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SubjectRE: [PATCH 1/1] Staging: hv: mousevsc: Move the mouse driver out of staging
Date


> -----Original Message-----
> From: Dmitry Torokhov [mailto:dmitry.torokhov@gmail.com]
> Sent: Sunday, October 23, 2011 3:24 AM
> To: KY Srinivasan
> Cc: gregkh@suse.de; linux-kernel@vger.kernel.org;
> devel@linuxdriverproject.org; virtualization@lists.osdl.org; linux-
> input@vger.kernel.org; Haiyang Zhang; Jiri Kosina
> Subject: Re: [PATCH 1/1] Staging: hv: mousevsc: Move the mouse driver out of
> staging
>
> Hi K. Y.,
>
> On Fri, Oct 14, 2011 at 11:08:27PM -0700, K. Y. Srinivasan wrote:
> > In preparation for moving the mouse driver out of staging, seek community
> > review of the mouse driver code.
> >
>
> Because it is a HID driver it should go through Jiri Kosina's tree
> (CCed). Still, a few comments below.
>
> > Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
> > Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com>
> > ---
> > drivers/hid/Kconfig | 6 +
> > drivers/hid/Makefile | 1 +
> > drivers/hid/hv_mouse.c | 599
> +++++++++++++++++++++++++++++++++++++++++
> > drivers/staging/hv/Kconfig | 6 -
> > drivers/staging/hv/Makefile | 1 -
> > drivers/staging/hv/hv_mouse.c | 599 -----------------------------------------
> > 6 files changed, 606 insertions(+), 606 deletions(-)
> > create mode 100644 drivers/hid/hv_mouse.c
> > delete mode 100644 drivers/staging/hv/hv_mouse.c
> >
> > diff --git a/drivers/hid/Kconfig b/drivers/hid/Kconfig
> > index 1130a89..f8b98b8 100644
> > --- a/drivers/hid/Kconfig
> > +++ b/drivers/hid/Kconfig
> > @@ -613,6 +613,12 @@ config HID_ZYDACRON
> > ---help---
> > Support for Zydacron remote control.
> >
> > +config HYPERV_MOUSE
> > + tristate "Microsoft Hyper-V mouse driver"
> > + depends on HYPERV
> > + help
> > + Select this option to enable the Hyper-V mouse driver.
> > +
> > endmenu
> >
> > endif # HID_SUPPORT
> > diff --git a/drivers/hid/Makefile b/drivers/hid/Makefile
> > index 0a0a38e..436ac2e 100644
> > --- a/drivers/hid/Makefile
> > +++ b/drivers/hid/Makefile
> > @@ -76,6 +76,7 @@ obj-$(CONFIG_HID_ZYDACRON) += hid-zydacron.o
> > obj-$(CONFIG_HID_WACOM) += hid-wacom.o
> > obj-$(CONFIG_HID_WALTOP) += hid-waltop.o
> > obj-$(CONFIG_HID_WIIMOTE) += hid-wiimote.o
> > +obj-$(CONFIG_HYPERV_MOUSE) += hv_mouse.o
> >
> > obj-$(CONFIG_USB_HID) += usbhid/
> > obj-$(CONFIG_USB_MOUSE) += usbhid/
> > diff --git a/drivers/hid/hv_mouse.c b/drivers/hid/hv_mouse.c
> > new file mode 100644
> > index 0000000..ccd39c7
> > --- /dev/null
> > +++ b/drivers/hid/hv_mouse.c
> > @@ -0,0 +1,599 @@
> > +/*
> > + * Copyright (c) 2009, Citrix Systems, Inc.
> > + * Copyright (c) 2010, Microsoft Corporation.
> > + * Copyright (c) 2011, Novell Inc.
> > + *
> > + * This program is free software; you can redistribute it and/or modify it
> > + * under the terms and conditions of the GNU General Public License,
> > + * version 2, as published by the Free Software Foundation.
> > + *
> > + * This program is distributed in the hope it will be useful, but WITHOUT
> > + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
> or
> > + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
> for
> > + * more details.
> > + */
> > +#include <linux/init.h>
> > +#include <linux/module.h>
> > +#include <linux/delay.h>
> > +#include <linux/device.h>
> > +#include <linux/workqueue.h>
>
> Is this really needed?
>
> > +#include <linux/sched.h>
>
> You probably want completion.h instead.

