Re: USB mass storage and ARM cache coherency

[Oliver Neukum]

Am Dienstag, 2. Februar 2010 13:39:35 schrieb Catalin Marinas:
> > For storage that is correct. But what about other sources of pages,
> > for example iSCSI?
> 
> In the iSCSI case, does the HCD driver write directly to a page cache
> page? Or it just fills in network packets that are copied to page cache
> pages by the iSCSI code (sorry, I'm not familiar with this part of the
> kernel). If the latter, the cache flushing in the HCD driver would not
> help and it needs to be done in the iSCSI code.

As far as I can tell iSCSI does a private copy. But I don't know how
many methods to transfer code pages over USB exist. I'd say the
conservative solution is to flush for everything but control transfers.

	Regards
		Oliver
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