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-rw-r--r--drivers/vhost/scsi.c82
1 files changed, 60 insertions, 22 deletions
diff --git a/drivers/vhost/scsi.c b/drivers/vhost/scsi.c
index 82389e2ac0c9..f6f5a7ac7894 100644
--- a/drivers/vhost/scsi.c
+++ b/drivers/vhost/scsi.c
@@ -45,6 +45,11 @@
#define VHOST_SCSI_PREALLOC_SGLS 2048
#define VHOST_SCSI_PREALLOC_UPAGES 2048
#define VHOST_SCSI_PREALLOC_PROT_SGLS 2048
+/*
+ * For the legacy descriptor case we allocate an iov per byte in the
+ * virtio_scsi_cmd_resp struct.
+ */
+#define VHOST_SCSI_MAX_RESP_IOVS sizeof(struct virtio_scsi_cmd_resp)
static unsigned int vhost_scsi_inline_sg_cnt = VHOST_SCSI_PREALLOC_SGLS;
@@ -106,8 +111,6 @@ struct vhost_scsi_inflight {
struct vhost_scsi_cmd {
/* Descriptor from vhost_get_vq_desc() for virt_queue segment */
int tvc_vq_desc;
- /* virtio-scsi response incoming iovecs */
- int tvc_in_iovs;
/* The number of scatterlists associated with this cmd */
u32 tvc_sgl_count;
u32 tvc_prot_sgl_count;
@@ -118,8 +121,12 @@ struct vhost_scsi_cmd {
struct sg_table table;
struct scatterlist *prot_sgl;
struct sg_table prot_table;
- /* Pointer to response header iovec */
- struct iovec *tvc_resp_iov;
+ /* Fast path response header iovec used when only one vec is needed */
+ struct iovec tvc_resp_iov;
+ /* Number of iovs for response */
+ unsigned int tvc_resp_iovs_cnt;
+ /* Pointer to response header iovecs if more than one is needed */
+ struct iovec *tvc_resp_iovs;
/* Pointer to vhost_virtqueue for the cmd */
struct vhost_virtqueue *tvc_vq;
/* The TCM I/O descriptor that is accessed via container_of() */
@@ -391,6 +398,8 @@ static void vhost_scsi_release_cmd_res(struct se_cmd *se_cmd)
sg_free_table_chained(&tv_cmd->prot_table, vs->inline_sg_cnt);
}
+ if (tv_cmd->tvc_resp_iovs != &tv_cmd->tvc_resp_iov)
+ kfree(tv_cmd->tvc_resp_iovs);
sbitmap_clear_bit(&svq->scsi_tags, se_cmd->map_tag);
vhost_scsi_put_inflight(inflight);
}
@@ -638,8 +647,8 @@ static void vhost_scsi_complete_cmd_work(struct vhost_work *work)
se_cmd->scsi_sense_length);
}
- iov_iter_init(&iov_iter, ITER_DEST, cmd->tvc_resp_iov,
- cmd->tvc_in_iovs, sizeof(v_rsp));
+ iov_iter_init(&iov_iter, ITER_DEST, cmd->tvc_resp_iovs,
+ cmd->tvc_resp_iovs_cnt, sizeof(v_rsp));
ret = copy_to_iter(&v_rsp, sizeof(v_rsp), &iov_iter);
if (likely(ret == sizeof(v_rsp))) {
signal = true;
@@ -662,7 +671,6 @@ vhost_scsi_get_cmd(struct vhost_virtqueue *vq, u64 scsi_tag)
struct vhost_scsi_virtqueue, vq);
struct vhost_scsi_cmd *cmd;
struct scatterlist *sgl, *prot_sgl;
- struct iovec *tvc_resp_iov;
int tag;
tag = sbitmap_get(&svq->scsi_tags);
@@ -674,13 +682,11 @@ vhost_scsi_get_cmd(struct vhost_virtqueue *vq, u64 scsi_tag)
cmd = &svq->scsi_cmds[tag];
sgl = cmd->sgl;
prot_sgl = cmd->prot_sgl;
- tvc_resp_iov = cmd->tvc_resp_iov;
memset(cmd, 0, sizeof(*cmd));
cmd->sgl = sgl;
cmd->prot_sgl = prot_sgl;
cmd->tvc_se_cmd.map_tag = tag;
cmd->inflight = vhost_scsi_get_inflight(vq);
- cmd->tvc_resp_iov = tvc_resp_iov;
return cmd;
}
@@ -1124,6 +1130,43 @@ out:
return ret;
}
+static int
+vhost_scsi_setup_resp_iovs(struct vhost_scsi_cmd *cmd, struct iovec *in_iovs,
+ unsigned int in_iovs_cnt)
+{
+ int i, cnt;
+
+ if (!in_iovs_cnt)
+ return 0;
+ /*
+ * Initiator's normally just put the virtio_scsi_cmd_resp in the first
+ * iov, but just in case they wedged in some data with it we check for
+ * greater than or equal to the response struct.
