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, 40 insertions, 66 deletions

diff --git a/drivers/scsi/libsas/sas_host_smp.c b/drivers/scsi/libsas/sas_host_smp.c
index 45cbbc44f4d7..9ead93df3a6e 100644
--- a/drivers/scsi/libsas/sas_host_smp.c
+++ b/drivers/scsi/libsas/sas_host_smp.c
@@ -225,47 +225,36 @@ static void sas_phy_control(struct sas_ha_struct *sas_ha, u8 phy_id,
 		resp_data[2] = SMP_RESP_FUNC_ACC;
 }
 
-int sas_smp_host_handler(struct Scsi_Host *shost, struct request *req,
-			 struct request *rsp)
+void sas_smp_host_handler(struct bsg_job *job, struct Scsi_Host *shost)
 {
-	u8 *req_data = NULL, *resp_data = NULL, *buf;
 	struct sas_ha_struct *sas_ha = SHOST_TO_SAS_HA(shost);
+	u8 *req_data, *resp_data;
+	unsigned int reslen = 0;
 	int error = -EINVAL;
 
 	/* eight is the minimum size for request and response frames */
-	if (blk_rq_bytes(req) < 8 || blk_rq_bytes(rsp) < 8)
+	if (job->request_payload.payload_len < 8 ||
+	    job->reply_payload.payload_len < 8)
 		goto out;
 
-	if (bio_offset(req->bio) + blk_rq_bytes(req) > PAGE_SIZE ||
-	    bio_offset(rsp->bio) + blk_rq_bytes(rsp) > PAGE_SIZE) {
-		shost_printk(KERN_ERR, shost,
-			"SMP request/response frame crosses page boundary");
+	error = -ENOMEM;
+	req_data = kzalloc(job->request_payload.payload_len, GFP_KERNEL);
+	if (!req_data)
 		goto out;
-	}
-
-	req_data = kzalloc(blk_rq_bytes(req), GFP_KERNEL);
+	sg_copy_to_buffer(job->request_payload.sg_list,
+			  job->request_payload.sg_cnt, req_data,
+			  job->request_payload.payload_len);
 
 	/* make sure frame can always be built ... we copy
 	 * back only the requested length */
-	resp_data = kzalloc(max(blk_rq_bytes(rsp), 128U), GFP_KERNEL);
-
-	if (!req_data || !resp_data) {
-		error = -ENOMEM;
-		goto out;
-	}
-
-	local_irq_disable();
-	buf = kmap_atomic(bio_page(req->bio));
-	memcpy(req_data, buf, blk_rq_bytes(req));
-	kunmap_atomic(buf - bio_offset(req->bio));
-	local_irq_enable();
+	resp_data = kzalloc(max(job->reply_payload.payload_len, 128U),
+			GFP_KERNEL);
+	if (!resp_data)
+		goto out_free_req;
 
+	error = -EINVAL;
 	if (req_data[0] != SMP_REQUEST)
-		goto out;
-
-	/* always succeeds ... even if we can't process the request
-	 * the result is in the response frame */
-	error = 0;
+		goto out_free_resp;
 
 	/* set up default don't know response */
 	resp_data[0] = SMP_RESPONSE;
@@ -274,20 +263,18 @@ int sas_smp_host_handler(struct Scsi_Host *shost, struct request *req,
 
 	switch (req_data[1]) {
 	case SMP_REPORT_GENERAL:
-		scsi_req(req)->resid_len -= 8;
-		scsi_req(rsp)->resid_len -= 32;
 		resp_data[2] = SMP_RESP_FUNC_ACC;
 		resp_data[9] = sas_ha->num_phys;
+		reslen = 32;
 		break;
 
 	case SMP_REPORT_MANUF_INFO:
-		scsi_req(req)->resid_len -= 8;
-		scsi_req(rsp)->resid_len -= 64;
 		resp_data[2] = SMP_RESP_FUNC_ACC;
 		memcpy(resp_data + 12, shost->hostt->name,
 		       SAS_EXPANDER_VENDOR_ID_LEN);
 		memcpy(resp_data + 20, "libsas virt phy",
 		       SAS_EXPANDER_PRODUCT_ID_LEN);
+		reslen = 64;
 		break;
 
