Hugh Dickins 78ac34ad31 swap: fix shmem swapping when more than 8 areas ... commit 9b15b817f3 upstream. Minchan Kim reports that when a system has many swap areas, and tmpfs swaps out to the ninth or more, shmem_getpage_gfp()'s attempts to read back the page cannot locate it, and the read fails with -ENOMEM. Whoops. Yes, I blindly followed read_swap_header()'s pte_to_swp_entry( swp_entry_to_pte()) technique for determining maximum usable swap offset, without stopping to realize that that actually depends upon the pte swap encoding shifting swap offset to the higher bits and truncating it there. Whereas our radix_tree swap encoding leaves offset in the lower bits: it's swap "type" (that is, index of swap area) that was truncated. Fix it by reducing the SWP_TYPE_SHIFT() in swapops.h, and removing the broken radix_to_swp_entry(swp_to_radix_entry()) from read_swap_header(). This does not reduce the usable size of a swap area any further, it leaves it as claimed when making the original commit: no change from 3.0 on x86_64, nor on i386 without PAE; but 3.0's 512GB is reduced to 128GB per swapfile on i386 with PAE. It's not a change I would have risked five years ago, but with x86_64 supported for ten years, I believe it's appropriate now. Hmm, and what if some architecture implements its swap pte with offset encoded below type? That would equally break the maximum usable swap offset check. Happily, they all follow the same tradition of encoding offset above type, but I'll prepare a check on that for next. Reported-and-Reviewed-and-Tested-by: Minchan Kim <minchan@kernel.org> Signed-off-by: Hugh Dickins <hughd@google.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		2012-06-22 11:36:55 -07:00
..
backing-dev.c	backing-dev: fix wakeup timer races with bdi_unregister()	2012-02-01 16:52:49 +08:00
bootmem.c	bootmem/sparsemem: remove limit constraint in alloc_bootmem_section	2012-03-21 17:54:58 -07:00
bounce.c	mm: remove the second argument of k[un]map_atomic()	2012-03-20 21:48:27 +08:00
cleancache.c	mm: cleancache: Use __read_mostly as appropiate.	2012-01-23 16:08:09 -05:00
compaction.c	mm: compaction: make compact_control order signed	2012-03-21 17:54:56 -07:00
debug-pagealloc.c	mm, x86: Remove debug_pagealloc_enabled	2011-12-06 09:24:07 +01:00
dmapool.c	mm: fix implicit stat.h usage in dmapool.c	2011-10-31 09:20:12 -04:00
fadvise.c	fadvise: only initiate writeback for specified range with FADV_DONTNEED	2012-01-10 16:30:43 -08:00
failslab.c	switch debugfs to umode_t	2012-01-03 22:54:56 -05:00
filemap_xip.c	mm/filemap_xip.c: fix race condition in xip_file_fault()	2012-02-03 16:16:41 -08:00
filemap.c	radix-tree: use iterators in find_get_pages* functions	2012-03-28 17:14:37 -07:00
fremap.c	mm: delete various needless include <linux/module.h>	2011-10-31 09:20:11 -04:00
highmem.c	Merge branch 'modsplit-Oct31_2011' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux	2011-11-06 19:44:47 -08:00
huge_memory.c	thp: optimize away unnecessary page table locking	2012-03-21 17:54:57 -07:00
hugetlb.c	mm: fix vma_resv_map() NULL pointer	2012-06-10 00:36:11 +09:00
hwpoison-inject.c	HWPOISON: Clean up memory_failure() vs. __memory_failure()	2012-01-03 12:06:32 -08:00
init-mm.c	atomic: use <linux/atomic.h>	2011-07-26 16:49:47 -07:00
internal.h	mm: thp: tail page refcounting fix	2011-11-02 16:06:57 -07:00
Kconfig	Merge branch 'master' into x86/memblock	2011-11-28 09:46:22 -08:00
Kconfig.debug	mm: more intensive memory corruption debugging	2012-01-10 16:30:42 -08:00
kmemcheck.c
kmemleak-test.c	kmemleak: remove memset by using kzalloc	2011-01-27 18:31:51 +00:00
kmemleak.c	kmemleak: Disable early logging when kmemleak is off by default	2012-01-20 16:57:05 +00:00
ksm.c	ksm: cleanup: introduce find_mergeable_vma()	2012-03-21 17:54:59 -07:00
maccess.c	mm: Map most files to use export.h instead of module.h	2011-10-31 09:20:12 -04:00
madvise.c	coredump: add VM_NODUMP, MADV_NODUMP, MADV_CLEAR_NODUMP	2012-03-23 16:58:42 -07:00
Makefile	Cross Memory Attach	2011-10-31 17:30:44 -07:00
memblock.c	memblock: memblock should be able to handle zero length operations	2012-04-20 11:18:46 -07:00
memcontrol.c	memcg,thp: fix res_counter:96 regression	2012-05-19 10:10:27 -07:00
memory_hotplug.c	mm: compaction: introduce sync-light migration for use by compaction	2012-01-12 20:13:09 -08:00