I will fix this.
>
> > +#include <linux/wait.h>
> > +#include <linux/input.h>
> > +#include <linux/hid.h>
> > +#include <linux/hiddev.h>
> > +#include <linux/hyperv.h>
> > +
> > +
> > +struct hv_input_dev_info {
> > + unsigned int size;
> > + unsigned short vendor;
> > + unsigned short product;
> > + unsigned short version;
> > + unsigned short reserved[11];
> > +};
> > +
> > +/* The maximum size of a synthetic input message. */
> > +#define SYNTHHID_MAX_INPUT_REPORT_SIZE 16
> > +
> > +/*
> > + * Current version
> > + *
> > + * History:
> > + * Beta, RC < 2008/1/22 1,0
> > + * RC > 2008/1/22 2,0
> > + */
> > +#define SYNTHHID_INPUT_VERSION_MAJOR 2
> > +#define SYNTHHID_INPUT_VERSION_MINOR 0
> > +#define SYNTHHID_INPUT_VERSION
> (SYNTHHID_INPUT_VERSION_MINOR | \
> > + (SYNTHHID_INPUT_VERSION_MAJOR <<
> 16))
> > +
> > +
> > +#pragma pack(push, 1)
> > +/*
> > + * Message types in the synthetic input protocol
> > + */
> > +enum synthhid_msg_type {
> > + SYNTH_HID_PROTOCOL_REQUEST,
> > + SYNTH_HID_PROTOCOL_RESPONSE,
> > + SYNTH_HID_INITIAL_DEVICE_INFO,
> > + SYNTH_HID_INITIAL_DEVICE_INFO_ACK,
> > + SYNTH_HID_INPUT_REPORT,
> > + SYNTH_HID_MAX
> > +};
> > +
> > +/*
> > + * Basic message structures.
> > + */
> > +struct synthhid_msg_hdr {
> > + enum synthhid_msg_type type;
> > + u32 size;
> > +};
> > +
> > +struct synthhid_msg {
> > + struct synthhid_msg_hdr header;
> > + char data[1]; /* Enclosed message */
> > +};
> > +
> > +union synthhid_version {
> > + struct {
> > + u16 minor_version;
> > + u16 major_version;
> > + };
> > + u32 version;
> > +};
> > +
> > +/*
> > + * Protocol messages
> > + */
> > +struct synthhid_protocol_request {
> > + struct synthhid_msg_hdr header;
> > + union synthhid_version version_requested;
> > +};
> > +
> > +struct synthhid_protocol_response {
> > + struct synthhid_msg_hdr header;
> > + union synthhid_version version_requested;
> > + unsigned char approved;
> > +};
> > +
> > +struct synthhid_device_info {
> > + struct synthhid_msg_hdr header;
> > + struct hv_input_dev_info hid_dev_info;
> > + struct hid_descriptor hid_descriptor;
> > +};
> > +
> > +struct synthhid_device_info_ack {
> > + struct synthhid_msg_hdr header;
> > + unsigned char reserved;
> > +};
> > +
> > +struct synthhid_input_report {
> > + struct synthhid_msg_hdr header;
> > + char buffer[1];
> > +};
> > +
> > +#pragma pack(pop)
> > +
> > +#define INPUTVSC_SEND_RING_BUFFER_SIZE (10*PAGE_SIZE)
> > +#define INPUTVSC_RECV_RING_BUFFER_SIZE (10*PAGE_SIZE)
> > +
> > +#define NBITS(x) (((x)/BITS_PER_LONG)+1)
> > +
> > +enum pipe_prot_msg_type {
> > + PIPE_MESSAGE_INVALID,
> > + PIPE_MESSAGE_DATA,
> > + PIPE_MESSAGE_MAXIMUM
> > +};
> > +
> > +
> > +struct pipe_prt_msg {
> > + enum pipe_prot_msg_type type;
> > + u32 size;
> > + char data[1];
> > +};
> > +
> > +struct mousevsc_prt_msg {
> > + enum pipe_prot_msg_type type;
> > + u32 size;
> > + union {
> > + struct synthhid_protocol_request request;
