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From: Jason Gunthorpe <jgg@mellanox.com>
To: Ira Weiny <ira.weiny@intel.com>
Cc: "john.hubbard@gmail.com" <john.hubbard@gmail.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	"linux-mm@kvack.org" <linux-mm@kvack.org>,
	LKML <linux-kernel@vger.kernel.org>,
	"linux-rdma@vger.kernel.org" <linux-rdma@vger.kernel.org>,
	"linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>,
	John Hubbard <jhubbard@nvidia.com>,
	Doug Ledford <dledford@redhat.com>,
	Mike Marciniszyn <mike.marciniszyn@intel.com>,
	Dennis Dalessandro <dennis.dalessandro@intel.com>,
	Christian Benvenuti <benve@cisco.com>, Jan Kara <jack@suse.cz>
Subject: Re: [PATCH 1/1] infiniband/mm: convert put_page() to put_user_page*()
Date: Thu, 23 May 2019 17:32:26 +0000	[thread overview]
Message-ID: <20190523173222.GH12145@mellanox.com> (raw)
In-Reply-To: <20190523172852.GA27175@iweiny-DESK2.sc.intel.com>

On Thu, May 23, 2019 at 10:28:52AM -0700, Ira Weiny wrote:
> >  
> > @@ -686,8 +686,8 @@ int ib_umem_odp_map_dma_pages(struct ib_umem_odp *umem_odp, u64 user_virt,
> >  			 * ib_umem_odp_map_dma_single_page().
> >  			 */
> >  			if (npages - (j + 1) > 0)
> > -				release_pages(&local_page_list[j+1],
> > -					      npages - (j + 1));
> > +				put_user_pages(&local_page_list[j+1],
> > +					       npages - (j + 1));
> 
> I don't know if we discussed this before but it looks like the use of
> release_pages() was not entirely correct (or at least not necessary) here.  So
> I think this is ok.

Oh? John switched it from a put_pages loop to release_pages() here:

commit 75a3e6a3c129cddcc683538d8702c6ef998ec589
Author: John Hubbard <jhubbard@nvidia.com>
Date:   Mon Mar 4 11:46:45 2019 -0800

    RDMA/umem: minor bug fix in error handling path
    
    1. Bug fix: fix an off by one error in the code that cleans up if it fails
       to dma-map a page, after having done a get_user_pages_remote() on a
       range of pages.
    
    2. Refinement: for that same cleanup code, release_pages() is better than
       put_page() in a loop.
    

And now we are going to back something called put_pages() that
implements the same for loop the above removed?

Seems like we are going in circles?? John?

Jason

  reply	other threads:[~2019-05-23 17:32 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-05-23  7:25 [PATCH 0/1] " john.hubbard
2019-05-23  7:25 ` [PATCH 1/1] " john.hubbard
2019-05-23 15:31   ` Jerome Glisse
2019-05-23 17:56     ` John Hubbard
2019-05-23 17:28   ` Ira Weiny
2019-05-23 17:32     ` Jason Gunthorpe [this message]
2019-05-23 17:46       ` John Hubbard
2019-05-23 19:04         ` Ira Weiny
2019-05-23 19:13           ` John Hubbard
2019-05-23 22:37             ` Ira Weiny
2019-05-23 22:50               ` John Hubbard
2019-05-23 22:54                 ` John Hubbard
2019-05-23 19:17         ` Jason Gunthorpe

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