scsi: qla2xxx: Fix DMA error when the DIF sg buffer crosses 4GB boundary

When SGE buffer containing DIF information crosses 4G boundary, it results
in DMA error. This patch fixes this issue by calculating SGE buffer size
and if it crosses 4G boundary, driver will split it into multiple SGE
buffers to avoid DMA error.
Signed-off-by: Giridhar Malavali <gmalavali@marvell.com>
Signed-off-by: Himanshu Madhani <hmadhani@marvell.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/qla2xxx/qla_attr.c

@@ -1002,7 +1002,7 @@ qla2x00_free_sysfs_attr(scsi_qla_host_t *vha, bool stop_beacon)
 /* Scsi_Host attributes. */
 
 static ssize_t
-qla2x00_drvr_version_show(struct device *dev,
+qla2x00_driver_version_show(struct device *dev,
 			  struct device_attribute *attr, char *buf)
 {
 	return scnprintf(buf, PAGE_SIZE, "%s\n", qla2x00_version_str);
@@ -2059,7 +2059,21 @@ ql2xiniexchg_store(struct device *dev, struct device_attribute *attr,
 	return strlen(buf);
 }
 
-static DEVICE_ATTR(driver_version, S_IRUGO, qla2x00_drvr_version_show, NULL);
+static ssize_t
+qla2x00_dif_bundle_statistics_show(struct device *dev,
+    struct device_attribute *attr, char *buf)
+{
+	scsi_qla_host_t *vha = shost_priv(class_to_shost(dev));
+	struct qla_hw_data *ha = vha->hw;
+
+	return scnprintf(buf, PAGE_SIZE,
+	    "cross=%llu read=%llu write=%llu kalloc=%llu dma_alloc=%llu unusable=%u\n",
+	    ha->dif_bundle_crossed_pages, ha->dif_bundle_reads,
+	    ha->dif_bundle_writes, ha->dif_bundle_kallocs,
+	    ha->dif_bundle_dma_allocs, ha->pool.unusable.count);
+}
+
+static DEVICE_ATTR(driver_version, S_IRUGO, qla2x00_driver_version_show, NULL);
 static DEVICE_ATTR(fw_version, S_IRUGO, qla2x00_fw_version_show, NULL);
 static DEVICE_ATTR(serial_num, S_IRUGO, qla2x00_serial_num_show, NULL);
 static DEVICE_ATTR(isp_name, S_IRUGO, qla2x00_isp_name_show, NULL);
@@ -2112,6 +2126,8 @@ static DEVICE_ATTR(zio_threshold, 0644,
 static DEVICE_ATTR_RW(qlini_mode);
 static DEVICE_ATTR_RW(ql2xexchoffld);
 static DEVICE_ATTR_RW(ql2xiniexchg);
+static DEVICE_ATTR(dif_bundle_statistics, 0444,
+    qla2x00_dif_bundle_statistics_show, NULL);
 
 
 struct device_attribute *qla2x00_host_attrs[] = {
@@ -2150,6 +2166,7 @@ struct device_attribute *qla2x00_host_attrs[] = {
 	&dev_attr_min_link_speed,
 	&dev_attr_max_speed_sup,
 	&dev_attr_zio_threshold,
+	&dev_attr_dif_bundle_statistics,
 	NULL, /* reserve for qlini_mode */
 	NULL, /* reserve for ql2xiniexchg */
 	NULL, /* reserve for ql2xexchoffld */

drivers/scsi/qla2xxx/qla_def.h

@@ -314,6 +314,7 @@ struct srb_cmd {
 #define SRB_CRC_PROT_DMA_VALID		BIT_4	/* DIF: prot DMA valid */
 #define SRB_CRC_CTX_DSD_VALID		BIT_5	/* DIF: dsd_list valid */
 #define SRB_WAKEUP_ON_COMP		BIT_6
+#define SRB_DIF_BUNDL_DMA_VALID		BIT_7   /* DIF: DMA list valid */
 
 /* To identify if a srb is of T10-CRC type. @sp => srb_t pointer */
 #define IS_PROT_IO(sp)	(sp->flags & SRB_CRC_CTX_DSD_VALID)
@@ -1892,6 +1893,13 @@ struct crc_context {
 	/* List of DMA context transfers */
 	struct list_head dsd_list;
 
+	/* List of DIF Bundling context DMA address */
+	struct list_head ldif_dsd_list;
+	u8 no_ldif_dsd;
+
+	struct list_head ldif_dma_hndl_list;
+	u32 dif_bundl_len;
+	u8 no_dif_bundl;
 	/* This structure should not exceed 512 bytes */
 };
 
@@ -4184,6 +4192,26 @@ struct qla_hw_data {
 	uint16_t min_link_speed;
 	uint16_t max_speed_sup;
 
