Re: [PATCHv2 1/9] mm: Introduce new vm_insert_range and vm_insert_range_buggy API

From: Heiko Stuebner <heiko@sntech.de>
To: Souptick Joarder <jrdr.linux@gmail.com>
Cc: mhocko@suse.com, peterz@infradead.org,
	dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org,
	linux-mm@kvack.org, linux1394-devel@lists.sourceforge.net,
	m.szyprowski@samsung.com, sfr@canb.auug.org.au,
	oleksandr_andrushchenko@epam.com, linux@armlinux.org.uk,
	willy@infradead.org, airlied@linux.ie,
	linux-arm-kernel@lists.infradead.org,
	linux-rockchip@lists.infradead.org, treding@nvidia.com,
	linux-media@vger.kernel.org, keescook@chromium.org,
	pawel@osciak.com, riel@surriel.com,
	iommu@lists.linux-foundation.org, rppt@linux.vnet.ibm.com,
	boris.ostrovsky@oracle.com, mchehab@kernel.org,
	iamjoonsoo.kim@lge.com, vbabka@suse.cz, jgross@suse.com,
	xen-devel@lists.xen.org, kyungmin.park@samsung.com,
	stefanr@s5r6.in-berlin.de, akpm@linux-foundation.org,
	robin.murphy@arm.com, kirill.shutemov@linux.intel.com
Subject: Re: [PATCHv2 1/9] mm: Introduce new vm_insert_range and vm_insert_range_buggy API
Date: Thu, 31 Jan 2019 13:06:49 +0100	[thread overview]
Message-ID: <1701923.z6LKAITQJA@phil> (raw)
In-Reply-To: <20190131030812.GA2174@jordon-HP-15-Notebook-PC>

Am Donnerstag, 31. Januar 2019, 04:08:12 CET schrieb Souptick Joarder:
> Previouly drivers have their own way of mapping range of
> kernel pages/memory into user vma and this was done by
> invoking vm_insert_page() within a loop.
> 
> As this pattern is common across different drivers, it can
> be generalized by creating new functions and use it across
> the drivers.
> 
> vm_insert_range() is the API which could be used to mapped
> kernel memory/pages in drivers which has considered vm_pgoff
> 
> vm_insert_range_buggy() is the API which could be used to map
> range of kernel memory/pages in drivers which has not considered
> vm_pgoff. vm_pgoff is passed default as 0 for those drivers.
> 
> We _could_ then at a later "fix" these drivers which are using
> vm_insert_range_buggy() to behave according to the normal vm_pgoff
> offsetting simply by removing the _buggy suffix on the function
> name and if that causes regressions, it gives us an easy way to revert.
> 
> Signed-off-by: Souptick Joarder <jrdr.linux@gmail.com>
> Suggested-by: Russell King <linux@armlinux.org.uk>
> Suggested-by: Matthew Wilcox <willy@infradead.org>

hmm, I'm missing a changelog here between v1 and v2.
Nevertheless I managed to test v1 on Rockchip hardware
and display is still working, including talking to Lima via prime.

So if there aren't any big changes for v2, on Rockchip
Tested-by: Heiko Stuebner <heiko@sntech.de>

Heiko

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