Re: [PATCH] Add support for usbfs zerocopy.

From: Christoph Hellwig
Date: Wed Jan 06 2016 - 01:49:55 EST


This is a completely broken usage of the mmap interface. if you use
mmap on a device file you must use the actual mmap for the data
transfer.

Our interface for zero copy reads/writes is O_DIRECT, and that requires
not special memory allocation, just proper alignment.
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