The vhost-scsi I/O queue uses vhost_scsi_cmd. Pre-allocate the log buffer
during vhost_scsi_cmd allocation, and free it when vhost_scsi_cmd is
reclaimed.
The cached log buffer will be uses in upcoming patches to log write
descriptors for the I/O queue. The core idea is to cache the log in the
per-command log buffer in the submission path, and use them to log write
descriptors in the completion path.
Suggested-by: Joao Martins <joao.m.mart...@oracle.com>
Signed-off-by: Dongli Zhang <dongli.zh...@oracle.com>
---
drivers/vhost/scsi.c | 21 +++++++++++++++++++++
1 file changed, 21 insertions(+)
diff --git a/drivers/vhost/scsi.c b/drivers/vhost/scsi.c
index ee2310555740..5e6221cbbe9e 100644
--- a/drivers/vhost/scsi.c
+++ b/drivers/vhost/scsi.c
@@ -98,6 +98,11 @@ struct vhost_scsi_cmd {
unsigned char tvc_cdb[VHOST_SCSI_MAX_CDB_SIZE];
/* Sense buffer that will be mapped into outgoing status */
unsigned char tvc_sense_buf[TRANSPORT_SENSE_BUFFER];
+ /*
+ * Dirty write descriptors of this command.
+ */
+ struct vhost_log *tvc_log;
+ unsigned int tvc_log_num;
/* Completed commands list, serviced from vhost worker thread */
struct llist_node tvc_completion_list;
/* Used to track inflight cmd */
@@ -619,6 +624,7 @@ vhost_scsi_get_cmd(struct vhost_virtqueue *vq, struct
vhost_scsi_tpg *tpg,
struct vhost_scsi_nexus *tv_nexus;
struct scatterlist *sg, *prot_sg;
struct iovec *tvc_resp_iov;
+ struct vhost_log *log;
struct page **pages;
int tag;
@@ -639,6 +645,7 @@ vhost_scsi_get_cmd(struct vhost_virtqueue *vq, struct
vhost_scsi_tpg *tpg,
prot_sg = cmd->tvc_prot_sgl;
pages = cmd->tvc_upages;
tvc_resp_iov = cmd->tvc_resp_iov;
+ log = cmd->tvc_log;
memset(cmd, 0, sizeof(*cmd));
cmd->tvc_sgl = sg;
cmd->tvc_prot_sgl = prot_sg;
@@ -652,6 +659,7 @@ vhost_scsi_get_cmd(struct vhost_virtqueue *vq, struct
vhost_scsi_tpg *tpg,
cmd->tvc_nexus = tv_nexus;
cmd->inflight = vhost_scsi_get_inflight(vq);
cmd->tvc_resp_iov = tvc_resp_iov;
+ cmd->tvc_log = log;
memcpy(cmd->tvc_cdb, cdb, VHOST_SCSI_MAX_CDB_SIZE);
@@ -1604,6 +1612,7 @@ static void vhost_scsi_destroy_vq_cmds(struct
vhost_virtqueue *vq)
kfree(tv_cmd->tvc_prot_sgl);
kfree(tv_cmd->tvc_upages);
kfree(tv_cmd->tvc_resp_iov);
+ kfree(tv_cmd->tvc_log);
}
sbitmap_free(&svq->scsi_tags);
@@ -1666,6 +1675,18 @@ static int vhost_scsi_setup_vq_cmds(struct
vhost_virtqueue *vq, int max_cmds)
pr_err("Unable to allocate tv_cmd->tvc_prot_sgl\n");
goto out;
}
+
+ /*
+ * tv_cmd->tvc_log and vq->log need to have the same max
+ * length.
+ */
+ tv_cmd->tvc_log = kcalloc(vq->dev->iov_limit,
+ sizeof(struct vhost_log),
+ GFP_KERNEL);
+ if (!tv_cmd->tvc_log) {
+ pr_err("Unable to allocate tv_cmd->tvc_log\n");
+ goto out;
+ }
}
return 0;
out:
--
2.39.3
