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[14/16] block: use memcpy_from_bvec in __blk_queue_bounce

Message ID 20210608160603.1535935-15-hch@lst.de
State Superseded
Headers show
Series [01/16] mm: use kmap_local_page in memzero_page | expand

Commit Message

Christoph Hellwig June 8, 2021, 4:06 p.m. UTC
Rewrite the actual bounce buffering loop in __blk_queue_bounce to that
the memcpy_to_bvec helper can be used to perform the data copies.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 block/bounce.c | 21 +++++++--------------
 1 file changed, 7 insertions(+), 14 deletions(-)

Comments

Ira Weiny June 9, 2021, 1:58 a.m. UTC | #1
On Tue, Jun 08, 2021 at 06:06:01PM +0200, Christoph Hellwig wrote:
> Rewrite the actual bounce buffering loop in __blk_queue_bounce to that

> the memcpy_to_bvec helper can be used to perform the data copies.

> 

> Signed-off-by: Christoph Hellwig <hch@lst.de>

> ---

>  block/bounce.c | 21 +++++++--------------

>  1 file changed, 7 insertions(+), 14 deletions(-)

> 

> diff --git a/block/bounce.c b/block/bounce.c

> index a2fc6326b6c9..b5ad09e07bcf 100644

> --- a/block/bounce.c

> +++ b/block/bounce.c

> @@ -243,24 +243,17 @@ void __blk_queue_bounce(struct request_queue *q, struct bio **bio_orig)

>  	 * because the 'bio' is single-page bvec.

>  	 */

>  	for (i = 0, to = bio->bi_io_vec; i < bio->bi_vcnt; to++, i++) {

> -		struct page *page = to->bv_page;

> +		struct page *bounce_page;

>  

> -		if (!PageHighMem(page))

> +		if (!PageHighMem(to->bv_page))

>  			continue;

>  

> -		to->bv_page = mempool_alloc(&page_pool, GFP_NOIO);

> -		inc_zone_page_state(to->bv_page, NR_BOUNCE);

> +		bounce_page = mempool_alloc(&page_pool, GFP_NOIO);

> +		inc_zone_page_state(bounce_page, NR_BOUNCE);

>  

> -		if (rw == WRITE) {

> -			char *vto, *vfrom;

> -

> -			flush_dcache_page(page);

> -

> -			vto = page_address(to->bv_page) + to->bv_offset;

> -			vfrom = kmap_atomic(page) + to->bv_offset;

> -			memcpy(vto, vfrom, to->bv_len);

> -			kunmap_atomic(vfrom);

> -		}

> +		if (rw == WRITE)

> +			memcpy_from_bvec(page_address(bounce_page), to);


NIT: the fact that the copy is from 'to' makes my head hurt...  But I don't
see a good way to change that without declaring unnecessary variables...  :-(

The logic seems right.

Ira

> +		to->bv_page = bounce_page;

>  	}

>  

>  	trace_block_bio_bounce(*bio_orig);

> -- 

> 2.30.2

>
diff mbox series

Patch

diff --git a/block/bounce.c b/block/bounce.c
index a2fc6326b6c9..b5ad09e07bcf 100644
--- a/block/bounce.c
+++ b/block/bounce.c
@@ -243,24 +243,17 @@  void __blk_queue_bounce(struct request_queue *q, struct bio **bio_orig)
 	 * because the 'bio' is single-page bvec.
 	 */
 	for (i = 0, to = bio->bi_io_vec; i < bio->bi_vcnt; to++, i++) {
-		struct page *page = to->bv_page;
+		struct page *bounce_page;
 
-		if (!PageHighMem(page))
+		if (!PageHighMem(to->bv_page))
 			continue;
 
-		to->bv_page = mempool_alloc(&page_pool, GFP_NOIO);
-		inc_zone_page_state(to->bv_page, NR_BOUNCE);
+		bounce_page = mempool_alloc(&page_pool, GFP_NOIO);
+		inc_zone_page_state(bounce_page, NR_BOUNCE);
 
-		if (rw == WRITE) {
-			char *vto, *vfrom;
-
-			flush_dcache_page(page);
-
-			vto = page_address(to->bv_page) + to->bv_offset;
-			vfrom = kmap_atomic(page) + to->bv_offset;
-			memcpy(vto, vfrom, to->bv_len);
-			kunmap_atomic(vfrom);
-		}
+		if (rw == WRITE)
+			memcpy_from_bvec(page_address(bounce_page), to);
+		to->bv_page = bounce_page;
 	}
 
 	trace_block_bio_bounce(*bio_orig);