On 26. 06. 21, 8:30, longli@xxxxxxxxxxxxxxxxx wrote:
Azure Blob storage provides scalable and durable data storage for Azure.
(https://azure.microsoft.com/en-us/services/storage/blobs/)
This driver adds support for accelerated access to Azure Blob storage. As an
alternative to REST APIs, it provides a fast data path that uses host native
network stack and secure direct data link for storage server access.
...
Cc: Jiri Slaby <jirislaby@xxxxxxxxxx>
I am just curious, why am I CCed? Anyway, some comments below:
--- /dev/null
+++ b/drivers/hv/azure_blob.c
@@ -0,0 +1,655 @@
...
+static void az_blob_on_channel_callback(void *context)
+{
+ struct vmbus_channel *channel = (struct vmbus_channel *)context;
Have you fed this patch through checkpatch?
+ const struct vmpacket_descriptor *desc;
+
+ az_blob_dbg("entering interrupt from vmbus\n");
+ foreach_vmbus_pkt(desc, channel) {
+ struct az_blob_vsp_request_ctx *request_ctx;
+ struct az_blob_vsp_response *response;
+ u64 cmd_rqst = vmbus_request_addr(&channel->requestor,
+ desc->trans_id);
+ if (cmd_rqst == VMBUS_RQST_ERROR) {
+ az_blob_err("incorrect transaction id %llu\n",
+ desc->trans_id);
+ continue;
+ }
+ request_ctx = (struct az_blob_vsp_request_ctx *) cmd_rqst;
+ response = hv_pkt_data(desc);
+
+ az_blob_dbg("got response for request %pUb status %u "
+ "response_len %u\n",
+ &request_ctx->request->guid, response->error,
+ response->response_len);
+ request_ctx->request->response.status = response->error;
+ request_ctx->request->response.response_len =
+ response->response_len;
+ complete(&request_ctx->wait_vsp);
+ }
+
+}
...
+static long az_blob_ioctl_user_request(struct file *filp, unsigned long arg)
+{
+ struct az_blob_device *dev = &az_blob_dev;
+ struct az_blob_file_ctx *file_ctx = filp->private_data;
+ char __user *argp = (char __user *) arg;
+ struct az_blob_request_sync request;
+ struct az_blob_vsp_request_ctx request_ctx;
+ unsigned long flags;
+ int ret;
+ size_t request_start, request_num_pages = 0;
+ size_t response_start, response_num_pages = 0;
+ size_t data_start, data_num_pages = 0, total_num_pages;
+ struct page **request_pages = NULL, **response_pages = NULL;
+ struct page **data_pages = NULL;
+ struct vmbus_packet_mpb_array *desc;
+ u64 *pfn_array;
+ int desc_size;
+ int page_idx;
+ struct az_blob_vsp_request *vsp_request;
Ugh, see further.
+
+ /* Fast fail if device is being removed */
+ if (dev->removing)
+ return -ENODEV;
+
+ if (!az_blob_safe_file_access(filp)) {
+ az_blob_dbg("process %d(%s) changed security contexts after"
+ " opening file descriptor\n",
+ task_tgid_vnr(current), current->comm);
+ return -EACCES;
+ }
+
+ if (copy_from_user(&request, argp, sizeof(request))) {
+ az_blob_dbg("don't have permission to user provided buffer\n");
+ return -EFAULT;
+ }
+
+ az_blob_dbg("az_blob ioctl request guid %pUb timeout %u request_len %u"
+ " response_len %u data_len %u request_buffer %llx "
+ "response_buffer %llx data_buffer %llx\n",
+ &request.guid, request.timeout, request.request_len,
+ request.response_len, request.data_len, request.request_buffer,
+ request.response_buffer, request.data_buffer);
+
+ if (!request.request_len || !request.response_len)
+ return -EINVAL;
+
+ if (request.data_len && request.data_len < request.data_valid)
+ return -EINVAL;
+
+ init_completion(&request_ctx.wait_vsp);
+ request_ctx.request = &request;
+
+ /*
+ * Need to set rw to READ to have page table set up for passing to VSP.
