USB: usbtmc: repeat usb_bulk_msg until whole message is transfered

commit ec412b92dbe3ea839716853eea058d1bcc5e6ca4 upstream.

usb_bulk_msg() transfers only bytes up to the maximum packet size.
It must be repeated by the usbtmc driver until all bytes of a TMC message
are transfered.

Without this patch, ETIMEDOUT is reported when writing TMC messages
larger than the maximum USB bulk size and the transfer remains incomplete.
The user will notice that the device hangs and must be reset by either closing
the application or pulling the plug.

Signed-off-by: Andre Herms <andre.herms@tec-venture.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/usb/class/usbtmc.c b/drivers/usb/class/usbtmc.c
index 21b37191e9b0426b602020e858e4071ee3cc6376..aa145f7b4e2599ef65d1679aff3b8bceb499230f 100644 (file)
--- a/drivers/usb/class/usbtmc.c
+++ b/drivers/usb/class/usbtmc.c
@@ -545,10 +545,16 @@ static ssize_t usbtmc_write(struct file *filp, const char __user *buf,
                n_bytes = roundup(12 + this_part, 4);
                memset(buffer + 12 + this_part, 0, n_bytes - (12 + this_part));
 
-               retval = usb_bulk_msg(data->usb_dev,
-                                     usb_sndbulkpipe(data->usb_dev,
-                                                     data->bulk_out),
-                                     buffer, n_bytes, &actual, USBTMC_TIMEOUT);
+               do {
+                       retval = usb_bulk_msg(data->usb_dev,
+                                             usb_sndbulkpipe(data->usb_dev,
+                                                             data->bulk_out),
+                                             buffer, n_bytes,
+                                             &actual, USBTMC_TIMEOUT);
+                       if (retval != 0)
+                               break;
+                       n_bytes -= actual;
+               } while (n_bytes);
 
                data->bTag_last_write = data->bTag;
                data->bTag++;