 	case SMP_READ_GPIO_REG:
@@ -295,14 +282,10 @@ int sas_smp_host_handler(struct Scsi_Host *shost, struct request *req,
 		break;
 
 	case SMP_DISCOVER:
-		scsi_req(req)->resid_len -= 16;
-		if ((int)scsi_req(req)->resid_len < 0) {
-			scsi_req(req)->resid_len = 0;
-			error = -EINVAL;
-			goto out;
-		}
-		scsi_req(rsp)->resid_len -= 56;
+		if (job->request_payload.payload_len < 16)
+			goto out_free_resp;
 		sas_host_smp_discover(sas_ha, resp_data, req_data[9]);
+		reslen = 56;
 		break;
 
 	case SMP_REPORT_PHY_ERR_LOG:
@@ -311,14 +294,10 @@ int sas_smp_host_handler(struct Scsi_Host *shost, struct request *req,
 		break;
 
 	case SMP_REPORT_PHY_SATA:
-		scsi_req(req)->resid_len -= 16;
-		if ((int)scsi_req(req)->resid_len < 0) {
-			scsi_req(req)->resid_len = 0;
-			error = -EINVAL;
-			goto out;
-		}
-		scsi_req(rsp)->resid_len -= 60;
+		if (job->request_payload.payload_len < 16)
+			goto out_free_resp;
 		sas_report_phy_sata(sas_ha, resp_data, req_data[9]);
+		reslen = 60;
 		break;
 
 	case SMP_REPORT_ROUTE_INFO:
@@ -330,16 +309,15 @@ int sas_smp_host_handler(struct Scsi_Host *shost, struct request *req,
 		const int base_frame_size = 11;
 		int to_write = req_data[4];
 
-		if (blk_rq_bytes(req) < base_frame_size + to_write * 4 ||
-		    scsi_req(req)->resid_len < base_frame_size + to_write * 4) {
+		if (job->request_payload.payload_len <
+				base_frame_size + to_write * 4) {
 			resp_data[2] = SMP_RESP_INV_FRM_LEN;
 			break;
 		}
 
 		to_write = sas_host_smp_write_gpio(sas_ha, resp_data, req_data[2],
 						   req_data[3], to_write, &req_data[8]);
-		scsi_req(req)->resid_len -= base_frame_size + to_write * 4;
-		scsi_req(rsp)->resid_len -= 8;
+		reslen = 8;
 		break;
 	}
 
@@ -348,16 +326,12 @@ int sas_smp_host_handler(struct Scsi_Host *shost, struct request *req,
 		break;
 
 	case SMP_PHY_CONTROL:
-		scsi_req(req)->resid_len -= 44;
-		if ((int)scsi_req(req)->resid_len < 0) {
-			scsi_req(req)->resid_len = 0;
-			error = -EINVAL;
-			goto out;
-		}
-		scsi_req(rsp)->resid_len -= 8;
+		if (job->request_payload.payload_len < 44)
+			goto out_free_resp;
 		sas_phy_control(sas_ha, req_data[9], req_data[10],
 				req_data[32] >> 4, req_data[33] >> 4,
 				resp_data);
+		reslen = 8;
 		break;
 
 	case SMP_PHY_TEST_FUNCTION:
@@ -369,15 +343,15 @@ int sas_smp_host_handler(struct Scsi_Host *shost, struct request *req,
 		break;
 	}
 
-	local_irq_disable();
-	buf = kmap_atomic(bio_page(rsp->bio));
-	memcpy(buf, resp_data, blk_rq_bytes(rsp));
-	flush_kernel_dcache_page(bio_page(rsp->bio));
-	kunmap_atomic(buf - bio_offset(rsp->bio));
-	local_irq_enable();
+	sg_copy_from_buffer(job->reply_payload.sg_list,
+			    job->reply_payload.sg_cnt, resp_data,
+			    job->reply_payload.payload_len);
 
- out:
-	kfree(req_data);
+	error = 0;
+out_free_resp:
 	kfree(resp_data);
-	return error;
+out_free_req:
+	kfree(req_data);
+out:
+	bsg_job_done(job, error, reslen);
 }