[PATCH v2] mm: dmapool: use provided gfp flags for all dma_alloc_coherent() calls

Greg KH gregkh at linuxfoundation.org
Tue Jan 15 12:50:20 EST 2013


On Tue, Jan 15, 2013 at 11:56:42AM -0500, Jason Cooper wrote:
> Greg,
> 
> I've added you to the this thread hoping for a little insight into USB
> drivers and their use of coherent and GFP_ATOMIC.  Am I barking up the
> wrong tree by looking a the drivers?

I don't understand, which drivers are you referring to?  USB host
controller drivers, or the "normal" drivers?  Most USB drivers use
GFP_ATOMIC if they are creating memory during their URB callback path,
as that is interrupt context.  But it shouldn't be all that bad, and the
USB core hasn't changed in a while, so something else must be causing
this.

greg k-h



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