+ */
+ if (in_iovs[0].iov_len >= sizeof(struct virtio_scsi_cmd_resp)) {
+ cmd->tvc_resp_iovs = &cmd->tvc_resp_iov;
+ cmd->tvc_resp_iovs_cnt = 1;
+ } else {
+ /*
+ * Legacy descriptor layouts didn't specify that we must put
+ * the entire response in one iov. Worst case we have a
+ * iov per byte.
+ */
+ cnt = min(VHOST_SCSI_MAX_RESP_IOVS, in_iovs_cnt);
+ cmd->tvc_resp_iovs = kcalloc(cnt, sizeof(struct iovec),
+ GFP_KERNEL);
+ if (!cmd->tvc_resp_iovs)
+ return -ENOMEM;
+
+ cmd->tvc_resp_iovs_cnt = cnt;
+ }
+
+ for (i = 0; i < cmd->tvc_resp_iovs_cnt; i++)
+ cmd->tvc_resp_iovs[i] = in_iovs[i];
+
+ return 0;
+}
+
static u16 vhost_buf_to_lun(u8 *lun_buf)
{
return ((lun_buf[2] << 8) | lun_buf[3]) & 0x3FFF;
@@ -1141,7 +1184,7 @@ vhost_scsi_handle_vq(struct vhost_scsi *vs, struct vhost_virtqueue *vq)
struct iov_iter in_iter, prot_iter, data_iter;
u64 tag;
u32 exp_data_len, data_direction;
- int ret, prot_bytes, i, c = 0;
+ int ret, prot_bytes, c = 0;
u16 lun;
u8 task_attr;
bool t10_pi = vhost_has_feature(vq, VIRTIO_SCSI_F_T10_PI);
@@ -1303,9 +1346,13 @@ vhost_scsi_handle_vq(struct vhost_scsi *vs, struct vhost_virtqueue *vq)
goto err;
}
cmd->tvc_vq = vq;
- for (i = 0; i < vc.in ; i++)
- cmd->tvc_resp_iov[i] = vq->iov[vc.out + i];
- cmd->tvc_in_iovs = vc.in;
+
+ ret = vhost_scsi_setup_resp_iovs(cmd, &vq->iov[vc.out], vc.in);
+ if (ret) {
+ vq_err(vq, "Failed to alloc recv iovs\n");
+ vhost_scsi_release_cmd_res(&cmd->tvc_se_cmd);
+ goto err;
+ }
pr_debug("vhost_scsi got command opcode: %#02x, lun: %d\n",
cdb[0], lun);
@@ -1686,7 +1733,6 @@ static void vhost_scsi_destroy_vq_cmds(struct vhost_virtqueue *vq)
kfree(tv_cmd->sgl);
kfree(tv_cmd->prot_sgl);
- kfree(tv_cmd->tvc_resp_iov);
}
sbitmap_free(&svq->scsi_tags);
@@ -1735,14 +1781,6 @@ static int vhost_scsi_setup_vq_cmds(struct vhost_virtqueue *vq, int max_cmds)
}
}
- tv_cmd->tvc_resp_iov = kcalloc(UIO_MAXIOV,
- sizeof(struct iovec),
- GFP_KERNEL);
- if (!tv_cmd->tvc_resp_iov) {
- pr_err("Unable to allocate tv_cmd->tvc_resp_iov\n");
- goto out;
- }
-
if (vhost_has_feature(vq, VIRTIO_SCSI_F_T10_PI) &&
vs->inline_sg_cnt) {
tv_cmd->prot_sgl = kcalloc(vs->inline_sg_cnt,
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.