On Thu 28-05-15 16:24:02, Andrew Morton wrote:
> On Wed, 13 May 2015 15:08:08 +0200 Jan Kara <jack@xxxxxxx> wrote:
>
> > Provide new function get_vaddr_frames(). This function maps virtual
> > addresses from given start and fills given array with page frame numbers of
> > the corresponding pages. If given start belongs to a normal vma, the function
> > grabs reference to each of the pages to pin them in memory. If start
> > belongs to VM_IO | VM_PFNMAP vma, we don't touch page structures. Caller
> > must make sure pfns aren't reused for anything else while he is using
> > them.
> >
> > This function is created for various drivers to simplify handling of
> > their buffers.
> >
> > Acked-by: Mel Gorman <mgorman@xxxxxxx>
> > Acked-by: Vlastimil Babka <vbabka@xxxxxxx>
> > Signed-off-by: Jan Kara <jack@xxxxxxx>
> > ---
> > include/linux/mm.h | 44 +++++++++++
> > mm/gup.c | 226 +++++++++++++++++++++++++++++++++++++++++++++++++++++
>
> That's a lump of new code which many kernels won't be needing. Can we
> put all this in a new .c file and select it within drivers/media
> Kconfig?
So the attached patch should do what you had in mind. OK?
Honza
--
Jan Kara <jack@xxxxxxx>
SUSE Labs, CR
>From d18fc7863fc62d8ad0c1747b789a0dcf032ccf42 Mon Sep 17 00:00:00 2001
From: Jan Kara <jack@xxxxxxx>
Date: Tue, 2 Jun 2015 16:40:32 +0200
Subject: [PATCH] mm: Move get_vaddr_frames() behind a config option
get_vaddr_frames() is used by relatively rare drivers so hide it and the
related functions behind a config option that is selected only by
drivers that need the infrastructure.
Suggested-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Jan Kara <jack@xxxxxxx>
---
drivers/gpu/drm/exynos/Kconfig | 1 +
drivers/media/platform/omap/Kconfig | 1 +
drivers/media/v4l2-core/Kconfig | 1 +
mm/Kconfig | 3 +
mm/Makefile | 1 +
mm/frame-vec.c | 233 ++++++++++++++++++++++++++++++++++++
mm/gup.c | 225 ----------------------------------
7 files changed, 240 insertions(+), 225 deletions(-)
create mode 100644 mm/frame-vec.c
diff --git a/drivers/gpu/drm/exynos/Kconfig b/drivers/gpu/drm/exynos/Kconfig
index 0a6780367d28..b2fac87137c7 100644
--- a/drivers/gpu/drm/exynos/Kconfig
+++ b/drivers/gpu/drm/exynos/Kconfig
@@ -71,6 +71,7 @@ config DRM_EXYNOS_VIDI
config DRM_EXYNOS_G2D
bool "Exynos DRM G2D"
depends on DRM_EXYNOS && !VIDEO_SAMSUNG_S5P_G2D
+ select FRAME_VEC
help
Choose this option if you want to use Exynos G2D for DRM.
diff --git a/drivers/media/platform/omap/Kconfig b/drivers/media/platform/omap/Kconfig
index dc2aaab54aef..7cceca7b184d 100644
--- a/drivers/media/platform/omap/Kconfig
+++ b/drivers/media/platform/omap/Kconfig
@@ -10,6 +10,7 @@ config VIDEO_OMAP2_VOUT
select OMAP2_DSS if HAS_IOMEM && ARCH_OMAP2PLUS
select OMAP2_VRFB if ARCH_OMAP2 || ARCH_OMAP3
select VIDEO_OMAP2_VOUT_VRFB if VIDEO_OMAP2_VOUT && OMAP2_VRFB
+ select FRAME_VEC
default n
---help---
V4L2 Display driver support for OMAP2/3 based boards.
diff --git a/drivers/media/v4l2-core/Kconfig b/drivers/media/v4l2-core/Kconfig
index ba7e21a73023..957e5a18b0ff 100644
--- a/drivers/media/v4l2-core/Kconfig
+++ b/drivers/media/v4l2-core/Kconfig
@@ -73,6 +73,7 @@ config VIDEOBUF2_CORE
config VIDEOBUF2_MEMOPS
tristate
+ select FRAME_VEC
config VIDEOBUF2_DMA_CONTIG
tristate
diff --git a/mm/Kconfig b/mm/Kconfig
index 390214da4546..d039615e8f82 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -635,3 +635,6 @@ config MAX_STACK_SIZE_MB
changed to a smaller value in which case that is used.
A sane initial value is 80 MB.
