[PATCH 5/5] block: move dma_pad handling from blk_rq_map_sg into the callers

Christoph Hellwig
2020-04-14T07:43:02Z

There are only two callers of blk_rq_map_sg/__blk_rq_map_sg that set
the dma_pad value in the queue. Move the handling into those callers
instead of burdening the common code, and move the ->extra_len field
from struct request to struct scsi_cmnd.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
block/blk-core.c | 1 -
block/blk-merge.c | 8 --------
block/blk-mq.c | 1 -
drivers/ata/libata-scsi.c | 2 +-
drivers/ide/ide-io.c | 7 +++++--
drivers/scsi/scsi_lib.c | 10 +++++++++-
include/linux/blkdev.h | 2 --
include/scsi/scsi_cmnd.h | 1 +
8 files changed, 16 insertions(+), 16 deletions(-)

diff --git a/block/blk-core.c b/block/blk-core.c
index 7e4a1da0715e..311596d5dbc4 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -1638,7 +1638,6 @@ int blk_rq_prep_clone(struct request *rq, struct request *rq_src,
}
rq->nr_phys_segments = rq_src->nr_phys_segments;
rq->ioprio = rq_src->ioprio;
- rq->extra_len = rq_src->extra_len;

return 0;

diff --git a/block/blk-merge.c b/block/blk-merge.c
index 25f5a5e00ee6..c49eb3bdd0be 100644
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -531,14 +531,6 @@ int __blk_rq_map_sg(struct request_queue *q, struct request *rq,
else if (rq->bio)
nsegs = __blk_bios_map_sg(q, rq->bio, sglist, last_sg);

- if (blk_rq_bytes(rq) && (blk_rq_bytes(rq) & q->dma_pad_mask)) {
- unsigned int pad_len =
- (q->dma_pad_mask & ~blk_rq_bytes(rq)) + 1;
-
- (*last_sg)->length += pad_len;
- rq->extra_len += pad_len;
- }
-
if (*last_sg)
sg_mark_end(*last_sg);

diff --git a/block/blk-mq.c b/block/blk-mq.c
index 28ad7e1e850b..983773214ee3 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -318,7 +318,6 @@ static struct request *blk_mq_rq_ctx_init(struct blk_mq_alloc_data *data,
rq->nr_integrity_segments = 0;
#endif
/* tag was already set */
- rq->extra_len = 0;
WRITE_ONCE(rq->deadline, 0);

rq->timeout = 0;
diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
index feb13b8f93d7..435781a16875 100644
--- a/drivers/ata/libata-scsi.c
+++ b/drivers/ata/libata-scsi.c
@@ -649,7 +649,7 @@ static void ata_qc_set_pc_nbytes(struct ata_queued_cmd *qc)
{
struct scsi_cmnd *scmd = qc->scsicmd;

- qc->extrabytes = scmd->request->extra_len;
+ qc->extrabytes = scmd->extra_len;
qc->nbytes = scsi_bufflen(scmd) + qc->extrabytes;
}

diff --git a/drivers/ide/ide-io.c b/drivers/ide/ide-io.c
index b137f27a34d5..c31f1d2b3b07 100644
--- a/drivers/ide/ide-io.c
+++ b/drivers/ide/ide-io.c
@@ -233,10 +233,13 @@ static ide_startstop_t do_special(ide_drive_t *drive)
void ide_map_sg(ide_drive_t *drive, struct ide_cmd *cmd)
{
ide_hwif_t *hwif = drive->hwif;
- struct scatterlist *sg = hwif->sg_table;
+ struct scatterlist *sg = hwif->sg_table, *last_sg = NULL;
struct request *rq = cmd->rq;

- cmd->sg_nents = blk_rq_map_sg(drive->queue, rq, sg);
+ cmd->sg_nents = __blk_rq_map_sg(drive->queue, rq, sg, &last_sg);
+ if (blk_rq_bytes(rq) && (blk_rq_bytes(rq) & rq->q->dma_pad_mask))
+ last_sg->length +=
+ (rq->q->dma_pad_mask & ~blk_rq_bytes(rq)) + 1;
}
EXPORT_SYMBOL_GPL(ide_map_sg);

diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index b561c6dbda6b..8396b9f56dc7 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -1030,13 +1030,21 @@ blk_status_t scsi_init_io(struct scsi_cmnd *cmd)
*/
count = __blk_rq_map_sg(rq->q, rq, cmd->sdb.table.sgl, &last_sg);

+ if (blk_rq_bytes(rq) & rq->q->dma_pad_mask) {
+ unsigned int pad_len =
+ (rq->q->dma_pad_mask & ~blk_rq_bytes(rq)) + 1;
+
+ last_sg->length += pad_len;
+ cmd->extra_len += pad_len;
+ }
+
if (need_drain) {
sg_unmark_end(last_sg);
last_sg = sg_next(last_sg);
sg_set_buf(last_sg, sdev->dma_drain_buf, sdev->dma_drain_len);
sg_mark_end(last_sg);

- rq->extra_len += sdev->dma_drain_len;
+ cmd->extra_len += sdev->dma_drain_len;
count++;
}

diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 8e4726bce498..f00bd4042295 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -224,8 +224,6 @@ struct request {
unsigned short write_hint;
unsigned short ioprio;

- unsigned int extra_len; /* length of alignment and padding */
-
enum mq_rq_state state;
refcount_t ref;

diff --git a/include/scsi/scsi_cmnd.h b/include/scsi/scsi_cmnd.h
index 80ac89e47b47..f93c0b800790 100644
--- a/include/scsi/scsi_cmnd.h
+++ b/include/scsi/scsi_cmnd.h
@@ -142,6 +142,7 @@ struct scsi_cmnd {
unsigned long state; /* Command completion state */

unsigned char tag; /* SCSI-II queued command tag */
+ unsigned int extra_len; /* length of alignment and padding */
};

/*
--
2.25.1