Re: [PATCH-v2 11/17] target/iblock: Add blk_integrity + BIP passthrough support

[Sagi Grimberg <sagig@dev.mellanox.co.il>]

On 1/19/2014 4:44 AM, Nicholas A. Bellinger wrote:
> From: Nicholas Bellinger <nab@linux-iscsi.org>
>
> This patch adds blk_integrity passthrough support for block_device
> backends using IBLOCK.

Nice!

> This includes iblock_alloc_bip() + setup of bio_integrity_payload
> information that attaches to the leading struct bio once bio_list
> is populated during fast-path iblock_execute_rw() I/O dispatch.
>
> It also updates setup in iblock_configure_device() to detect modes
> of protection + se dev->dev_attrib.pi_prot_type accordingly, along
> with creating required bio_set integrity mempools.
>
> 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>
> ---
>   drivers/target/Kconfig              |    1 +
>   drivers/target/target_core_iblock.c |   91 ++++++++++++++++++++++++++++++++++-
>   2 files changed, 90 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/target/Kconfig b/drivers/target/Kconfig
> index 50aad2e..dc2d84a 100644
> --- a/drivers/target/Kconfig
> +++ b/drivers/target/Kconfig
> @@ -14,6 +14,7 @@ if TARGET_CORE
>   
>   config TCM_IBLOCK
>   	tristate "TCM/IBLOCK Subsystem Plugin for Linux/BLOCK"
> +	select BLK_DEV_INTEGRITY
>   	help
>   	Say Y here to enable the TCM/IBLOCK subsystem plugin for non-buffered
>   	access to Linux/Block devices using BIO
> diff --git a/drivers/target/target_core_iblock.c b/drivers/target/target_core_iblock.c
> index 15d9121..293d9b0 100644
> --- a/drivers/target/target_core_iblock.c
> +++ b/drivers/target/target_core_iblock.c
> @@ -91,6 +91,7 @@ static int iblock_configure_device(struct se_device *dev)
>   	struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
>   	struct request_queue *q;
>   	struct block_device *bd = NULL;
> +	struct blk_integrity *bi;
>   	fmode_t mode;
>   	int ret = -ENOMEM;
>   
> @@ -155,8 +156,40 @@ static int iblock_configure_device(struct se_device *dev)
>   	if (blk_queue_nonrot(q))
>   		dev->dev_attrib.is_nonrot = 1;
>   
> +	bi = bdev_get_integrity(bd);
> +	if (bi) {
> +		struct bio_set *bs = ib_dev->ibd_bio_set;
> +
> +		if (!strcmp(bi->name, "T10-DIF-TYPE3-IP") ||
> +		    !strcmp(bi->name, "T10-DIF-TYPE1-IP")) {
> +			pr_err("IBLOCK export of blk_integrity: %s not"
> +			       " supported\n", bi->name);
> +			ret = -ENOSYS;
> +			goto out_blkdev_put;
> +		}

Please remind me why we ignore IP-CSUM guard type again?
MKP, will this be irrelevant for the initiator as well? if so, I don't 
see a reason to expose this in RDMA verbs.

