vhost/scsi: Add preallocation of protection SGLs

This patch updates tcm_vhost_make_nexus() to pre-allocate per descriptor
tcm_vhost_cmd->tvc_prot_sgl[] used to expose protection SGLs from within
virtio-scsi guest memory to vhost-scsi.

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>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

diff --git a/drivers/vhost/scsi.c b/drivers/vhost/scsi.c
index ae434db2d3847452fc576a9135de7a7b9742edc8..30402e618078ffefd93de2b918b5f8b03ecf96ad 100644 (file)
--- a/drivers/vhost/scsi.c
+++ b/drivers/vhost/scsi.c
@@ -58,6 +58,7 @@
 #define TCM_VHOST_DEFAULT_TAGS 256
 #define TCM_VHOST_PREALLOC_SGLS 2048
 #define TCM_VHOST_PREALLOC_UPAGES 2048
+#define TCM_VHOST_PREALLOC_PROT_SGLS 512
 
 struct vhost_scsi_inflight {
        /* Wait for the flush operation to finish */
@@ -83,6 +84,7 @@ struct tcm_vhost_cmd {
        u32 tvc_lun;
        /* Pointer to the SGL formatted memory from virtio-scsi */
        struct scatterlist *tvc_sgl;
+       struct scatterlist *tvc_prot_sgl;
        struct page **tvc_upages;
        /* Pointer to response */
        struct virtio_scsi_cmd_resp __user *tvc_resp;
@@ -722,7 +724,7 @@ vhost_scsi_get_tag(struct vhost_virtqueue *vq,
        struct tcm_vhost_cmd *cmd;
        struct tcm_vhost_nexus *tv_nexus;
        struct se_session *se_sess;
-       struct scatterlist *sg;
+       struct scatterlist *sg, *prot_sg;
        struct page **pages;
        int tag;
 
@@ -741,10 +743,12 @@ vhost_scsi_get_tag(struct vhost_virtqueue *vq,
 
        cmd = &((struct tcm_vhost_cmd *)se_sess->sess_cmd_map)[tag];
        sg = cmd->tvc_sgl;
+       prot_sg = cmd->tvc_prot_sgl;
        pages = cmd->tvc_upages;
        memset(cmd, 0, sizeof(struct tcm_vhost_cmd));
 
        cmd->tvc_sgl = sg;
+       cmd->tvc_prot_sgl = prot_sg;
        cmd->tvc_upages = pages;
        cmd->tvc_se_cmd.map_tag = tag;
        cmd->tvc_tag = v_req->tag;
@@ -1703,6 +1707,7 @@ static void tcm_vhost_free_cmd_map_res(struct tcm_vhost_nexus *nexus,
                tv_cmd = &((struct tcm_vhost_cmd *)se_sess->sess_cmd_map)[i];
 
                kfree(tv_cmd->tvc_sgl);
+               kfree(tv_cmd->tvc_prot_sgl);
                kfree(tv_cmd->tvc_upages);
        }
 }
@@ -1762,6 +1767,14 @@ static int tcm_vhost_make_nexus(struct tcm_vhost_tpg *tpg,
                        pr_err("Unable to allocate tv_cmd->tvc_upages\n");
                        goto out;
                }
+
+               tv_cmd->tvc_prot_sgl = kzalloc(sizeof(struct scatterlist) *
+                                       TCM_VHOST_PREALLOC_PROT_SGLS, GFP_KERNEL);
+               if (!tv_cmd->tvc_prot_sgl) {
+                       mutex_unlock(&tpg->tv_tpg_mutex);
+                       pr_err("Unable to allocate tv_cmd->tvc_prot_sgl\n");
+                       goto out;
+               }
        }
        /*
         * Since we are running in 'demo mode' this call with generate a