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authorFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>2008-07-04 09:31:11 +0200
committerJens Axboe <jens.axboe@oracle.com>2008-07-04 09:52:13 +0200
commit30c00eda73d5db5bd64dd0c370161abd8df5ba4a (patch)
tree87b5a34323eb98edf504e51b2d8e0291559579e3 /block/blk-map.c
parent27f8221af406e43b529a5425bc99c9b1e9bdf521 (diff)
downloadkernel-30c00eda73d5db5bd64dd0c370161abd8df5ba4a.tar.gz
block: blk_rq_map_kern uses the bounce buffers for stack buffers
blk_rq_map_kern is used for kernel internal I/Os. Some callers use this function with stack buffers but DMA to/from the stack buffers leads to memory corruption on a non-coherent platform. This patch make blk_rq_map_kern uses the bounce buffers if a caller passes a stack buffer (on the all platforms for simplicity). 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: James Bottomley <James.Bottomley@HansenPartnership.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Diffstat (limited to 'block/blk-map.c')
-rw-r--r--block/blk-map.c5
1 files changed, 5 insertions, 0 deletions
diff --git a/block/blk-map.c b/block/blk-map.c
index 813011ef8276..ddd96fb11a7d 100644
--- a/block/blk-map.c
+++ b/block/blk-map.c
@@ -269,6 +269,7 @@ 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;
@@ -279,6 +280,10 @@ int blk_rq_map_kern(struct request_queue *q, struct request *rq, void *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;
+
if (do_copy)
bio = bio_copy_kern(q, kbuf, len, gfp_mask, reading);
else