USB mass storage and ARM cache coherency
benh at kernel.crashing.org
Wed Feb 24 16:13:56 EST 2010
On Wed, 2010-02-24 at 11:19 -0500, Alan Stern wrote:
> > It is but I'm not confident the responsibility for doing that
> > is at the HCD level. That would impact a lot of HCD activities that
> > don't need such flushing since the use of the page is purely
> That's right. The HCD merely puts data wherever it's told to. It
> doesn't know whether the destination is in the page cache, in
> userspace, or anywhere else. The same is true for usb-storage.
I'm surprised that usb-storage has an issue here. It shouldn't afaik,
since it's just a SCSI driver (or not anymore ?) and the BIO or
filesystems handle things there no ? I haven't seen a single call to
flush_dcache_page() in any of drivers/scsi, drivers/ata or drivers/ide
when I looked...
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