Messages in this thread | | | Subject | Re: [Patch v2 2/3] Drivers: hv: add Azure Blob driver | From | Jiri Slaby <> | Date | Tue, 29 Jun 2021 10:43:03 +0200 |
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On 26. 06. 21, 8:30, longli@linuxonhyperv.com 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@kernel.org>
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
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