it by declaring the stack in terms of 'long' instead
of 'char'.
Force alignment of poll and select stacks to long to avoid unaligned
access on 64 bit architectures.
Signed-off-by: Jes Sorensen <jes@sgi.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The attached patch documents the Linux kernel's memory barriers.
I've updated it from the comments I've been given.
The per-arch notes sections are gone because it's clear that there are so many
exceptions, that it's not worth having them.
I've added a list of references to other documents.
I've tried to get rid of the concept of memory accesses appearing on the bus;
what matters is apparent behaviour with respect to other observers in the
system.
Interrupts barrier effects are now considered to be non-existent. They may be
there, but you may not rely on them.
I've added a couple of definition sections at the top of the document: one to
specify the minimum execution model that may be assumed, the other to specify
what this document refers to by the term "memory".
I've made greater mention of the use of mmiowb().
I've adjusted the way in which caches are described, and described the fun
that can be had with cache coherence maintenance being unordered and data
dependency not being necessarily implicit.
I've described (smp_)read_barrier_depends().
I've rearranged the order of the sections, so that memory barriers are
discussed in abstract first, and then described the memory barrier facilities
available on Linux, before going on to more real-world discussions and examples.
I've added information about the lack of memory barriering effects with atomic
ops and bitops.
I've added information about control dependencies.
I've added more diagrams to illustrate caching interactions between CPUs.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Wrong error path in dup_fd() - it should return NULL on error,
not an address of already freed memory :/
Triggered by OpenVZ stress test suite.
What is interesting is that it was causing different oopses in RCU like
below:
Call Trace:
[<c013492c>] rcu_do_batch+0x2c/0x80
[<c0134bdd>] rcu_process_callbacks+0x3d/0x70
[<c0126cf3>] tasklet_action+0x73/0xe0
[<c01269aa>] __do_softirq+0x10a/0x130
[<c01058ff>] do_softirq+0x4f/0x60
=======================
[<c0113817>] smp_apic_timer_interrupt+0x77/0x110
[<c0103b54>] apic_timer_interrupt+0x1c/0x24
Code: Bad EIP value.
<0>Kernel panic - not syncing: Fatal exception in interrupt
Signed-Off-By: Pavel Emelianov <xemul@sw.ru>
Signed-Off-By: Dmitry Mishin <dim@openvz.org>
Signed-Off-By: Kirill Korotaev <dev@openvz.org>
Signed-Off-By: Linus Torvalds <torvalds@osdl.org>
Turn some macros into inline functions and add proper type checking as
well as being more readable. Also a minor comment adjustment.
Signed-off-by: Nicolas Pitre <nico@cam.org>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Decrease the number of pointer derefs in drivers/serial/jsm/jsm_tty.c
Benefits of the patch:
- Fewer pointer dereferences should make the code slightly faster.
- Size of generated code is smaller
- Improved readability
Signed-off-by: Jesper Juhl <jesper.juhl@gmail.com>
Acked-by: "V. ANANDA KRISHNAN" <mansarov@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
As announced, lookup_hash() can now become static.
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The only user of get_wchan is the proc fs - and proc can't be built modular.
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
And remove the comments that were put in inplace of a fix too....
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Currently a device failure during recovery leaves bits set in the bitmap.
This normally isn't a problem as the offending device will be rejected because
of errors. However if device re-adding is being used with non-persistent
bitmaps, this can be a problem.
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This patch removes the old radeon driver which has been replaced by a
newer one.
Signed-off-by: Michael Hanselmann <linux-kernel@hansmi.ch>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Acked-by: Antonino Daplas <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The monochrome->color expansion routine that handles bitmaps which have
(widths % 8) != 0 (slow_imageblit) produces corrupt characters in big-endian.
This is caused by a bogus bit test in slow_imageblit().
Fix.
This patch may deserve to go to the stable tree. The code has already been
well tested in little-endian machines. It's only in big-endian where there is
uncertainty and Herbert confirmed that this is the correct way to go.
It should not introduce regressions.
