[SCSI] scsi_debug: reduce duplication between prot_verify_read and prot_verify_write

In order to reduce code duplication between prot_verify_read() and
prot_verify_write(), this moves common code into the new functions.

[jejb: fix unitialised variable warning]
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Acked-by: Douglas Gilbert <dgilbert@interlog.com>
Acked-by: "Martin K. Petersen" <martin.petersen@oracle.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>

1 files changed, 52 insertions, 85 deletions

diff --git a/drivers/scsi/scsi_debug.c b/drivers/scsi/scsi_debug.c
index fc8b3aa083d4..3f096a6681ac 100644
--- a/drivers/scsi/scsi_debug.c
+++ b/drivers/scsi/scsi_debug.c
@@ -1710,6 +1710,50 @@ static int do_device_access(struct scsi_cmnd *scmd,
         return ret;
 }
 
+static u16 dif_compute_csum(const void *buf, int len)
+{
+        u16 csum;
+
+        switch (scsi_debug_guard) {
+        case 1:
+                csum = ip_compute_csum(buf, len);
+                break;
+        case 0:
+                csum = cpu_to_be16(crc_t10dif(buf, len));
+                break;
+        }
+        return csum;
+}
+
+static int dif_verify(struct sd_dif_tuple *sdt, const void *data,
+                      sector_t sector, u32 ei_lba)
+{
+        u16 csum = dif_compute_csum(data, scsi_debug_sector_size);
+
+        if (sdt->guard_tag != csum) {
+                pr_err("%s: GUARD check failed on sector %lu rcvd 0x%04x, data 0x%04x\n",
+                        __func__,
+                        (unsigned long)sector,
+                        be16_to_cpu(sdt->guard_tag),
+                        be16_to_cpu(csum));
+                return 0x01;
+        }
+        if (scsi_debug_dif == SD_DIF_TYPE1_PROTECTION &&
+            be32_to_cpu(sdt->ref_tag) != (sector & 0xffffffff)) {
+                pr_err("%s: REF check failed on sector %lu\n",
+                        __func__, (unsigned long)sector);
+                return 0x03;
+        }
+        if (scsi_debug_dif == SD_DIF_TYPE2_PROTECTION &&
+            be32_to_cpu(sdt->ref_tag) != ei_lba) {
+                pr_err("%s: REF check failed on sector %lu\n",
+                        __func__, (unsigned long)sector);
+                        dif_errors++;
+                return 0x03;
+        }
+        return 0;
+}
+
 static int prot_verify_read(struct scsi_cmnd *SCpnt, sector_t start_sec,
                             unsigned int sectors, u32 ei_lba)
 {
@@ -1725,53 +1769,19 @@ static int prot_verify_read(struct scsi_cmnd *SCpnt, sector_t start_sec,
         sdt = dif_storep + start_sec;
 
         for (i = 0 ; i < sectors ; i++) {
-                u16 csum;
+                int ret;
 
                 if (sdt[i].app_tag == 0xffff)
                         continue;
 
                 sector = start_sec + i;
 
-                switch (scsi_debug_guard) {
-                case 1:
-                        csum = ip_compute_csum(fake_storep +
-                                               sector * scsi_debug_sector_size,
-                                               scsi_debug_sector_size);
-                        break;
-                case 0:
-                        csum = crc_t10dif(fake_storep +
-                                          sector * scsi_debug_sector_size,
-                                          scsi_debug_sector_size);
-                        csum = cpu_to_be16(csum);
-                        break;
-                default:
-                        BUG();
-                }
-
-                if (sdt[i].guard_tag != csum) {
-                        printk(KERN_ERR "%s: GUARD check failed on sector %lu" \
-                               " rcvd 0x%04x, data 0x%04x\n", __func__,
-                               (unsigned long)sector,
-                               be16_to_cpu(sdt[i].guard_tag),
-                               be16_to_cpu(csum));
-                        dif_errors++;
-                        return 0x01;
-                }
-
-                if (scsi_debug_dif == SD_DIF_TYPE1_PROTECTION &&
-                    be32_to_cpu(sdt[i].ref_tag) != (sector & 0xffffffff)) {
-                        printk(KERN_ERR "%s: REF check failed on sector %lu\n",
-                               __func__, (unsigned long)sector);
-                        dif_errors++;
-                        return 0x03;
-                }
-
-                if (scsi_debug_dif == SD_DIF_TYPE2_PROTECTION &&
-                    be32_to_cpu(sdt[i].ref_tag) != ei_lba) {
-                        printk(KERN_ERR "%s: REF check failed on sector %lu\n",
-                               __func__, (unsigned long)sector);
+                ret = dif_verify(&sdt[i],
+                                 fake_storep + sector * scsi_debug_sector_size,
+                                 sector, ei_lba);
+                if (ret) {
                         dif_errors++;
-                        return 0x03;
+                        return ret;
                 }
 
                 ei_lba++;
@@ -1880,7 +1890,6 @@ static int prot_verify_write(struct scsi_cmnd *SCpnt, sector_t start_sec,
         sector_t tmp_sec = start_sec;
         sector_t sector;
         int ppage_offset;
-        unsigned short csum;
 
         sector = do_div(tmp_sec, sdebug_store_sectors);
 
@@ -1911,50 +1920,8 @@ static int prot_verify_write(struct scsi_cmnd *SCpnt, sector_t start_sec,
 
                         sdt = paddr + ppage_offset;
 
-                        switch (scsi_debug_guard) {
-                        case 1:
-                                csum = ip_compute_csum(daddr + j,
-                                                       scsi_debug_sector_size);
-                                break;
-                        case 0:
-                                csum = cpu_to_be16(crc_t10dif(daddr + j,
-                                                      scsi_debug_sector_size));
-                                break;
-                        default:
-                                BUG();
-                                ret = 0;
-                                goto out;
-                        }
-
-                        if (sdt->guard_tag != csum) {
-                                printk(KERN_ERR
-                                       "%s: GUARD check failed on sector %lu " \
-                                       "rcvd 0x%04x, calculated 0x%04x\n",
-                                       __func__, (unsigned long)sector,
-                                       be16_to_cpu(sdt->guard_tag),
-                                       be16_to_cpu(csum));
-                                ret = 0x01;
-                                dump_sector(daddr + j, scsi_debug_sector_size);
-                                goto out;
-                        }
-
-                        if (scsi_debug_dif == SD_DIF_TYPE1_PROTECTION &&
-                            be32_to_cpu(sdt->ref_tag)
-                            != (start_sec & 0xffffffff)) {
-                                printk(KERN_ERR
-                                       "%s: REF check failed on sector %lu\n",
-                                       __func__, (unsigned long)sector);
-                                ret = 0x03;
-                                dump_sector(daddr + j, scsi_debug_sector_size);
-                                goto out;
-                        }
-
-                        if (scsi_debug_dif == SD_DIF_TYPE2_PROTECTION &&
-                            be32_to_cpu(sdt->ref_tag) != ei_lba) {
-                                printk(KERN_ERR
-                                       "%s: REF check failed on sector %lu\n",
-                                       __func__, (unsigned long)sector);
-                                ret = 0x03;
+                        ret = dif_verify(sdt, daddr + j, start_sec, ei_lba);
+                        if (ret) {
                                 dump_sector(daddr + j, scsi_debug_sector_size);
                                 goto out;
                         }