[SCSI] scsi_debug: factor out copying PI from dif_storep to prot_sglist

If data integrity support is enabled, prot_verify_read() is called in
response to READ commands and it verifies protection info from dif_storep
by comparing against fake_storep, and copies protection info to
prot_sglist.

This factors out the portion of copying protection info into a separate
function.  It will also be reused in the next change after supporting
the opposite direction (copying prot_sglist to dif_storep).

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Acked-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>

1 files changed, 29 insertions, 23 deletions

diff --git a/drivers/scsi/scsi_debug.c b/drivers/scsi/scsi_debug.c
index f640b6b380bd..99e74d75cf08 100644
--- a/drivers/scsi/scsi_debug.c
+++ b/drivers/scsi/scsi_debug.c
@@ -1789,37 +1789,16 @@ static int dif_verify(struct sd_dif_tuple *sdt, const void *data,
         return 0;
 }
 
-static int prot_verify_read(struct scsi_cmnd *SCpnt, sector_t start_sec,
-                            unsigned int sectors, u32 ei_lba)
+static void dif_copy_prot(struct scsi_cmnd *SCpnt, sector_t sector,
+                          unsigned int sectors)
 {
         unsigned int i, resid;
         struct scatterlist *psgl;
-        struct sd_dif_tuple *sdt;
-        sector_t sector;
         void *paddr;
         const void *dif_store_end = dif_storep + sdebug_store_sectors;
 
-        for (i = 0; i < sectors; i++) {
-                int ret;
-
-                sector = start_sec + i;
-                sdt = dif_store(sector);
-
-                if (sdt->app_tag == 0xffff)
-                        continue;
-
-                ret = dif_verify(sdt, fake_store(sector), sector, ei_lba);
-                if (ret) {
-                        dif_errors++;
-                        return ret;
-                }
-
-                ei_lba++;
-        }
-
         /* Bytes of protection data to copy into sgl */
         resid = sectors * sizeof(*dif_storep);
-        sector = start_sec;
 
         scsi_for_each_prot_sg(SCpnt, psgl, scsi_prot_sg_count(SCpnt), i) {
                 int len = min(psgl->length, resid);
@@ -1839,7 +1818,34 @@ static int prot_verify_read(struct scsi_cmnd *SCpnt, sector_t start_sec,
                 resid -= len;
                 kunmap_atomic(paddr);
         }
+}
+
+static int prot_verify_read(struct scsi_cmnd *SCpnt, sector_t start_sec,
+                            unsigned int sectors, u32 ei_lba)
+{
+        unsigned int i;
+        struct sd_dif_tuple *sdt;
+        sector_t sector;
+
+        for (i = 0; i < sectors; i++) {
+                int ret;
+
+                sector = start_sec + i;
+                sdt = dif_store(sector);
+
+                if (sdt->app_tag == 0xffff)
+                        continue;
+
+                ret = dif_verify(sdt, fake_store(sector), sector, ei_lba);
+                if (ret) {
+                        dif_errors++;
+                        return ret;
+                }
+
+                ei_lba++;
+        }
 
+        dif_copy_prot(SCpnt, start_sec, sectors);
         dix_reads++;
 
         return 0;