From 6a70c943a26f0673bebc01b4f01d5eda84984e2f Mon Sep 17 00:00:00 2001 From: Sudhakar Panneerselvam Date: Fri, 22 May 2020 16:51:57 +0000 Subject: [PATCH] scsi: vhost: Notify TCM about the maximum sg entries supported per command [ 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.panneerselvam@oracle.com Cc: Michael S. Tsirkin Cc: Jason Wang Cc: Paolo Bonzini Cc: Stefan Hajnoczi Reviewed-by: Mike Christie Signed-off-by: Sudhakar Panneerselvam Signed-off-by: Martin K. Petersen Signed-off-by: Sasha Levin --- drivers/vhost/scsi.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/vhost/scsi.c b/drivers/vhost/scsi.c index a9caf1b..88ce114 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, -- 2.7.4