From: Jens Wiklander <jens.wiklander@linaro.org>
To: John Hubbard <jhubbard@nvidia.com>
Cc: linaro-mm-sig@lists.linaro.org, linux-kernel@vger.kernel.org,
dri-devel@lists.freedesktop.org, tee-dev@lists.linaro.org,
soc@kernel.org, arm@kernel.org, olof@lixom.net,
Sumit Semwal <sumit.semwal@linaro.org>,
linux-arm-kernel@lists.infradead.org,
linux-media@vger.kernel.org
Subject: Re: [PATCH v3] tee: convert convert get_user_pages() --> pin_user_pages()
Date: Tue, 25 Aug 2020 10:32:04 +0200 [thread overview]
Message-ID: <20200825083204.GA2068961@jade> (raw)
In-Reply-To: <20200824211125.1867329-1-jhubbard@nvidia.com>
On Mon, Aug 24, 2020 at 02:11:25PM -0700, John Hubbard wrote:
> This code was using get_user_pages*(), in a "Case 2" scenario
> (DMA/RDMA), using the categorization from [1]. That means that it's
> time to convert the get_user_pages*() + put_page() calls to
> pin_user_pages*() + unpin_user_pages() calls.
>
> Factor out a new, small release_registered_pages() function, in
> order to consolidate the logic for discerning between
> TEE_SHM_USER_MAPPED and TEE_SHM_KERNEL_MAPPED pages. This also
> absorbs the kfree() call that is also required there.
>
> There is some helpful background in [2]: basically, this is a small
> part of fixing a long-standing disconnect between pinning pages, and
> file systems' use of those pages.
>
> [1] Documentation/core-api/pin_user_pages.rst
>
> [2] "Explicit pinning of user-space pages":
> https://lwn.net/Articles/807108/
>
> Cc: Jens Wiklander <jens.wiklander@linaro.org>
> Cc: Sumit Semwal <sumit.semwal@linaro.org>
> Cc: tee-dev@lists.linaro.org
> Cc: linux-media@vger.kernel.org
> Cc: dri-devel@lists.freedesktop.org
> Cc: linaro-mm-sig@lists.linaro.org
> Signed-off-by: John Hubbard <jhubbard@nvidia.com>
> ---
>
> OK, one more try, this time actually handling the _USER_MAPPED vs.
> _KERNEL_MAPPED pages!
>
> thanks,
> John Hubbard
> NVIDIA
Looks good and it works too! :-) I've tested it on my Hikey board with
the OP-TEE test suite.
I'm picking this up.
Thanks,
Jens
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next prev parent reply other threads:[~2020-08-25 8:33 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-26 13:12 [GIT PULL] tee subsystem pin_user_pages for v5.8 Jens Wiklander
2020-08-21 18:49 ` Olof Johansson
2020-08-21 19:58 ` John Hubbard
2020-08-21 21:18 ` Olof Johansson
2020-08-24 6:51 ` Jens Wiklander
2020-08-24 7:18 ` John Hubbard
2020-08-24 7:46 ` Jens Wiklander
2020-08-24 18:36 ` [PATCH v2] tee: convert convert get_user_pages() --> pin_user_pages() John Hubbard
2020-08-24 18:42 ` John Hubbard
2020-08-24 21:11 ` [PATCH v3] " John Hubbard
2020-08-25 8:32 ` Jens Wiklander [this message]
2020-08-25 8:54 ` John Hubbard
2020-08-25 9:02 ` Jens Wiklander
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