xiaomi-sm8450/android_kernel_xiaomi_sm8450
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

fs: add support for LOOKUP_CACHED

Browse Source 
[ Upstream commit 6c6ec2b0a3e0381d886d531bd1471dfdb1509237 ]

io_uring always punts opens to async context, since there's no control
over whether the lookup blocks or not. Add LOOKUP_CACHED to support
just doing the fast RCU based lookups, which we know will not block. If
we can do a cached path resolution of the filename, then we don't have
to always punt lookups for a worker.

During path resolution, we always do LOOKUP_RCU first. If that fails and
we terminate LOOKUP_RCU, then fail a LOOKUP_CACHED attempt as well.

Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Jens Axboe
2020-12-17 09:19:09 -07:00
committed by Greg Kroah-Hartman
parent 36ec31201a
commit c1fe7bd3e1
2 changed files with 10 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files

1
include/linux/namei.h
View File

@@ -46,6 +46,7 @@ enum {LAST_NORM, LAST_ROOT, LAST_DOT, LAST_DOTDOT};
#define LOOKUP_NO_XDEV 0x040000 /* No mountpoint crossing. */
#define LOOKUP_BENEATH 0x080000 /* No escaping from starting point. */
#define LOOKUP_IN_ROOT 0x100000 /* Treat dirfd as fs root. */
#define LOOKUP_CACHED 0x200000 /* Only do cached lookup */
/* LOOKUP_* flags which do scope-related checks based on the dirfd. */
#define LOOKUP_IS_SCOPED (LOOKUP_BENEATH | LOOKUP_IN_ROOT)