[RFC 3/6] vhost/scsi: Add T10 PI IOV -> SGL memory mapping logic

Nicholas A. Bellinger
2014-02-24T05:32:27Z

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: Martin K. Petersen <martin.petersen@oracle.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Sagi Grimberg <sagig@dev.mellanox.co.il>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
---
drivers/vhost/scsi.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/vhost/scsi.c b/drivers/vhost/scsi.c
index 314cbd4..0cf5948 100644
--- a/drivers/vhost/scsi.c
+++ b/drivers/vhost/scsi.c
@@ -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);
--
1.7.10.4