Re: [PATCH v2 1/3] net/usb/r815x: replace USB buffer from stack toDMA-able

From: David Miller
Date: Sat Jul 27 2013 - 23:21:43 EST


From: Hayes Wang <hayeswang@xxxxxxxxxxx>
Date: Thu, 25 Jul 2013 15:59:02 +0800

> Some USB buffers use stack which may not be DMA-able.
> Use the buffers from kmalloc to replace those one.
>
> Signed-off-by: Hayes Wang <hayeswang@xxxxxxxxxxx>

I don't think it's reasonable to kmalloc() a small integer every time
you want to use a USB message transfer to read or write chip
registers.

Instead, add a scratch buffer to struct r8152 which is allocated once
at driver attach time and which you can use for the transfers.

I think you only need an array of two u32's so something like:

u32 transfer_buf[2];

ought to be sufficient.

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