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 2473cf0c6b1d4ba294677c4259941f56151c41e4..d9461c91b8c9fe3026cd63801566f1dc3ef3a2c4 100644 (file)
--- a/drivers/usb/class/usbtmc.c
+++ b/drivers/usb/class/usbtmc.c
@@ -562,10 +562,16 @@ 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++;