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Commit 66a3d5bc authored by Nicholas Bellinger's avatar Nicholas Bellinger
Browse files

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: default avatarNicholas Bellinger <nab@linux-iscsi.org>
parent 2d335983

drivers/target/target_core_sbc.c

+44 −0
Original line number Diff line number Diff line
@@ -1096,6 +1096,50 @@ sbc_execute_unmap(struct se_cmd *cmd, 
}

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)

include/target/target_core_backend.h

+1 −0
Original line number Diff line number Diff line
@@ -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,