Signed-off-by: Antonino Daplas <adaplas@pol.net>
Acked-by: Herbert Poetzl <herbert@13thfloor.at>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Fixes for the pxafb driver:
* Return -EINVAL for resolutions that are too large as per framebuffer
driver policy.
* Increase the error timeout for disabling the LCD controller. The current
timeout is sometimes too short on the Sharp Zaurus Cxx00 hardware and an
extra delay in an error path shouldn't pose any problems.
* Fix a dev reference which causes a compile error when DEBUG is defined.
Signed-off-by: Richard Purdie <rpurdie@rpsys.net>
Signed-off-by: Antonino Daplas <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Generalise the Corgi backlight driver by moving the default intensity and
limit mask settings into the platform specific data structure. This enables
the driver to support other Zaurus hardware, specifically the SL-6000x (Tosa)
model.
Also change the spinlock to a mutex (the spinlock is overkill).
Signed-off-by: Richard Purdie <rpurdie@rpsys.net>
Signed-off-by: Antonino Daplas <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Updates to the HP Jornada 680 Backlight driver:
- Correct the suspend/resume functions so the driver compiles
(SUSPEND_POWER_DOWN/RESUME_POWER_ON no longer exist).
- Convert the driver to match the recent platform device changes.
- Replace the unsafe static struct platform_device with dynamic allocation.
- Convert the driver to the new backlight code.
This has not been tested on a device due to lack of hardware but wouldn't
compile beforehand.
Signed-off-by: Richard Purdie <rpurdie@rpsys.net>
Signed-off-by: Antonino Daplas <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Backlight class attributes are currently easy to implement incorrectly.
Moving certain handling into the backlight core prevents this whilst at the
same time makes the drivers simpler and consistent. The following changes are
included:
The brightness attribute only sets and reads the brightness variable in the
backlight_properties structure.
The power attribute only sets and reads the power variable in the
backlight_properties structure.
Any framebuffer blanking events change a variable fb_blank in the
backlight_properties structure.
The backlight driver has only two functions to implement. One function is
called when any of the above properties change (to update the backlight
brightness), the second is called to return the current backlight brightness
value. A new attribute "actual_brightness" is added to return this brightness
as determined by the driver having combined all the above factors (and any
driver/device specific factors).
Additionally, the backlight core takes care of checking the maximum brightness
is not exceeded and of turning off the backlight before device removal.
The corgi backlight driver is updated to reflect these changes.
Signed-off-by: Richard Purdie <rpurdie@rpsys.net>
Signed-off-by: Antonino Daplas <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Add acceleration support in w100fb.c (i.e. ATI Imageons) for the copyarea and
fillrect operations.
Signed-off-by: Alberto Mardegan <mardy@users.sourceforge.net>
Signed-off-by: Antonino Daplas <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The current display was not saved during initialization. This leads to hard
to track console corruption, such as a misplaced cursor, which is correctible
by switching consoles. Fix this minor bug.
Signed-off-by: Antonino Daplas <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
It is very common to hash a dentry and then to call lookup. If we take fs
specific hash functions into account the full hash logic can get ugly.
Further full_name_hash as an inline function is almost 100 bytes on x86 so
having a non-inline choice in some cases can measurably decrease code size.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Simplifies the code, reduces the need for 4 pid hash tables, and makes the
code more capable.
In the discussions I had with Oleg it was felt that to a large extent the
cleanup itself justified the work. With struct pid being dynamically
allocated meant we could create the hash table entry when the pid was
allocated and free the hash table entry when the pid was freed. Instead of
playing with the hash lists when ever a process would attach or detach to a
process.
For myself the fact that it gave what my previous task_ref patch gave for free
with simpler code was a big win. The problem is that if you hold a reference
to struct task_struct you lock in 10K of low memory. If you do that in a user
controllable way like /proc does, with an unprivileged but hostile user space
application with typical resource limits of 1000 fds and 100 processes I can
trigger the OOM killer by consuming all of low memory with task structs, on a
machine wight 1GB of low memory.
