ipc: shm: restore MADV_REMOVE functionality on shared memory segments
Commit 17cf28afea
("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>
hifive-unleashed-5.1
parent
4e791c98ae
commit
7d8a45695c
12
ipc/shm.c
12
ipc/shm.c
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@ -393,6 +393,16 @@ static int shm_fsync(struct file *file, loff_t start, loff_t end, int datasync)
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return sfd->file->f_op->fsync(sfd->file, start, end, datasync);
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return sfd->file->f_op->fsync(sfd->file, start, end, datasync);
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}
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}
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static long shm_fallocate(struct file *file, int mode, loff_t offset,
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loff_t len)
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{
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struct shm_file_data *sfd = shm_file_data(file);
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if (!sfd->file->f_op->fallocate)
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return -EOPNOTSUPP;
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return sfd->file->f_op->fallocate(file, mode, offset, len);
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}
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static unsigned long shm_get_unmapped_area(struct file *file,
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static unsigned long shm_get_unmapped_area(struct file *file,
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unsigned long addr, unsigned long len, unsigned long pgoff,
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unsigned long addr, unsigned long len, unsigned long pgoff,
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unsigned long flags)
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unsigned long flags)
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@ -410,6 +420,7 @@ static const struct file_operations shm_file_operations = {
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.get_unmapped_area = shm_get_unmapped_area,
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.get_unmapped_area = shm_get_unmapped_area,
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#endif
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#endif
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.llseek = noop_llseek,
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.llseek = noop_llseek,
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.fallocate = shm_fallocate,
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};
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};
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static const struct file_operations shm_file_operations_huge = {
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static const struct file_operations shm_file_operations_huge = {
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@ -418,6 +429,7 @@ static const struct file_operations shm_file_operations_huge = {
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.release = shm_release,
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.release = shm_release,
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.get_unmapped_area = shm_get_unmapped_area,
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.get_unmapped_area = shm_get_unmapped_area,
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.llseek = noop_llseek,
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.llseek = noop_llseek,
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.fallocate = shm_fallocate,
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};
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};
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int is_file_shm_hugepages(struct file *file)
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int is_file_shm_hugepages(struct file *file)
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