Messages in this thread | | | From | Michal Nazarewicz <> | Subject | Re: [PATCH] usb: gadget: f_fs: report error if excess data received | Date | Wed, 18 May 2016 15:39:11 +0200 |
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On Wed, May 18 2016, Felipe Balbi wrote: > we've been through this before. This needs to be done at the gadget > layer. Gadget driver can over-allocate ahead of time if > gadget->quirk_ep_out_aligned_size is true, then we avoid memcpy() at > the UDC driver level.
Right, all right, so let’s look at it from a regular USB function point of view. If a USB function allocates a request which is not aligned, UDC will align the buffer and *drop* excess data. Seeing how ugly f_fs’s code is becoming, I’m now leaning to letting to f_fs do the same thing: if user space makes an unaligned read, f_fs aligns the buffer and then drops excess data.
Any arguments for f_fs to not drop the data apply to UDC, so they should behave identically.
-- Best regards ミハウ “𝓶𝓲𝓷𝓪86” ナザレヴイツ «If at first you don’t succeed, give up skydiving»
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