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Date:   Sun, 16 Feb 2020 18:37:31 -0800 (PST)
Message-Id: <20200216.183731.2157450869886971370.davem@davemloft.net>
To:     jhubbard@nvidia.com
Cc:     akpm@linux-foundation.org, santosh.shilimkar@oracle.com,
        hans.westgaard.ry@oracle.com, leonro@mellanox.com, kuba@kernel.org,
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        linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/1] net/rds: Track user mapped pages through special
 API
From:   David Miller <davem@davemloft.net>
In-Reply-To: <20200212030355.1600749-2-jhubbard@nvidia.com>
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        <20200212030355.1600749-2-jhubbard@nvidia.com>
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From: John Hubbard <jhubbard@nvidia.com>
Date: Tue, 11 Feb 2020 19:03:55 -0800

> From: Leon Romanovsky <leonro@mellanox.com>
> 
> Convert net/rds to use the newly introduces pin_user_pages() API,
> which properly sets FOLL_PIN. Setting FOLL_PIN is now required for
> code that requires tracking of pinned pages.
> 
> Note that this effectively changes the code's behavior: it now
> ultimately calls set_page_dirty_lock(), instead of set_page_dirty().
> This is probably more accurate.
> 
> As Christoph Hellwig put it, "set_page_dirty() is only safe if we are
> dealing with a file backed page where we have reference on the inode it
> hangs off." [1]
> 
> [1] https://lore.kernel.org/r/20190723153640.GB720@lst.de
> 
> Cc: Hans Westgaard Ry <hans.westgaard.ry@oracle.com>
> Cc: Santosh Shilimkar <santosh.shilimkar@oracle.com>
> Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
> Signed-off-by: John Hubbard <jhubbard@nvidia.com>

Applied, thank you.