scsi: scsi_transport_sas: switch to bsg-lib for SMP passthrough

Simplify the SMP passthrough code by switching it to the generic bsg-lib
helpers that abstract away the details of the request code, and gets
drivers out of seeing struct scsi_request.

For the libsas host SMP code there is a small behavior difference in
that we now always clear the residual len for successful commands,
similar to the three other SMP handler implementations.  Given that
there is no partial command handling in the host SMP handler this should
not matter in practice.

[mkp: typos and checkpatch fixes]

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

1 files changed, 90 insertions, 140 deletions

diff --git a/drivers/scsi/mpt3sas/mpt3sas_transport.c b/drivers/scsi/mpt3sas/mpt3sas_transport.c
index e7a7a704a315..d3940c5d079d 100644
--- a/drivers/scsi/mpt3sas/mpt3sas_transport.c
+++ b/drivers/scsi/mpt3sas/mpt3sas_transport.c
@@ -1870,6 +1870,38 @@ _transport_phy_speed(struct sas_phy *phy, struct sas_phy_linkrates *rates)
 	return rc;
 }
 
+static int
+_transport_map_smp_buffer(struct device *dev, struct bsg_buffer *buf,
+		dma_addr_t *dma_addr, size_t *dma_len, void **p)
+{
+	/* Check if the request is split across multiple segments */
+	if (buf->sg_cnt > 1) {
+		*p = dma_alloc_coherent(dev, buf->payload_len, dma_addr,
+				GFP_KERNEL);
+		if (!*p)
+			return -ENOMEM;
+		*dma_len = buf->payload_len;
+	} else {
+		if (!dma_map_sg(dev, buf->sg_list, 1, DMA_BIDIRECTIONAL))
+			return -ENOMEM;
+		*dma_addr = sg_dma_address(buf->sg_list);
+		*dma_len = sg_dma_len(buf->sg_list);
+		*p = NULL;
+	}
+
+	return 0;
+}
+
+static void
+_transport_unmap_smp_buffer(struct device *dev, struct bsg_buffer *buf,
+		dma_addr_t dma_addr, void *p)
+{
+	if (p)
+		dma_free_coherent(dev, buf->payload_len, p, dma_addr);
+	else
+		dma_unmap_sg(dev, buf->sg_list, 1, DMA_BIDIRECTIONAL);
+}
+
 /**
  * _transport_smp_handler - transport portal for smp passthru
  * @shost: shost object
@@ -1880,9 +1912,9 @@ _transport_phy_speed(struct sas_phy *phy, struct sas_phy_linkrates *rates)
  * Example:
  *           smp_rep_general /sys/class/bsg/expander-5:0
  */
-static int
-_transport_smp_handler(struct Scsi_Host *shost, struct sas_rphy *rphy,
-	struct request *req)
+static void
+_transport_smp_handler(struct bsg_job *job, struct Scsi_Host *shost,
+		struct sas_rphy *rphy)
 {
 	struct MPT3SAS_ADAPTER *ioc = shost_priv(shost);
 	Mpi2SmpPassthroughRequest_t *mpi_request;
@@ -1891,33 +1923,25 @@ _transport_smp_handler(struct Scsi_Host *shost, struct sas_rphy *rphy,
 	u16 smid;
 	u32 ioc_state;
 	void *psge;
-	u8 issue_reset = 0;
-	dma_addr_t dma_addr_in = 0;
-	dma_addr_t dma_addr_out = 0;
-	dma_addr_t pci_dma_in = 0;
-	dma_addr_t pci_dma_out = 0;
-	void *pci_addr_in = NULL;
-	void *pci_addr_out = NULL;
+	dma_addr_t dma_addr_in;
+	dma_addr_t dma_addr_out;
+	void *addr_in = NULL;
+	void *addr_out = NULL;
+	size_t dma_len_in;
+	size_t dma_len_out;
 	u16 wait_state_count;
-	struct request *rsp = req->next_rq;
-	struct bio_vec bvec;
-	struct bvec_iter iter;
-
-	if (!rsp) {
-		pr_err(MPT3SAS_FMT "%s: the smp response space is missing\n",
-			ioc->name, __func__);
-		return -EINVAL;
-	}
+	unsigned int reslen = 0;
 
 	if (ioc->shost_recovery || ioc->pci_error_recovery) {
 		pr_info(MPT3SAS_FMT "%s: host reset in progress!\n",
 		    __func__, ioc->name);
-		return -EFAULT;
+		rc = -EFAULT;
+		goto out;
 	}
 
 	rc = mutex_lock_interruptible(&ioc->transport_cmds.mutex);
 	if (rc)
-		return rc;
+		goto out;
 
 	if (ioc->transport_cmds.status != MPT3_CMD_NOT_USED) {
 		pr_err(MPT3SAS_FMT "%s: transport_cmds in use\n", ioc->name,
@@ -1927,58 +1951,20 @@ _transport_smp_handler(struct Scsi_Host *shost, struct sas_rphy *rphy,
 	}
 	ioc->transport_cmds.status = MPT3_CMD_PENDING;
 
