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| author | FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> | 2008-07-04 09:31:11 +0200 |
|---|---|---|
| committer | Jens Axboe <jens.axboe@oracle.com> | 2008-07-04 09:52:13 +0200 |
| commit | 30c00eda73d5db5bd64dd0c370161abd8df5ba4a (patch) | |
| tree | 87b5a34323eb98edf504e51b2d8e0291559579e3 | |
| parent | 27f8221af406e43b529a5425bc99c9b1e9bdf521 (diff) | |
| download | linux-30c00eda73d5db5bd64dd0c370161abd8df5ba4a.tar.bz2 | |
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>
| -rw-r--r-- | block/blk-map.c | 5 |
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 |