From: Lorenzo Stoakes <lstoakes@gmail.com>
Date: Tue, 1 Nov 2016 19:43:43 +0000 (+0000)
Subject: platform: goldfish: pipe: use get_user_pages_unlocked()
X-Git-Tag: v4.10-rc1~146^2~63
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=052662cada1f2104dedfab68866e403a508e045c;p=karo-tx-linux.git

platform: goldfish: pipe: use get_user_pages_unlocked()

Moving from get_user_pages() to get_user_pages_unlocked() simplifies the code
and takes advantage of VM_FAULT_RETRY functionality when faulting in pages.

Signed-off-by: Lorenzo Stoakes <lstoakes@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/drivers/platform/goldfish/goldfish_pipe.c b/drivers/platform/goldfish/goldfish_pipe.c
index 1aba2c74160e..2b21033f11f0 100644
--- a/drivers/platform/goldfish/goldfish_pipe.c
+++ b/drivers/platform/goldfish/goldfish_pipe.c
@@ -308,10 +308,8 @@ static ssize_t goldfish_pipe_read_write(struct file *filp, char __user *buffer,
 		 * returns a small amount, then there's no need to pin that
 		 * much memory to the process.
 		 */
-		down_read(&current->mm->mmap_sem);
-		ret = get_user_pages(address, 1, is_write ? 0 : FOLL_WRITE,
-				&page, NULL);
-		up_read(&current->mm->mmap_sem);
+		ret = get_user_pages_unlocked(address, 1, &page,
+				is_write ? 0 : FOLL_WRITE);
 		if (ret < 0)
 			break;