+ * Setting it to WRITE will cause the page table entry not allocated
+ * as it's waiting on Copy-On-Write on next page fault. This doesn't
+ * work in this scenario because VSP wants all the pages to be present.
+ */
+ ret = get_buffer_pages(READ, (void __user *) request.request_buffer,
Does this need __force for sparse not to complain?
+ request.request_len, &request_pages, &request_start,
+ &request_num_pages);
+ if (ret)
+ goto get_user_page_failed;
+
+ ret = get_buffer_pages(READ, (void __user *) request.response_buffer,
+ request.response_len, &response_pages, &response_start,
+ &response_num_pages);
+ if (ret)
+ goto get_user_page_failed;
+
+ if (request.data_len) {
+ ret = get_buffer_pages(READ,
+ (void __user *) request.data_buffer, request.data_len,
+ &data_pages, &data_start, &data_num_pages);
+ if (ret)
+ goto get_user_page_failed;
+ }
+
+ total_num_pages = request_num_pages + response_num_pages +
+ data_num_pages;
+ if (total_num_pages > AZ_BLOB_MAX_PAGES) {
+ az_blob_dbg("number of DMA pages %lu buffer exceeding %u\n",
+ total_num_pages, AZ_BLOB_MAX_PAGES);
+ ret = -EINVAL;
+ goto get_user_page_failed;
+ }
+
+ /* Construct a VMBUS packet and send it over to VSP */
+ desc_size = sizeof(struct vmbus_packet_mpb_array) +
+ sizeof(u64) * total_num_pages;
+ desc = kzalloc(desc_size, GFP_KERNEL);
Smells like a call for struct_size().
+ vsp_request = kzalloc(sizeof(*vsp_request), GFP_KERNEL);
+ if (!desc || !vsp_request) {
+ kfree(desc);
+ kfree(vsp_request);
+ ret = -ENOMEM;
+ goto get_user_page_failed;
+ }
+
+ desc->range.offset = 0;
+ desc->range.len = total_num_pages * PAGE_SIZE;
+ pfn_array = desc->range.pfn_array;
+ page_idx = 0;
+
+ if (request.data_len) {
+ fill_in_page_buffer(pfn_array, &page_idx, data_pages,
+ data_num_pages);
+ vsp_request->data_buffer_offset = data_start;
+ vsp_request->data_buffer_length = request.data_len;
+ vsp_request->data_buffer_valid = request.data_valid;
+ }
+
+ fill_in_page_buffer(pfn_array, &page_idx, request_pages,
+ request_num_pages);
+ vsp_request->request_buffer_offset = request_start +
+ data_num_pages * PAGE_SIZE;
+ vsp_request->request_buffer_length = request.request_len;
+
+ fill_in_page_buffer(pfn_array, &page_idx, response_pages,
+ response_num_pages);
+ vsp_request->response_buffer_offset = response_start +
+ (data_num_pages + request_num_pages) * PAGE_SIZE;
+ vsp_request->response_buffer_length = request.response_len;
+
+ vsp_request->version = 0;
+ vsp_request->timeout_ms = request.timeout;
+ vsp_request->operation_type = AZ_BLOB_DRIVER_USER_REQUEST;
+ guid_copy(&vsp_request->transaction_id, &request.guid);
+
+ spin_lock_irqsave(&file_ctx->vsp_pending_lock, flags);
+ list_add_tail(&request_ctx.list, &file_ctx->vsp_pending_requests);
+ spin_unlock_irqrestore(&file_ctx->vsp_pending_lock, flags);
+
+ az_blob_dbg("sending request to VSP\n");
+ az_blob_dbg("desc_size %u desc->range.len %u desc->range.offset %u\n",
+ desc_size, desc->range.len, desc->range.offset);
+ az_blob_dbg("vsp_request data_buffer_offset %u data_buffer_length %u "
+ "data_buffer_valid %u request_buffer_offset %u "
+ "request_buffer_length %u response_buffer_offset %u "
+ "response_buffer_length %u\n",
+ vsp_request->data_buffer_offset,
+ vsp_request->data_buffer_length,
+ vsp_request->data_buffer_valid,
+ vsp_request->request_buffer_offset,
+ vsp_request->request_buffer_length,
+ vsp_request->response_buffer_offset,
+ vsp_request->response_buffer_length);
+
+ ret = vmbus_sendpacket_mpb_desc(dev->device->channel, desc, desc_size,
+ vsp_request, sizeof(*vsp_request), (u64) &request_ctx);
+
+ kfree(desc);
+ kfree(vsp_request);
+ if (ret)
+ goto vmbus_send_failed;
+
+ wait_for_completion(&request_ctx.wait_vsp);
Provided this is ioctl, this should likely be interruptible. You don't
want to account to I/O load. The same likely for az_blob_fop_release.
