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Message-ID: <20120130011323.GA30274@oksana.dev.rtsoft.ru>
Date: Mon, 30 Jan 2012 05:13:23 +0400
From: Anton Vorontsov <anton.vorontsov@...aro.org>
To: Arve Hjønnevåg <arve@...roid.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@...il.com>,
Greg Kroah-Hartman <gregkh@...e.de>,
San Mehat <san@...gle.com>, Colin Cross <ccross@...roid.com>,
Oleg Nesterov <oleg@...hat.com>,
"Eric W. Biederman" <ebiederm@...ssion.com>,
linux-kernel@...r.kernel.org, kernel-team@...roid.com,
linaro-kernel@...ts.linaro.org
Subject: [PATCH 1/3] procfs: Export next_tgid(), move it to kernel/pid.c
We'd like to use this function in the android low memory killer driver, so
let's export it.
Also, move next_tgid() to kernel/pid.c, so now it lives with the rest of
pid library functions and does not depend on procfs. Plus, we may now hide
find_ge_pid() from the global namespace.
While at it, also turn next_tgid()'s comments into kerneldoc format.
There should be no functional changes.
Signed-off-by: Anton Vorontsov <anton.vorontsov@...aro.org>
---
fs/proc/base.c | 43 -------------------------------------------
include/linux/pid.h | 9 ++++++++-
kernel/pid.c | 41 ++++++++++++++++++++++++++++++++++++++++-
3 files changed, 48 insertions(+), 45 deletions(-)
diff --git a/fs/proc/base.c b/fs/proc/base.c
index 5485a53..84b8625 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -3324,49 +3324,6 @@ out:
return result;
}
-/*
- * Find the first task with tgid >= tgid
- *
- */
-struct tgid_iter {
- unsigned int tgid;
- struct task_struct *task;
-};
-static struct tgid_iter next_tgid(struct pid_namespace *ns, struct tgid_iter iter)
-{
- struct pid *pid;
-
- if (iter.task)
- put_task_struct(iter.task);
- rcu_read_lock();
-retry:
- iter.task = NULL;
- pid = find_ge_pid(iter.tgid, ns);
- if (pid) {
- iter.tgid = pid_nr_ns(pid, ns);
- iter.task = pid_task(pid, PIDTYPE_PID);
- /* What we to know is if the pid we have find is the
- * pid of a thread_group_leader. Testing for task
- * being a thread_group_leader is the obvious thing
- * todo but there is a window when it fails, due to
- * the pid transfer logic in de_thread.
- *
- * So we perform the straight forward test of seeing
- * if the pid we have found is the pid of a thread
- * group leader, and don't worry if the task we have
- * found doesn't happen to be a thread group leader.
- * As we don't care in the case of readdir.
- */
- if (!iter.task || !has_group_leader_pid(iter.task)) {
- iter.tgid += 1;
- goto retry;
- }
- get_task_struct(iter.task);
- }
- rcu_read_unlock();
- return iter;
-}
-
#define TGID_OFFSET (FIRST_PROCESS_ENTRY + ARRAY_SIZE(proc_base_stuff))
static int proc_pid_fill_cache(struct file *filp, void *dirent, filldir_t filldir,
diff --git a/include/linux/pid.h b/include/linux/pid.h
index b152d44..33e350b 100644
--- a/include/linux/pid.h
+++ b/include/linux/pid.h
@@ -116,7 +116,6 @@ extern struct pid *find_vpid(int nr);
* Lookup a PID in the hash table, and return with it's count elevated.
*/
extern struct pid *find_get_pid(int nr);
-extern struct pid *find_ge_pid(int nr, struct pid_namespace *);
int next_pidmap(struct pid_namespace *pid_ns, unsigned int last);
extern struct pid *alloc_pid(struct pid_namespace *ns);
@@ -199,4 +198,12 @@ pid_t pid_vnr(struct pid *pid);
} while_each_thread(tg___, task); \
task = tg___; \
} while_each_pid_task(pid, type, task)
+
+struct tgid_iter {
+ unsigned int tgid;
+ struct task_struct *task;
+};
+
+struct tgid_iter next_tgid(struct pid_namespace *ns, struct tgid_iter iter);
+
#endif /* _LINUX_PID_H */
diff --git a/kernel/pid.c b/kernel/pid.c
index ce8e00d..34a52a6 100644
--- a/kernel/pid.c
+++ b/kernel/pid.c
@@ -522,7 +522,7 @@ EXPORT_SYMBOL_GPL(task_active_pid_ns);
*
* If there is a pid at nr this function is exactly the same as find_pid_ns.
*/
-struct pid *find_ge_pid(int nr, struct pid_namespace *ns)
+static struct pid *find_ge_pid(int nr, struct pid_namespace *ns)
{
struct pid *pid;
@@ -536,6 +536,45 @@ struct pid *find_ge_pid(int nr, struct pid_namespace *ns)
return pid;
}
+/**
+ * next_tgid() - Find the first task with tgid >= tgid
+ * @ns: pointer to the pid namespace
+ * @iter: iterator
+ */
+struct tgid_iter next_tgid(struct pid_namespace *ns, struct tgid_iter iter)
+{
+ struct pid *pid;
+
+ if (iter.task)
+ put_task_struct(iter.task);
+ rcu_read_lock();
+retry:
+ iter.task = NULL;
+ pid = find_ge_pid(iter.tgid, ns);
+ if (pid) {
+ iter.tgid = pid_nr_ns(pid, ns);
+ iter.task = pid_task(pid, PIDTYPE_PID);
+ /* What we to know is if the pid we have find is the
+ * pid of a thread_group_leader. Testing for task
+ * being a thread_group_leader is the obvious thing
+ * todo but there is a window when it fails, due to
+ * the pid transfer logic in de_thread.
+ *
+ * So we perform the straight forward test of seeing
+ * if the pid we have found is the pid of a thread
+ * group leader, and don't worry if the task we have
+ * found doesn't happen to be a thread group leader.
+ */
+ if (!iter.task || !has_group_leader_pid(iter.task)) {
+ iter.tgid += 1;
+ goto retry;
+ }
+ get_task_struct(iter.task);
+ }
+ rcu_read_unlock();
+ return iter;
+}
+
/*
* The pid hash table is scaled according to the amount of memory in the
* machine. From a minimum of 16 slots up to 4096 slots at one gigabyte or
--
1.7.7
--
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