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Message-ID: <CAFqt6zbvyaPF3tUA1-=RsfSM14p7Rx5NgQqAeW5-JUfd+NrJ2g@mail.gmail.com>
Date: Mon, 3 Dec 2018 09:51:45 +0530
From: Souptick Joarder <jrdr.linux@...il.com>
To: rppt@...ux.ibm.com
Cc: Andrew Morton <akpm@...ux-foundation.org>,
Matthew Wilcox <willy@...radead.org>,
Michal Hocko <mhocko@...e.com>,
"Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>,
vbabka@...e.cz, Rik van Riel <riel@...riel.com>,
Stephen Rothwell <sfr@...b.auug.org.au>,
rppt@...ux.vnet.ibm.com, Peter Zijlstra <peterz@...radead.org>,
Russell King - ARM Linux <linux@...linux.org.uk>,
robin.murphy@....com, iamjoonsoo.kim@....com, treding@...dia.com,
Kees Cook <keescook@...omium.org>,
Marek Szyprowski <m.szyprowski@...sung.com>,
stefanr@...6.in-berlin.de, hjc@...k-chips.com,
Heiko Stuebner <heiko@...ech.de>, airlied@...ux.ie,
oleksandr_andrushchenko@...m.com, joro@...tes.org,
pawel@...iak.com, Kyungmin Park <kyungmin.park@...sung.com>,
mchehab@...nel.org, Boris Ostrovsky <boris.ostrovsky@...cle.com>,
Juergen Gross <jgross@...e.com>, linux-kernel@...r.kernel.org,
Linux-MM <linux-mm@...ck.org>,
linux-arm-kernel@...ts.infradead.org,
linux1394-devel@...ts.sourceforge.net,
dri-devel@...ts.freedesktop.org,
linux-rockchip@...ts.infradead.org, xen-devel@...ts.xen.org,
iommu@...ts.linux-foundation.org, linux-media@...r.kernel.org
Subject: Re: [PATCH v2 1/9] mm: Introduce new vm_insert_range API
Hi Mike,
On Sun, Dec 2, 2018 at 4:43 PM Mike Rapoport <rppt@...ux.ibm.com> wrote:
>
> On Sun, Dec 02, 2018 at 11:49:44AM +0530, Souptick Joarder wrote:
> > 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 a new function and use it across
> > the drivers.
> >
> > vm_insert_range is the new API which will be used to map a
> > range of kernel memory/pages to user vma.
> >
> > This API is tested by Heiko for Rockchip drm driver, on rk3188,
> > rk3288, rk3328 and rk3399 with graphics.
> >
> > Signed-off-by: Souptick Joarder <jrdr.linux@...il.com>
> > Reviewed-by: Matthew Wilcox <willy@...radead.org>
> > Tested-by: Heiko Stuebner <heiko@...ech.de>
> > ---
> > include/linux/mm_types.h | 3 +++
> > mm/memory.c | 38 ++++++++++++++++++++++++++++++++++++++
> > mm/nommu.c | 7 +++++++
> > 3 files changed, 48 insertions(+)
> >
> > diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
> > index 5ed8f62..15ae24f 100644
> > --- a/include/linux/mm_types.h
> > +++ b/include/linux/mm_types.h
> > @@ -523,6 +523,9 @@ extern void tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm,
> > extern void tlb_finish_mmu(struct mmu_gather *tlb,
> > unsigned long start, unsigned long end);
> >
> > +int vm_insert_range(struct vm_area_struct *vma, unsigned long addr,
> > + struct page **pages, unsigned long page_count);
> > +
>
> This seem to belong to include/linux/mm.h, near vm_insert_page()
Ok, I will change it. Apart from this change does it looks good ?
>
> > static inline void init_tlb_flush_pending(struct mm_struct *mm)
> > {
> > atomic_set(&mm->tlb_flush_pending, 0);
> > diff --git a/mm/memory.c b/mm/memory.c
> > index 15c417e..84ea46c 100644
> > --- a/mm/memory.c
> > +++ b/mm/memory.c
> > @@ -1478,6 +1478,44 @@ static int insert_page(struct vm_area_struct *vma, unsigned long addr,
> > }
> >
> > /**
> > + * vm_insert_range - insert range of kernel pages into user vma
> > + * @vma: user vma to map to
> > + * @addr: target user address of this page
> > + * @pages: pointer to array of source kernel pages
> > + * @page_count: number of pages need to insert into user vma
> > + *
> > + * This allows drivers to insert range of kernel pages they've allocated
> > + * into a user vma. This is a generic function which drivers can use
> > + * rather than using their own way of mapping range of kernel pages into
> > + * user vma.
> > + *
> > + * If we fail to insert any page into the vma, the function will return
> > + * immediately leaving any previously-inserted pages present. Callers
> > + * from the mmap handler may immediately return the error as their caller
> > + * will destroy the vma, removing any successfully-inserted pages. Other
> > + * callers should make their own arrangements for calling unmap_region().
> > + *
> > + * Context: Process context. Called by mmap handlers.
> > + * Return: 0 on success and error code otherwise
> > + */
> > +int vm_insert_range(struct vm_area_struct *vma, unsigned long addr,
> > + struct page **pages, unsigned long page_count)
> > +{
> > + unsigned long uaddr = addr;
> > + int ret = 0, i;
> > +
> > + for (i = 0; i < page_count; i++) {
> > + ret = vm_insert_page(vma, uaddr, pages[i]);
> > + if (ret < 0)
> > + return ret;
> > + uaddr += PAGE_SIZE;
> > + }
> > +
> > + return ret;
> > +}
> > +EXPORT_SYMBOL(vm_insert_range);
> > +
> > +/**
> > * vm_insert_page - insert single page into user vma
> > * @vma: user vma to map to
> > * @addr: target user address of this page
> > diff --git a/mm/nommu.c b/mm/nommu.c
> > index 749276b..d6ef5c7 100644
> > --- a/mm/nommu.c
> > +++ b/mm/nommu.c
> > @@ -473,6 +473,13 @@ int vm_insert_page(struct vm_area_struct *vma, unsigned long addr,
> > }
> > EXPORT_SYMBOL(vm_insert_page);
> >
> > +int vm_insert_range(struct vm_area_struct *vma, unsigned long addr,
> > + struct page **pages, unsigned long page_count)
> > +{
> > + return -EINVAL;
> > +}
> > +EXPORT_SYMBOL(vm_insert_range);
> > +
> > /*
> > * sys_brk() for the most part doesn't need the global kernel
> > * lock, except when an application is doing something nasty
> > --
> > 1.9.1
> >
>
> --
> Sincerely yours,
> Mike.
>
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