target/sbc: Add DIF TYPE1+TYPE3 read/write verify emulation

This patch adds support for DIF read/write verify emulation
for TARGET_DIF_TYPE1_PROT + TARGET_DIF_TYPE3_PROT operation.

This includes sbc_dif_verify_write() + sbc_dif_verify_read()
calls accessable by backend drivers to perform DIF verify
for SGL based data and protection information.

Also included is sbc_dif_copy_prot() logic to copy protection
information to/from backend provided protection SGLs.

Based on scsi_debug.c DIF TYPE1+TYPE3 emulation.

v2 changes:
  - Select CRC_T10DIF for TARGET_CORE in Kconfig (Fengguang)
  - Drop IP checksum logic from sbc_dif_v1_verify (MKP)
  - Fix offset on app_tag = 0xffff in sbc_dif_verify_read()

Cc: Martin K. Petersen <martin.petersen@oracle.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Sagi Grimberg <sagig@mellanox.com>
Cc: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

diff --git a/drivers/target/Kconfig b/drivers/target/Kconfig
index 1830368..50aad2e 100644 (file)
--- a/drivers/target/Kconfig
+++ b/drivers/target/Kconfig
@@ -3,6 +3,7 @@ menuconfig TARGET_CORE
        tristate "Generic Target Core Mod (TCM) and ConfigFS Infrastructure"
        depends on SCSI && BLOCK
        select CONFIGFS_FS
+       select CRC_T10DIF
        default n
        help
        Say Y or M here to enable the TCM Storage Engine and ConfigFS enabled

