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Merge branch 'for-4.9' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup

Browse Source 
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()
This commit is contained in:
Linus Torvalds
2016-10-14 12:18:50 -07:00
parent b6daa51b9a bbb427e342
commit f34d3606f7
10 changed files with 267 additions and 131 deletions
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84
fs/kernfs/dir.c
View File

@@ -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;
}
/**
@@ -185,29 +179,6 @@ int kernfs_name(struct kernfs_node *kn, char *buf, size_t buflen)
return ret;
}
/**
* 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
@@ -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)
@@ -236,28 +208,6 @@ 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

6
fs/sysfs/dir.c
View File

@@ -21,14 +21,14 @@ DEFINE_SPINLOCK(sysfs_symlink_target_lock);
void sysfs_warn_dup(struct kernfs_node *parent, const char *name)
{
char *buf, *path = NULL;
char *buf;
buf = kzalloc(PATH_MAX, GFP_KERNEL);
if (buf)
path = kernfs_path(parent, buf, PATH_MAX);
kernfs_path(parent, buf, PATH_MAX);
WARN(1, KERN_WARNING "sysfs: cannot create duplicate filename '%s/%s'\n",
path, name);
buf, name);
kfree(buf);
}