usb: gadget: f_fs: Allow scatter-gather buffers

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Some protocols implemented in userspace with FunctionFS might require large
buffers, e.g. 64kB or more. Currently the said memory is allocated with
kmalloc, which might fail should system memory be highly fragmented.

On the other hand, some UDC hardware allows scatter-gather operation and
this patch takes advantage of this capability: if the requested buffer
is larger than PAGE_SIZE and the UDC allows scatter-gather operation, then
the buffer is allocated with vmalloc and a scatterlist describing it is
created and passed to usb request.

Signed-off-by: Andrzej Pietrasiewicz <andrzej.p@samsung.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>

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Andrzej Pietrasiewicz 2018-11-14 10:47:48 +01:00 • committed by Felipe Balbi

parent 7f7c548c5f

commit 772a7a724f

1 changed files with 86 additions and 7 deletions

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drivers/usb/gadget/function/f_fs.c

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