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  1. 02 11月, 2013 2 次提交
    • T
      sysfs: rename sysfs_assoc_lock and explain what it's about · 0cae60f9
      由 Tejun Heo 提交于 
      sysfs_assoc_lock is an odd piece of locking.  In general, whoever owns
a kobject is responsible for synchronizing sysfs operations and sysfs
proper assumes that, for example, removal won't race with any other
operation; however, this doesn't work for symlinking because an entity
performing symlink doesn't usually own the target kobject and thus has
no control over its removal.

sysfs_assoc_lock synchronizes symlink operations against kobj->sd
disassociation so that symlink code doesn't end up dereferencing
already freed sysfs_dirent by racing with removal of the target
kobject.

This is quite obscure and the generic name of the lock and lack of
comments make it difficult to understand its role.  Let's rename it to
sysfs_symlink_target_lock and add comments explaining what's going on.
Signed-off-by: NTejun Heo <tj@kernel.org>
Reported-by: NLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      0cae60f9
    • T
      sysfs: use generic_file_llseek() for sysfs_file_operations · 044e3bc3
      由 Tejun Heo 提交于 
      13c589d5 ("sysfs: use seq_file when reading regular files")
converted regular sysfs files to use seq_file.  The commit substituted
generic_file_llseek() with seq_lseek() for llseek implementation.

Before the change, all regular sysfs files were allowed to seek to any
position in [0, PAGE_SIZE] as the file size is always PAGE_SIZE and
generic_file_llseek() allows any seeking inside the range under file
size; however, seq_lseek()'s behavior is different.  It traverses the
output by repeatedly invoking ->show() until it reaches the target
offset or traversal indicates EOF.  As seq_files are fully dynamic and
may not end at all, it doesn't support seeking from the end
(SEEK_END).

Apparently, there are userland tools which uses SEEK_END to discover
the buffer size to use and the switch to seq_lseek() disturbs them as
SEEK_END fails with -EINVAL.

The only benefits of using seq_lseek() instead of
generic_file_llseek() are

* Early failure.  If traversing to certain file position should fail,
  seq_lseek() will report such failures on lseek(2) instead of the
  following read/write operations.

* EOF detection.  While SEEK_END is not supported, SEEK_SET/CUR +
  large offset can be used to detect eof - eof at the time of the seek
  anyway as the file size may change dynamically.

Both aren't necessary for sysfs or prospect kernfs users.  Revert to
genefic_file_llseek() and preserve the original behavior.
Signed-off-by: NTejun Heo <tj@kernel.org>
Reported-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Link: https://lkml.kernel.org/r/20131031114358.GA5551@osirisTested-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      044e3bc3
  3. 31 10月, 2013 1 次提交
  5. 30 10月, 2013 7 次提交
  7. 25 10月, 2013 2 次提交
  9. 20 10月, 2013 5 次提交
  11. 19 10月, 2013 4 次提交
  13. 18 10月, 2013 12 次提交
  15. 17 10月, 2013 7 次提交
    • R
      ACPI / PM: Drop two functions that are not used any more · 2421ad48
      由 Rafael J. Wysocki 提交于 
      Two functions defined in device_pm.c, acpi_dev_pm_add_dependent()
and acpi_dev_pm_remove_dependent(), have no callers and may be
dropped, so drop them.

Moreover, they are the only functions adding entries to and removing
entries from the power_dependent list in struct acpi_device, so drop
that list too.
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
      2421ad48
    • A
      ATA / ACPI: remove power dependent device handling · b08fc109
      由 Aaron Lu 提交于 
      Previously, we wanted SCSI devices corrsponding to ATA devices to
be runtime resumed when the power resource for those ATA device was
turned on by some other device, so we added the SCSI device to the
dependent device list of the ATA device's ACPI node.  However, this
code has no effect after commit 41863fce (ACPI / power: Drop automaitc
resume of power resource dependent devices) and the mechanism it was
supposed to implement is regarded as a bad idea now, so drop it.

[rjw: Changelog]
Signed-off-by: NAaron Lu <aaron.lu@intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
      b08fc109
    • L
      Merge branch 'akpm' (fixes from Andrew Morton) · 056cdce0
      由 Linus Torvalds 提交于 
      Merge misc fixes from Andrew Morton.

