From 27f8221af406e43b529a5425bc99c9b1e9bdf521 Mon Sep 17 00:00:00 2001 From: FUJITA Tomonori Date: Fri, 4 Jul 2008 09:30:03 +0200 Subject: 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 Cc: Tejun Heo Cc: Bartlomiej Zolnierkiewicz Cc: Thomas Bogendoerfer Cc: James Bottomley Signed-off-by: Andrew Morton Signed-off-by: Jens Axboe --- block/blk-settings.c | 24 ++++++++++++++++++++---- 1 file changed, 20 insertions(+), 4 deletions(-) (limited to 'block') diff --git a/block/blk-settings.c b/block/blk-settings.c index 8dd8641..dfc7701 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 -- cgit v1.1