Re: [PATCH v3 1/3] net/usb/r815x: replace USB buffer from stack toDMA-able

From: David Miller
Date: Tue Jul 30 2013 - 14:49:57 EST

From: Joe Perches <joe@xxxxxxxxxxx>
Date: Tue, 30 Jul 2013 11:41:17 -0700

> On Tue, 2013-07-30 at 11:33 -0700, David Miller wrote:
>> From: Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx>
>> Date: Tue, 30 Jul 2013 07:00:59 -0700
>> > This call is so slow, you can afford to make a call to kmalloc for the
>> > data, as it sure just did for other structures it needed :)
>> I told him to implement things this way, to avoid calling kmalloc every
>> single register access.
>> Using kmalloc all the time makes the access fragile, since a badly timed
>> call during high memory pressure can fail.
>> I'd rather the potential failure happen at one time, probe time.
>> In any event, Ming Lei has suggested using usbnet_{read,write}_cmd()
>> instead, which sounds like a good solution to this problem.
> Those do per-call allocs too.

Sigh... Ok I won't fight this any longer then :-)
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