target/sbc: Fix sbc_dif_verify inconsistent map/unmap

Fix map/unmap consistency and get rid of a redundant
local variable psg.

Reported-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

1 files changed, 14 insertions, 14 deletions

diff --git a/drivers/target/target_core_sbc.c b/drivers/target/target_core_sbc.c
index ca95fab3521a..3df2cd538478 100644
--- a/drivers/target/target_core_sbc.c
+++ b/drivers/target/target_core_sbc.c
@@ -1312,30 +1312,30 @@ EXPORT_SYMBOL(sbc_dif_copy_prot);
 
 sense_reason_t
 sbc_dif_verify(struct se_cmd *cmd, sector_t start, unsigned int sectors,
-               unsigned int ei_lba, struct scatterlist *sg, int sg_off)
+               unsigned int ei_lba, struct scatterlist *psg, int psg_off)
 {
         struct se_device *dev = cmd->se_dev;
         struct se_dif_v1_tuple *sdt;
-        struct scatterlist *dsg, *psg = sg;
+        struct scatterlist *dsg;
         sector_t sector = start;
         void *daddr, *paddr;
-        int i, j, offset = sg_off;
+        int i, j;
         sense_reason_t rc;
 
         for_each_sg(cmd->t_data_sg, dsg, cmd->t_data_nents, i) {
                 daddr = kmap_atomic(sg_page(dsg)) + dsg->offset;
-                paddr = kmap_atomic(sg_page(psg)) + sg->offset;
+                paddr = kmap_atomic(sg_page(psg)) + psg->offset;
 
                 for (j = 0; j < dsg->length; j += dev->dev_attrib.block_size) {
 
-                        if (offset >= psg->length) {
-                                kunmap_atomic(paddr);
+                        if (psg_off >= psg->length) {
+                                kunmap_atomic(paddr - psg->offset);
                                 psg = sg_next(psg);
                                 paddr = kmap_atomic(sg_page(psg)) + psg->offset;
-                                offset = 0;
+                                psg_off = 0;
                         }
 
-                        sdt = paddr + offset;
+                        sdt = paddr + psg_off;
 
                         pr_debug("DIF READ sector: %llu guard_tag: 0x%04x"
                                  " app_tag: 0x%04x ref_tag: %u\n",
@@ -1344,26 +1344,26 @@ sbc_dif_verify(struct se_cmd *cmd, sector_t start, unsigned int sectors,
 
                         if (sdt->app_tag == cpu_to_be16(0xffff)) {
                                 sector++;
-                                offset += sizeof(struct se_dif_v1_tuple);
+                                psg_off += sizeof(struct se_dif_v1_tuple);
                                 continue;
                         }
 
                         rc = sbc_dif_v1_verify(cmd, sdt, daddr + j, sector,
                                                ei_lba);
                         if (rc) {
-                                kunmap_atomic(paddr);
-                                kunmap_atomic(daddr);
+                                kunmap_atomic(paddr - psg->offset);
+                                kunmap_atomic(daddr - dsg->offset);
                                 cmd->bad_sector = sector;
                                 return rc;
                         }
 
                         sector++;
                         ei_lba++;
-                        offset += sizeof(struct se_dif_v1_tuple);
+                        psg_off += sizeof(struct se_dif_v1_tuple);
                 }
 
-                kunmap_atomic(paddr);
-                kunmap_atomic(daddr);
+                kunmap_atomic(paddr - psg->offset);
+                kunmap_atomic(daddr - dsg->offset);
         }
 
         return 0;