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authorLinus Torvalds <torvalds@linux-foundation.org>2016-10-14 22:18:50 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2016-10-14 22:18:50 +0300
commitf34d3606f76a8121b9d4940d2dd436bebeb2f9d7 (patch)
tree61a9deb6a950568df274580fbbd44a7015af9f7c /fs/kernfs/dir.c
parentb6daa51b9a6a02a644dcf6b880fd50c1f70ec07f (diff)
parentbbb427e342495df1cda10051d0566388697499c0 (diff)
downloadlinux-f34d3606f76a8121b9d4940d2dd436bebeb2f9d7.tar.xz
Merge branch 'for-4.9' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup
Pull cgroup updates from Tejun Heo: - tracepoints for basic cgroup management operations added - kernfs and cgroup path formatting functions updated to behave in the style of strlcpy() - non-critical bug fixes * 'for-4.9' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: blkcg: Unlock blkcg_pol_mutex only once when cpd == NULL cgroup: fix error handling regressions in proc_cgroup_show() and cgroup_release_agent() cpuset: fix error handling regression in proc_cpuset_show() cgroup: add tracepoints for basic operations cgroup: make cgroup_path() and friends behave in the style of strlcpy() kernfs: remove kernfs_path_len() kernfs: make kernfs_path*() behave in the style of strlcpy() kernfs: add dummy implementation of kernfs_path_from_node()
Diffstat (limited to 'fs/kernfs/dir.c')
-rw-r--r--fs/kernfs/dir.c84
1 files changed, 17 insertions, 67 deletions
diff --git a/fs/kernfs/dir.c b/fs/kernfs/dir.c
index dcd96aac02f5..cf4c636ff4da 100644
--- a/fs/kernfs/dir.c
+++ b/fs/kernfs/dir.c
@@ -110,8 +110,9 @@ static struct kernfs_node *kernfs_common_ancestor(struct kernfs_node *a,
* kn_to: /n1/n2/n3 [depth=3]
* result: /../..
*
- * return value: length of the string. If greater than buflen,
- * then contents of buf are undefined. On error, -1 is returned.
+ * Returns the length of the full path. If the full length is equal to or
+ * greater than @buflen, @buf contains the truncated path with the trailing
+ * '\0'. On error, -errno is returned.
*/
static int kernfs_path_from_node_locked(struct kernfs_node *kn_to,
struct kernfs_node *kn_from,
@@ -119,9 +120,8 @@ static int kernfs_path_from_node_locked(struct kernfs_node *kn_to,
{
struct kernfs_node *kn, *common;
const char parent_str[] = "/..";
- size_t depth_from, depth_to, len = 0, nlen = 0;
- char *p;
- int i;
+ size_t depth_from, depth_to, len = 0;
+ int i, j;
if (!kn_from)
kn_from = kernfs_root(kn_to)->kn;
@@ -131,7 +131,7 @@ static int kernfs_path_from_node_locked(struct kernfs_node *kn_to,
common = kernfs_common_ancestor(kn_from, kn_to);
if (WARN_ON(!common))
- return -1;
+ return -EINVAL;
depth_to = kernfs_depth(common, kn_to);
depth_from = kernfs_depth(common, kn_from);
@@ -144,22 +144,16 @@ static int kernfs_path_from_node_locked(struct kernfs_node *kn_to,
len < buflen ? buflen - len : 0);
/* Calculate how many bytes we need for the rest */
- for (kn = kn_to; kn != common; kn = kn->parent)
- nlen += strlen(kn->name) + 1;
-
- if (len + nlen >= buflen)
- return len + nlen;
-
- p = buf + len + nlen;
- *p = '\0';
- for (kn = kn_to; kn != common; kn = kn->parent) {
- size_t tmp = strlen(kn->name);
- p -= tmp;
- memcpy(p, kn->name, tmp);
- *(--p) = '/';
+ for (i = depth_to - 1; i >= 0; i--) {
+ for (kn = kn_to, j = 0; j < i; j++)
+ kn = kn->parent;
+ len += strlcpy(buf + len, "/",
+ len < buflen ? buflen - len : 0);
+ len += strlcpy(buf + len, kn->name,
+ len < buflen ? buflen - len : 0);
}
- return len + nlen;
+ return len;
}
/**
@@ -186,29 +180,6 @@ int kernfs_name(struct kernfs_node *kn, char *buf, size_t buflen)
}
/**
- * kernfs_path_len - determine the length of the full path of a given node
- * @kn: kernfs_node of interest
- *
- * The returned length doesn't include the space for the terminating '\0'.
- */
-size_t kernfs_path_len(struct kernfs_node *kn)
-{
- size_t len = 0;
- unsigned long flags;
-
- spin_lock_irqsave(&kernfs_rename_lock, flags);
-
- do {
- len += strlen(kn->name) + 1;
- kn = kn->parent;
- } while (kn && kn->parent);
-
- spin_unlock_irqrestore(&kernfs_rename_lock, flags);
-
- return len;
-}
-
-/**
* kernfs_path_from_node - build path of node @to relative to @from.
* @from: parent kernfs_node relative to which we need to build the path
* @to: kernfs_node of interest
@@ -220,8 +191,9 @@ size_t kernfs_path_len(struct kernfs_node *kn)
* path (which includes '..'s) as needed to reach from @from to @to is
* returned.
*
- * If @buf isn't long enough, the return value will be greater than @buflen
- * and @buf contents are undefined.
+ * Returns the length of the full path. If the full length is equal to or
+ * greater than @buflen, @buf contains the truncated path with the trailing
+ * '\0'. On error, -errno is returned.
*/
int kernfs_path_from_node(struct kernfs_node *to, struct kernfs_node *from,
char *buf, size_t buflen)
@@ -237,28 +209,6 @@ int kernfs_path_from_node(struct kernfs_node *to, struct kernfs_node *from,
EXPORT_SYMBOL_GPL(kernfs_path_from_node);
/**
- * kernfs_path - build full path of a given node
- * @kn: kernfs_node of interest
- * @buf: buffer to copy @kn's name into
- * @buflen: size of @buf
- *
- * Builds and returns the full path of @kn in @buf of @buflen bytes. The
- * path is built from the end of @buf so the returned pointer usually
- * doesn't match @buf. If @buf isn't long enough, @buf is nul terminated
- * and %NULL is returned.
- */
-char *kernfs_path(struct kernfs_node *kn, char *buf, size_t buflen)
-{
- int ret;
-
- ret = kernfs_path_from_node(kn, NULL, buf, buflen);
- if (ret < 0 || ret >= buflen)
- return NULL;
- return buf;
-}
-EXPORT_SYMBOL_GPL(kernfs_path);
-
-/**
* pr_cont_kernfs_name - pr_cont name of a kernfs_node
* @kn: kernfs_node of interest
*