> > + struct synthhid_protocol_response response;
> > + struct synthhid_device_info_ack ack;
> > + };
> > +};
> > +
> > +/*
> > + * Represents an mousevsc device
> > + */
> > +struct mousevsc_dev {
> > + struct hv_device *device;
> > + unsigned char init_complete;
> > + struct mousevsc_prt_msg protocol_req;
> > + struct mousevsc_prt_msg protocol_resp;
> > + /* Synchronize the request/response if needed */
> > + struct completion wait_event;
> > + int dev_info_status;
> > +
> > + struct hid_descriptor *hid_desc;
> > + unsigned char *report_desc;
> > + u32 report_desc_size;
> > + struct hv_input_dev_info hid_dev_info;
> > + int connected;
>
> bool?
>
> > + struct hid_device *hid_device;
> > +};
> > +
> > +
> > +static struct mousevsc_dev *alloc_input_device(struct hv_device *device)
> > +{
> > + struct mousevsc_dev *input_dev;
> > +
> > + input_dev = kzalloc(sizeof(struct mousevsc_dev), GFP_KERNEL);
> > +
>
> This blank line is extra.
>
> > + if (!input_dev)
> > + return NULL;
> > +
> > + input_dev->device = device;
> > + hv_set_drvdata(device, input_dev);
> > + init_completion(&input_dev->wait_event);
> > +
> > + return input_dev;
> > +}
> > +
> > +static void free_input_device(struct mousevsc_dev *device)
> > +{
> > + kfree(device->hid_desc);
> > + kfree(device->report_desc);
> > + hv_set_drvdata(device->device, NULL);
> > + kfree(device);
> > +}
> > +
> > +
> > +static void mousevsc_on_receive_device_info(struct mousevsc_dev
> *input_device,
> > + struct synthhid_device_info *device_info)
> > +{
> > + int ret = 0;
> > + struct hid_descriptor *desc;
> > + struct mousevsc_prt_msg ack;
> > +
> > + /* Assume success for now */
> > + input_device->dev_info_status = 0;
> > +
> > + memcpy(&input_device->hid_dev_info, &device_info->hid_dev_info,
> > + sizeof(struct hv_input_dev_info));
> > +
> > + desc = &device_info->hid_descriptor;
> > + WARN_ON(desc->bLength == 0);
> > +
> > + input_device->hid_desc = kzalloc(desc->bLength, GFP_ATOMIC);
> > +
> > + if (!input_device->hid_desc)
> > + goto cleanup;
> > +
> > + memcpy(input_device->hid_desc, desc, desc->bLength);
> > +
> > + input_device->report_desc_size = desc->desc[0].wDescriptorLength;
> > + if (input_device->report_desc_size == 0)
> > + goto cleanup;
> > + input_device->report_desc = kzalloc(input_device->report_desc_size,
> > + GFP_ATOMIC);
> > +
> > + if (!input_device->report_desc)
> > + goto cleanup;
> > +
> > + memcpy(input_device->report_desc,
> > + ((unsigned char *)desc) + desc->bLength,
> > + desc->desc[0].wDescriptorLength);
> > +
> > + /* Send the ack */
> > + memset(&ack, 0, sizeof(struct mousevsc_prt_msg));
> > +
> > + ack.type = PIPE_MESSAGE_DATA;
> > + ack.size = sizeof(struct synthhid_device_info_ack);
> > +
> > + ack.ack.header.type = SYNTH_HID_INITIAL_DEVICE_INFO_ACK;
> > + ack.ack.header.size = 1;
> > + ack.ack.reserved = 0;
>
> That looks like a constant structure...

