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From: Christoph Hellwig <hch@lst.de>
To: tj@kernel.org, martin.petersen@oracle.com, axboe@kernel.dk
Cc: linux-ide@vger.kernel.org, linux-scsi@vger.kernel.org,
	linux-block@vger.kernel.org
Subject: [PATCH 7/7] sd: use ZERO_PAGE for WRITE_SAME payloads
Date: Mon, 20 Mar 2017 16:43:19 -0400	[thread overview]
Message-ID: <20170320204319.12628-8-hch@lst.de> (raw)
In-Reply-To: <20170320204319.12628-1-hch@lst.de>

We're never touching the contents of the page, so save a memory
allocation for these cases.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 drivers/scsi/sd.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index c18fe9ff1f8f..af632e350ab4 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -756,7 +756,7 @@ static int sd_setup_write_same16_cmnd(struct scsi_cmnd *cmd)
 	u32 nr_sectors = blk_rq_sectors(rq) >> (ilog2(sdp->sector_size) - 9);
 	u32 data_len = sdp->sector_size;
 
-	rq->special_vec.bv_page = alloc_page(GFP_ATOMIC | __GFP_ZERO);
+	rq->special_vec.bv_page = ZERO_PAGE(0);
 	if (!rq->special_vec.bv_page)
 		return BLKPREP_DEFER;
 	rq->special_vec.bv_offset = 0;
@@ -785,7 +785,7 @@ static int sd_setup_write_same10_cmnd(struct scsi_cmnd *cmd, bool unmap)
 	u32 nr_sectors = blk_rq_sectors(rq) >> (ilog2(sdp->sector_size) - 9);
 	u32 data_len = sdp->sector_size;
 
-	rq->special_vec.bv_page = alloc_page(GFP_ATOMIC | __GFP_ZERO);
+	rq->special_vec.bv_page = ZERO_PAGE(0);
 	if (!rq->special_vec.bv_page)
 		return BLKPREP_DEFER;
 	rq->special_vec.bv_offset = 0;
@@ -1256,7 +1256,8 @@ static void sd_uninit_command(struct scsi_cmnd *SCpnt)
 {
 	struct request *rq = SCpnt->request;
 
-	if (rq->rq_flags & RQF_SPECIAL_PAYLOAD)
+	if ((rq->rq_flags & RQF_SPECIAL_PAYLOAD) &&
+	    rq->special_vec.bv_page != ZERO_PAGE(0))
 		__free_page(rq->special_vec.bv_page);
 
 	if (SCpnt->cmnd != scsi_req(rq)->cmd) {
-- 
2.11.0

  parent reply	other threads:[~2017-03-20 20:43 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-03-20 20:43 support ranges TRIM for libata Christoph Hellwig
2017-03-20 20:43 ` [PATCH 1/7] ѕd: split sd_setup_discard_cmnd Christoph Hellwig
2017-03-27 22:24   ` Bart Van Assche
2017-03-27 22:24     ` Bart Van Assche
2017-03-28 14:05     ` axboe
2017-03-30  8:49       ` hch
2017-03-20 20:43 ` [PATCH 2/7] sd: provide a new ata trim provisioning mode Christoph Hellwig
2017-03-27 22:40   ` Bart Van Assche
2017-03-27 22:40     ` Bart Van Assche
2017-03-20 20:43 ` [PATCH 3/7] libata: remove SCT WRITE SAME support Christoph Hellwig
2017-03-20 20:43 ` [PATCH 4/7] libata: simplify the trim implementation Christoph Hellwig
2017-03-20 20:43 ` [PATCH 5/7] block: add a max_discard_segment_size queue limit Christoph Hellwig
2017-03-27 23:09   ` Bart Van Assche
2017-03-27 23:09     ` Bart Van Assche
2017-03-20 20:43 ` [PATCH 6/7] sd: support multi-range TRIM for ATA disks Christoph Hellwig
2017-03-27 23:38   ` Bart Van Assche
2017-03-27 23:38     ` Bart Van Assche
2017-03-20 20:43 ` Christoph Hellwig [this message]
2017-03-27 23:40   ` [PATCH 7/7] sd: use ZERO_PAGE for WRITE_SAME payloads Bart Van Assche
2017-03-27 23:40     ` Bart Van Assche
2017-03-21 18:59 ` support ranges TRIM for libata Tejun Heo
2017-03-22 18:19   ` Christoph Hellwig
2017-03-23 13:47     ` James Bottomley
2017-03-23 13:55       ` Christoph Hellwig
2017-03-23 14:35         ` James Bottomley
2017-03-23 14:43           ` Christoph Hellwig
2017-03-23 15:04             ` Tejun Heo
2017-03-23 15:27               ` Christoph Hellwig
2017-03-23 15:30             ` Christoph Hellwig
2017-03-23 15:39               ` Martin K. Petersen

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