Merge branch 'percpu-for-linus' into percpu-for-next

Conflicts:
	arch/sparc/kernel/smp_64.c
	arch/x86/kernel/cpu/perf_counter.c
	arch/x86/kernel/setup_percpu.c
	drivers/cpufreq/cpufreq_ondemand.c
	mm/percpu.c

Conflicts in core and arch percpu codes are mostly from commit
ed78e1e078dd44249f88b1dd8c76dafb39567161 which substituted many
num_possible_cpus() with nr_cpu_ids.  As for-next branch has moved all
the first chunk allocators into mm/percpu.c, the changes are moved
from arch code to mm/percpu.c.

Signed-off-by: Tejun Heo <tj@kernel.org>

1 files changed, 12 insertions, 15 deletions

diff --git a/fs/proc/base.c b/fs/proc/base.c
index 3ce5ae9e3d2d..175db258942f 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -234,23 +234,20 @@ static int check_mem_permission(struct task_struct *task)
 
 struct mm_struct *mm_for_maps(struct task_struct *task)
 {
-        struct mm_struct *mm = get_task_mm(task);
-        if (!mm)
+        struct mm_struct *mm;
+
+        if (mutex_lock_killable(&task->cred_guard_mutex))
                 return NULL;
-        down_read(&mm->mmap_sem);
-        task_lock(task);
-        if (task->mm != mm)
-                goto out;
-        if (task->mm != current->mm &&
-            __ptrace_may_access(task, PTRACE_MODE_READ) < 0)
-                goto out;
-        task_unlock(task);
+
+        mm = get_task_mm(task);
+        if (mm && mm != current->mm &&
+                        !ptrace_may_access(task, PTRACE_MODE_READ)) {
+                mmput(mm);
+                mm = NULL;
+        }
+        mutex_unlock(&task->cred_guard_mutex);
+
         return mm;
-out:
-        task_unlock(task);
-        up_read(&mm->mmap_sem);
-        mmput(mm);
-        return NULL;
 }
 
 static int proc_pid_cmdline(struct task_struct *task, char * buffer)