kernfs_walk_ns() uses a static path_buf[PATH_MAX] to separate out path
components. Keeping around the 4k buffer just for kernfs_walk_ns() is
wasteful. This patch makes it piggyback on kernfs_pr_cont_buf[]
instead. This requires kernfs_walk_ns() to hold kernfs_rename_lock.
Signed-off-by: Tejun Heo <tj@xxxxxxxxxx>
Reported-by: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>
---
Hello,
Greg, can you please route this one?
Thanks.
fs/kernfs/dir.c | 19 ++++++++++++++-----
1 file changed, 14 insertions(+), 5 deletions(-)
--- a/fs/kernfs/dir.c
+++ b/fs/kernfs/dir.c
@@ -698,15 +698,22 @@ static struct kernfs_node *kernfs_walk_n
const unsigned char *path,
const void *ns)
{
- static char path_buf[PATH_MAX]; /* protected by kernfs_mutex */
- size_t len = strlcpy(path_buf, path, PATH_MAX);
- char *p = path_buf;
- char *name;
+ size_t len;
+ char *p, *name;
lockdep_assert_held(&kernfs_mutex);
- if (len >= PATH_MAX)
+ /* grab kernfs_rename_lock to piggy back on kernfs_pr_cont_buf */
+ spin_lock_irq(&kernfs_rename_lock);
+
+ len = strlcpy(kernfs_pr_cont_buf, path, sizeof(kernfs_pr_cont_buf));
+
+ if (len >= sizeof(kernfs_pr_cont_buf)) {
+ spin_unlock_irq(&kernfs_rename_lock);
return NULL;
+ }
+
+ p = kernfs_pr_cont_buf;
while ((name = strsep(&p, "/")) && parent) {
if (*name == '\0')
@@ -714,6 +721,8 @@ static struct kernfs_node *kernfs_walk_n
parent = kernfs_find_ns(parent, name, ns);
}
+ spin_unlock_irq(&kernfs_rename_lock);
+
return parent;
}
--
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