Commit 46460c1d authored by Jeff Layton's avatar Jeff Layton Committed by Christian Brauner
Browse files

fs: add a kerneldoc header over lookup_fast 



The lookup_fast helper in fs/namei.c has some subtlety in how dentries
are returned. Document them.

Signed-off-by: default avatarJeff Layton <jlayton@kernel.org>
Link: https://lore.kernel.org/r/20240802-openfast-v1-2-a1cff2a33063@kernel.org


Signed-off-by: default avatarChristian Brauner <brauner@kernel.org>
parent 45fab40d

fs/namei.c

+14 −0
Original line number Diff line number Diff line
@@ -1639,6 +1639,20 @@ struct dentry *lookup_one_qstr_excl(const struct qstr *name, 
}

EXPORT_SYMBOL(lookup_one_qstr_excl);



/**

 * lookup_fast - do fast lockless (but racy) lookup of a dentry

 * @nd: current nameidata

 *

 * Do a fast, but racy lookup in the dcache for the given dentry, and

 * revalidate it. Returns a valid dentry pointer or NULL if one wasn't

 * found. On error, an ERR_PTR will be returned.

 *

 * If this function returns a valid dentry and the walk is no longer

 * lazy, the dentry will carry a reference that must later be put. If

 * RCU mode is still in force, then this is not the case and the dentry

 * must be legitimized before use. If this returns NULL, then the walk

 * will no longer be in RCU mode.

 */

static struct dentry *lookup_fast(struct nameidata *nd)

{

	struct dentry *dentry, *parent = nd->path.dentry;