memory-failure.c	Merge branch 'x86-mce-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2012-03-22 09:42:04 -07:00
memory.c	coredump: remove VM_ALWAYSDUMP flag	2012-03-23 16:58:42 -07:00
mempolicy.c	mm: mempolicy: Let vma_merge and vma_split handle vma->vm_policy linkages	2012-06-01 15:18:19 +08:00
mempool.c	mempool: fix first round failure behavior	2012-01-10 16:30:45 -08:00
migrate.c	mm: fix NULL ptr dereference in move_pages	2012-04-25 21:26:34 -07:00
mincore.c	mm: thp: fix pmd_bad() triggering in code paths holding mmap_sem read mode	2012-03-21 17:54:54 -07:00
mlock.c	vm: avoid using find_vma_prev() unnecessarily	2012-03-06 18:23:36 -08:00
mm_init.c	mm: Map most files to use export.h instead of module.h	2011-10-31 09:20:12 -04:00
mmap.c	kill mm argument of vm_munmap()	2012-04-21 01:58:20 -04:00
mmu_context.c	mm, counters: remove task argument to sync_mm_rss() and __sync_task_rss_stat()	2012-03-21 17:54:59 -07:00
mmu_notifier.c	mm: Map most files to use export.h instead of module.h	2011-10-31 09:20:12 -04:00
mmzone.c	mm: delete various needless include <linux/module.h>	2011-10-31 09:20:11 -04:00
mprotect.c	Merge branch 'akpm' (Andrew's patch-bomb)	2012-03-22 09:04:48 -07:00
mremap.c	mm: collapse security_vm_enough_memory() variants into a single function	2012-02-14 10:45:39 +11:00
msync.c
nobootmem.c	mm: nobootmem: fix sign extend problem in __free_pages_memory()	2012-05-10 15:06:44 -07:00
nommu.c	kill mm argument of vm_munmap()	2012-04-21 01:58:20 -04:00
oom_kill.c	signal: oom_kill_task: use SEND_SIG_FORCED instead of force_sig()	2012-03-23 16:58:41 -07:00
page_alloc.c	mm: raise MemFree by reverting percpu_pagelist_fraction to 0	2012-05-11 09:23:39 -07:00
page_cgroup.c	page_cgroup: fix horrid swap accounting regression	2012-03-06 08:18:23 -08:00
page_io.c	block: kill off REQ_UNPLUG	2011-03-10 08:52:27 +01:00
page_isolation.c	mm: page_isolation: codeclean fix comment and rm unneeded val init	2010-10-26 16:52:11 -07:00
page-writeback.c	Ext4 commits for 3.3 merge window; mostly cleanups and bug fixes	2012-03-28 10:02:55 -07:00
pagewalk.c	mm: thp: fix pmd_bad() triggering in code paths holding mmap_sem read mode	2012-03-21 17:54:54 -07:00
percpu-km.c	percpu: clear memory allocated with the km allocator	2010-10-02 10:28:42 +03:00
percpu-vm.c	percpu: use bitmap_clear	2012-01-20 09:23:16 -08:00
percpu.c	kmemleak: Fix the kmemleak tracking of the percpu areas with !SMP	2012-05-09 10:13:29 -07:00
pgtable-generic.c	thp: add HPAGE_PMD_* definitions for !CONFIG_TRANSPARENT_HUGEPAGE	2012-03-21 17:55:02 -07:00
prio_tree.c	sanitize <linux/prefetch.h> usage	2011-05-20 12:50:29 -07:00
process_vm_access.c	Fix race in process_vm_rw_core	2012-02-02 12:55:17 -08:00
quicklist.c	mm: delete various needless include <linux/module.h>	2011-10-31 09:20:11 -04:00
readahead.c	mm: Map most files to use export.h instead of module.h	2011-10-31 09:20:12 -04:00
rmap.c	memcg: use new logic for page stat accounting	2012-03-21 17:55:01 -07:00
shmem.c	Merge branch 'akpm' (Andrew's patch-bomb)	2012-03-22 09:04:48 -07:00
slab.c	Merge branch 'slab/for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg/linux	2012-03-28 15:04:26 -07:00
slob.c	mm: Map most files to use export.h instead of module.h	2011-10-31 09:20:12 -04:00
slub.c	slub: fix a memory leak in get_partial_node()	2012-06-10 00:36:11 +09:00
sparse-vmemmap.c	mm: delete various needless include <linux/module.h>	2011-10-31 09:20:11 -04:00
sparse.c	bootmem/sparsemem: remove limit constraint in alloc_bootmem_section	2012-03-21 17:54:58 -07:00
swap_state.c	mm: fix s390 BUG by __set_page_dirty_no_writeback on swap	2012-04-23 18:19:22 -07:00
swap.c	mm: drain percpu lru add/rotate page-vectors on cpu hot-unplug	2012-03-21 17:54:58 -07:00
swapfile.c	swap: fix shmem swapping when more than 8 areas	2012-06-22 11:36:55 -07:00
thrash.c	mm/thrash.c: quiet sparse noise	2011-10-31 17:30:50 -07:00
truncate.c	mm for fs: add truncate_pagecache_range()	2012-03-28 17:14:35 -07:00
util.c	procfs: mark thread stack correctly in proc/<pid>/maps	2012-03-21 17:54:58 -07:00
vmalloc.c	mm: fix faulty initialization in vmalloc_init()	2012-06-10 00:36:06 +09:00
vmscan.c	mm: consider all swapped back pages in used-once logic	2012-06-10 00:36:06 +09:00
vmstat.c	mm: fix up the vmscan stat in vmstat	2012-04-25 21:26:33 -07:00