From: Al Viro <viro@ZenIV.linux.org.uk>
To: Sean Fu <fxinrong@gmail.com>
Cc: tytso@mit.edu, adilger.kernel@dilger.ca,
linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] ext4: Remove repeated test in ext4_file_read_iter.
Date: Wed, 3 Jan 2018 02:08:05 +0000 [thread overview]
Message-ID: <20180103020805.GB21978@ZenIV.linux.org.uk> (raw)
In-Reply-To: <1514362798-5850-1-git-send-email-fxinrong@gmail.com>
On Wed, Dec 27, 2017 at 04:19:58PM +0800, Sean Fu wrote:
> generic_file_read_iter has done the count test.
> So ext4_file_read_iter don't need to test the count repeatedly.
Huh? You do realize that generic_file_read_iter() is not the
only variant possible there, right?
static ssize_t ext4_dax_read_iter(struct kiocb *iocb, struct iov_iter *to)
{
struct inode *inode = file_inode(iocb->ki_filp);
ssize_t ret;
if (!inode_trylock_shared(inode)) {
if (iocb->ki_flags & IOCB_NOWAIT)
return -EAGAIN;
inode_lock_shared(inode);
}
... and now IOCB_NOWAIT read with zero count can fail with -EAGAIN.
next prev parent reply other threads:[~2018-01-03 2:08 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-12-27 8:19 [PATCH] ext4: Remove repeated test in ext4_file_read_iter Sean Fu
2018-01-03 2:08 ` Al Viro [this message]
2018-01-10 14:01 ` Sean Fu
2018-01-10 20:02 ` Theodore Ts'o
2018-01-16 8:10 ` Sean Fu
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