[PATCH] [SCSI] libsas: fix test for negative unsigned and typos

[roel kluin <roel.kluin@gmail.com>]

unsigned req->data_len cannot be negative, and fix typo

Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
---
I am not sure whether this is what was intended, please review.

diff --git a/drivers/scsi/libsas/sas_host_smp.c b/drivers/scsi/libsas/sas_host_smp.c
index 16f9312..6eb0779 100644
--- a/drivers/scsi/libsas/sas_host_smp.c
+++ b/drivers/scsi/libsas/sas_host_smp.c
@@ -199,12 +199,12 @@ int sas_smp_host_handler(struct Scsi_Host *shost, struct request *req,
 		break;
 
 	case SMP_DISCOVER:
-		req->data_len =- 16;
-		if (req->data_len < 0) {
+		if (req->data_len < 15) {
 			req->data_len = 0;
 			error = -EINVAL;
 			goto out;
 		}
+		req->data_len -= 16;
 		resp_data_len -= 56;
 		sas_host_smp_discover(sas_ha, resp_data, req_data[9]);
 		break;
@@ -215,12 +215,12 @@ int sas_smp_host_handler(struct Scsi_Host *shost, struct request *req,
 		break;
 
 	case SMP_REPORT_PHY_SATA:
-		req->data_len =- 16;
-		if (req->data_len < 0) {
+		if (req->data_len < 15) {
 			req->data_len = 0;
 			error = -EINVAL;
 			goto out;
 		}
+		req->data_len -= 16;
 		resp_data_len -= 60;
 		sas_report_phy_sata(sas_ha, resp_data, req_data[9]);
 		break;
@@ -238,12 +238,12 @@ int sas_smp_host_handler(struct Scsi_Host *shost, struct request *req,
 		break;
 
 	case SMP_PHY_CONTROL:
-		req->data_len =- 44;
-		if (req->data_len < 0) {
+		if (req->data_len < 43) {
 			req->data_len = 0;
 			error = -EINVAL;
 			goto out;
 		}
+		req->data_len -= 44;
 		resp_data_len -= 8;
 		sas_phy_control(sas_ha, req_data[9], req_data[10],
 				req_data[32] >> 4, req_data[33] >> 4,