If I instead hold a reference to struct pid which holds a pointer to my
task_struct, I don't suffer from that problem because struct pid is 2 orders
of magnitude smaller. In fact struct pid is small enough that most other
kernel data structures dwarf it, so simply limiting the number of referring
data structures is enough to prevent exhaustion of low memory.
This splits the current struct pid into two structures, struct pid and struct
pid_link, and reduces our number of hash tables from PIDTYPE_MAX to just one.
struct pid_link is the per process linkage into the hash tables and lives in
struct task_struct. struct pid is given an indepedent lifetime, and holds
pointers to each of the pid types.
The independent life of struct pid simplifies attach_pid, and detach_pid,
because we are always manipulating the list of pids and not the hash table.
In addition in giving struct pid an indpendent life it makes the concept much
more powerful.
Kernel data structures can now embed a struct pid * instead of a pid_t and
not suffer from pid wrap around problems or from keeping unnecessarily
large amounts of memory allocated.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
A big problem with rcu protected data structures that are also reference
counted is that you must jump through several hoops to increase the reference
count. I think someone finally implemented atomic_inc_not_zero(&count) to
automate the common case. Unfortunately this means you must special case the
rcu access case.
When data structures are only visible via rcu in a manner that is not
determined by the reference count on the object (i.e. tasks are visible until
their zombies are reaped) there is a much simpler technique we can employ.
Simply delaying the decrement of the reference count until the rcu interval is
over.
What that means is that the proc code that looks up a task and later
wants to sleep can now do:
rcu_read_lock();
task = find_task_by_pid(some_pid);
if (task) {
get_task_struct(task);
}
rcu_read_unlock();
The effect on the rest of the kernel is that put_task_struct becomes cheaper
and immediate, and in the case where the task has been reaped it frees the
task immediate instead of unnecessarily waiting an until the rcu interval is
over.
Cleanup of task_struct does not happen when its reference count drops to
zero, instead cleanup happens when release_task is called. Tasks can only
be looked up via rcu before release_task is called. All rcu protected
members of task_struct are freed by release_task.
Therefore we can move call_rcu from put_task_struct into release_task. And
we can modify release_task to not immediately release the reference count
but instead have it call put_task_struct from the function it gives to
call_rcu.
The end result:
- get_task_struct is safe in an rcu context where we have just looked
up the task.
- put_task_struct() simplifies into its old pre rcu self.
This reorganization also makes put_task_struct uncallable from modules as
it is not exported but it does not appear to be called from any modules so
this should not be an issue, and is trivially fixed.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
proc_check_chroot() does the check in a very unintuitive way (keeping a
copy of the argument, then modifying the argument), and has uncommented
sideeffects.
Signed-off-by: Herbert Poetzl <herbert@13thfloor.at>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This just got nuked in mainline. Bring it back because Eric's patches use it.
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The core problem: setsid fails if it is called by init. The effect in 2.6.16
and the earlier kernels that have this problem is that if you do a "ps -j 1 or
ps -ej 1" you will see that init and several of it's children have process
group and session == 0. Instead of process group == session == 1. Despite
init calling setsid.
The reason it fails is that daemonize calls set_special_pids(1,1) on kernel
threads that are launched before /sbin/init is called.
The only remaining effect in that current->signal->leader == 0 for init
instead of 1. And the setsid call fails. No one has noticed because
/sbin/init does not check the return value of setsid.
In 2.4 where we don't have the pidhash table, and daemonize doesn't exist
setsid actually works for init.
I care a lot about pid == 1 not being a special case that we leave broken,
because of the container/jail work that I am doing.
- Carefully allow init (pid == 1) to call setsid despite the kernel using
its session.
- Use find_task_by_pid instead of find_pid because find_pid taking a
pidtype is going away.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Horms
Uwe Zeisberger
Eric Sesterhenn
Adrian Bunk
Anders Larsen
Linus Torvalds
Jes Sorensen
David Howells
Kirill Korotaev
Nicolas Pitre
Jesper Juhl
NeilBrown
Michael Hanselmann
Antonino A. Daplas
Richard Purdie
Alberto Mardegan
Eric W. Biederman
Herbert Poetzl
Andrew Morton