usb: usbtmc: Optimize usbtmc_read (d7604ff0) · Commits · 戴 / test

drivers/usb/class/usbtmc.c

+88 −100

Original line number	Diff line number	Diff line
		@@ -1293,7 +1293,7 @@ static ssize_t usbtmc_ioctl_write_result(struct usbtmc_file_data *file_data,
		* Also updates bTag_last_write.
		*/
		static int send_request_dev_dep_msg_in(struct usbtmc_file_data *file_data,
		size_t transfer_size)
		u32 transfer_size)
		{
		struct usbtmc_device_data *data = file_data->data;
		int retval;
		@@ -1336,12 +1336,11 @@ static int send_request_dev_dep_msg_in(struct usbtmc_file_data *file_data,
		data->bTag++;

		kfree(buffer);
		if (retval < 0) {
		dev_err(&data->intf->dev, "usb_bulk_msg in send_request_dev_dep_msg_in() returned %d\n", retval);
		return retval;
		}
		if (retval < 0)
		dev_err(&data->intf->dev, "%s returned %d\n",
		__func__, retval);

		return 0;
		return retval;
		}

		static ssize_t usbtmc_read(struct file filp, char __user buf,
		@@ -1350,20 +1349,20 @@ static ssize_t usbtmc_read(struct file filp, char __user buf,
		struct usbtmc_file_data *file_data;
		struct usbtmc_device_data *data;
		struct device *dev;
		const u32 bufsize = USBTMC_BUFSIZE;
		u32 n_characters;
		u8 *buffer;
		int actual;
		size_t done;
		size_t remaining;
		u32 done = 0;
		u32 remaining;
		int retval;
		size_t this_part;

		/* Get pointer to private data structure */
		file_data = filp->private_data;
		data = file_data->data;
		dev = &data->intf->dev;

		buffer = kmalloc(USBTMC_SIZE_IOBUFFER, GFP_KERNEL);
		buffer = kmalloc(bufsize, GFP_KERNEL);
		if (!buffer)
		return -ENOMEM;

		@@ -1373,7 +1372,10 @@ static ssize_t usbtmc_read(struct file filp, char __user buf,
		goto exit;
		}

		dev_dbg(dev, "usb_bulk_msg_in: count(%zu)\n", count);
		if (count > INT_MAX)
		count = INT_MAX;

		dev_dbg(dev, "%s(count:%zu)\n", __func__, count);

		retval = send_request_dev_dep_msg_in(file_data, count);

		@@ -1385,48 +1387,46 @@ static ssize_t usbtmc_read(struct file filp, char __user buf,

		/* Loop until we have fetched everything we requested */
		remaining = count;
		this_part = remaining;
		done = 0;

		while (remaining > 0) {
		/* Send bulk URB */
		retval = usb_bulk_msg(data->usb_dev,
		usb_rcvbulkpipe(data->usb_dev,
		data->bulk_in),
		buffer, USBTMC_SIZE_IOBUFFER, &actual,
		buffer, bufsize, &actual,
		file_data->timeout);

		dev_dbg(dev, "usb_bulk_msg: retval(%u), done(%zu), remaining(%zu), actual(%d)\n", retval, done, remaining, actual);
		dev_dbg(dev, "%s: bulk_msg retval(%u), actual(%d)\n",
		__func__, retval, actual);

		/* Store bTag (in case we need to abort) */
		data->bTag_last_read = data->bTag;

		if (retval < 0) {
		dev_dbg(dev, "Unable to read data, error %d\n", retval);
		if (file_data->auto_abort)
		usbtmc_ioctl_abort_bulk_in(data);
		goto exit;
		}