> +
> +		if (!strcmp(bi->name, "T10-DIF-TYPE3-CRC")) {
> +			dev->dev_attrib.pi_prot_type = TARGET_DIF_TYPE3_PROT;
> +		} else if (!strcmp(bi->name, "T10-DIF-TYPE1-CRC")) {
> +			dev->dev_attrib.pi_prot_type = TARGET_DIF_TYPE1_PROT;
> +		}
> +
> +		if (dev->dev_attrib.pi_prot_type) {
> +			if (bioset_integrity_create(bs, IBLOCK_BIO_POOL_SIZE) < 0) {
> +				pr_err("Unable to allocate bioset for PI\n");
> +				ret = -ENOMEM;
> +				goto out_blkdev_put;
> +			}
> +			pr_debug("IBLOCK setup BIP bs->bio_integrity_pool: %p\n",
> +				 bs->bio_integrity_pool);
> +		}
> +		dev->dev_attrib.hw_pi_prot_type = dev->dev_attrib.pi_prot_type;
> +	}
> +
>   	return 0;
>   
> +out_blkdev_put:
> +	blkdev_put(ib_dev->ibd_bd, FMODE_WRITE|FMODE_READ|FMODE_EXCL);
>   out_free_bioset:
>   	bioset_free(ib_dev->ibd_bio_set);
>   	ib_dev->ibd_bio_set = NULL;
> @@ -170,8 +203,10 @@ static void iblock_free_device(struct se_device *dev)
>   
>   	if (ib_dev->ibd_bd != NULL)
>   		blkdev_put(ib_dev->ibd_bd, FMODE_WRITE|FMODE_READ|FMODE_EXCL);
> -	if (ib_dev->ibd_bio_set != NULL)
> +	if (ib_dev->ibd_bio_set != NULL) {
> +		bioset_integrity_free(ib_dev->ibd_bio_set);
>   		bioset_free(ib_dev->ibd_bio_set);
> +	}
>   	kfree(ib_dev);
>   }
>   
> @@ -586,13 +621,58 @@ static ssize_t iblock_show_configfs_dev_params(struct se_device *dev, char *b)
>   	return bl;
>   }
>   
> +static int
> +iblock_alloc_bip(struct se_cmd *cmd, struct bio *bio)
> +{
> +	struct se_device *dev = cmd->se_dev;
> +	struct blk_integrity *bi;
> +	struct bio_integrity_payload *bip;
> +	struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
> +	struct scatterlist *sg;
> +	int i, rc;
> +
> +	bi = bdev_get_integrity(ib_dev->ibd_bd);
> +	if (!bi) {
> +		pr_err("Unable to locate bio_integrity\n");
> +		return -ENODEV;
> +	}
> +
> +	bip = bio_integrity_alloc(bio, GFP_NOIO, cmd->t_prot_nents);
> +	if (!bip) {
> +		pr_err("Unable to allocate bio_integrity_payload\n");
> +		return -ENOMEM;
> +	}
> +
> +	bip->bip_size = (cmd->data_length / dev->dev_attrib.block_size) *
> +			 dev->prot_length;
> +	bip->bip_sector = bio->bi_sector;
> +
> +	pr_debug("IBLOCK BIP Size: %u Sector: %llu\n", bip->bip_size,
> +		 (unsigned long long)bip->bip_sector);
> +
> +	for_each_sg(cmd->t_prot_sg, sg, cmd->t_prot_nents, i) {
> +
> +		rc = bio_integrity_add_page(bio, sg_page(sg), sg->length,
> +					    sg->offset);
> +		if (rc != sg->length) {
> +			pr_err("bio_integrity_add_page() failed; %d\n", rc);
> +			return -ENOMEM;
> +		}
> +
> +		pr_debug("Added bio integrity page: %p length: %d offset; %d\n",
> +			 sg_page(sg), sg->length, sg->offset);
> +	}
> +
> +	return 0;
> +}
> +
>   static sense_reason_t
>   iblock_execute_rw(struct se_cmd *cmd, struct scatterlist *sgl, u32 sgl_nents,
>   		  enum dma_data_direction data_direction)
>   {
>   	struct se_device *dev = cmd->se_dev;
>   	struct iblock_req *ibr;
> -	struct bio *bio;
> +	struct bio *bio, *bio_start;
>   	struct bio_list list;
>   	struct scatterlist *sg;
>   	u32 sg_num = sgl_nents;
> @@ -655,6 +735,7 @@ iblock_execute_rw(struct se_cmd *cmd, struct scatterlist *sgl, u32 sgl_nents,
>   	if (!bio)
>   		goto fail_free_ibr;
>   
> +	bio_start = bio;
>   	bio_list_init(&list);
>   	bio_list_add(&list, bio);
>   
> @@ -688,6 +769,12 @@ iblock_execute_rw(struct se_cmd *cmd, struct scatterlist *sgl, u32 sgl_nents,
>   		sg_num--;
>   	}
>   
> +	if (cmd->prot_type) {
> +		int rc = iblock_alloc_bip(cmd, bio_start);
> +		if (rc)
> +			goto fail_put_bios;
> +	}
> +
>   	iblock_submit_bios(&list, rw);
>   	iblock_complete_cmd(cmd);
>   	return 0;