[PATCH] simply fix first_tgid
Like the bug Oleg spotted in first_tid there was also a small off by one
error in first_tgid, when a seek was done on the /proc directory. This
fixes that and changes the code structure to make it a little more obvious
what is going on.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/fs/proc/base.c b/fs/proc/base.c
index 8180579..bbcaef9 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -2040,34 +2040,32 @@
* In the case of a seek we start with &init_task and walk nr
* threads past it.
*/
-static struct task_struct *first_tgid(int tgid, int nr)
+static struct task_struct *first_tgid(int tgid, unsigned int nr)
{
- struct task_struct *pos = NULL;
+ struct task_struct *pos;
rcu_read_lock();
if (tgid && nr) {
pos = find_task_by_pid(tgid);
- if (pos && !thread_group_leader(pos))
- pos = NULL;
- if (pos)
- nr = 0;
+ if (pos && thread_group_leader(pos))
+ goto found;
}
/* If nr exceeds the number of processes get out quickly */
+ pos = NULL;
if (nr && nr >= nr_processes())
goto done;
/* If we haven't found our starting place yet start with
* the init_task and walk nr tasks forward.
*/
- if (!pos && (nr >= 0))
- pos = next_task(&init_task);
-
- for (; pos && pid_alive(pos); pos = next_task(pos)) {
- if (--nr > 0)
- continue;
- get_task_struct(pos);
- goto done;
+ for (pos = next_task(&init_task); nr > 0; --nr) {
+ pos = next_task(pos);
+ if (pos == &init_task) {
+ pos = NULL;
+ goto done;
+ }
}
- pos = NULL;
+found:
+ get_task_struct(pos);
done:
rcu_read_unlock();
return pos;