[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>

diff --git a/drivers/scsi/scsi_debug.c b/drivers/scsi/scsi_debug.c
index fc8b3aa..3f096a6 100644 (file)
--- 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;
                        }