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From: Theodore Tso <tytso@mit.edu>
To: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: cmm@us.ibm.com, sandeen@redhat.com, linux-ext4@vger.kernel.org
Subject: Re: [RFC PATCH -V3 1/9] ext4: sparse fixes
Date: Thu, 6 Nov 2008 17:09:54 -0500	[thread overview]
Message-ID: <20081106220954.GM18939@mit.edu> (raw)
In-Reply-To: <1225997374-10846-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com>

On Fri, Nov 07, 2008 at 12:19:26AM +0530, Aneesh Kumar K.V wrote:
>  #define EXT4_HAS_COMPAT_FEATURE(sb,mask)			\
> -	(EXT4_SB(sb)->s_es->s_feature_compat & cpu_to_le32(mask))
> +	(le32_to_cpu(EXT4_SB(sb)->s_es->s_feature_compat) & mask)
>  #define EXT4_HAS_RO_COMPAT_FEATURE(sb,mask)			\
> -	(EXT4_SB(sb)->s_es->s_feature_ro_compat & cpu_to_le32(mask))
> +	(le32_to_cpu(EXT4_SB(sb)->s_es->s_feature_ro_compat) & mask)
>  #define EXT4_HAS_INCOMPAT_FEATURE(sb,mask)			\
> -	(EXT4_SB(sb)->s_es->s_feature_incompat & cpu_to_le32(mask))
> +	(le32_to_cpu(EXT4_SB(sb)->s_es->s_feature_incompat) & mask)

This is going to force a byte-swap instruction on every single
big-endian system out there, which could potentially be costly, or at
least undeed given that all of the times that these functions are
called, the result gets used only as a booelan.

Can we shut up sparse by using a explicit cast to an unsigned int?

       	       	      	       	 	  - Ted

  parent reply	other threads:[~2008-11-06 22:09 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-11-06 18:49 [RFC PATCH -V3 1/9] ext4: sparse fixes Aneesh Kumar K.V
2008-11-06 18:49 ` [RFC PATCH -V3 2/9] ext4: Add blocks added during resize to bitmap Aneesh Kumar K.V
2008-11-06 18:49   ` [RFC PATCH -V3 3/9] ext4: Use EXT4_GROUP_INFO_NEED_INIT_BIT during resize Aneesh Kumar K.V
2008-11-06 18:49     ` [RFC PATCH -V3 4/9] ext4: cleanup mballoc header files Aneesh Kumar K.V
2008-11-06 18:49       ` [RFC PATCH -V3 5/9] ext4: Add sparse annotations for the group info semaphore Aneesh Kumar K.V
2008-11-06 18:49         ` [RFC PATCH -V3 6/9] jbd2: Call journal commit callback without holding j_list_lock Aneesh Kumar K.V
2008-11-06 18:49           ` [RFC PATCH -V3 7/9] ext4: don't use blocks freed but not yet committed in buddy cache init Aneesh Kumar K.V
2008-11-06 18:49             ` [RFC PATCH -V3 8/9] ext4: Fix double free of blocks Aneesh Kumar K.V
2008-11-06 18:49               ` [RFC PATCH -V3 9/9] ext4: Fix lockdep recursive locking warning Aneesh Kumar K.V
2008-11-07  8:04                 ` Li Zefan
2008-11-07 16:22                   ` Aneesh Kumar K.V
2008-11-08  1:21                     ` Li Zefan
2008-11-06 22:37               ` [RFC PATCH -V3 8/9] ext4: Fix double free of blocks Theodore Tso
2008-11-07 16:01                 ` Aneesh Kumar K.V
2008-11-06 22:09 ` Theodore Tso [this message]
2008-11-07 14:20   ` [RFC PATCH -V3 1/9] ext4: sparse fixes Aneesh Kumar K.V
2008-11-07 14:45     ` Theodore Tso
2008-11-07 15:07     ` Christoph Hellwig

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