Linus Torvalds 1ac5cd4978 block: don't use un-ordered __set_current_state(TASK_UNINTERRUPTIBLE) ... This mostly reverts commit 849a370016 ("block: avoid ordered task state change for polled IO"). It was wrongly claiming that the ordering wasn't necessary. The memory barrier _is_ necessary. If something is truly polling and not going to sleep, it's the whole state setting that is unnecessary, not the memory barrier. Whenever you set your state to a sleeping state, you absolutely need the memory barrier. Note that sometimes the memory barrier can be elsewhere. For example, the ordering might be provided by an external lock, or by setting the process state to sleeping before adding yourself to the wait queue list that is used for waking up (where the wait queue lock itself will guarantee that any wakeup will correctly see the sleeping state). But none of those cases were true here. NOTE! Some of the polling paths may indeed be able to drop the state setting entirely, at which point the memory barrier also goes away. (Also note that this doesn't revert the TASK_RUNNING cases: there is no race between a wakeup and setting the process state to TASK_RUNNING, since the end result doesn't depend on ordering). Cc: Jens Axboe <axboe@kernel.dk> Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>		2019-01-02 10:46:03 -08:00
..
kasan	mm: convert totalram_pages and totalhigh_pages variables to atomic	2018-12-28 12:11:47 -08:00
Kconfig	ksm: replace jhash2 with xxhash	2018-12-28 12:11:46 -08:00
Kconfig.debug	…
Makefile	mm: remove nobootmem	2018-10-31 08:54:16 -07:00
backing-dev.c	…
balloon_compaction.c	…
cleancache.c	…
cma.c	kasan, mm, arm64: tag non slab memory allocated via pagealloc	2018-12-28 12:11:44 -08:00
cma.h	…
cma_debug.c	…
compaction.c	mm: move zone watermark accesses behind an accessor	2018-12-28 12:11:48 -08:00
debug.c	mm/debug.c: make "migrate_reason_names[]" const char *	2018-12-28 12:11:48 -08:00
debug_page_ref.c	…
dmapool.c	…
early_ioremap.c	…
fadvise.c	…
failslab.c	…
filemap.c	mm, fault_around: do not take a reference to a locked page	2018-12-28 12:11:51 -08:00
frame_vector.c	…
frontswap.c	…
gup.c	mm/gup: finish consolidating error handling	2018-11-30 14:56:13 -08:00
gup_benchmark.c	mm/gup_benchmark.c: prevent integer overflow in ioctl	2018-10-31 08:54:12 -07:00
highmem.c	mm: convert totalram_pages and totalhigh_pages variables to atomic	2018-12-28 12:11:47 -08:00
hmm.c	mm/hmm: fix memremap.h, move dev_page_fault_t callback to hmm	2018-12-28 12:11:52 -08:00
huge_memory.c	mm, thp, proc: report THP eligibility for each vma	2018-12-28 12:11:50 -08:00
hugetlb.c	hugetlbfs: Use i_mmap_rwsem to fix page fault/truncate race	2018-12-28 12:11:52 -08:00
hugetlb_cgroup.c	…
hwpoison-inject.c	…
init-mm.c	…
internal.h	mm: use alloc_flags to record if kswapd can wake	2018-12-28 12:11:48 -08:00
interval_tree.c	…
khugepaged.c	mm/mmu_notifier: use structure for invalidate_range_start/end calls v2	2018-12-28 12:11:50 -08:00
kmemleak-test.c	…
kmemleak.c	kmemleak: add config to select auto scan	2018-12-28 12:11:51 -08:00
ksm.c	ksm: react on changing "sleep_millisecs" parameter faster	2018-12-28 12:11:51 -08:00
list_lru.c	…
maccess.c	…
madvise.c	mm/mmu_notifier: use structure for invalidate_range_start/end calls v2	2018-12-28 12:11:50 -08:00
memblock.c	mm/memblock.c: skip kmemleak for kasan_init()	2018-12-28 12:11:49 -08:00
memcontrol.c	memcg, oom: notify on oom killer invocation from the charge path	2018-12-28 12:11:52 -08:00
memfd.c	…
memory-failure.c	hugetlbfs: use i_mmap_rwsem for more pmd sharing synchronization	2018-12-28 12:11:51 -08:00
memory.c	mm, thp, proc: report THP eligibility for each vma	2018-12-28 12:11:50 -08:00
memory_hotplug.c	mm, memory_hotplug: deobfuscate migration part of offlining	2018-12-28 12:11:50 -08:00
mempolicy.c	Revert "mm, thp: consolidate THP gfp handling into alloc_hugepage_direct_gfpmask"	2018-12-08 10:26:20 -08:00
mempool.c	…
memtest.c	…
migrate.c	hugetlbfs: use i_mmap_rwsem for more pmd sharing synchronization	2018-12-28 12:11:51 -08:00
mincore.c	…
mlock.c	…
mm_init.c	mm: convert totalram_pages and totalhigh_pages variables to atomic	2018-12-28 12:11:47 -08:00
