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From:   David Laight <David.Laight@ACULAB.COM>
To:     'Al Viro' <viro@zeniv.linux.org.uk>
CC:     'Mikulas Patocka' <mpatocka@redhat.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Dan Williams <dan.j.williams@intel.com>,
        "Vishal Verma" <vishal.l.verma@intel.com>,
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        Matthew Wilcox <willy@infradead.org>, Jan Kara <jack@suse.cz>,
        Steven Whitehouse <swhiteho@redhat.com>,
        Eric Sandeen <esandeen@redhat.com>,
        Dave Chinner <dchinner@redhat.com>,
        Theodore Ts'o <tytso@mit.edu>,
        Wang Jianchao <jianchao.wan9@gmail.com>,
        "Kani, Toshi" <toshi.kani@hpe.com>,
        "Norton, Scott J" <scott.norton@hpe.com>,
        "Tadakamadla, Rajesh" <rajesh.tadakamadla@hpe.com>,
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Subject: RE: [RFC v2] nvfs: a filesystem for persistent memory
Thread-Topic: [RFC v2] nvfs: a filesystem for persistent memory
Thread-Index: AQHW52zcFLyucqAcQUmnqwhwPozPcaoiOfvQgAAVUICAAALF8IAAL2SAgAAB4jA=
Date:   Mon, 11 Jan 2021 14:54:11 +0000
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From: Al Viro <viro@ftp.linux.org.uk> On Behalf Of Al Viro
> Sent: 11 January 2021 14:44
> On Mon, Jan 11, 2021 at 11:57:08AM +0000, David Laight wrote:
> > > > > 		size = copy_to_iter(to, ptr, size);
> > > > > 		if (unlikely(!size)) {
> > > > > 			r = -EFAULT;
> > > > > 			goto ret_r;
> > > > > 		}
> > > > >
> > > > > 		pos += size;
> > > > > 		total += size;
> > > > > 	}
> > > >
> > > > 	David
> > >
> > > I fixed the arguments to
> > > copy_to_iter - other than that, Al's function works.
> >
> 
> > Oh - the error return for copy_to_iter() is wrong.
> > It should (probably) return 'total' if it is nonzero.
> 
> 	copy_to_iter() call there has an obvious problem
> (arguments in the wrong order), but return value is handled
> correctly.  It does not do a blind return -EFAULT.  RTFS...

Ah I was looking at the version I'd cut the tail off...

	David

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