From: 黄涛 <huangtao@rock-chips.com>
Date: Sat, 30 Jul 2011 14:16:44 +0000 (+0800)
Subject: Revert "Revert "proc: pagemap: Hold mmap_sem during page walk""
X-Git-Tag: firefly_0821_release~10012
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=b1d3b6d349dc81b7881469633b8cc5ba60534f8e;p=firefly-linux-kernel-4.4.55.git

Revert "Revert "proc: pagemap: Hold mmap_sem during page walk""

This reverts commit 2c07d75caea45852bb9a58648a6be476ffc57a02.
---

diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 2a1bef9203c6..3f300c1a9bd0 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -726,8 +726,6 @@ static ssize_t pagemap_read(struct file *file, char __user *buf,
 	down_read(&current->mm->mmap_sem);
 	ret = get_user_pages(current, current->mm, uaddr, pagecount,
 			     1, 0, pages, NULL);
-	up_read(&current->mm->mmap_sem);
-
 	if (ret < 0)
 		goto out_free;
 
@@ -776,6 +774,7 @@ out_pages:
 		page_cache_release(page);
 	}
 out_free:
+	up_read(&current->mm->mmap_sem);
 	kfree(pages);
 out_mm:
 	mmput(mm);