From: James Bottomley <James.Bottomley@HansenPartnership.com>
To: Ilya Loginov <isloginov@gmail.com>
Cc: Jens Axboe <jens.axboe@oracle.com>, linux-arch@vger.kernel.org
Subject: Re: problems in commit 2d4dc890b5c8 (block: add helpers to run flush_dcache_page() against a bio and a request's pages)
Date: Thu, 10 Dec 2009 14:28:04 -0600 [thread overview]
Message-ID: <1260476884.2457.116.camel@mulgrave.site> (raw)
In-Reply-To: <20091210224637.cb9712f7.isloginov@gmail.com>
On Thu, 2009-12-10 at 22:46 +0300, Ilya Loginov wrote:
> On Thu, 10 Dec 2009 11:07:31 -0600
> James Bottomley <James.Bottomley@HansenPartnership.com> wrote:
>
> > What MTD device is this? The subsystem is very complex, but I suppose I
> > could trace the read path in a single device to see what the actual
> > problem is.
>
> Oh! There is a FPGA. There are kernel and diskimage(via slram) in memory.
> So, kernel just copy a part of libc from fs in RAM to RAM.
Right, so this is the problem. Where you do the ram to ram copy
in-kernel, you need kmap/kunmap. If you copy from the FPGA RAM to the
kernel RAM, before you do the kunmap, you also need a
flush_kernel_dcache_page(). This (plus implementing
flush_kernel_dcache_page() on mips) will fix all coherency issues.
Which exact driver in drivers/mtd? I can probably just look at it and
see where the kmap/flush is supposed to be.
James
next prev parent reply other threads:[~2009-12-10 20:28 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-12-09 22:39 problems in commit 2d4dc890b5c8 (block: add helpers to run flush_dcache_page() against a bio and a request's pages) James Bottomley
2009-12-09 22:45 ` Russell King
2009-12-09 22:56 ` James Bottomley
2009-12-09 23:03 ` Ilya Loginov
2009-12-09 23:11 ` James Bottomley
2009-12-09 23:36 ` Ilya Loginov
2009-12-09 23:47 ` James Bottomley
2009-12-10 0:06 ` Ilya Loginov
2009-12-10 0:19 ` James Bottomley
2009-12-10 4:40 ` Ilya Loginov
2009-12-10 17:07 ` James Bottomley
2009-12-10 17:48 ` Russell King
2009-12-10 17:59 ` James Bottomley
2009-12-10 18:06 ` Russell King
2009-12-10 18:20 ` James Bottomley
2009-12-10 19:05 ` Russell King
2009-12-10 20:29 ` James Bottomley
2009-12-10 20:39 ` Russell King
2009-12-10 19:42 ` Ilya Loginov
2009-12-10 19:43 ` Russell King
2009-12-10 19:48 ` Ilya Loginov
2009-12-10 19:46 ` Ilya Loginov
2009-12-10 20:28 ` James Bottomley [this message]
2009-12-10 20:41 ` Ilya Loginov
2009-12-10 20:48 ` Ilya Loginov
2009-12-10 20:59 ` James Bottomley
2009-12-10 21:27 ` Ilya Loginov
2009-12-10 21:43 ` Ilya Loginov
2009-12-10 22:00 ` James Bottomley
2009-12-10 22:03 ` David Miller
2009-12-10 22:33 ` Ilya Loginov
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