mmap.c	mm/mmap.c: remove verify_mm_writelocked()	2018-12-28 12:11:47 -08:00
mmu_context.c	…
mmu_gather.c	mm: Replace call_rcu_sched() with call_rcu()	2018-11-27 09:21:46 -08:00
mmu_notifier.c	mm/mmu_notifier: use structure for invalidate_range_start/end calls v2	2018-12-28 12:11:50 -08:00
mmzone.c	…
mprotect.c	mm/mmu_notifier: use structure for invalidate_range_start/end calls v2	2018-12-28 12:11:50 -08:00
mremap.c	mm/mmu_notifier: use structure for invalidate_range_start/end calls v2	2018-12-28 12:11:50 -08:00
msync.c	…
nommu.c	mm/gup: cache dev_pagemap while pinning pages	2018-10-26 16:38:15 -07:00
oom_kill.c	mm/mmu_notifier: use structure for invalidate_range_start/end calls v2	2018-12-28 12:11:50 -08:00
page-writeback.c	mm/page-writeback.c: don't break integrity writeback on ->writepage() error	2018-12-28 12:11:49 -08:00
page_alloc.c	mm/page_alloc.c: allow error injection	2018-12-28 12:11:51 -08:00
page_counter.c	…
page_ext.c	mm: remove include/linux/bootmem.h	2018-10-31 08:54:16 -07:00
page_idle.c	mm: remove include/linux/bootmem.h	2018-10-31 08:54:16 -07:00
page_io.c	block: don't use un-ordered __set_current_state(TASK_UNINTERRUPTIBLE)	2019-01-02 10:46:03 -08:00
page_isolation.c	mm: only report isolation failures when offlining memory	2018-12-28 12:11:46 -08:00
page_owner.c	mm/page_owner: clamp read count to PAGE_SIZE	2018-12-28 12:11:46 -08:00
page_poison.c	virtio, vhost: fixes, tweaks	2018-11-01 14:42:49 -07:00
page_vma_mapped.c	mm/rmap: map_pte() was not handling private ZONE_DEVICE page properly	2018-10-31 08:54:11 -07:00
pagewalk.c	…
percpu-internal.h	…
percpu-km.c	percpu: convert spin_lock_irq to spin_lock_irqsave.	2018-12-18 09:04:08 -08:00
percpu-stats.c	…
percpu-vm.c	…
percpu.c	Merge branch 'for-4.20' of git://git.kernel.org/pub/scm/linux/kernel/git/dennis/percpu	2018-11-01 09:27:57 -07:00
pgtable-generic.c	…
process_vm_access.c	…
quicklist.c	…
readahead.c	mm/readahead.c: simplify get_next_ra_size()	2018-12-28 12:11:46 -08:00
rmap.c	hugetlbfs: use i_mmap_rwsem for more pmd sharing synchronization	2018-12-28 12:11:51 -08:00
rodata_test.c	…
shmem.c	mm: convert totalram_pages and totalhigh_pages variables to atomic	2018-12-28 12:11:47 -08:00
slab.c	mm: convert totalram_pages and totalhigh_pages variables to atomic	2018-12-28 12:11:47 -08:00
slab.h	kasan, mm: change hooks signatures	2018-12-28 12:11:43 -08:00
slab_common.c	A fairly normal cycle for documentation stuff. We have a new	2018-12-29 11:21:49 -08:00
slob.c	…
slub.c	mm/slub.c: record final state of slub action in deactivate_slab()	2018-12-28 12:11:46 -08:00
sparse-vmemmap.c	mm: remove include/linux/bootmem.h	2018-10-31 08:54:16 -07:00
sparse.c	mm, sparse: pass nid instead of pgdat to sparse_add_one_section()	2018-12-28 12:11:49 -08:00
swap.c	mm: convert totalram_pages and totalhigh_pages variables to atomic	2018-12-28 12:11:47 -08:00
swap_cgroup.c	…
swap_slots.c	…
swap_state.c	Merge branch 'xarray' of git://git.infradead.org/users/willy/linux-dax	2018-10-28 11:35:40 -07:00
swapfile.c	mm, swap: fix swapoff with KSM pages	2018-12-28 12:11:52 -08:00
truncate.c	mm: cleancache: fix corruption on missed inode invalidation	2018-11-30 14:56:14 -08:00
usercopy.c	…
userfaultfd.c	hugetlbfs: use i_mmap_rwsem for more pmd sharing synchronization	2018-12-28 12:11:51 -08:00
util.c	mm: convert totalram_pages and totalhigh_pages variables to atomic	2018-12-28 12:11:47 -08:00
vmacache.c	…
vmalloc.c	mm: convert totalram_pages and totalhigh_pages variables to atomic	2018-12-28 12:11:47 -08:00
vmpressure.c	…
vmscan.c	mm: put_and_wait_on_page_locked() while page is migrated	2018-12-28 12:11:48 -08:00
vmstat.c	mm: convert zone->managed_pages to atomic variable	2018-12-28 12:11:47 -08:00
workingset.c	mm: convert totalram_pages and totalhigh_pages variables to atomic	2018-12-28 12:11:47 -08:00
z3fold.c	z3fold: fix possible reclaim races	2018-11-18 10:15:09 -08:00
zbud.c	…
zpool.c	…
zsmalloc.c	mm/zsmalloc.c: fix fall-through annotation	2018-10-26 16:26:35 -07:00
zswap.c	mm: convert totalram_pages and totalhigh_pages variables to atomic	2018-12-28 12:11:47 -08:00