[PATCH 49/97] callers of iov_copy_from_user_atomic() don't need pagecache_disable()

[Mel Gorman]

From: Al Viro <v...@zeniv.linux.org.uk>

commit 9e8c2af96e0d2d5fe298dd796fb6bc16e888a48d upstream.

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

Signed-off-by: Al Viro <v...@zeniv.linux.org.uk>
Signed-off-by: Mel Gorman <mgor...@suse.de>
---
 fs/btrfs/file.c | 5 -----
 fs/fuse/file.c  | 2 --
 mm/filemap.c    | 3 ---
 3 files changed, 10 deletions(-)

diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index 72da4df..9952a2a 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -426,13 +426,8 @@ 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 4598345..bf9a755 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -985,9 +985,7 @@ 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 d0f765f..8144c27 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -2190,7 +2190,6 @@ 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;
@@ -2564,9 +2563,7 @@ 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);
-- 
1.8.4.5

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