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Subject: [PATCH] scsi: ufs: Fix proper API to send HPB pre-request
Reply-To: daejun7.park@samsung.com
Sender: Daejun Park <daejun7.park@samsung.com>
From:   Daejun Park <daejun7.park@samsung.com>
To:     ALIM AKHTAR <alim.akhtar@samsung.com>,
        "avri.altman@wdc.com" <avri.altman@wdc.com>,
        "jejb@linux.ibm.com" <jejb@linux.ibm.com>,
        "martin.petersen@oracle.com" <martin.petersen@oracle.com>,
        Daejun Park <daejun7.park@samsung.com>,
        "huobean@gmail.com" <huobean@gmail.com>,
        "bvanassche@acm.org" <bvanassche@acm.org>,
        Keoseong Park <keosung.park@samsung.com>
CC:     "linux-scsi@vger.kernel.org" <linux-scsi@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Message-ID: <20211027223619epcms2p60bbc74c9ba9757c58709a99acd0892ff@epcms2p6>
Date:   Thu, 28 Oct 2021 07:36:19 +0900
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References: <CGME20211027223619epcms2p60bbc74c9ba9757c58709a99acd0892ff@epcms2p6>
Precedence: bulk

This patch addresses the issue of using the wrong API to create a
pre_request for HPB READ.
HPB READ candidate that require a pre-request will try to allocate a
pre-request only during request_timeout_ms (default: 0). Otherwise, it is
passed as normal READ, so deadlock problem can be resolved.

Signed-off-by: Daejun Park <daejun7.park@samsung.com>
---
 drivers/scsi/ufs/ufshpb.c | 11 +++++------
 drivers/scsi/ufs/ufshpb.h |  1 +
 2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/drivers/scsi/ufs/ufshpb.c b/drivers/scsi/ufs/ufshpb.c
index 02fb51ae8b25..3117bd47d762 100644
--- a/drivers/scsi/ufs/ufshpb.c
+++ b/drivers/scsi/ufs/ufshpb.c
@@ -548,8 +548,7 @@ static int ufshpb_execute_pre_req(struct ufshpb_lu *hpb, struct scsi_cmnd *cmd,
 				 read_id);
 	rq->cmd_len = scsi_command_size(rq->cmd);
 
-	if (blk_insert_cloned_request(q, req) != BLK_STS_OK)
-		return -EAGAIN;
+	blk_execute_rq_nowait(NULL, req, true, ufshpb_pre_req_compl_fn);
 
 	hpb->stats.pre_req_cnt++;
 
@@ -2315,19 +2314,19 @@ struct attribute_group ufs_sysfs_hpb_param_group = {
 static int ufshpb_pre_req_mempool_init(struct ufshpb_lu *hpb)
 {
 	struct ufshpb_req *pre_req = NULL, *t;
-	int qd = hpb->sdev_ufs_lu->queue_depth / 2;
 	int i;
 
 	INIT_LIST_HEAD(&hpb->lh_pre_req_free);
 
-	hpb->pre_req = kcalloc(qd, sizeof(struct ufshpb_req), GFP_KERNEL);
-	hpb->throttle_pre_req = qd;
+	hpb->pre_req = kcalloc(HPB_INFLIGHT_PRE_REQ, sizeof(struct ufshpb_req),
+			       GFP_KERNEL);
+	hpb->throttle_pre_req = HPB_INFLIGHT_PRE_REQ;
 	hpb->num_inflight_pre_req = 0;
 
 	if (!hpb->pre_req)
 		goto release_mem;
 
-	for (i = 0; i < qd; i++) {
+	for (i = 0; i < HPB_INFLIGHT_PRE_REQ; i++) {
 		pre_req = hpb->pre_req + i;
 		INIT_LIST_HEAD(&pre_req->list_req);
 		pre_req->req = NULL;
diff --git a/drivers/scsi/ufs/ufshpb.h b/drivers/scsi/ufs/ufshpb.h
index a79e07398970..411a6d625f53 100644
--- a/drivers/scsi/ufs/ufshpb.h
+++ b/drivers/scsi/ufs/ufshpb.h
@@ -50,6 +50,7 @@
 #define HPB_RESET_REQ_RETRIES			10
 #define HPB_MAP_REQ_RETRIES			5
 #define HPB_REQUEUE_TIME_MS			0
+#define HPB_INFLIGHT_PRE_REQ			4
 
 #define HPB_SUPPORT_VERSION			0x200
 #define HPB_SUPPORT_LEGACY_VERSION		0x100
-- 
2.25.1