evie/android_kernel_oneplus_msm8998
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Shrink ashmem directly through shmem_fallocate

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When ashmem_shrink is called from direct reclaim on a user thread, a
call to do_fallocate will check for permissions against the security
policy of that user thread.  It can thus fail by chance if called on a
thread that isn't permitted to modify the relevant ashmem areas.

Because we know that we have a shmem file underneath, call the shmem
implementation of fallocate directly instead of going through the
user-space interface for fallocate.

FIX=DMS06243560
Area: Kernel/Linux Kernel

Bug: 21951515
Change-Id: Ie98fff18a2bdeb535cd24d4fbdd13677e12681a7
Signed-off-by: Jeff Vander Stoep <jeffv@google.com>
This commit is contained in:
Tobias Lindskog 2015-02-09 08:10:39 +01:00 • committed by Amit Pundir
parent bedf47303d
commit 9cba14efb8
1 changed files with 3 additions and 3 deletions
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2
drivers/staging/android/ashmem.c
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@ -440,7 +440,7 @@ ashmem_shrink_scan(struct shrinker *shrink, struct shrink_control *sc)
loff_t start = range->pgstart * PAGE_SIZE; loff_t start = range->pgstart * PAGE_SIZE;
loff_t end = (range->pgend + 1) * PAGE_SIZE; loff_t end = (range->pgend + 1) * PAGE_SIZE;
vfs_fallocate(range->asma->file, range->asma->file->f_op->fallocate(range->asma->file,
FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE, FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE,
start, end - start); start, end - start);
range->purged = ASHMEM_WAS_PURGED; range->purged = ASHMEM_WAS_PURGED;