T10 PI is not a widely used feature. This has us only allocate the
structs for it if the feature has been enabled. For a common small setup
where you have 1 virtqueue and 128 commands per queue, this saves:
8MB = 32 bytes per sg * 2048 entries * 128 commands
per vhost-scsi device.
Signed-off-by: Mike Christie <michael.christie@xxxxxxxxxx>
---
drivers/vhost/scsi.c | 14 ++++++++------
1 file changed, 8 insertions(+), 6 deletions(-)
diff --git a/drivers/vhost/scsi.c b/drivers/vhost/scsi.c
index 0cfa56d08450..776051577a5f 100644
--- a/drivers/vhost/scsi.c
+++ b/drivers/vhost/scsi.c
@@ -1648,12 +1648,14 @@ static int vhost_scsi_setup_vq_cmds(struct vhost_virtqueue *vq, int max_cmds)
goto out;
}
- tv_cmd->tvc_prot_sgl = kcalloc(VHOST_SCSI_PREALLOC_PROT_SGLS,
- sizeof(struct scatterlist),
- GFP_KERNEL);
- if (!tv_cmd->tvc_prot_sgl) {
- pr_err("Unable to allocate tv_cmd->tvc_prot_sgl\n");
- goto out;
+ if (vhost_has_feature(vq, VIRTIO_SCSI_F_T10_PI)) {
+ tv_cmd->tvc_prot_sgl = kcalloc(VHOST_SCSI_PREALLOC_PROT_SGLS,
+ sizeof(struct scatterlist),
+ GFP_KERNEL);
+ if (!tv_cmd->tvc_prot_sgl) {
+ pr_err("Unable to allocate tv_cmd->tvc_prot_sgl\n");
+ goto out;
+ }
}
}
return 0;
--
2.34.1