Will clean this up.
>
> > +
> > + ret = vmbus_sendpacket(input_device->device->channel,
> > + &ack,
> > + sizeof(struct pipe_prt_msg) - sizeof(unsigned char) +
> > + sizeof(struct synthhid_device_info_ack),
> > + (unsigned long)&ack,
> > + VM_PKT_DATA_INBAND,
> > +
> VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
> > + if (ret != 0)
> > + goto cleanup;
> > +
> > + complete(&input_device->wait_event);
> > +
> > + return;
> > +
> > +cleanup:
> > + kfree(input_device->hid_desc);
> > + input_device->hid_desc = NULL;
> > +
> > + kfree(input_device->report_desc);
> > + input_device->report_desc = NULL;
> > +
> > + input_device->dev_info_status = -1;
> > + complete(&input_device->wait_event);
> > +}
> > +
> > +static void mousevsc_on_receive(struct hv_device *device,
> > + struct vmpacket_descriptor *packet)
> > +{
> > + struct pipe_prt_msg *pipe_msg;
> > + struct synthhid_msg *hid_msg;
> > + struct mousevsc_dev *input_dev = hv_get_drvdata(device);
> > + struct synthhid_input_report *input_report;
> > +
> > + pipe_msg = (struct pipe_prt_msg *)((unsigned long)packet +
> > + (packet->offset8 << 3));
> > +
> > + if (pipe_msg->type != PIPE_MESSAGE_DATA)
> > + return;
> > +
> > + hid_msg = (struct synthhid_msg *)&pipe_msg->data[0];
> > +
> > + switch (hid_msg->header.type) {
> > + case SYNTH_HID_PROTOCOL_RESPONSE:
> > + memcpy(&input_dev->protocol_resp, pipe_msg,
> > + pipe_msg->size + sizeof(struct pipe_prt_msg) -
> > + sizeof(unsigned char));
> > + complete(&input_dev->wait_event);
> > + break;
> > +
> > + case SYNTH_HID_INITIAL_DEVICE_INFO:
> > + WARN_ON(pipe_msg->size < sizeof(struct hv_input_dev_info));
> > +
> > + /*
> > + * Parse out the device info into device attr,
> > + * hid desc and report desc
> > + */
> > + mousevsc_on_receive_device_info(input_dev,
> > + (struct synthhid_device_info *)&pipe_msg->data[0]);
> > + break;
> > + case SYNTH_HID_INPUT_REPORT:
> > + input_report =
> > + (struct synthhid_input_report *)&pipe_msg->data[0];
> > + if (!input_dev->init_complete)
> > + break;
> > + hid_input_report(input_dev->hid_device,
> > + HID_INPUT_REPORT, input_report->buffer,
> > + input_report->header.size, 1);
> > + break;
> > + default:
> > + pr_err("unsupported hid msg type - type %d len %d",
> > + hid_msg->header.type, hid_msg->header.size);
> > + break;
> > + }
> > +
> > +}
> > +
> > +static void mousevsc_on_channel_callback(void *context)
> > +{
> > + const int packetSize = 0x100;
> > + int ret = 0;
> > + struct hv_device *device = (struct hv_device *)context;
>
> No need to cast.
>
> > +
> > + u32 bytes_recvd;
> > + u64 req_id;
> > + unsigned char packet[0x100];
>
> Hmm, 100 bytes on stack... and are we in interrupt context by any
> chance?
>
> > + struct vmpacket_descriptor *desc;
> > + unsigned char *buffer = packet;
> > + int bufferlen = packetSize;
> > +
> > +
> > + do {
> > + ret = vmbus_recvpacket_raw(device->channel, buffer,
> > + bufferlen, &bytes_recvd, &req_id);
> > +
> > + if (ret == 0) {
> > + if (bytes_recvd > 0) {
> > + desc = (struct vmpacket_descriptor *)buffer;
> > +
> > + switch (desc->type) {
> > + case VM_PKT_COMP:
> > + break;
> > +
> > + case VM_PKT_DATA_INBAND:
> > + mousevsc_on_receive(
> > + device, desc);
> > + break;
> > +
> > + default:
> > + pr_err("unhandled packet type %d, tid
> %llx len %d\n",
> > + desc->type,
> > + req_id,
> > + bytes_recvd);
> > + break;
> > + }
> > +
> > + /* reset */
> > + if (bufferlen > packetSize) {
> > + kfree(buffer);
> > +
> > + buffer = packet;
> > + bufferlen = packetSize;
> > + }
> > + } else {
> > + if (bufferlen > packetSize) {
> > + kfree(buffer);
> > +
> > + buffer = packet;
> > + bufferlen = packetSize;
> > + }
> > + break;
> > + }
> > + } else if (ret == -ENOBUFS) {
> > + /* Handle large packet */
> > + bufferlen = bytes_recvd;
> > + buffer = kzalloc(bytes_recvd, GFP_ATOMIC);
> > +
>
> What happens if we receive even larger amount of data after allocating
> the buffer?

