vhost-scsi: Return queue full for page alloc failures during copy

This has us return queue full if we can't allocate a page during the
copy operation so the initiator can retry.

Signed-off-by: Mike Christie <michael.christie@oracle.com>
Message-Id: <20241203191705.19431-5-michael.christie@oracle.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Stefan Hajnoczi <stefanha@redhat.com>

Author: mikechristie

drivers/vhost/scsi.c

@@ -756,7 +756,7 @@ vhost_scsi_copy_iov_to_sgl(struct vhost_scsi_cmd *cmd, struct iov_iter *iter,
 	size_t len = iov_iter_count(iter);
 	unsigned int nbytes = 0;
 	struct page *page;
-	int i;
+	int i, ret;
 
 	if (cmd->tvc_data_direction == DMA_FROM_DEVICE) {
 		cmd->saved_iter_addr = dup_iter(&cmd->saved_iter, iter,
@@ -769,15 +769,18 @@ vhost_scsi_copy_iov_to_sgl(struct vhost_scsi_cmd *cmd, struct iov_iter *iter,
 		page = alloc_page(GFP_KERNEL);
 		if (!page) {
 			i--;
+			ret = -ENOMEM;
 			goto err;
 		}
 
 		nbytes = min_t(unsigned int, PAGE_SIZE, len);
 		sg_set_page(&sg[i], page, nbytes, 0);
 
 		if (cmd->tvc_data_direction == DMA_TO_DEVICE &&
-		    copy_page_from_iter(page, 0, nbytes, iter) != nbytes)
+		    copy_page_from_iter(page, 0, nbytes, iter) != nbytes) {
+			ret = -EFAULT;
 			goto err;
+		}
 
 		len -= nbytes;
 	}
@@ -792,7 +795,7 @@ vhost_scsi_copy_iov_to_sgl(struct vhost_scsi_cmd *cmd, struct iov_iter *iter,
 	for (; i >= 0; i--)
 		__free_page(sg_page(&sg[i]));
 	kfree(cmd->saved_iter_addr);
-	return -ENOMEM;
+	return ret;
 }
 
 static int
@@ -1249,9 +1252,9 @@ vhost_scsi_handle_vq(struct vhost_scsi *vs, struct vhost_virtqueue *vq)
 			 " %d\n", cmd, exp_data_len, prot_bytes, data_direction);
 
 		if (data_direction != DMA_NONE) {
-			if (unlikely(vhost_scsi_mapal(cmd, prot_bytes,
-						      &prot_iter, exp_data_len,
-						      &data_iter))) {
+			ret = vhost_scsi_mapal(cmd, prot_bytes, &prot_iter,
+					       exp_data_len, &data_iter);
+			if (unlikely(ret)) {
 				vq_err(vq, "Failed to map iov to sgl\n");
 				vhost_scsi_release_cmd_res(&cmd->tvc_se_cmd);
 				goto err;