From: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>
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.
Cc: Martin K. Petersen <martin.petersen@xxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Cc: Hannes Reinecke <hare@xxxxxxx>
Cc: Sagi Grimberg <sagig@xxxxxxxxxxxx>
Cc: Or Gerlitz <ogerlitz@xxxxxxxxxxxx>
Signed-off-by: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>
---
drivers/target/target_core_sbc.c | 180 ++++++++++++++++++++++++++++++++++
include/target/target_core_backend.h | 4 +
2 files changed, 184 insertions(+)
diff --git a/drivers/target/target_core_sbc.c b/drivers/target/target_core_sbc.c
index 600ffcb..366b9bb 100644
--- 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>
@@ -998,3 +999,182 @@ 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;
+
+ if (dev->dev_attrib.pi_guard_type == TARGET_DIX_GUARD_CRC)
+ csum = cpu_to_be16(crc_t10dif(p, block_size));
+ else
+ csum = (__force __be16)ip_compute_csum(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++;
+ 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 930f30d..eb1dbbe 100644
--- a/include/target/target_core_backend.h
+++ b/include/target/target_core_backend.h
@@ -72,6 +72,10 @@ 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 *);
--
1.7.10.4
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