From: Al Viro <viro@zeniv.linux.org.uk>
Date: Mon, 3 Feb 2014 03:10:25 +0000 (-0500)
Subject: callers of iov_copy_from_user_atomic() don't need pagecache_disable()
X-Git-Tag: upstream/snapshot3+hdmi~17^2~18
X-Git-Url: http://review.tizen.org/git/?p=platform%2Fadaptation%2Frenesas_rcar%2Frenesas_kernel.git;a=commitdiff_plain;h=9fb77c771373c078f93807f077c29ebafe720a25

callers of iov_copy_from_user_atomic() don't need pagecache_disable()

commit 9e8c2af96e0d2d5fe298dd796fb6bc16e888a48d upstream.

... it does that itself (via kmap_atomic())

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Mel Gorman <mgorman@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index a9a881e..f6d00df 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -425,13 +425,8 @@ static noinline int btrfs_copy_from_user(loff_t pos, int num_pages,
 		struct page *page = prepared_pages[pg];
 		/*
 		 * Copy data from userspace to the current page
-		 *
-		 * Disable pagefault to avoid recursive lock since
-		 * the pages are already locked
 		 */
-		pagefault_disable();
 		copied = iov_iter_copy_from_user_atomic(page, i, offset, count);
-		pagefault_enable();
 
 		/* Flush processor's dcache for this page */
 		flush_dcache_page(page);
diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index 77bcc30..a91d3b4 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -1003,9 +1003,7 @@ static ssize_t fuse_fill_write_pages(struct fuse_req *req,
 		if (mapping_writably_mapped(mapping))
 			flush_dcache_page(page);
 
-		pagefault_disable();
 		tmp = iov_iter_copy_from_user_atomic(page, ii, offset, bytes);
-		pagefault_enable();
 		flush_dcache_page(page);
 
 		mark_page_accessed(page);
diff --git a/mm/filemap.c b/mm/filemap.c
index f287e25..bdaa215 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -2188,7 +2188,6 @@ size_t iov_iter_copy_from_user_atomic(struct page *page,
 	char *kaddr;
 	size_t copied;
 
-	BUG_ON(!in_atomic());
 	kaddr = kmap_atomic(page);
 	if (likely(i->nr_segs == 1)) {
 		int left;
@@ -2562,9 +2561,7 @@ again:
 		if (mapping_writably_mapped(mapping))
 			flush_dcache_page(page);
 
-		pagefault_disable();
 		copied = iov_iter_copy_from_user_atomic(page, i, offset, bytes);
-		pagefault_enable();
 		flush_dcache_page(page);
 
 		mark_page_accessed(page);