Commit 173a4906 authored by Tobias Lindskog's avatar Tobias Lindskog Committed by Greg Kroah-Hartman
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staging: android: ashmem: Shrink directly through shmem_fallocate 



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.

Signed-off-by: default avatarTobias Lindskog <tobias.lindskog@sonymobile.com>
Signed-off-by: default avatarJeff Vander Stoep <jeffv@google.com>
Signed-off-by: default avatarJoel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent ab608b34

drivers/staging/android/ashmem.c

+3 −3
Original line number Diff line number Diff line
@@ -450,7 +450,7 @@ ashmem_shrink_scan(struct shrinker *shrink, struct shrink_control *sc) 
		loff_t start = range->pgstart * 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,

				start, end - start);

		range->purged = ASHMEM_WAS_PURGED;