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| author | FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> | 2008-07-04 09:30:03 +0200 |
|---|---|---|
| committer | Jens Axboe <jens.axboe@oracle.com> | 2008-07-04 09:52:13 +0200 |
| commit | 27f8221af406e43b529a5425bc99c9b1e9bdf521 (patch) | |
| tree | 6e847b9359327449b77d4b6350cc9d44fd9208b6 /block | |
| parent | 2610324fcacf38a24b630090ebcb802538763187 (diff) | |
| download | linux-27f8221af406e43b529a5425bc99c9b1e9bdf521.tar.gz linux-27f8221af406e43b529a5425bc99c9b1e9bdf521.tar.bz2 linux-27f8221af406e43b529a5425bc99c9b1e9bdf521.zip | |
block: add blk_queue_update_dma_pad
This adds blk_queue_update_dma_pad to prevent LLDs from overwriting
the dma pad mask wrongly (we added blk_queue_update_dma_alignment due
to the same reason).
This also converts libata to use blk_queue_update_dma_pad instead of
blk_queue_dma_pad.
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: Tejun Heo <htejun@gmail.com>
Cc: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
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')
| -rw-r--r-- | block/blk-settings.c | 24 |
1 files changed, 20 insertions, 4 deletions
diff --git a/block/blk-settings.c b/block/blk-settings.c index 8dd86418f35d..dfc77012843f 100644 --- a/block/blk-settings.c +++ b/block/blk-settings.c @@ -302,11 +302,10 @@ EXPORT_SYMBOL(blk_queue_stack_limits); * @q: the request queue for the device * @mask: pad mask * - * Set pad mask. Direct IO requests are padded to the mask specified. + * Set dma pad mask. * - * Appending pad buffer to a request modifies ->data_len such that it - * includes the pad buffer. The original requested data length can be - * obtained using blk_rq_raw_data_len(). + * Appending pad buffer to a request modifies the last entry of a + * scatter list such that it includes the pad buffer. **/ void blk_queue_dma_pad(struct request_queue *q, unsigned int mask) { @@ -315,6 +314,23 @@ void blk_queue_dma_pad(struct request_queue *q, unsigned int mask) EXPORT_SYMBOL(blk_queue_dma_pad); /** + * blk_queue_update_dma_pad - update pad mask + * @q: the request queue for the device + * @mask: pad mask + * + * Update dma pad mask. + * + * Appending pad buffer to a request modifies the last entry of a + * scatter list such that it includes the pad buffer. + **/ +void blk_queue_update_dma_pad(struct request_queue *q, unsigned int mask) +{ + if (mask > q->dma_pad_mask) + q->dma_pad_mask = mask; +} +EXPORT_SYMBOL(blk_queue_update_dma_pad); + +/** * blk_queue_dma_drain - Set up a drain buffer for excess dma. * @q: the request queue for the device * @dma_drain_needed: fn which returns non-zero if drain is necessary |