From: Cestonaro Thilo <thilo.cestonaro-RJz4owOZxyXQFUHtdCDX3A@public.gmane.org>
To: "linux-spi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org"
<linux-spi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>
Subject: Re: mtdblock read sector and cache_data == NULL
Date: Tue, 11 Feb 2014 09:46:56 +0100 [thread overview]
Message-ID: <52F9E380.7050700@ts.fujitsu.com> (raw)
In-Reply-To: <52F9E10F.8060904-RJz4owOZxyXQFUHtdCDX3A@public.gmane.org>
hey,
forget it :) ... I got confused ....
Greetings Thilo
On 11.02.2014 09:36, Cestonaro Thilo wrote:
> Hey,
>
> I think the cache_data buffer is used uninitialized in case no write
> prepends the first read.
>
> Initialization of cache_data buffer:
> https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/drivers/mtd/mtdblock.c?id=refs/tags/v3.14-rc2#n300
> --------------------
>
> if (!(mbd->mtd->flags & MTD_NO_ERASE) && mbd->mtd->erasesize) {
> mtdblk->cache_size = mbd->mtd->erasesize;
> mtdblk->cache_data = NULL;
> }
> ----------------
>
> And later in do_cached_read it is just used with mtdblock->cache_data +
> offset.
> https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/drivers/mtd/mtdblock.c?id=refs/tags/v3.14-rc2#n243
>
> The only allocation I can find is in writesector function, so I figured
> that the mtd_read will get NULL+offset in the first read.
> https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/drivers/mtd/mtdblock.c?id=refs/tags/v3.14-rc2#n272
>
> Is it correct to place the same if unlikely stuff in the
> mtdblock_readsect function like in the mtdblock_writesect one?
>
> Greetings
> Thilo
>
--
With best regards
Thilo Cestonaro
FTS PBG PDG WPS R&D EPC
Fujitsu Technology Solutions GmbH
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prev parent reply other threads:[~2014-02-11 8:46 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-02-11 8:36 mtdblock read sector and cache_data == NULL Cestonaro Thilo
[not found] ` <52F9E10F.8060904-RJz4owOZxyXQFUHtdCDX3A@public.gmane.org>
2014-02-11 8:46 ` Cestonaro Thilo [this message]
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