Gitweb: http://git.kernel.org/linus/8053bdd5ce15dcf043d41a4dd6cac4a5567effdc
Commit: 8053bdd5ce15dcf043d41a4dd6cac4a5567effdc
Parent: 4b105cbbaf7c06e01c27391957dc3c446328d087
Author: Oleg Nesterov <oleg@redhat.com>
AuthorDate: Wed Jun 17 16:27:34 2009 -0700
Committer: Linus Torvalds <torvalds@linux-foundation.org>
CommitDate: Thu Jun 18 13:03:51 2009 -0700
ptrace_get_task_struct: s/tasklist/rcu/, make it static
- Use rcu_read_lock() instead of tasklist_lock to find/get the task
in ptrace_get_task_struct().
- Make it static, it has no callers outside of ptrace.c.
- The comment doesn't match the reality, this helper does not do
any checks. Beacuse it is really trivial and static I removed the
whole comment.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
include/linux/ptrace.h | 1 -
kernel/ptrace.c | 16 +++-------------
2 files changed, 3 insertions(+), 14 deletions(-)
diff --git a/include/linux/ptrace.h b/include/linux/ptrace.h
index 59e133d..7456d7d 100644
--- a/include/linux/ptrace.h
+++ b/include/linux/ptrace.h
@@ -81,7 +81,6 @@
extern long arch_ptrace(struct task_struct *child, long request, long addr, long data);
-extern struct task_struct *ptrace_get_task_struct(pid_t pid);
extern int ptrace_traceme(void);
extern int ptrace_readdata(struct task_struct *tsk, unsigned long src, char __user *dst, int len);
extern int ptrace_writedata(struct task_struct *tsk, char __user *src, unsigned long dst, int len);
diff --git a/kernel/ptrace.c b/kernel/ptrace.c
index 38fdfea..a64fe75 100644
--- a/kernel/ptrace.c
+++ b/kernel/ptrace.c
@@ -581,26 +581,16 @@ int ptrace_request(struct task_struct *child, long request,
return ret;
}
-/**
- * ptrace_get_task_struct -- grab a task struct reference for ptrace
- * @pid: process id to grab a task_struct reference of
- *
- * This function is a helper for ptrace implementations. It checks
- * permissions and then grabs a task struct for use of the actual
- * ptrace implementation.
- *
- * Returns the task_struct for @pid or an ERR_PTR() on failure.
- */
-struct task_struct *ptrace_get_task_struct(pid_t pid)
+static struct task_struct *ptrace_get_task_struct(pid_t pid)
{
struct task_struct *child;
- read_lock(&tasklist_lock);
+ rcu_read_lock();
child = find_task_by_vpid(pid);
if (child)
get_task_struct(child);
+ rcu_read_unlock();
- read_unlock(&tasklist_lock);
if (!child)
return ERR_PTR(-ESRCH);
return child;
--
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