+	/* DMA pool for the DIF bundling buffers */
+	struct dma_pool *dif_bundl_pool;
+	#define DIF_BUNDLING_DMA_POOL_SIZE  1024
+	struct {
+		struct {
+			struct list_head head;
+			uint count;
+		} good;
+		struct {
+			struct list_head head;
+			uint count;
+		} unusable;
+	} pool;
+
+	unsigned long long dif_bundle_crossed_pages;
+	unsigned long long dif_bundle_reads;
+	unsigned long long dif_bundle_writes;
+	unsigned long long dif_bundle_kallocs;
+	unsigned long long dif_bundle_dma_allocs;
+
 	atomic_t        nvme_active_aen_cnt;
 	uint16_t        nvme_last_rptd_aen;             /* Last recorded aen count */
 

drivers/scsi/qla2xxx/qla_gbl.h

@@ -160,6 +160,7 @@ extern int ql2xautodetectsfp;
 extern int ql2xenablemsix;
 extern int qla2xuseresexchforels;
 extern int ql2xexlogins;
+extern int ql2xdifbundlinginternalbuffers;
 
 extern int qla2x00_loop_reset(scsi_qla_host_t *);
 extern void qla2x00_abort_all_cmds(scsi_qla_host_t *, int);
@@ -285,7 +286,7 @@ extern int qla24xx_walk_and_build_sglist_no_difb(struct qla_hw_data *, srb_t *,
 extern int qla24xx_walk_and_build_sglist(struct qla_hw_data *, srb_t *,
 	uint32_t *, uint16_t, struct qla_tc_param *);
 extern int qla24xx_walk_and_build_prot_sglist(struct qla_hw_data *, srb_t *,
-	uint32_t *, uint16_t, struct qla_tc_param *);
+	uint32_t *, uint16_t, struct qla_tgt_cmd *);
 extern int qla24xx_get_one_block_sg(uint32_t, struct qla2_sgx *, uint32_t *);
 extern int qla24xx_configure_prot_mode(srb_t *, uint16_t *);
 extern int qla24xx_build_scsi_crc_2_iocbs(srb_t *,

drivers/scsi/qla2xxx/qla_isr.c

@@ -2725,6 +2725,17 @@ qla2x00_status_entry(scsi_qla_host_t *vha, struct rsp_que *rsp, void *pkt)
 			    cp->device->vendor);
 		break;
 
+	case CS_DMA:
+		ql_log(ql_log_info, fcport->vha, 0x3022,
+		    "CS_DMA error: 0x%x-0x%x (0x%x) nexus=%ld:%d:%llu portid=%06x oxid=0x%x cdb=%10phN len=0x%x rsp_info=0x%x resid=0x%x fw_resid=0x%x sp=%p cp=%p.\n",
+		    comp_status, scsi_status, res, vha->host_no,
+		    cp->device->id, cp->device->lun, fcport->d_id.b24,
+		    ox_id, cp->cmnd, scsi_bufflen(cp), rsp_info_len,
+		    resid_len, fw_resid_len, sp, cp);
+		ql_dump_buffer(ql_dbg_tgt + ql_dbg_verbose, vha, 0xe0ee,
+		    pkt, sizeof(*sts24));
+		res = DID_ERROR << 16;
+		break;
 	default:
 		res = DID_ERROR << 16;
 		break;

drivers/scsi/qla2xxx/qla_os.c

@@ -299,6 +299,13 @@ MODULE_PARM_DESC(ql2xprotguard, "Override choice of DIX checksum\n"
 		 "  1 -- Force T10 CRC\n"
 		 "  2 -- Force IP checksum\n");
 
