From: Andi Kleen <andi@firstfloor.org>
To: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Nick Piggin <npiggin@kernel.dk>,
Al Viro <viro@zeniv.linux.org.uk>,
linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: DNAME_INLINE_LEN versus CONFIG_GENERIC_LOCKBREAK
Date: Thu, 03 Jul 2014 12:53:01 -0700 [thread overview]
Message-ID: <87fviite1u.fsf@tassilo.jf.intel.com> (raw)
In-Reply-To: <8761je94wk.fsf@rasmusvillemoes.dk> (Rasmus Villemoes's message of "Thu, 03 Jul 2014 11:18:35 +0200")
Rasmus Villemoes <linux@rasmusvillemoes.dk> writes:
> In dcache.h, DNAME_INLINE_LEN is carefully chosen so that sizeof(struct
> dentry) is a (specific) multiple of 64 bytes. Obviously this breaks when
> certain debug options are chosen (DEBUG_LOCK_ALLOC and DEBUG_SPINLOCK),
> but also, AFAICT, on architectures with CONFIG_GENERIC_LOCKBREAK.
>
> I'm not sure it matters, but if it does, I'd suggest putting a
> BUILD_BUG_ON somewhere, protected by suitable #ifdefs, so that the code
> documents the assumptions that went into the particular choice of
> DNAME_INLINE_LEN (this would also help catch changes to some of the
> structures embedded in struct dentry which would violate those
> assumptions).
The right fix would be to pad it correctly for these other variants
too.
Checking for magic numbers would be nasty though.
-Andi
--
ak@linux.intel.com -- Speaking for myself only
next prev parent reply other threads:[~2014-07-03 19:53 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-07-03 9:18 DNAME_INLINE_LEN versus CONFIG_GENERIC_LOCKBREAK Rasmus Villemoes
2014-07-03 19:53 ` Andi Kleen [this message]
2014-07-04 1:32 ` Dave Chinner
2014-07-04 3:16 ` Andi Kleen
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