block/blk-map.c: use the new object_is_on_stack() helper

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Tejun Heo <htejun@gmail.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
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/block/blk-map.c b/block/blk-map.c
index ddd96fb11a7d..af37e4ae62f5 100644
--- a/block/blk-map.c
+++ b/block/blk-map.c
@@ -269,7 +269,6 @@ int blk_rq_map_kern(struct request_queue *q, struct request *rq, void *kbuf,
         int reading = rq_data_dir(rq) == READ;
         int do_copy = 0;
         struct bio *bio;
-        unsigned long stack_mask = ~(THREAD_SIZE - 1);
 
         if (len > (q->max_hw_sectors << 9))
                 return -EINVAL;
@@ -278,11 +277,8 @@ int blk_rq_map_kern(struct request_queue *q, struct request *rq, void *kbuf,
 
         kaddr = (unsigned long)kbuf;
         alignment = queue_dma_alignment(q) | q->dma_pad_mask;
-        do_copy = ((kaddr & alignment) || (len & alignment));
-
-        if (!((kaddr & stack_mask) ^
-              ((unsigned long)current->stack & stack_mask)))
-                do_copy = 1;
+        do_copy = ((kaddr & alignment) || (len & alignment) ||
+                   object_is_on_stack(kbuf));
 
         if (do_copy)
                 bio = bio_copy_kern(q, kbuf, len, gfp_mask, reading);