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27 March 2024, 02:37:15 UTC
Revision 7d8a45695cc8f9fcdf4121fcbd897ecb63f758e4 authored by Will Deacon on 07 June 2012, 21:21:13 UTC, committed by Linus Torvalds on 07 June 2012, 21:43:55 UTC 
ipc: shm: restore MADV_REMOVE functionality on shared memory segments
 
Commit 17cf28afea2a ("mm/fs: remove truncate_range") removed the
truncate_range inode operation in favour of the fallocate file
operation.

When using SYSV IPC shared memory segments, calling madvise with the
MADV_REMOVE advice on an area of shared memory will attempt to invoke
the .fallocate function for the shm_file_operations, which is NULL and
therefore returns -EOPNOTSUPP to userspace.  The previous behaviour
would inherit the inode_operations from the underlying tmpfs file and
invoke truncate_range there.

This patch restores the previous behaviour by wrapping the underlying
fallocate function in shm_fallocate, as we do for fsync.

[hughd@google.com: use -ENOTSUPP in shm_fallocate()]
Signed-off-by: Will Deacon <will.deacon@arm.com>
Acked-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 parent 4e791c9
History
Tip revision: 7d8a45695cc8f9fcdf4121fcbd897ecb63f758e4 authored by Will Deacon on 07 June 2012, 21:21:13 UTC
ipc: shm: restore MADV_REMOVE functionality on shared memory segments
Tip revision: 7d8a456
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