linux-kernel - Re: [PATCH v3] efivars,efi-pstore: Hold off deletion of sysfs entry until, the scan is completed

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Message-ID: <20131017131821.GH10834@console-pimps.org>
Date:	Thu, 17 Oct 2013 14:18:21 +0100
From:	Matt Fleming <matt@...sole-pimps.org>
To:	Seiji Aguchi <seiji.aguchi@....com>
Cc:	linux-kernel@...r.kernel.org, linux-efi@...r.kernel.org,
	matt.fleming@...el.com, tony.luck@...el.com,
	tomoki.sekiyama@....com, dle-develop@...ts.sourceforge.net
Subject: Re: [PATCH v3] efivars,efi-pstore: Hold off deletion of sysfs entry
 until, the scan is completed

On Fri, 11 Oct, at 02:29:07PM, Seiji Aguchi wrote:
> Change from v2:
> - Move dynamic memory allocation to efi_pstore_read() before holding
>   efivars->lock to protect entry->var.Data.
> - Access to entry->scanning while holding efivars->lock.
> - Move a comment about a returned value from efi_pstore_read_func() to
>   efi_pstore_read() because "size < 0" case may happen in efi_pstore_read().

It seems to me that because you're no longer dropping __efivars->lock
when reading from the EFI variable store, you actually don't need all
the ->scanning and ->deleting logic because anything that sets those
flags runs to completion while holding the lock.

Can't the patch be simplified to just allocating data.buf at the
beginning of efi_pstore_read()? Also, it would be a good idea to
introduce a #define for the 1024 magic number, e.g.

#define EFIVARS_DATA_SIZE_MAX	1024

-- 
Matt Fleming, Intel Open Source Technology Center
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