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| author | Mateusz Guzik <mjguzik@gmail.com> | 2024-06-25 17:18:06 +0200 |
|---|---|---|
| committer | Christian Brauner <brauner@kernel.org> | 2024-06-27 18:31:20 +0200 |
| commit | 0ef625bba6fb2bc0c8ed2aab9524fdf423f67dd5 (patch) | |
| tree | dac526478b2be72640552a7ab9def6664ece9052 /fs/internal.h | |
| parent | stat: use vfs_empty_path() helper (diff) | |
| download | linux-0ef625bba6fb2bc0c8ed2aab9524fdf423f67dd5.tar.xz linux-0ef625bba6fb2bc0c8ed2aab9524fdf423f67dd5.zip | |
vfs: support statx(..., NULL, AT_EMPTY_PATH, ...)
The newly used helper also checks for empty ("") paths.
NULL paths with any flag value other than AT_EMPTY_PATH go the usual
route and end up with -EFAULT to retain compatibility (Rust is abusing
calls of the sort to detect availability of statx).
This avoids path lookup code, lockref management, memory allocation and
in case of NULL path userspace memory access (which can be quite
expensive with SMAP on x86_64).
Benchmarked with statx(..., AT_EMPTY_PATH, ...) running on Sapphire
Rapids, with the "" path for the first two cases and NULL for the last
one.
Results in ops/s:
stock: 4231237
pre-check: 5944063 (+40%)
NULL path: 6601619 (+11%/+56%)
Signed-off-by: Mateusz Guzik <mjguzik@gmail.com>
Link: https://lore.kernel.org/r/20240625151807.620812-1-mjguzik@gmail.com
Tested-by: Xi Ruoyao <xry111@xry111.site>
[brauner: use path_mounted() and other tweaks]
Signed-off-by: Christian Brauner <brauner@kernel.org>
Diffstat (limited to 'fs/internal.h')
| -rw-r--r-- | fs/internal.h | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/fs/internal.h b/fs/internal.h index ab2225136f60..f26454c60a98 100644 --- a/fs/internal.h +++ b/fs/internal.h @@ -247,6 +247,8 @@ extern const struct dentry_operations ns_dentry_operations; int getname_statx_lookup_flags(int flags); int do_statx(int dfd, struct filename *filename, unsigned int flags, unsigned int mask, struct statx __user *buffer); +int do_statx_fd(int fd, unsigned int flags, unsigned int mask, + struct statx __user *buffer); /* * fs/splice.c: @@ -321,3 +323,15 @@ struct stashed_operations { int path_from_stashed(struct dentry **stashed, struct vfsmount *mnt, void *data, struct path *path); void stashed_dentry_prune(struct dentry *dentry); +/** + * path_mounted - check whether path is mounted + * @path: path to check + * + * Determine whether @path refers to the root of a mount. + * + * Return: true if @path is the root of a mount, false if not. + */ +static inline bool path_mounted(const struct path *path) +{ + return path->mnt->mnt_root == path->dentry; +} |