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Date:   Wed, 20 Mar 2019 19:53:33 +0800
From:   Baoquan He <bhe@redhat.com>
To:     Matthew Wilcox <willy@infradead.org>
Cc:     linux-kernel@vger.kernel.org, akpm@linux-foundation.org,
        pasha.tatashin@oracle.com, mhocko@suse.com,
        rppt@linux.vnet.ibm.com, richard.weiyang@gmail.com,
        linux-mm@kvack.org
Subject: Re: [PATCH 1/3] mm/sparse: Clean up the obsolete code comment
Message-ID: <20190320115333.GR18740@MiWiFi-R3L-srv>
References: <20190320073540.12866-1-bhe@redhat.com>
 <20190320111959.GV19508@bombadil.infradead.org>
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On 03/20/19 at 04:19am, Matthew Wilcox wrote:
> On Wed, Mar 20, 2019 at 03:35:38PM +0800, Baoquan He wrote:
> >  /*
> > - * returns the number of sections whose mem_maps were properly
> > - * set.  If this is <=0, then that means that the passed-in
> > - * map was not consumed and must be freed.
> > + * sparse_add_one_section - add a memory section
> > + * @nid:	The node to add section on
> > + * @start_pfn:	start pfn of the memory range
> > + * @altmap:	device page map
> > + *
> > + * Return 0 on success and an appropriate error code otherwise.
> >   */
> 
> I think it's worth documenting what those error codes are.  Seems to be
> just -ENOMEM and -EEXIST, but it'd be nice for users to know what they
> can expect under which circumstances.
> 
> Also, -EEXIST is a bad errno to return here:
> 
> $ errno EEXIST
> EEXIST 17 File exists
> 
> What file?  I think we should be using -EBUSY instead in case this errno
> makes it back to userspace:
> 
> $ errno EBUSY
> EBUSY 16 Device or resource busy

OK, will update per your comments. Thanks.
>