From: Sudhakar Panneerselvam sudhakar.panneerselvam@oracle.com
[ Upstream commit 5ae6a6a915033bfee79e76e0c374d4f927909edc ]
vhost-scsi pre-allocates the maximum sg entries per command and if a command requires more than VHOST_SCSI_PREALLOC_SGLS entries, then that command is failed by it. This patch lets vhost communicate the max sg limit when it registers vhost_scsi_ops with TCM. With this change, TCM would report the max sg entries through "Block Limits" VPD page which will be typically queried by the SCSI initiator during device discovery. By knowing this limit, the initiator could ensure the maximum transfer length is less than or equal to what is reported by vhost-scsi.
Link: https://lore.kernel.org/r/1590166317-953-1-git-send-email-sudhakar.panneerse... Cc: Michael S. Tsirkin mst@redhat.com Cc: Jason Wang jasowang@redhat.com Cc: Paolo Bonzini pbonzini@redhat.com Cc: Stefan Hajnoczi stefanha@redhat.com Reviewed-by: Mike Christie mchristi@redhat.com Signed-off-by: Sudhakar Panneerselvam sudhakar.panneerselvam@oracle.com Signed-off-by: Martin K. Petersen martin.petersen@oracle.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/vhost/scsi.c | 1 + 1 file changed, 1 insertion(+)
diff --git a/drivers/vhost/scsi.c b/drivers/vhost/scsi.c index a9caf1bc3c3e..88ce114790d7 100644 --- a/drivers/vhost/scsi.c +++ b/drivers/vhost/scsi.c @@ -2290,6 +2290,7 @@ static struct configfs_attribute *vhost_scsi_wwn_attrs[] = { static const struct target_core_fabric_ops vhost_scsi_ops = { .module = THIS_MODULE, .fabric_name = "vhost", + .max_data_sg_nents = VHOST_SCSI_PREALLOC_SGLS, .tpg_get_wwn = vhost_scsi_get_fabric_wwn, .tpg_get_tag = vhost_scsi_get_tpgt, .tpg_check_demo_mode = vhost_scsi_check_true,