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (21 commits)
  mm: revert mremap pud_free anti-fix
  mm: fix BUG in __split_huge_page_pmd
  swap: fix set_blocksize race during swapon/swapoff
  procfs: call default get_unmapped_area on MMU-present architectures
  procfs: fix unintended truncation of returned mapped address
  writeback: fix negative bdi max pause
  percpu_refcount: export symbols
  fs: buffer: move allocation failure loop into the allocator
  mm: memcg: handle non-error OOM situations more gracefully
  tools/testing/selftests: fix uninitialized variable
  block/partitions/efi.c: treat size mismatch as a warning, not an error
  mm: hugetlb: initialize PG_reserved for tail pages of gigantic compound pages
  mm/zswap: bugfix: memory leak when re-swapon
  mm: /proc/pid/pagemap: inspect _PAGE_SOFT_DIRTY only on present pages
  mm: migration: do not lose soft dirty bit if page is in migration state
  gcov: MAINTAINERS: Add an entry for gcov
  mm/hugetlb.c: correct missing private flag clearing
  mm/vmscan.c: don't forget to free shrinker->nr_deferred
  ipc/sem.c: synchronize semop and semctl with IPC_RMID
  ipc: update locking scheme comments
  ...
      056cdce0
    • H
      mm: revert mremap pud_free anti-fix · 57a8f0cd
      由 Hugh Dickins 提交于 
      Revert commit 1ecfd533 ("mm/mremap.c: call pud_free() after fail
calling pmd_alloc()").

The original code was correct: pud_alloc(), pmd_alloc(), pte_alloc_map()
ensure that the pud, pmd, pt is already allocated, and seldom do they
need to allocate; on failure, upper levels are freed if appropriate by
the subsequent do_munmap().  Whereas commit 1ecfd533 did an
unconditional pud_free() of a most-likely still-in-use pud: saved only
by the near-impossiblity of pmd_alloc() failing.
Signed-off-by: NHugh Dickins <hughd@google.com>
Cc: Chen Gang <gang.chen@asianux.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      57a8f0cd
    • H
      mm: fix BUG in __split_huge_page_pmd · 750e8165
      由 Hugh Dickins 提交于 
      Occasionally we hit the BUG_ON(pmd_trans_huge(*pmd)) at the end of
__split_huge_page_pmd(): seen when doing madvise(,,MADV_DONTNEED).

It's invalid: we don't always have down_write of mmap_sem there: a racing
do_huge_pmd_wp_page() might have copied-on-write to another huge page
before our split_huge_page() got the anon_vma lock.

Forget the BUG_ON, just go back and try again if this happens.
Signed-off-by: NHugh Dickins <hughd@google.com>
Acked-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: David Rientjes <rientjes@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      750e8165
    • K
      swap: fix set_blocksize race during swapon/swapoff · 5b808a23
      由 Krzysztof Kozlowski 提交于 
      Fix race between swapoff and swapon.  Swapoff used old_block_size from
swap_info outside of swapon_mutex so it could be overwritten by
concurrent swapon.

The race has visible effect only if more than one swap block device
exists with different block sizes (e.g.  /dev/sda1 with block size 4096
and /dev/sdb1 with 512).  In such case it leads to setting the blocksize
of swapped off device with wrong blocksize.

The bug can be triggered with multiple concurrent swapoff and swapon:
0. Swap for some device is on.
1. swapoff:
First the swapoff is called on this device and "struct swap_info_struct
*p" is assigned. This is done under swap_lock however this lock is
released for the call try_to_unuse().

2. swapon:
After the assignment above (and before acquiring swapon_mutex &
swap_lock by swapoff) the swapon is called on the same device.
The p->old_block_size is assigned to the value of block_size the device.
This block size should be the same as previous but sometimes it is not.
The swapon ends successfully.

3. swapoff:
Swapoff resumes, grabs the locks and mutex and continues to disable this
swap device. Now it sets the block size to value taken from swap_info
which was overwritten by swapon in 2.
Signed-off-by: NKrzysztof Kozlowski <k.kozlowski@samsung.com>
Reported-by: NWeijie Yang <weijie.yang.kh@gmail.com>
Cc: Bob Liu <bob.liu@oracle.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Shaohua Li <shli@fusionio.com>
Cc: Minchan Kim <minchan@kernel.org>
Acked-by: NHugh Dickins <hughd@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      5b808a23
    • H
      procfs: call default get_unmapped_area on MMU-present architectures · fad1a86e
      由 HATAYAMA Daisuke 提交于 
      Commit c4fe2448 ("sparc: fix PCI device proc file mmap(2)") added
proc_reg_get_unmapped_area in proc_reg_file_ops and
proc_reg_file_ops_no_compat, by which now mmap always returns EIO if
get_unmapped_area method is not defined for the target procfs file,
which causes regression of mmap on /proc/vmcore.

To address this issue, like get_unmapped_area(), call default
current->mm->get_unmapped_area on MMU-present architectures if
pde->proc_fops->get_unmapped_area, i.e.  the one in actual file
operation in the procfs file, is not defined.
Reported-by: NMichael Holzheu <holzheu@linux.vnet.ibm.com>
Signed-off-by: NHATAYAMA Daisuke <d.hatayama@jp.fujitsu.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: David S. Miller <davem@davemloft.net>
Tested-by: NMichael Holzheu <holzheu@linux.vnet.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      fad1a86e