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| author | Paulo Alcantara <pc@manguebit.org> | 2026-09-26 19:20:30 -0300 |
|---|---|---|
| committer | Paulo Alcantara <pc@manguebit.org> | 2026-09-30 14:24:12 -0300 |
| commit | dd05add7b2b6004c5fa3a1f276f56d8668f86b65 (patch) | |
| tree | 23efdcaa0b8031f6ac6f57b6734d18d6c1adc6f2 /include/asm-generic/cache.h | |
| download | linux-stable-dd05add7b2b6004c5fa3a1f276f56d8668f86b65.tar.gz linux-stable-dd05add7b2b6004c5fa3a1f276f56d8668f86b65.zip | |
netfs: zero the tail of a short DIO/unbuffered readgrafted
The buffered read collector zero-fills the tail of a short read that
stops below the inode's i_size (netfs_clear_unread()), so a read that
races an extending write still returns the expected number of bytes.
The non-buffered collector path does no such thing: it just records
how much was transferred.
Add the same zero-fill for the non-buffered case, gated on
NETFS_SREQ_CLEAR_TAIL: a subreq's source sets that flag when a short
result from it is known to be safe to treat as a hole, as opposed to
NETFS_SREQ_HIT_EOF, which means the read genuinely ran off the end of
the file and should be reported short as-is. Only CLEAR_TAIL should
zero-fill here; a real EOF must stay a real short read.
No source currently sets CLEAR_TAIL on an unbuffered/DIO subrequest,
so this is inert on its own -- a following change teaches cifs to set
it in the one case that needs it.
Fixes: e2d46f2ec332 ("netfs: Change the read result collector to only use one work item")
Reviewed-by: David Howells <dhowells@redhat.com>
Reviewed-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Paulo Alcantara <pc@manguebit.org>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Ronnie Sahlberg <ronniesahlberg@gmail.com>
Cc: Shyam Prasad N <sprasad@microsoft.com>
Cc: Tom Talpey <tom@talpey.com>
Cc: Bharath SM <bharathsm@microsoft.com>
Cc: stable@vger.kernel.org
Diffstat (limited to 'include/asm-generic/cache.h')
| -rw-r--r-- | include/asm-generic/cache.h | 13 |
1 files changed, 13 insertions, 0 deletions
diff --git a/include/asm-generic/cache.h b/include/asm-generic/cache.h new file mode 100644 index 000000000..60386e164 --- /dev/null +++ b/include/asm-generic/cache.h @@ -0,0 +1,13 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __ASM_GENERIC_CACHE_H +#define __ASM_GENERIC_CACHE_H +/* + * 32 bytes appears to be the most common cache line size, + * so make that the default here. Architectures with larger + * cache lines need to provide their own cache.h. + */ + +#define L1_CACHE_SHIFT 5 +#define L1_CACHE_BYTES (1 << L1_CACHE_SHIFT) + +#endif /* __ASM_GENERIC_CACHE_H */ |