From mboxrd@z Thu Jan 1 00:00:00 1970 From: benh@kernel.crashing.org (Benjamin Herrenschmidt) Date: Sat, 27 Feb 2010 08:36:03 +1100 Subject: USB mass storage and ARM cache coherency In-Reply-To: <1267200044.14703.31.camel@e102109-lin.cambridge.arm.com> References: <1267046036.23523.1693.camel@pasglop> <1267200044.14703.31.camel@e102109-lin.cambridge.arm.com> Message-ID: <1267220163.23523.1806.camel@pasglop> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Fri, 2010-02-26 at 16:00 +0000, Catalin Marinas wrote: > > 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... > > The BIO or filesystem code don't call flush_dcache_page() either (well > some do like cramfs or jffs but they decompress the data received from > the block device). That's weird... that would mean that all existing PIO IDE or SCSI is broken etc... Including I$/D$ cache coherency on powerpc and more. That surprises me :-) On an older kernel tree here: $ grep -r flush_dcache_page fs | wc -l 118 So maybe that's where things need fixing ? Cheers, Ben.