linux-kernel - [PATCH v2 3/4] scsi: ufs: Let command trace only for the cmd != null case

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Message-Id: <20210531104308.391842-4-huobean@gmail.com>
Date:   Mon, 31 May 2021 12:43:07 +0200
From:   Bean Huo <huobean@...il.com>
To:     alim.akhtar@...sung.com, avri.altman@....com,
        asutoshd@...eaurora.org, jejb@...ux.ibm.com,
        martin.petersen@...cle.com, stanley.chu@...iatek.com,
        beanhuo@...ron.com, bvanassche@....org, tomas.winkler@...el.com,
        cang@...eaurora.org
Cc:     linux-scsi@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH v2 3/4] scsi: ufs: Let command trace only for the cmd != null case

From: Bean Huo <beanhuo@...ron.com>

For the query request, we already have query_trace, but in
ufshcd_send_command (), there will add two more redundant
traces. Since lrbp->cmd is null in the query request, the
below these two trace events provide nothing except the tag
and DB. Instead of letting them take up the limited trace
ring buffer, it’s better not to print these traces in case
of cmd == null.

ufshcd_command: send_req: ff3b0000.ufs: tag: 28, DB: 0x0, size: -1, IS: 0, LBA: 18446744073709551615, opcode: 0x0 (0x0), group_id: 0x0
ufshcd_command: dev_complete: ff3b0000.ufs: tag: 28, DB: 0x0, size: -1, IS: 0, LBA: 18446744073709551615, opcode: 0x0 (0x0), group_id: 0x0

Signed-off-by: Bean Huo <beanhuo@...ron.com>
---
 drivers/scsi/ufs/ufshcd.c | 44 +++++++++++++++++++--------------------
 1 file changed, 21 insertions(+), 23 deletions(-)

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index c5754d5486c9..c84bd8e045f6 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -378,35 +378,33 @@ static void ufshcd_add_command_trace(struct ufs_hba *hba, unsigned int tag,
 	struct scsi_cmnd *cmd = lrbp->cmd;
 	int transfer_len = -1;
 
+	if (!cmd)
+		return;
+
 	if (!trace_ufshcd_command_enabled()) {
 		/* trace UPIU W/O tracing command */
-		if (cmd)
-			ufshcd_add_cmd_upiu_trace(hba, tag, str_t);
+		ufshcd_add_cmd_upiu_trace(hba, tag, str_t);
 		return;
 	}
 
-	if (cmd) { /* data phase exists */
-		/* trace UPIU also */
-		ufshcd_add_cmd_upiu_trace(hba, tag, str_t);
-		opcode = cmd->cmnd[0];
-		lba = sectors_to_logical(cmd->device, blk_rq_pos(cmd->request));
+	/* trace UPIU also */
+	ufshcd_add_cmd_upiu_trace(hba, tag, str_t);
+	opcode = cmd->cmnd[0];
+	lba = sectors_to_logical(cmd->device, blk_rq_pos(cmd->request));
 
-		if ((opcode == READ_10) || (opcode == WRITE_10)) {
-			/*
-			 * Currently we only fully trace read(10) and write(10)
-			 * commands
-			 */
-			transfer_len = be32_to_cpu(
-				lrbp->ucd_req_ptr->sc.exp_data_transfer_len);
-			if (opcode == WRITE_10)
-				group_id = lrbp->cmd->cmnd[6];
-		} else if (opcode == UNMAP) {
-			/*
-			 * The number of Bytes to be unmapped beginning with the
-			 * lba.
-			 */
-			transfer_len = blk_rq_bytes(cmd->request);
-		}
+	if (opcode == READ_10 || opcode == WRITE_10) {
+		/*
+		 * Currently we only fully trace read(10) and write(10) commands
+		 */
+		transfer_len =
+		       be32_to_cpu(lrbp->ucd_req_ptr->sc.exp_data_transfer_len);
+		if (opcode == WRITE_10)
+			group_id = lrbp->cmd->cmnd[6];
+	} else if (opcode == UNMAP) {
+		/*
+		 * The number of Bytes to be unmapped beginning with the lba.
+		 */
+		transfer_len = blk_rq_bytes(cmd->request);
 	}
 
 	intr = ufshcd_readl(hba, REG_INTERRUPT_STATUS);
-- 
2.25.1