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Date: Mon, 10 Oct 2016 16:05:50 -0600
From: Ross Zwisler <ross.zwisler@linux.intel.com>
Subject: Re: [PATCH v5 13/17] dax: dax_iomap_fault() needs to call iomap_end()
Message-ID: <20161010220550.GA22793@linux.intel.com>
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To: Christoph Hellwig <hch@lst.de>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>, linux-kernel@vger.kernel.org, Theodore Ts'o <tytso@mit.edu>, Alexander Viro <viro@zeniv.linux.org.uk>, Andreas Dilger <adilger.kernel@dilger.ca>, Andrew Morton <akpm@linux-foundation.org>, Dan Williams <dan.j.williams@intel.com>, Dave Chinner <david@fromorbit.com>, Jan Kara <jack@suse.com>, Matthew Wilcox <mawilcox@microsoft.com>, linux-ext4@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-nvdimm@lists.01.org, linux-xfs@vger.kernel.org

On Mon, Oct 10, 2016 at 05:50:04PM +0200, Christoph Hellwig wrote:
> On Fri, Oct 07, 2016 at 03:09:00PM -0600, Ross Zwisler wrote:
> > Currently iomap_end() doesn't do anything for DAX page faults for both ext2
> > and XFS.  ext2_iomap_end() just checks for a write underrun, and
> > xfs_file_iomap_end() checks to see if it needs to finish a delayed
> > allocation.  However, in the future iomap_end() calls might be needed to
> > make sure we have balanced allocations, locks, etc.  So, add calls to
> > iomap_end() with appropriate error handling to dax_iomap_fault().
> 
> Is there a way to just have a single call to iomap_end at the end of
> the function, after which we just return a previosuly setup return
> value?
> 
> e.g.
> 
> out:
> 	if (ops->iomap_end) {
> 		error = ops->iomap_end(inode, pos, PAGE_SIZE,
> 				PAGE_SIZE, flags, &iomap);
> 	}
> 
> 	if (error == -ENOMEM)
> 		return VM_FAULT_OOM | major;
> 	if (error < 0 && error != -EBUSY)
> 		return VM_FAULT_SIGBUS | major;
> 	return ret;

Sure, will do.