[PATCH 05/43] qla2xxx: Add boundary checks for exchanges to be offloaded

From: Himanshu Madhani <himanshu.madhani@cavium.com>
To: James.Bottomley@HansenPartnership.com, martin.petersen@oracle.com
Cc: himanshu.madhani@cavium.com, linux-scsi@vger.kernel.org
Subject: [PATCH 05/43] qla2xxx: Add boundary checks for exchanges to be offloaded
Date: Tue, 19 Dec 2017 22:56:06 -0800	[thread overview]
Message-ID: <20171220065644.21511-6-himanshu.madhani@cavium.com> (raw)
In-Reply-To: <20171220065644.21511-1-himanshu.madhani@cavium.com>

From: Quinn Tran <quinn.tran@cavium.com>

Max boundary for exchange off load is 32k exchanges. If system
is unable to allocate large memory buffer to support this feature,
then driver will reduce the number exchanges down to a value
system can support.

Signed-off-by: Quinn Tran <quinn.tran@cavium.com>
Signed-off-by: Himanshu Madhani <himanshu.madhani@cavium.com>
---
 drivers/scsi/qla2xxx/qla_def.h |  3 +++
 drivers/scsi/qla2xxx/qla_os.c  | 39 ++++++++++++++++++++++++++++++---------
 2 files changed, 33 insertions(+), 9 deletions(-)

diff --git a/drivers/scsi/qla2xxx/qla_def.h b/drivers/scsi/qla2xxx/qla_def.h
index 50a570595969..ca3ef9360ab9 100644
--- a/drivers/scsi/qla2xxx/qla_def.h
+++ b/drivers/scsi/qla2xxx/qla_def.h
@@ -288,6 +288,8 @@ struct name_list_extended {
 #define ATIO_ENTRY_CNT_24XX		4096	/* Number of ATIO entries. */
 #define RESPONSE_ENTRY_CNT_FX00		256     /* Number of response entries.*/
 #define FW_DEF_EXCHANGES_CNT 2048
+#define FW_MAX_EXCHANGES_CNT (32 * 1024)
+#define REDUCE_EXCHANGES_CNT  (8 * 1024)
 
 struct req_que;
 struct qla_tgt_sess;
@@ -3542,6 +3544,7 @@ struct qla_hw_data {
 		uint32_t	using_lr_setting:1;
 	} flags;
 
+	uint16_t max_exchg;
 	uint16_t long_range_distance;	/* 32G & above */
 #define LR_DISTANCE_5K  1
 #define LR_DISTANCE_10K 0
diff --git a/drivers/scsi/qla2xxx/qla_os.c b/drivers/scsi/qla2xxx/qla_os.c
index 987bade1c606..029b95b2bd8a 100644
--- a/drivers/scsi/qla2xxx/qla_os.c
+++ b/drivers/scsi/qla2xxx/qla_os.c
@@ -2789,6 +2789,7 @@ qla2x00_probe_one(struct pci_dev *pdev, const struct pci_device_id *id)
 	ha->init_cb_size = sizeof(init_cb_t);
 	ha->link_data_rate = PORT_SPEED_UNKNOWN;
 	ha->optrom_size = OPTROM_SIZE_2300;
+	ha->max_exchg = FW_MAX_EXCHANGES_CNT;
 
 	/* Assign ISP specific operations. */
 	if (IS_QLA2100(ha)) {
@@ -4230,6 +4231,9 @@ qla2x00_number_of_exch(scsi_qla_host_t *vha, u32 *ret_cnt, u16 max_cnt)
 	u32 temp;
 	*ret_cnt = FW_DEF_EXCHANGES_CNT;
 
+	if (max_cnt > vha->hw->max_exchg)
+		max_cnt = vha->hw->max_exchg;
+
 	if (qla_ini_mode_enabled(vha)) {
 		if (ql2xiniexchg > max_cnt)
 			ql2xiniexchg = max_cnt;
@@ -4259,8 +4263,8 @@ int
 qla2x00_set_exchoffld_buffer(scsi_qla_host_t *vha)
 {
 	int rval;
-	u16 size, max_cnt;
-	u32 temp;
+	u16	size, max_cnt;
+	u32 actual_cnt, totsz;
 	struct qla_hw_data *ha = vha->hw;
 
 	if (!ha->flags.exchoffld_enabled)
@@ -4277,16 +4281,19 @@ qla2x00_set_exchoffld_buffer(scsi_qla_host_t *vha)
 		return rval;
 	}
 
-	qla2x00_number_of_exch(vha, &temp, max_cnt);
-	temp *= size;
+	qla2x00_number_of_exch(vha, &actual_cnt, max_cnt);
+	ql_log(ql_log_info, vha, 0xd014,
+	    "Actual exchange offload count: %d.\n", actual_cnt);
+
+	totsz = actual_cnt * size;
 
-	if (temp != ha->exchoffld_size) {
+	if (totsz != ha->exchoffld_size) {
 		qla2x00_free_exchoffld_buffer(ha);
-		ha->exchoffld_size = temp;
+		ha->exchoffld_size = totsz;
 
 		ql_log(ql_log_info, vha, 0xd016,
-		    "Exchange offload: max_count=%d, buffers=0x%x, total=%d.\n",
-		    max_cnt, size, temp);
+		    "Exchange offload: max_count=%d, actual count=%d entry sz=0x%x, total sz=0x%x\n",
+		    max_cnt, actual_cnt, size, totsz);
 
 		ql_log(ql_log_info, vha, 0xd017,
 		    "Exchange Buffers requested size = 0x%x\n",
@@ -4297,7 +4304,21 @@ qla2x00_set_exchoffld_buffer(scsi_qla_host_t *vha)
 			ha->exchoffld_size, &ha->exchoffld_buf_dma, GFP_KERNEL);
 		if (!ha->exchoffld_buf) {
 			ql_log_pci(ql_log_fatal, ha->pdev, 0xd013,
-			"Failed to allocate memory for exchoffld_buf_dma.\n");
+			"Failed to allocate memory for Exchange Offload.\n");
+
+			if (ha->max_exchg >
+			    (FW_DEF_EXCHANGES_CNT + REDUCE_EXCHANGES_CNT)) {
+				ha->max_exchg -= REDUCE_EXCHANGES_CNT;
+			} else if (ha->max_exchg >
+			    (FW_DEF_EXCHANGES_CNT + 512)) {
+				ha->max_exchg -= 512;
+			} else {
+				ha->flags.exchoffld_enabled = 0;
+				ql_log_pci(ql_log_fatal, ha->pdev, 0xd013,
+				    "Disabling Exchange offload due to lack of memory\n");
+			}
+			ha->exchoffld_size = 0;
+
 			return -ENOMEM;
 		}
 	}
-- 
2.12.0