		/* Parse header in first packet */
		if (done == 0) {
		/* Sanity checks for the header */
		if (actual < USBTMC_HEADER_SIZE) {
		dev_err(dev, "Device sent too small first packet: %u < %u\n", actual, USBTMC_HEADER_SIZE);
		dev_err(dev, "Device sent too small first packet: %u < %u\n",
		actual, USBTMC_HEADER_SIZE);
		if (file_data->auto_abort)
		usbtmc_ioctl_abort_bulk_in(data);
		goto exit;
		}

		if (buffer[0] != 2) {
		dev_err(dev, "Device sent reply with wrong MsgID: %u != 2\n", buffer[0]);
		dev_err(dev, "Device sent reply with wrong MsgID: %u != 2\n",
		buffer[0]);
		if (file_data->auto_abort)
		usbtmc_ioctl_abort_bulk_in(data);
		goto exit;
		}

		if (buffer[1] != data->bTag_last_write) {
		dev_err(dev, "Device sent reply with wrong bTag: %u != %u\n", buffer[1], data->bTag_last_write);
		dev_err(dev, "Device sent reply with wrong bTag: %u != %u\n",
		buffer[1], data->bTag_last_write);
		if (file_data->auto_abort)
		usbtmc_ioctl_abort_bulk_in(data);
		goto exit;
		@@ -1440,59 +1440,47 @@ static ssize_t usbtmc_read(struct file filp, char __user buf,

		file_data->bmTransferAttributes = buffer[8];

		if (n_characters > this_part) {
		dev_err(dev, "Device wants to return more data than requested: %u > %zu\n", n_characters, count);
		dev_dbg(dev, "Bulk-IN header: N_characters(%u), bTransAttr(%u)\n",
		n_characters, buffer[8]);

		if (n_characters > remaining) {
		dev_err(dev, "Device wants to return more data than requested: %u > %zu\n",
		n_characters, count);
		if (file_data->auto_abort)
		usbtmc_ioctl_abort_bulk_in(data);
		goto exit;
		}

		print_hex_dump_debug("usbtmc ", DUMP_PREFIX_NONE,
		16, 1, buffer, actual, true);

		remaining = n_characters;

		/* Remove the USBTMC header */
		actual -= USBTMC_HEADER_SIZE;

		/* Check if the message is smaller than requested */
		if (remaining > n_characters)
		remaining = n_characters;
		/* Remove padding if it exists */
		if (actual > remaining)
		actual = remaining;

		dev_dbg(dev, "Bulk-IN header: N_characters(%u), bTransAttr(%u)\n", n_characters, buffer[8]);

		remaining -= actual;

		/* Terminate if end-of-message bit received from device */
		if ((buffer[8] & 0x01) && (actual >= n_characters))
		remaining = 0;

		dev_dbg(dev, "Bulk-IN header: remaining(%zu), buf(%p), buffer(%p) done(%zu)\n", remaining,buf,buffer,done);


		/* Copy buffer to user space */
		if (copy_to_user(buf + done, &buffer[USBTMC_HEADER_SIZE], actual)) {
		if (copy_to_user(buf, &buffer[USBTMC_HEADER_SIZE], actual)) {
		/* There must have been an addressing problem */
		retval = -EFAULT;
		goto exit;
		}
		done += actual;
		}
		else {
		if (actual > remaining)
		actual = remaining;

		remaining -= actual;

		dev_dbg(dev, "Bulk-IN header cont: actual(%u), done(%zu), remaining(%zu), buf(%p), buffer(%p)\n", actual, done, remaining,buf,buffer);

		/* Copy buffer to user space */
		if (copy_to_user(buf + done, buffer, actual)) {
		/* There must have been an addressing problem */
		retval = -EFAULT;
		if ((actual + USBTMC_HEADER_SIZE) == bufsize) {
		retval = usbtmc_generic_read(file_data, buf + actual,
		remaining,
		&done,
		USBTMC_FLAG_IGNORE_TRAILER);
		if (retval < 0)
		goto exit;
		}
		done += actual;
		}
		}

		/* Update file position value */
		f_pos = f_pos + done;

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