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>

diff --git a/drivers/target/target_core_sbc.c b/drivers/target/target_core_sbc.c
index ca95fab3521a915db2e0a42cb143ce24de009bbe..3df2cd53847831f09476aae1d614035c599ceb42 100644 (file)
--- 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;