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Commit e31885dd authored by Nicholas Bellinger's avatar Nicholas Bellinger
Browse files

vhost/scsi: Add T10 PI IOV -> SGL memory mapping logic 



This patch adds vhost_scsi_map_iov_to_prot() to perform the mapping of
T10 data integrity memory between virtio iov + struct scatterlist using
get_user_pages_fast() following existing code.

As with vhost_scsi_map_iov_to_sgl(), this does sanity checks against the
total prot_sgl_count vs. pre-allocated SGLs, and loops across protection
iovs using vhost_scsi_map_to_sgl() to perform the actual memory mapping.

Also update tcm_vhost_release_cmd() to release associated tvc_prot_sgl[]
struct page.

Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Martin K. Petersen <martin.petersen@oracle.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Sagi Grimberg <sagig@dev.mellanox.co.il>
Cc: H. Peter Anvin <hpa@zytor.com>
Acked-by: default avatarMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: default avatarNicholas Bellinger <nab@linux-iscsi.org>
parent b1935f68

drivers/vhost/scsi.c

+47 −1
Original line number Diff line number Diff line
@@ -80,6 +80,7 @@ struct tcm_vhost_cmd { 
	u64 tvc_tag;

	/* The number of scatterlists associated with this cmd */

	u32 tvc_sgl_count;

	u32 tvc_prot_sgl_count;

	/* Saved unpacked SCSI LUN for tcm_vhost_submission_work() */

	u32 tvc_lun;

	/* Pointer to the SGL formatted memory from virtio-scsi */
@@ -458,12 +459,16 @@ static void tcm_vhost_release_cmd(struct se_cmd *se_cmd) 
	struct tcm_vhost_cmd *tv_cmd = container_of(se_cmd,

				struct tcm_vhost_cmd, tvc_se_cmd);

	struct se_session *se_sess = se_cmd->se_sess;

	int i;



	if (tv_cmd->tvc_sgl_count) {

		u32 i;

		for (i = 0; i < tv_cmd->tvc_sgl_count; i++)

			put_page(sg_page(&tv_cmd->tvc_sgl[i]));

	}

	if (tv_cmd->tvc_prot_sgl_count) {

		for (i = 0; i < tv_cmd->tvc_prot_sgl_count; i++)

			put_page(sg_page(&tv_cmd->tvc_prot_sgl[i]));

	}



	tcm_vhost_put_inflight(tv_cmd->inflight);

	percpu_ida_free(&se_sess->sess_tag_pool, se_cmd->map_tag);
@@ -861,6 +866,47 @@ vhost_scsi_map_iov_to_sgl(struct tcm_vhost_cmd *cmd, 
	return 0;

}



static int

vhost_scsi_map_iov_to_prot(struct tcm_vhost_cmd *cmd,

			   struct iovec *iov,

			   int niov,

			   bool write)

{

	struct scatterlist *prot_sg = cmd->tvc_prot_sgl;

	unsigned int prot_sgl_count = 0;

	int ret, i;



	for (i = 0; i < niov; i++)

		prot_sgl_count += iov_num_pages(&iov[i]);



	if (prot_sgl_count > TCM_VHOST_PREALLOC_PROT_SGLS) {

		pr_err("vhost_scsi_map_iov_to_prot() sgl_count: %u greater than"

			" preallocated TCM_VHOST_PREALLOC_PROT_SGLS: %u\n",

			prot_sgl_count, TCM_VHOST_PREALLOC_PROT_SGLS);

		return -ENOBUFS;

	}



	pr_debug("%s prot_sg %p prot_sgl_count %u\n", __func__,

		 prot_sg, prot_sgl_count);

	sg_init_table(prot_sg, prot_sgl_count);

	cmd->tvc_prot_sgl_count = prot_sgl_count;



	for (i = 0; i < niov; i++) {

		ret = vhost_scsi_map_to_sgl(cmd, prot_sg, prot_sgl_count, &iov[i],

					    cmd->tvc_upages, write);

		if (ret < 0) {

			for (i = 0; i < cmd->tvc_prot_sgl_count; i++)

				put_page(sg_page(&cmd->tvc_prot_sgl[i]));



			cmd->tvc_prot_sgl_count = 0;

			return ret;

		}

		prot_sg += ret;

		prot_sgl_count -= ret;

	}

	return 0;

}



static void tcm_vhost_submission_work(struct work_struct *work)

{

	struct tcm_vhost_cmd *cmd =