-	/* Check if the request is split across multiple segments */
-	if (bio_multiple_segments(req->bio)) {
-		u32 offset = 0;
-
-		/* Allocate memory and copy the request */
-		pci_addr_out = pci_alloc_consistent(ioc->pdev,
-		    blk_rq_bytes(req), &pci_dma_out);
-		if (!pci_addr_out) {
-			pr_info(MPT3SAS_FMT "%s(): PCI Addr out = NULL\n",
-			    ioc->name, __func__);
-			rc = -ENOMEM;
-			goto out;
-		}
-
-		bio_for_each_segment(bvec, req->bio, iter) {
-			memcpy(pci_addr_out + offset,
-			    page_address(bvec.bv_page) + bvec.bv_offset,
-			    bvec.bv_len);
-			offset += bvec.bv_len;
-		}
-	} else {
-		dma_addr_out = pci_map_single(ioc->pdev, bio_data(req->bio),
-		    blk_rq_bytes(req), PCI_DMA_BIDIRECTIONAL);
-		if (pci_dma_mapping_error(ioc->pdev, dma_addr_out)) {
-			pr_info(MPT3SAS_FMT "%s(): DMA Addr out = NULL\n",
-			    ioc->name, __func__);
-			rc = -ENOMEM;
-			goto free_pci;
-		}
+	rc = _transport_map_smp_buffer(&ioc->pdev->dev, &job->request_payload,
+			&dma_addr_out, &dma_len_out, &addr_out);
+	if (rc)
+		goto out;
+	if (addr_out) {
+		sg_copy_to_buffer(job->request_payload.sg_list,
+				job->request_payload.sg_cnt, addr_out,
+				job->request_payload.payload_len);
 	}
 
-	/* Check if the response needs to be populated across
-	 * multiple segments */
-	if (bio_multiple_segments(rsp->bio)) {
-		pci_addr_in = pci_alloc_consistent(ioc->pdev, blk_rq_bytes(rsp),
-		    &pci_dma_in);
-		if (!pci_addr_in) {
-			pr_info(MPT3SAS_FMT "%s(): PCI Addr in = NULL\n",
-			    ioc->name, __func__);
-			rc = -ENOMEM;
-			goto unmap;
-		}
-	} else {
-		dma_addr_in =  pci_map_single(ioc->pdev, bio_data(rsp->bio),
-		    blk_rq_bytes(rsp), PCI_DMA_BIDIRECTIONAL);
-		if (pci_dma_mapping_error(ioc->pdev, dma_addr_in)) {
-			pr_info(MPT3SAS_FMT "%s(): DMA Addr in = NULL\n",
-			    ioc->name, __func__);
-			rc = -ENOMEM;
-			goto unmap;
-		}
-	}
+	rc = _transport_map_smp_buffer(&ioc->pdev->dev, &job->reply_payload,
+			&dma_addr_in, &dma_len_in, &addr_in);
+	if (rc)
+		goto unmap_out;
 
 	wait_state_count = 0;
 	ioc_state = mpt3sas_base_get_iocstate(ioc, 1);
@@ -1988,7 +1974,7 @@ _transport_smp_handler(struct Scsi_Host *shost, struct sas_rphy *rphy,
 			    "%s: failed due to ioc not operational\n",
 			    ioc->name, __func__);
 			rc = -EFAULT;
-			goto unmap;
+			goto unmap_in;
 		}
 		ssleep(1);
 		ioc_state = mpt3sas_base_get_iocstate(ioc, 1);
@@ -2005,7 +1991,7 @@ _transport_smp_handler(struct Scsi_Host *shost, struct sas_rphy *rphy,
 		pr_err(MPT3SAS_FMT "%s: failed obtaining a smid\n",
 		    ioc->name, __func__);
 		rc = -EAGAIN;
-		goto unmap;
+		goto unmap_in;
 	}
 
 	rc = 0;
@@ -2018,15 +2004,11 @@ _transport_smp_handler(struct Scsi_Host *shost, struct sas_rphy *rphy,
 	mpi_request->SASAddress = (rphy) ?
 	    cpu_to_le64(rphy->identify.sas_address) :
 	    cpu_to_le64(ioc->sas_hba.sas_address);
-	mpi_request->RequestDataLength = cpu_to_le16(blk_rq_bytes(req) - 4);
+	mpi_request->RequestDataLength = cpu_to_le16(dma_len_out - 4);
 	psge = &mpi_request->SGL;
 
