dio: use get_user_pages_fast

Use get_user_pages_fast in the common/generic block and fs direct IO paths.

Signed-off-by: Nick Piggin <npiggin@suse.de>
Cc: Dave Kleikamp <shaggy@austin.ibm.com>
Cc: Andy Whitcroft <apw@shadowen.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Dave Kleikamp <shaggy@austin.ibm.com>
Cc: Badari Pulavarty <pbadari@us.ibm.com>
Cc: Zach Brown <zach.brown@oracle.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
Reviewed-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 2 insertions, 6 deletions

diff --git a/fs/bio.c b/fs/bio.c
index 88322b066acb..25f1af0d81e5 100644
--- a/fs/bio.c
+++ b/fs/bio.c
@@ -721,12 +721,8 @@ static struct bio *__bio_map_user_iov(struct request_queue *q,
                 const int local_nr_pages = end - start;
                 const int page_limit = cur_page + local_nr_pages;
                 
-                down_read(&current->mm->mmap_sem);
-                ret = get_user_pages(current, current->mm, uaddr,
-                                     local_nr_pages,
-                                     write_to_vm, 0, &pages[cur_page], NULL);
-                up_read(&current->mm->mmap_sem);
-
+                ret = get_user_pages_fast(uaddr, local_nr_pages,
+                                write_to_vm, &pages[cur_page]);
                 if (ret < local_nr_pages) {
                         ret = -EFAULT;
                         goto out_unmap;