[PATCH 09/15] scsi: add scsi_alloc_integrity_sgtables() for integrity process

[Jinyoung CHOI <j-young.choi@xxxxxxxxxxx>]

Separate the integrity mapping process of scsi_alloc_sgtables() into a
new function for readability.

Cc: Christoph Hellwig <hch@xxxxxx>
Cc: Martin K. Petersen <martin.petersen@xxxxxxxxxx>

Signed-off-by: Jinyoung Choi <j-young.choi@xxxxxxxxxxx>
---
 drivers/scsi/scsi_lib.c | 71 ++++++++++++++++++++++-------------------
 1 file changed, 38 insertions(+), 33 deletions(-)

diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index b7c569a42aa4..89cf21345e1a 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -1003,6 +1003,40 @@ static inline bool scsi_cmd_needs_dma_drain(struct scsi_device *sdev,
 	       sdev->host->hostt->dma_need_drain(rq);
 }
 
+static blk_status_t scsi_alloc_integrity_sgtables(struct scsi_cmnd *cmd)
+{
+	struct request *rq = scsi_cmd_to_rq(cmd);
+	struct scsi_data_buffer *prot_sdb = cmd->prot_sdb;
+	int count, ivecs;
+
+	if (WARN_ON_ONCE(!prot_sdb)) {
+		/*
+		 * This can happen if someone (e.g. multipath)
+		 * queues a command to a device on an adapter
+		 * that does not support DIX.
+		 */
+		return BLK_STS_IOERR;
+	}
+
+	ivecs = blk_rq_count_integrity_sg(rq->q, rq->bio);
+
+	if (sg_alloc_table_chained(&prot_sdb->table, ivecs,
+				   prot_sdb->table.sgl,
+				   SCSI_INLINE_PROT_SG_CNT)) {
+		return BLK_STS_RESOURCE;
+	}
+
+	count = blk_rq_map_integrity_sg(rq->q, rq->bio, prot_sdb->table.sgl);
+
+	BUG_ON(count > ivecs);
+	BUG_ON(count > queue_max_integrity_segments(rq->q));
+
+	cmd->prot_sdb = prot_sdb;
+	cmd->prot_sdb->table.nents = count;
+
+	return BLK_STS_OK;
+}
+
 /**
  * scsi_alloc_sgtables - Allocate and initialize data and integrity scatterlists
  * @cmd: SCSI command data structure to initialize.
@@ -1021,7 +1055,7 @@ blk_status_t scsi_alloc_sgtables(struct scsi_cmnd *cmd)
 	struct request *rq = scsi_cmd_to_rq(cmd);
 	unsigned short nr_segs = blk_rq_nr_phys_segments(rq);
 	struct scatterlist *last_sg = NULL;
-	blk_status_t ret;
+	blk_status_t ret = BLK_STS_OK;
 	bool need_drain = scsi_cmd_needs_dma_drain(sdev, rq);
 	int count;
 
@@ -1071,40 +1105,11 @@ blk_status_t scsi_alloc_sgtables(struct scsi_cmnd *cmd)
 	cmd->sdb.length = blk_rq_payload_bytes(rq);
 
 	if (blk_integrity_rq(rq)) {
-		struct scsi_data_buffer *prot_sdb = cmd->prot_sdb;
-		int ivecs;
-
-		if (WARN_ON_ONCE(!prot_sdb)) {
-			/*
-			 * This can happen if someone (e.g. multipath)
-			 * queues a command to a device on an adapter
-			 * that does not support DIX.
-			 */
-			ret = BLK_STS_IOERR;
-			goto out_free_sgtables;
-		}
-
-		ivecs = blk_rq_count_integrity_sg(rq->q, rq->bio);
-
-		if (sg_alloc_table_chained(&prot_sdb->table, ivecs,
-				prot_sdb->table.sgl,
-				SCSI_INLINE_PROT_SG_CNT)) {
-			ret = BLK_STS_RESOURCE;
-			goto out_free_sgtables;
-		}
-
-		count = blk_rq_map_integrity_sg(rq->q, rq->bio,
-						prot_sdb->table.sgl);
-		BUG_ON(count > ivecs);
-		BUG_ON(count > queue_max_integrity_segments(rq->q));
-
-		cmd->prot_sdb = prot_sdb;
-		cmd->prot_sdb->table.nents = count;
+		ret = scsi_alloc_integrity_sgtables(cmd);
+		if (ret != BLK_STS_OK)
+			scsi_free_sgtables(cmd);
 	}
 
-	return BLK_STS_OK;
-out_free_sgtables:
-	scsi_free_sgtables(cmd);
 	return ret;
 }
 EXPORT_SYMBOL(scsi_alloc_sgtables);
-- 
2.34.1