+int ql2xdifbundlinginternalbuffers;
+module_param(ql2xdifbundlinginternalbuffers, int, 0644);
+MODULE_PARM_DESC(ql2xdifbundlinginternalbuffers,
+    "Force using internal buffers for DIF information\n"
+    "0 (Default). Based on check.\n"
+    "1 Force using internal buffers\n");
+
 /*
  * SCSI host template entry points
  */
@@ -818,7 +825,44 @@ qla2xxx_qpair_sp_free_dma(void *ptr)
 		ha->gbl_dsd_inuse -= ctx1->dsd_use_cnt;
 		ha->gbl_dsd_avail += ctx1->dsd_use_cnt;
 		mempool_free(ctx1, ha->ctx_mempool);
+		sp->flags &= ~SRB_FCP_CMND_DMA_VALID;
+	}
+	if (sp->flags & SRB_DIF_BUNDL_DMA_VALID) {
+		struct crc_context *difctx = sp->u.scmd.ctx;
+		struct dsd_dma *dif_dsd, *nxt_dsd;
+
+		list_for_each_entry_safe(dif_dsd, nxt_dsd,
+		    &difctx->ldif_dma_hndl_list, list) {
+			list_del(&dif_dsd->list);
+			dma_pool_free(ha->dif_bundl_pool, dif_dsd->dsd_addr,
+			    dif_dsd->dsd_list_dma);
+			kfree(dif_dsd);
+			difctx->no_dif_bundl--;
+		}
+
+		list_for_each_entry_safe(dif_dsd, nxt_dsd,
+		    &difctx->ldif_dsd_list, list) {
+			list_del(&dif_dsd->list);
+			dma_pool_free(ha->dl_dma_pool, dif_dsd->dsd_addr,
+			    dif_dsd->dsd_list_dma);
+			kfree(dif_dsd);
+			difctx->no_ldif_dsd--;
+		}
+
+		if (difctx->no_ldif_dsd) {
+			ql_dbg(ql_dbg_tgt+ql_dbg_verbose, sp->vha, 0xe022,
+			    "%s: difctx->no_ldif_dsd=%x\n",
+			    __func__, difctx->no_ldif_dsd);
+		}
+
+		if (difctx->no_dif_bundl) {
+			ql_dbg(ql_dbg_tgt+ql_dbg_verbose, sp->vha, 0xe022,
+			    "%s: difctx->no_dif_bundl=%x\n",
+			    __func__, difctx->no_dif_bundl);
+		}
+		sp->flags &= ~SRB_DIF_BUNDL_DMA_VALID;
 	}
+
 end:
 	CMD_SP(cmd) = NULL;
 	qla2xxx_rel_qpair_sp(sp->qpair, sp);
@@ -4017,9 +4061,86 @@ qla2x00_mem_alloc(struct qla_hw_data *ha, uint16_t req_len, uint16_t rsp_len,
 			    "Failed to allocate memory for fcp_cmnd_dma_pool.\n");
 			goto fail_dl_dma_pool;
 		}
+
+		if (ql2xenabledif) {
+			u64 bufsize = DIF_BUNDLING_DMA_POOL_SIZE;
+			struct dsd_dma *dsd, *nxt;
+			uint i;
+			/* Creata a DMA pool of buffers for DIF bundling */
+			ha->dif_bundl_pool = dma_pool_create(name,
+			    &ha->pdev->dev, DIF_BUNDLING_DMA_POOL_SIZE, 8, 0);
+			if (!ha->dif_bundl_pool) {
+				ql_dbg_pci(ql_dbg_init, ha->pdev, 0x0024,
+				    "%s: failed create dif_bundl_pool\n",
+				    __func__);
+				goto fail_dif_bundl_dma_pool;
+			}
+
+			INIT_LIST_HEAD(&ha->pool.good.head);
+			INIT_LIST_HEAD(&ha->pool.unusable.head);
+			ha->pool.good.count = 0;
+			ha->pool.unusable.count = 0;
+			for (i = 0; i < 128; i++) {
+				dsd = kzalloc(sizeof(*dsd), GFP_ATOMIC);
+				if (!dsd) {
+					ql_dbg_pci(ql_dbg_init, ha->pdev,
+					    0xe0ee, "%s: failed alloc dsd\n",
+					    __func__);
+					return 1;
+				}
+				ha->dif_bundle_kallocs++;
+
+				dsd->dsd_addr = dma_pool_alloc(
+				    ha->dif_bundl_pool, GFP_ATOMIC,
+				    &dsd->dsd_list_dma);
+				if (!dsd->dsd_addr) {
+					ql_dbg_pci(ql_dbg_init, ha->pdev,
+					    0xe0ee,
+					    "%s: failed alloc ->dsd_addr\n",
+					    __func__);
+					kfree(dsd);
+					ha->dif_bundle_kallocs--;
+					continue;
+				}
+				ha->dif_bundle_dma_allocs++;
+
+				/*
+				 * if DMA buffer crosses 4G boundary,
+				 * put it on bad list
+				 */
+				if (MSD(dsd->dsd_list_dma) ^
+				    MSD(dsd->dsd_list_dma + bufsize)) {
+					list_add_tail(&dsd->list,
+					    &ha->pool.unusable.head);
+					ha->pool.unusable.count++;
+				} else {
+					list_add_tail(&dsd->list,
+					    &ha->pool.good.head);
+					ha->pool.good.count++;
+				}
+			}
+
+			/* return the good ones back to the pool */
+			list_for_each_entry_safe(dsd, nxt,
+			    &ha->pool.good.head, list) {
+				list_del(&dsd->list);
+				dma_pool_free(ha->dif_bundl_pool,
+				    dsd->dsd_addr, dsd->dsd_list_dma);
+				ha->dif_bundle_dma_allocs--;
+				kfree(dsd);
+				ha->dif_bundle_kallocs--;
+			}
+
+			ql_dbg_pci(ql_dbg_init, ha->pdev, 0x0024,
+			    "%s: dif dma pool (good=%u unusable=%u)\n",
+			    __func__, ha->pool.good.count,
+			    ha->pool.unusable.count);
+		}
+
 		ql_dbg_pci(ql_dbg_init, ha->pdev, 0x0025,
-		    "dl_dma_pool=%p fcp_cmnd_dma_pool=%p.\n",
-		    ha->dl_dma_pool, ha->fcp_cmnd_dma_pool);
+		    "dl_dma_pool=%p fcp_cmnd_dma_pool=%p dif_bundl_pool=%p.\n",
+		    ha->dl_dma_pool, ha->fcp_cmnd_dma_pool,
+		    ha->dif_bundl_pool);
 	}
 