diff --git a/drivers/target/target_core_sbc.c b/drivers/target/target_core_sbc.c
index 91a92f3..26e8bfb 100644 (file)
--- a/drivers/target/target_core_sbc.c
+++ b/drivers/target/target_core_sbc.c
@@ -23,6 +23,7 @@
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/ratelimit.h>
+#include <linux/crc-t10dif.h>
 #include <asm/unaligned.h>
 #include <scsi/scsi.h>
 #include <scsi/scsi_tcq.h>
@@ -1024,3 +1025,180 @@ err:
        return ret;
 }
 EXPORT_SYMBOL(sbc_execute_unmap);
+
+static sense_reason_t
+sbc_dif_v1_verify(struct se_device *dev, struct se_dif_v1_tuple *sdt,
+                 const void *p, sector_t sector, unsigned int ei_lba)
+{
+       int block_size = dev->dev_attrib.block_size;
+       __be16 csum;
+
+       csum = cpu_to_be16(crc_t10dif(p, block_size));
+
+       if (sdt->guard_tag != csum) {
+               pr_err("DIFv1 checksum failed on sector %llu guard tag 0x%04x"
+                       " csum 0x%04x\n", (unsigned long long)sector,
+                       be16_to_cpu(sdt->guard_tag), be16_to_cpu(csum));
+               return TCM_LOGICAL_BLOCK_GUARD_CHECK_FAILED;
+       }
+
+       if (dev->dev_attrib.pi_prot_type == TARGET_DIF_TYPE1_PROT &&
+           be32_to_cpu(sdt->ref_tag) != (sector & 0xffffffff)) {
+               pr_err("DIFv1 Type 1 reference failed on sector: %llu tag: 0x%08x"
+                      " sector MSB: 0x%08x\n", (unsigned long long)sector,
+                      be32_to_cpu(sdt->ref_tag), (u32)(sector & 0xffffffff));
+               return TCM_LOGICAL_BLOCK_REF_TAG_CHECK_FAILED;
+       }
+
+       if (dev->dev_attrib.pi_prot_type == TARGET_DIF_TYPE2_PROT &&
+           be32_to_cpu(sdt->ref_tag) != ei_lba) {
+               pr_err("DIFv1 Type 2 reference failed on sector: %llu tag: 0x%08x"
+                      " ei_lba: 0x%08x\n", (unsigned long long)sector,
+                       be32_to_cpu(sdt->ref_tag), ei_lba);
+               return TCM_LOGICAL_BLOCK_REF_TAG_CHECK_FAILED;
+       }
+
+       return 0;
+}
+
+static void
+sbc_dif_copy_prot(struct se_cmd *cmd, unsigned int sectors, bool read,
+                 struct scatterlist *sg, int sg_off)
+{
+       struct se_device *dev = cmd->se_dev;
+       struct scatterlist *psg;
+       void *paddr, *addr;
+       unsigned int i, len, left;
+
+       left = sectors * dev->prot_length;
+
+       for_each_sg(cmd->t_prot_sg, psg, cmd->t_prot_nents, i) {
+
+               len = min(psg->length, left);
+               paddr = kmap_atomic(sg_page(psg)) + psg->offset;
+               addr = kmap_atomic(sg_page(sg)) + sg_off;
+
+               if (read)
+                       memcpy(paddr, addr, len);
+               else
+                       memcpy(addr, paddr, len);
+
+               left -= len;
+               kunmap_atomic(paddr);
+               kunmap_atomic(addr);
+       }
+}
+
+sense_reason_t
+sbc_dif_verify_write(struct se_cmd *cmd, sector_t start, unsigned int sectors,
+                    unsigned int ei_lba, struct scatterlist *sg, int sg_off)
+{
+       struct se_device *dev = cmd->se_dev;
+       struct se_dif_v1_tuple *sdt;
+       struct scatterlist *dsg, *psg = cmd->t_prot_sg;
+       sector_t sector = start;
+       void *daddr, *paddr;
+       int i, j, offset = 0;
+       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)) + psg->offset;
+
+               for (j = 0; j < dsg->length; j += dev->dev_attrib.block_size) {
+
+                       if (offset >= psg->length) {
+                               kunmap_atomic(paddr);
+                               psg = sg_next(psg);
+                               paddr = kmap_atomic(sg_page(psg)) + psg->offset;
+                               offset = 0;
+                       }
+
+                       sdt = paddr + offset;
+
+                       pr_debug("DIF WRITE sector: %llu guard_tag: 0x%04x"
+                                " app_tag: 0x%04x ref_tag: %u\n",
+                                (unsigned long long)sector, sdt->guard_tag,
+                                sdt->app_tag, be32_to_cpu(sdt->ref_tag));
+
+                       rc = sbc_dif_v1_verify(dev, sdt, daddr + j, sector,
+                                              ei_lba);
+                       if (rc) {
+                               kunmap_atomic(paddr);
+                               kunmap_atomic(daddr);
+                               return rc;
+                       }
+
+                       sector++;
+                       ei_lba++;
+                       offset += sizeof(struct se_dif_v1_tuple);
+               }
+
+               kunmap_atomic(paddr);
+               kunmap_atomic(daddr);
+       }
+       sbc_dif_copy_prot(cmd, sectors, false, sg, sg_off);
+
+       return 0;
+}
+EXPORT_SYMBOL(sbc_dif_verify_write);
+
+sense_reason_t
+sbc_dif_verify_read(struct se_cmd *cmd, sector_t start, unsigned int sectors,
+                   unsigned int ei_lba, struct scatterlist *sg, int sg_off)
+{
+       struct se_device *dev = cmd->se_dev;
+       struct se_dif_v1_tuple *sdt;
+       struct scatterlist *dsg;
+       sector_t sector = start;
+       void *daddr, *paddr;
+       int i, j, offset = sg_off;
+       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(sg)) + sg->offset;
+
+               for (j = 0; j < dsg->length; j += dev->dev_attrib.block_size) {
+
+                       if (offset >= sg->length) {
+                               kunmap_atomic(paddr);
+                               sg = sg_next(sg);
+                               paddr = kmap_atomic(sg_page(sg)) + sg->offset;
+                               offset = 0;
+                       }
+
+                       sdt = paddr + offset;
+
+                       pr_debug("DIF READ sector: %llu guard_tag: 0x%04x"
+                                " app_tag: 0x%04x ref_tag: %u\n",
+                                (unsigned long long)sector, sdt->guard_tag,
+                                sdt->app_tag, be32_to_cpu(sdt->ref_tag));
+
+                       if (sdt->app_tag == cpu_to_be16(0xffff)) {
+                               sector++;
+                               offset += sizeof(struct se_dif_v1_tuple);
+                               continue;
+                       }
+
+                       rc = sbc_dif_v1_verify(dev, sdt, daddr + j, sector,
+                                              ei_lba);
+                       if (rc) {
+                               kunmap_atomic(paddr);
+                               kunmap_atomic(daddr);
+                               return rc;
+                       }
+
+                       sector++;
+                       ei_lba++;
+                       offset += sizeof(struct se_dif_v1_tuple);
+               }
+
+               kunmap_atomic(paddr);
+               kunmap_atomic(daddr);
+       }
+       sbc_dif_copy_prot(cmd, sectors, true, sg, sg_off);
+
+       return 0;
+}
+EXPORT_SYMBOL(sbc_dif_verify_read);

diff --git a/include/target/target_core_backend.h b/include/target/target_core_backend.h
index 0dc2745..7020e33 100644 (file)
--- a/include/target/target_core_backend.h
+++ b/include/target/target_core_backend.h
@@ -73,6 +73,10 @@ sense_reason_t sbc_execute_unmap(struct se_cmd *cmd,
        sense_reason_t (*do_unmap_fn)(struct se_cmd *cmd, void *priv,
                                      sector_t lba, sector_t nolb),
        void *priv);
+sense_reason_t sbc_dif_verify_write(struct se_cmd *, sector_t, unsigned int,
+                                    unsigned int, struct scatterlist *, int);
+sense_reason_t sbc_dif_verify_read(struct se_cmd *, sector_t, unsigned int,
+                                   unsigned int, struct scatterlist *, int);
 
 void   transport_set_vpd_proto_id(struct t10_vpd *, unsigned char *);
 int    transport_set_vpd_assoc(struct t10_vpd *, unsigned char *);