From: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>
This patch adds WRITE_INSERT emulation within target-core
using TYPE1 / TYPE3 PI modes.
This is useful in order for existing legacy fabrics that do not
support protection offloads to interact with backend devices that
currently have T10 PI enabled.
Cc: Martin K. Petersen <martin.petersen@xxxxxxxxxx>
Cc: Sagi Grimberg <sagig@xxxxxxxxxxxx>
Cc: Or Gerlitz <ogerlitz@xxxxxxxxxxxx>
Cc: Quinn Tran <quinn.tran@xxxxxxxxxx>
Cc: Giridhar Malavali <giridhar.malavali@xxxxxxxxxx>
Signed-off-by: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>
---
drivers/target/target_core_sbc.c | 44 ++++++++++++++++++++++++++++++++++
include/target/target_core_backend.h | 1 +
2 files changed, 45 insertions(+)
diff --git a/drivers/target/target_core_sbc.c b/drivers/target/target_core_sbc.c
index f2d73dd..97b207d 100644
--- a/drivers/target/target_core_sbc.c
+++ b/drivers/target/target_core_sbc.c
@@ -1096,6 +1096,50 @@ err:
}
EXPORT_SYMBOL(sbc_execute_unmap);
+void
+sbc_dif_write_insert(struct se_cmd *cmd)
+{
+ struct se_device *dev = cmd->se_dev;
+ struct se_dif_v1_tuple *sdt;
+ struct scatterlist *dsg, *psg = cmd->t_prot_sg;
+ sector_t sector = cmd->t_task_lba;
+ void *daddr, *paddr;
+ int i, j, offset = 0;
+
+ 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;
+ sdt->guard_tag = cpu_to_be16(crc_t10dif(daddr + j,
+ dev->dev_attrib.block_size));
+ if (dev->dev_attrib.pi_prot_type == TARGET_DIF_TYPE1_PROT)
+ sdt->ref_tag = cpu_to_be32(sector & 0xffffffff);
+ sdt->app_tag = 0;
+
+ pr_debug("DIF WRITE INSERT 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));
+
+ sector++;
+ offset += sizeof(struct se_dif_v1_tuple);
+ }
+
+ kunmap_atomic(paddr);
+ kunmap_atomic(daddr);
+ }
+}
+
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)
diff --git a/include/target/target_core_backend.h b/include/target/target_core_backend.h
index 7020e33..8e6eac6 100644
--- a/include/target/target_core_backend.h
+++ b/include/target/target_core_backend.h
@@ -73,6 +73,7 @@ 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);
+void sbc_dif_write_insert(struct se_cmd *);
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,
--
1.7.10.4
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