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target/sbc: Add sbc_dif_generate software emulation 

This patch adds WRITE_INSERT emulation within target-core
using TYPE1 / TYPE3 PI modes in sbc_dif_generate() code.

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.

v2 changes:
   - Rename to sbc_dif_generate() (Sagi)

Cc: Martin K. Petersen <martin.petersen@oracle.com>
Cc: Sagi Grimberg <sagig@mellanox.com>
Cc: Or Gerlitz <ogerlitz@mellanox.com>
Cc: Quinn Tran <quinn.tran@qlogic.com>
Cc: Giridhar Malavali <giridhar.malavali@qlogic.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
This commit is contained in:
Nicholas Bellinger 2014-04-02 14:19:09 -07:00
parent 2d33598325
commit 66a3d5bc47
2 changed files with 45 additions and 0 deletions
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44
drivers/target/target_core_sbc.c
View File

@ -1096,6 +1096,50 @@ err:
}
EXPORT_SYMBOL(sbc_execute_unmap);
void
sbc_dif_generate(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)

1
include/target/target_core_backend.h
View File

@ -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_generate(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,