proc: do translation + unlink atomically at remove_proc_entry()
remove_proc_entry() does
lock
lookup parent
unlock
lock
unlink proc entry from lists
unlock
which can be made bit more correct by doing parent translation + unlink
without dropping lock.
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/fs/proc/generic.c b/fs/proc/generic.c
index 9580abe..ce2d954 100644
--- a/fs/proc/generic.c
+++ b/fs/proc/generic.c
@@ -291,19 +291,17 @@
* returns the struct proc_dir_entry for "/proc/tty/driver", and
* returns "serial" in residual.
*/
-static int xlate_proc_name(const char *name,
- struct proc_dir_entry **ret, const char **residual)
+static int __xlate_proc_name(const char *name, struct proc_dir_entry **ret,
+ const char **residual)
{
const char *cp = name, *next;
struct proc_dir_entry *de;
int len;
- int rtn = 0;
de = *ret;
if (!de)
de = &proc_root;
- spin_lock(&proc_subdir_lock);
while (1) {
next = strchr(cp, '/');
if (!next)
@@ -314,17 +312,24 @@
if (proc_match(len, cp, de))
break;
}
- if (!de) {
- rtn = -ENOENT;
- goto out;
- }
+ if (!de)
+ return -ENOENT;
cp += len + 1;
}
*residual = cp;
*ret = de;
-out:
+ return 0;
+}
+
+static int xlate_proc_name(const char *name, struct proc_dir_entry **ret,
+ const char **residual)
+{
+ int rv;
+
+ spin_lock(&proc_subdir_lock);
+ rv = __xlate_proc_name(name, ret, residual);
spin_unlock(&proc_subdir_lock);
- return rtn;
+ return rv;
}
static DEFINE_IDA(proc_inum_ida);
@@ -797,11 +802,13 @@
const char *fn = name;
int len;
- if (xlate_proc_name(name, &parent, &fn) != 0)
+ spin_lock(&proc_subdir_lock);
+ if (__xlate_proc_name(name, &parent, &fn) != 0) {
+ spin_unlock(&proc_subdir_lock);
return;
+ }
len = strlen(fn);
- spin_lock(&proc_subdir_lock);
for (p = &parent->subdir; *p; p=&(*p)->next ) {
if (proc_match(len, fn, *p)) {
de = *p;