Re: [PATCH v3] usbdevfs: Fix broken scatter-gather transfer

From: Hans de Goede
Date: Sun Oct 14 2012 - 11:51:47 EST


Hi,

On 10/13/2012 12:20 PM, Henrik Rydberg wrote:
The handling of large output bulk transfers is broken; the same user
page is read over and over again. Fixed with this patch.

Cc: stable@xxxxxxxxxx
Acked-by: Peter Stuge <peter@xxxxxxxx>
Acked-by: Hans de Goede <hdegoede@xxxxxxxxxx>
Acked-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Henrik Rydberg <rydberg@xxxxxxxxxxx>
---
Hi Greg,

Here is the formal and third version of the patch. Version two still
made me nervous,

And it should, as as said before I believe it would have broken large
input transfers ...

so I moved the increment to where it is clear that
the buffer pointer is never referenced again later in the function. I
still kept the ACKS, hope that is alright with everyone.

Unlike the previous one, this version should work, so yes it may keep
my ACK :)

Regards,

Hans


Thanks,
Henrik

drivers/usb/core/devio.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/drivers/usb/core/devio.c b/drivers/usb/core/devio.c
index ebb8a9d..7f75343 100644
--- a/drivers/usb/core/devio.c
+++ b/drivers/usb/core/devio.c
@@ -1348,6 +1348,7 @@ static int proc_do_submiturb(struct dev_state *ps, struct usbdevfs_urb *uurb,
ret = -EFAULT;
goto error;
}
+ uurb->buffer += u;
}
totlen -= u;
}

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