[PATCH 2/5] block: move .dma_alignment into q->limits

[Ming Lei]

Turns out q->dma_alignement should be stack limit because now bvec table
is immutalbe, the underlying queue's dma alignment has to be perceptible
by stack driver, so IO buffer can be allocated as dma aligned before
adding to bio.

So this patch moves .dma_alignment into q->limits and prepares for
making it as one stacked limit.

Cc: Vitaly Kuznetsov <vkuzn...@redhat.com>
Cc: Dave Chinner <dchin...@redhat.com>
Cc: Linux FS Devel <linux-fsde...@vger.kernel.org>
Cc: Darrick J. Wong <darrick.w...@oracle.com>
Cc: x...@vger.kernel.org
Cc: Dave Chinner <dchin...@redhat.com>
Cc: Christoph Hellwig <h...@lst.de>
Cc: Bart Van Assche <bvanass...@acm.org>
Cc: Matthew Wilcox <wi...@infradead.org>
Signed-off-by: Ming Lei <ming....@redhat.com>
---
 block/blk-settings.c   | 6 +++---
 include/linux/blkdev.h | 4 ++--
 2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/block/blk-settings.c b/block/blk-settings.c
index ffd459969689..cf9cd241dc16 100644
--- a/block/blk-settings.c
+++ b/block/blk-settings.c
@@ -830,7 +830,7 @@ EXPORT_SYMBOL(blk_queue_virt_boundary);
  **/
 void blk_queue_dma_alignment(struct request_queue *q, int mask)
 {
-       q->dma_alignment = mask;
+       q->limits.dma_alignment = mask;
 }
 EXPORT_SYMBOL(blk_queue_dma_alignment);
 
@@ -852,8 +852,8 @@ void blk_queue_update_dma_alignment(struct request_queue 
*q, int mask)
 {
        BUG_ON(mask > PAGE_SIZE);
 
-       if (mask > q->dma_alignment)
-               q->dma_alignment = mask;
+       if (mask > q->limits.dma_alignment)
+               q->limits.dma_alignment = mask;
 }
 EXPORT_SYMBOL(blk_queue_update_dma_alignment);
 
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 61207560e826..be938a31bc2e 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -366,6 +366,7 @@ struct queue_limits {
        unsigned long           seg_boundary_mask;
        unsigned long           virt_boundary_mask;
 
+       unsigned int            dma_alignment;
        unsigned int            max_hw_sectors;
        unsigned int            max_dev_sectors;
        unsigned int            chunk_sectors;
@@ -561,7 +562,6 @@ struct request_queue {
        unsigned int            dma_drain_size;
        void                    *dma_drain_buffer;
        unsigned int            dma_pad_mask;
-       unsigned int            dma_alignment;
 
        struct blk_queue_tag    *queue_tags;
 
@@ -1617,7 +1617,7 @@ static inline unsigned int bdev_zone_sectors(struct 
block_device *bdev)
 
 static inline int queue_dma_alignment(struct request_queue *q)
 {
-       return q ? q->dma_alignment : 511;
+       return q ? q->limits.dma_alignment : 511;
 }
 
 static inline int blk_rq_aligned(struct request_queue *q, unsigned long addr,
-- 
2.9.5