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Message-ID: <20181206183945.GA20932@jordon-HP-15-Notebook-PC>
Date: Fri, 7 Dec 2018 00:09:45 +0530
From: Souptick Joarder <jrdr.linux@...il.com>
To: akpm@...ux-foundation.org, willy@...radead.org, mhocko@...e.com,
kirill.shutemov@...ux.intel.com, vbabka@...e.cz, riel@...riel.com,
sfr@...b.auug.org.au, rppt@...ux.vnet.ibm.com,
peterz@...radead.org, linux@...linux.org.uk, robin.murphy@....com,
iamjoonsoo.kim@....com, treding@...dia.com, keescook@...omium.org,
m.szyprowski@...sung.com, stefanr@...6.in-berlin.de,
hjc@...k-chips.com, heiko@...ech.de, airlied@...ux.ie,
oleksandr_andrushchenko@...m.com, joro@...tes.org,
pawel@...iak.com, kyungmin.park@...sung.com, mchehab@...nel.org,
boris.ostrovsky@...cle.com, jgross@...e.com
Cc: linux-kernel@...r.kernel.org, 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: [PATCH v3 1/9] mm: Introduce new vm_insert_range API
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>
Reviewed-by: Mike Rapoport <rppt@...ux.ibm.com>
Tested-by: Heiko Stuebner <heiko@...ech.de>
---
include/linux/mm.h | 2 ++
mm/memory.c | 38 ++++++++++++++++++++++++++++++++++++++
mm/nommu.c | 7 +++++++
3 files changed, 47 insertions(+)
diff --git a/include/linux/mm.h b/include/linux/mm.h
index fcf9cc9..2bc399f 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -2506,6 +2506,8 @@ unsigned long change_prot_numa(struct vm_area_struct *vma,
int remap_pfn_range(struct vm_area_struct *, unsigned long addr,
unsigned long pfn, unsigned long size, pgprot_t);
int vm_insert_page(struct vm_area_struct *, unsigned long addr, struct page *);
+int vm_insert_range(struct vm_area_struct *vma, unsigned long addr,
+ struct page **pages, unsigned long page_count);
vm_fault_t vmf_insert_pfn(struct vm_area_struct *vma, unsigned long addr,
unsigned long pfn);
vm_fault_t vmf_insert_pfn_prot(struct vm_area_struct *vma, unsigned long addr,
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
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