From: Matthew Wilcox <willy@infradead.org>
To: Harish Kasiviswanathan <Harish.Kasiviswanathan@amd.com>
Cc: guaneryu@gmail.com, linux-fsdevel@vger.kernel.org,
Felix.Kuehling@amd.com
Subject: Re: [PATCH v3] direct-io: Fix unsigned comparison overflow
Date: Wed, 6 Dec 2017 10:23:04 -0800 [thread overview]
Message-ID: <20171206182304.GA7829@bombadil.infradead.org> (raw)
In-Reply-To: <1512579438-4854-1-git-send-email-Harish.Kasiviswanathan@amd.com>
On Wed, Dec 06, 2017 at 11:57:18AM -0500, Harish Kasiviswanathan wrote:
> The first write after file create fails to take the direct IO
> (Peer-to-Peer) path and falls back to slower software copy. The function
> get_more_block() sets 'create' to 0 after comparing 'unsigned long
> fs_startblk = 0' with 'long long (i_size_read(dio->inode) - 1) >>
> i_blkbits = 0xfffffffffffff'.
>
> v2: Instead of casting to loff_t check explicitly if i_size > 0
> v3: Use cached dio->i_size instead of i_size_read() which isn't cheap on
> 32-bit SMP
>
> Signed-off-by: Harish Kasiviswanathan <Harish.Kasiviswanathan@amd.com>
Reviewed-by: Matthew Wilcox <mawilcox@microsoft.com>
prev parent reply other threads:[~2017-12-06 18:23 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-12-06 16:57 [PATCH v3] direct-io: Fix unsigned comparison overflow Harish Kasiviswanathan
2017-12-06 18:23 ` Matthew Wilcox [this message]
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