I will cleanup this function.
>
> > + if (buffer == NULL) {
> > + buffer = packet;
> > + bufferlen = packetSize;
> > + break;
> > + }
> > + }
> > + } while (1);
>
> So we can be looping indefinitely here as long as other side keeps
> sending data?
The current protocol requires that the consumer handle all available data on the
channel before exiting the handler; this is used to optimize signaling on the ring
buffer between the producer and the consumer.

>
> > +
> > + return;
>
> No naked returns please.
>
> > +}
> > +
> > +static int mousevsc_connect_to_vsp(struct hv_device *device)
> > +{
> > + int ret = 0;
> > + int t;
> > + struct mousevsc_dev *input_dev = hv_get_drvdata(device);
> > + struct mousevsc_prt_msg *request;
> > + struct mousevsc_prt_msg *response;
> > +
> > +
> > + request = &input_dev->protocol_req;
> > +
> > + memset(request, 0, sizeof(struct mousevsc_prt_msg));
> > +
> > + request->type = PIPE_MESSAGE_DATA;
> > + request->size = sizeof(struct synthhid_protocol_request);
> > +
> > + request->request.header.type = SYNTH_HID_PROTOCOL_REQUEST;
> > + request->request.header.size = sizeof(unsigned int);
> > + request->request.version_requested.version =
> SYNTHHID_INPUT_VERSION;
> > +
> > +
> > + ret = vmbus_sendpacket(device->channel, request,
> > + sizeof(struct pipe_prt_msg) -
> > + sizeof(unsigned char) +
> > + sizeof(struct synthhid_protocol_request),
> > + (unsigned long)request,
> > + VM_PKT_DATA_INBAND,
> > +
> VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
> > + if (ret != 0)
> > + goto cleanup;
> > +
> > + t = wait_for_completion_timeout(&input_dev->wait_event, 5*HZ);
> > + if (t == 0) {
> > + ret = -ETIMEDOUT;
> > + goto cleanup;
> > + }
> > +
> > + response = &input_dev->protocol_resp;
> > +
> > + if (!response->response.approved) {
> > + pr_err("synthhid protocol request failed (version %d)",
> > + SYNTHHID_INPUT_VERSION);
> > + ret = -ENODEV;
> > + goto cleanup;
> > + }
> > +
> > + t = wait_for_completion_timeout(&input_dev->wait_event, 5*HZ);
>
> We just completed the wait for this completion, why are we waiting on
> the same completion again?

In response to our initial query, we expect the host to respond back with two
distinct pieces of information; we wait for both these responses.

>
> > + if (t == 0) {
> > + ret = -ETIMEDOUT;
> > + goto cleanup;
> > + }
> > +
> > + /*
> > + * We should have gotten the device attr, hid desc and report
> > + * desc at this point
> > + */
> > + if (input_dev->dev_info_status)
> > + ret = -ENOMEM;
>
> -ENOMEM seems wrong.
>
There are many failures here and not being able to allocate memory is the
primary one; and so I chose to capture that.

> > +
> > +cleanup:
> > +
> > + return ret;
> > +}
> > +
> > +static int mousevsc_hid_open(struct hid_device *hid)
> > +{
> > + return 0;
> > +}
> > +
> > +static void mousevsc_hid_close(struct hid_device *hid)
> > +{
> > +}
> > +
> > +static struct hid_ll_driver mousevsc_ll_driver = {
> > + .open = mousevsc_hid_open,
> > + .close = mousevsc_hid_close,
> > +};
> > +
> > +static struct hid_driver mousevsc_hid_driver;
> > +
> > +static void reportdesc_callback(struct hv_device *dev, void *packet, u32 len)
> > +{
>
> This is called from mousevsc_on_device_add() which is part of device
> probe. Why it is split into separate function with bizzare arguments is
> beyond me.

