scsi_debug: support sg chaining

Signed-off-by: Douglas Gilbert <dougg@torque.net>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

1 files changed, 16 insertions, 14 deletions

diff --git a/drivers/scsi/scsi_debug.c b/drivers/scsi/scsi_debug.c
index 4947dfe625a6..72ee4c9cfb1a 100644
--- a/drivers/scsi/scsi_debug.c
+++ b/drivers/scsi/scsi_debug.c
@@ -38,6 +38,7 @@
 #include <linux/proc_fs.h>
 #include <linux/vmalloc.h>
 #include <linux/moduleparam.h>
+#include <linux/scatterlist.h>
 
 #include <linux/blkdev.h>
 #include "scsi.h"
@@ -600,7 +601,7 @@ static int fill_from_dev_buffer(struct scsi_cmnd * scp, unsigned char * arr,
         int k, req_len, act_len, len, active;
         void * kaddr;
         void * kaddr_off;
-        struct scatterlist * sgpnt;
+        struct scatterlist * sg;
 
         if (0 == scp->request_bufflen)
                 return 0;
@@ -619,16 +620,16 @@ static int fill_from_dev_buffer(struct scsi_cmnd * scp, unsigned char * arr,
                         scp->resid = req_len - act_len;
                 return 0;
         }
-        sgpnt = (struct scatterlist *)scp->request_buffer;
         active = 1;
-        for (k = 0, req_len = 0, act_len = 0; k < scp->use_sg; ++k, ++sgpnt) {
+        req_len = act_len = 0;
+        scsi_for_each_sg(scp, sg, scp->use_sg, k) {
                 if (active) {
                         kaddr = (unsigned char *)
-                                kmap_atomic(sgpnt->page, KM_USER0);
+                                kmap_atomic(sg->page, KM_USER0);
                         if (NULL == kaddr)
                                 return (DID_ERROR << 16);
-                        kaddr_off = (unsigned char *)kaddr + sgpnt->offset;
-                        len = sgpnt->length;
+                        kaddr_off = (unsigned char *)kaddr + sg->offset;
+                        len = sg->length;
                         if ((req_len + len) > arr_len) {
                                 active = 0;
                                 len = arr_len - req_len;
@@ -637,7 +638,7 @@ static int fill_from_dev_buffer(struct scsi_cmnd * scp, unsigned char * arr,
                         kunmap_atomic(kaddr, KM_USER0);
                         act_len += len;
                 }
-                req_len += sgpnt->length;
+                req_len += sg->length;
         }
         if (scp->resid)
                 scp->resid -= act_len;
@@ -653,7 +654,7 @@ static int fetch_to_dev_buffer(struct scsi_cmnd * scp, unsigned char * arr,
         int k, req_len, len, fin;
         void * kaddr;
         void * kaddr_off;
-        struct scatterlist * sgpnt;
+        struct scatterlist * sg;
 
         if (0 == scp->request_bufflen)
                 return 0;
@@ -668,13 +669,14 @@ static int fetch_to_dev_buffer(struct scsi_cmnd * scp, unsigned char * arr,
                 memcpy(arr, scp->request_buffer, len);
                 return len;
         }
-        sgpnt = (struct scatterlist *)scp->request_buffer;
-        for (k = 0, req_len = 0, fin = 0; k < scp->use_sg; ++k, ++sgpnt) {
-                kaddr = (unsigned char *)kmap_atomic(sgpnt->page, KM_USER0);
+        sg = scsi_sglist(scp);
+        req_len = fin = 0;
+        for (k = 0; k < scp->use_sg; ++k, sg = sg_next(sg)) {
+                kaddr = (unsigned char *)kmap_atomic(sg->page, KM_USER0);
                 if (NULL == kaddr)
                         return -1;
-                kaddr_off = (unsigned char *)kaddr + sgpnt->offset;
-                len = sgpnt->length;
+                kaddr_off = (unsigned char *)kaddr + sg->offset;
+                len = sg->length;
                 if ((req_len + len) > max_arr_len) {
                         len = max_arr_len - req_len;
                         fin = 1;
@@ -683,7 +685,7 @@ static int fetch_to_dev_buffer(struct scsi_cmnd * scp, unsigned char * arr,
                 kunmap_atomic(kaddr, KM_USER0);
                 if (fin)
                         return req_len + len;
-                req_len += sgpnt->length;
+                req_len += sg->length;
         }
         return req_len;
 }