 	/* Allocate memory for SNS commands */
@@ -4184,6 +4305,24 @@ qla2x00_mem_alloc(struct qla_hw_data *ha, uint16_t req_len, uint16_t rsp_len,
 		dma_free_coherent(&ha->pdev->dev, sizeof(struct sns_cmd_pkt),
 		    ha->sns_cmd, ha->sns_cmd_dma);
 fail_dma_pool:
+	if (ql2xenabledif) {
+		struct dsd_dma *dsd, *nxt;
+
+		list_for_each_entry_safe(dsd, nxt, &ha->pool.unusable.head,
+		    list) {
+			list_del(&dsd->list);
+			dma_pool_free(ha->dif_bundl_pool, dsd->dsd_addr,
+			    dsd->dsd_list_dma);
+			ha->dif_bundle_dma_allocs--;
+			kfree(dsd);
+			ha->dif_bundle_kallocs--;
+			ha->pool.unusable.count--;
+		}
+		dma_pool_destroy(ha->dif_bundl_pool);
+		ha->dif_bundl_pool = NULL;
+	}
+
+fail_dif_bundl_dma_pool:
 	if (IS_QLA82XX(ha) || ql2xenabledif) {
 		dma_pool_destroy(ha->fcp_cmnd_dma_pool);
 		ha->fcp_cmnd_dma_pool = NULL;
@@ -4564,6 +4703,32 @@ qla2x00_mem_free(struct qla_hw_data *ha)
 
 	mempool_destroy(ha->ctx_mempool);
 
+	if (ql2xenabledif) {
+		struct dsd_dma *dsd, *nxt;
+
+		list_for_each_entry_safe(dsd, nxt, &ha->pool.unusable.head,
+					 list) {
+			list_del(&dsd->list);
+			dma_pool_free(ha->dif_bundl_pool, dsd->dsd_addr,
+				      dsd->dsd_list_dma);
+			ha->dif_bundle_dma_allocs--;
+			kfree(dsd);
+			ha->dif_bundle_kallocs--;
+			ha->pool.unusable.count--;
+		}
+		list_for_each_entry_safe(dsd, nxt, &ha->pool.good.head, list) {
+			list_del(&dsd->list);
+			dma_pool_free(ha->dif_bundl_pool, dsd->dsd_addr,
+				      dsd->dsd_list_dma);
+			ha->dif_bundle_dma_allocs--;
+			kfree(dsd);
+			ha->dif_bundle_kallocs--;
+		}
+	}
+
+	if (ha->dif_bundl_pool)
+		dma_pool_destroy(ha->dif_bundl_pool);
+
 	qlt_mem_free(ha);
 
 	if (ha->init_cb)

drivers/scsi/qla2xxx/qla_target.c

@@ -3230,7 +3230,7 @@ qlt_build_ctio_crc2_pkt(struct qla_qpair *qpair, struct qla_tgt_prm *prm)
 
 		cur_dsd = (uint32_t *) &crc_ctx_pkt->u.bundling.dif_address;
 		if (qla24xx_walk_and_build_prot_sglist(ha, NULL, cur_dsd,
-			prm->prot_seg_cnt, &tc))
+			prm->prot_seg_cnt, cmd))
 			goto crc_queuing_error;
 	}
 	return QLA_SUCCESS;

drivers/scsi/qla2xxx/qla_target.h

@@ -928,6 +928,8 @@ struct qla_tgt_cmd {
 	uint64_t	lba;
 	uint16_t	a_guard, e_guard, a_app_tag, e_app_tag;
 	uint32_t	a_ref_tag, e_ref_tag;
+#define DIF_BUNDL_DMA_VALID 1
+	uint16_t prot_flags;
 
 	uint64_t jiffies_at_alloc;
 	uint64_t jiffies_at_free;