I will clean this up.

>
> > + struct hid_device *hid_dev;
> > + struct mousevsc_dev *input_device = hv_get_drvdata(dev);
> > +
> > + hid_dev = hid_allocate_device();
> > + if (IS_ERR(hid_dev))
> > + return;
>
> This is not very helpful.

I will clean this up.
>
> > +
> > + hid_dev->ll_driver = &mousevsc_ll_driver;
> > + hid_dev->driver = &mousevsc_hid_driver;
> > +
> > + if (hid_parse_report(hid_dev, packet, len))
> > + return;
>
> Neither is this.
>
> > +
> > + hid_dev->bus = BUS_VIRTUAL;
> > + hid_dev->vendor = input_device->hid_dev_info.vendor;
> > + hid_dev->product = input_device->hid_dev_info.product;
> > + hid_dev->version = input_device->hid_dev_info.version;
> > +
> > + sprintf(hid_dev->name, "%s", "Microsoft Vmbus HID-compliant Mouse");
> > +
> > + if (!hidinput_connect(hid_dev, 0)) {
> > + hid_dev->claimed |= HID_CLAIMED_INPUT;
>
> Why do you force hidinput claim? Let the normal rules do it.
>
> > +
> > + input_device->connected = 1;
>
> input_device->connected = true;
>
> > +
> > + }
> > +
> > + input_device->hid_device = hid_dev;
>
> This assignment is probably too late.
I will address this.
>
> > +}
> > +
> > +static int mousevsc_on_device_add(struct hv_device *device)
>
> The only caller of this is mousevsc_probe() so why do you have it

I will address this.

>
> > +{
> > + int ret = 0;
> > + struct mousevsc_dev *input_dev;
> > +
> > + input_dev = alloc_input_device(device);
> > +
> > + if (!input_dev)
> > + return -ENOMEM;
> > +
> > + input_dev->init_complete = false;
> > +
> > + ret = vmbus_open(device->channel,
> > + INPUTVSC_SEND_RING_BUFFER_SIZE,
> > + INPUTVSC_RECV_RING_BUFFER_SIZE,
> > + NULL,
> > + 0,
> > + mousevsc_on_channel_callback,
> > + device
> > + );
> > +
> > + if (ret != 0) {
> > + free_input_device(input_dev);
> > + return ret;
> > + }
> > +
> > +
> > + ret = mousevsc_connect_to_vsp(device);
> > +
> > + if (ret != 0) {
> > + vmbus_close(device->channel);
> > + free_input_device(input_dev);
> > + return ret;
> > + }
> > +
> > +
> > + /* workaround SA-167 */
> > + if (input_dev->report_desc[14] == 0x25)
> > + input_dev->report_desc[14] = 0x29;
> > +
> > + reportdesc_callback(device, input_dev->report_desc,
> > + input_dev->report_desc_size);
> > +
> > + input_dev->init_complete = true;
> > +
> > + return ret;
> > +}
> > +
> > +static int mousevsc_probe(struct hv_device *dev,
> > + const struct hv_vmbus_device_id *dev_id)
> > +{
> > +
> > + return mousevsc_on_device_add(dev);
> > +
> > +}
> > +
> > +static int mousevsc_remove(struct hv_device *dev)
> > +{
> > + struct mousevsc_dev *input_dev = hv_get_drvdata(dev);
> > +
> > + vmbus_close(dev->channel);
> > +
> > + if (input_dev->connected) {
> > + hidinput_disconnect(input_dev->hid_device);
> > + input_dev->connected = 0;
> > + hid_destroy_device(input_dev->hid_device);
>
> hid_destroy_device() should disconnect registered handlers for you; you
> do not need to do that manually.
>
> > + }
> > +
> > + free_input_device(input_dev);
>
> Calling it input device is terribly confusing to me. I'd also freed it
> inline (and used gotos to unwind errors in probe()).
>

I will clean this up.

Regards,

K. Y


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