+
+ /*
+ * At this point, the response is already written to request
+ * by VMBUS completion handler, copy them to user-mode buffers
+ * and return to user-mode
+ */
+ if (copy_to_user(argp +
+ offsetof(struct az_blob_request_sync,
+ response.status),
+ &request.response.status,
This is ugly, why don't you make argp the appropriate pointer instead of
char *? You'd need not do copy_to_user twice then, right?
+ sizeof(request.response.status))) {
+ ret = -EFAULT;
+ goto vmbus_send_failed;
+ }
+
+ if (copy_to_user(argp +
+ offsetof(struct az_blob_request_sync,
+ response.response_len),
The same here.
+ &request.response.response_len,
+ sizeof(request.response.response_len)))
+ ret = -EFAULT;
+
+vmbus_send_failed:
+ spin_lock_irqsave(&file_ctx->vsp_pending_lock, flags);
+ list_del(&request_ctx.list);
+ if (list_empty(&file_ctx->vsp_pending_requests))
+ wake_up(&file_ctx->wait_vsp_pending);
+ spin_unlock_irqrestore(&file_ctx->vsp_pending_lock, flags);
+
+get_user_page_failed:
+ free_buffer_pages(request_num_pages, request_pages);
+ free_buffer_pages(response_num_pages, response_pages);
+ free_buffer_pages(data_num_pages, data_pages);
+
+ return ret;
+}
This function is overly long. Care to split it (e.g. moving away the
initialization of the structs and the debug stuff)?
+
+static long az_blob_fop_ioctl(struct file *filp, unsigned int cmd,
+ unsigned long arg)
+{
+ long ret = -EIO;
EINVAL would be more appropriate.
+
+ switch (cmd) {
+ case IOCTL_AZ_BLOB_DRIVER_USER_REQUEST:
+ if (_IOC_SIZE(cmd) != sizeof(struct az_blob_request_sync))
+ return -EINVAL;
How can that happen, provided the switch (cmd) and case?
+ ret = az_blob_ioctl_user_request(filp, arg);
+ break;
Simply:
return az_blob_ioctl_user_request(filp, arg);
+
+ default:
+ az_blob_dbg("unrecognized IOCTL code %u\n", cmd);
+ }
+
+ return ret;
So return -EINVAL here directly now.
+}
...
+static int az_blob_connect_to_vsp(struct hv_device *device, u32 ring_size)
+{
+ int ret;
...
+ int rc;
Sometimes ret, sometimes rc, could you unify the two?
+static int __init az_blob_drv_init(void)
+{
+ int ret;
+
+ ret = vmbus_driver_register(&az_blob_drv);
+ return ret;
Simply:
return vmbus_driver_register(&az_blob_drv);
regards,
--
--
js
suse labs