-	if (bio_multiple_segments(req->bio))
-		ioc->build_sg(ioc, psge, pci_dma_out, (blk_rq_bytes(req) - 4),
-		    pci_dma_in, (blk_rq_bytes(rsp) + 4));
-	else
-		ioc->build_sg(ioc, psge, dma_addr_out, (blk_rq_bytes(req) - 4),
-		    dma_addr_in, (blk_rq_bytes(rsp) + 4));
+	ioc->build_sg(ioc, psge, dma_addr_out, dma_len_out - 4, dma_addr_in,
+			dma_len_in - 4);
 
 	dtransportprintk(ioc, pr_info(MPT3SAS_FMT
 		"%s - sending smp request\n", ioc->name, __func__));
@@ -2040,83 +2022,51 @@ _transport_smp_handler(struct Scsi_Host *shost, struct sas_rphy *rphy,
 		    __func__, ioc->name);
 		_debug_dump_mf(mpi_request,
 		    sizeof(Mpi2SmpPassthroughRequest_t)/4);
-		if (!(ioc->transport_cmds.status & MPT3_CMD_RESET))
-			issue_reset = 1;
-		goto issue_host_reset;
+		if (!(ioc->transport_cmds.status & MPT3_CMD_RESET)) {
+			mpt3sas_base_hard_reset_handler(ioc, FORCE_BIG_HAMMER);
+			rc = -ETIMEDOUT;
+			goto unmap_in;
+		}
 	}
 
 	dtransportprintk(ioc, pr_info(MPT3SAS_FMT
 		"%s - complete\n", ioc->name, __func__));
 
-	if (ioc->transport_cmds.status & MPT3_CMD_REPLY_VALID) {
-
-		mpi_reply = ioc->transport_cmds.reply;
-
-		dtransportprintk(ioc, pr_info(MPT3SAS_FMT
-		    "%s - reply data transfer size(%d)\n",
-		    ioc->name, __func__,
-		    le16_to_cpu(mpi_reply->ResponseDataLength)));
-
-		memcpy(scsi_req(req)->sense, mpi_reply, sizeof(*mpi_reply));
-		scsi_req(req)->sense_len = sizeof(*mpi_reply);
-		scsi_req(req)->resid_len = 0;
-		scsi_req(rsp)->resid_len -=
-		    le16_to_cpu(mpi_reply->ResponseDataLength);
-
-		/* check if the resp needs to be copied from the allocated
-		 * pci mem */
-		if (bio_multiple_segments(rsp->bio)) {
-			u32 offset = 0;
-			u32 bytes_to_copy =
-			    le16_to_cpu(mpi_reply->ResponseDataLength);
-			bio_for_each_segment(bvec, rsp->bio, iter) {
-				if (bytes_to_copy <= bvec.bv_len) {
-					memcpy(page_address(bvec.bv_page) +
-					    bvec.bv_offset, pci_addr_in +
-					    offset, bytes_to_copy);
-					break;
-				} else {
-					memcpy(page_address(bvec.bv_page) +
-					    bvec.bv_offset, pci_addr_in +
-					    offset, bvec.bv_len);
-					bytes_to_copy -= bvec.bv_len;
-				}
-				offset += bvec.bv_len;
-			}
-		}
-	} else {
+	if (!(ioc->transport_cmds.status & MPT3_CMD_REPLY_VALID)) {
 		dtransportprintk(ioc, pr_info(MPT3SAS_FMT
 		    "%s - no reply\n", ioc->name, __func__));
 		rc = -ENXIO;
+		goto unmap_in;
 	}
 
- issue_host_reset:
-	if (issue_reset) {
-		mpt3sas_base_hard_reset_handler(ioc, FORCE_BIG_HAMMER);
-		rc = -ETIMEDOUT;
-	}
+	mpi_reply = ioc->transport_cmds.reply;
 
- unmap:
-	if (dma_addr_out)
-		pci_unmap_single(ioc->pdev, dma_addr_out, blk_rq_bytes(req),
-		    PCI_DMA_BIDIRECTIONAL);
-	if (dma_addr_in)
-		pci_unmap_single(ioc->pdev, dma_addr_in, blk_rq_bytes(rsp),
-		    PCI_DMA_BIDIRECTIONAL);
+	dtransportprintk(ioc,
+		pr_info(MPT3SAS_FMT "%s - reply data transfer size(%d)\n",
+			ioc->name, __func__,
+			le16_to_cpu(mpi_reply->ResponseDataLength)));
 
- free_pci:
-	if (pci_addr_out)
-		pci_free_consistent(ioc->pdev, blk_rq_bytes(req), pci_addr_out,
-		    pci_dma_out);
+	memcpy(job->reply, mpi_reply, sizeof(*mpi_reply));
+	job->reply_len = sizeof(*mpi_reply);
+	reslen = le16_to_cpu(mpi_reply->ResponseDataLength);
 
-	if (pci_addr_in)
-		pci_free_consistent(ioc->pdev, blk_rq_bytes(rsp), pci_addr_in,
-		    pci_dma_in);
+	if (addr_in) {
+		sg_copy_to_buffer(job->reply_payload.sg_list,
+				job->reply_payload.sg_cnt, addr_in,
+				job->reply_payload.payload_len);
+	}
 
+	rc = 0;
+ unmap_in:
+	_transport_unmap_smp_buffer(&ioc->pdev->dev, &job->reply_payload,
+			dma_addr_in, addr_in);
+ unmap_out:
+	_transport_unmap_smp_buffer(&ioc->pdev->dev, &job->request_payload,
+			dma_addr_out, addr_out);
  out:
 	ioc->transport_cmds.status = MPT3_CMD_NOT_USED;
 	mutex_unlock(&ioc->transport_cmds.mutex);
-	return rc;
+	bsg_job_done(job, rc, reslen);
 }
 
 struct sas_function_template mpt3sas_transport_functions = {