+
+config FRAME_VEC
+ bool
diff --git a/mm/Makefile b/mm/Makefile
index 98c4eaeabdcb..d38305462e17 100644
--- a/mm/Makefile
+++ b/mm/Makefile
@@ -78,3 +78,4 @@ obj-$(CONFIG_CMA) += cma.o
obj-$(CONFIG_MEMORY_BALLOON) += balloon_compaction.o
obj-$(CONFIG_PAGE_EXTENSION) += page_ext.o
obj-$(CONFIG_CMA_DEBUGFS) += cma_debug.o
+obj-$(CONFIG_FRAME_VEC) += frame-vec.o
diff --git a/mm/frame-vec.c b/mm/frame-vec.c
new file mode 100644
index 000000000000..5d85bcd150ae
--- /dev/null
+++ b/mm/frame-vec.c
@@ -0,0 +1,233 @@
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/err.h>
+#include <linux/mm.h>
+#include <linux/slab.h>
+#include <linux/pagemap.h>
+#include <linux/sched.h>
+
+/*
+ * get_vaddr_frames() - map virtual addresses to pfns
+ * @start: starting user address
+ * @nr_frames: number of pages / pfns from start to map
+ * @write: whether pages will be written to by the caller
+ * @force: whether to force write access even if user mapping is
+ * readonly. See description of the same argument of
+ get_user_pages().
+ * @vec: structure which receives pages / pfns of the addresses mapped.
+ * It should have space for at least nr_frames entries.
+ *
+ * This function maps virtual addresses from @start and fills @vec structure
+ * with page frame numbers or page pointers to corresponding pages (choice
+ * depends on the type of the vma underlying the virtual address). If @start
+ * belongs to a normal vma, the function grabs reference to each of the pages
+ * to pin them in memory. If @start belongs to VM_IO | VM_PFNMAP vma, we don't
+ * touch page structures and the caller must make sure pfns aren't reused for
+ * anything else while he is using them.
+ *
+ * The function returns number of pages mapped which may be less than
+ * @nr_frames. In particular we stop mapping if there are more vmas of
+ * different type underlying the specified range of virtual addresses.
+ * When the function isn't able to map a single page, it returns error.
+ *
+ * This function takes care of grabbing mmap_sem as necessary.
+ */
+int get_vaddr_frames(unsigned long start, unsigned int nr_frames,
+ bool write, bool force, struct frame_vector *vec)
+{
+ struct mm_struct *mm = current->mm;
+ struct vm_area_struct *vma;
+ int ret = 0;
+ int err;
+ int locked;
+
+ if (nr_frames == 0)
+ return 0;
+
+ if (WARN_ON_ONCE(nr_frames > vec->nr_allocated))
+ nr_frames = vec->nr_allocated;
+
+ down_read(&mm->mmap_sem);
+ locked = 1;
+ vma = find_vma_intersection(mm, start, start + 1);
+ if (!vma) {
+ ret = -EFAULT;
+ goto out;
+ }
+ if (!(vma->vm_flags & (VM_IO | VM_PFNMAP))) {
+ vec->got_ref = true;
+ vec->is_pfns = false;
+ ret = get_user_pages_locked(current, mm, start, nr_frames,
+ write, force, (struct page **)(vec->ptrs), &locked);
+ goto out;
+ }
+
+ vec->got_ref = false;
+ vec->is_pfns = true;
+ do {
+ unsigned long *nums = frame_vector_pfns(vec);
+
+ while (ret < nr_frames && start + PAGE_SIZE <= vma->vm_end) {
+ err = follow_pfn(vma, start, &nums[ret]);
+ if (err) {
+ if (ret == 0)
+ ret = err;
+ goto out;
+ }
+ start += PAGE_SIZE;
+ ret++;
+ }
+ /*
+ * We stop if we have enough pages or if VMA doesn't completely
+ * cover the tail page.
+ */
+ if (ret >= nr_frames || start < vma->vm_end)
+ break;
+ vma = find_vma_intersection(mm, start, start + 1);
+ } while (vma && vma->vm_flags & (VM_IO | VM_PFNMAP));
+out:
+ if (locked)
+ up_read(&mm->mmap_sem);
+ if (!ret)
+ ret = -EFAULT;
+ if (ret > 0)
+ vec->nr_frames = ret;
+ return ret;
+}
+EXPORT_SYMBOL(get_vaddr_frames);
+
+/**
+ * put_vaddr_frames() - drop references to pages if get_vaddr_frames() acquired
+ * them
+ * @vec: frame vector to put
+ *
+ * Drop references to pages if get_vaddr_frames() acquired them. We also
+ * invalidate the frame vector so that it is prepared for the next call into
+ * get_vaddr_frames().
+ */
+void put_vaddr_frames(struct frame_vector *vec)
+{
+ int i;
+ struct page **pages;
+
+ if (!vec->got_ref)
+ goto out;
+ pages = frame_vector_pages(vec);
+ /*
+ * frame_vector_pages() might needed to do a conversion when
+ * get_vaddr_frames() got pages but vec was later converted to pfns.
+ * But it shouldn't really fail to convert pfns back...
+ */
+ if (WARN_ON(IS_ERR(pages)))
+ goto out;
+ for (i = 0; i < vec->nr_frames; i++)
+ put_page(pages[i]);
+ vec->got_ref = false;
+out:
+ vec->nr_frames = 0;
+}
+EXPORT_SYMBOL(put_vaddr_frames);
+
+/**
+ * frame_vector_to_pages - convert frame vector to contain page pointers
+ * @vec: frame vector to convert
+ *
+ * Convert @vec to contain array of page pointers. If the conversion is
+ * successful, return 0. Otherwise return an error. Note that we do not grab
+ * page references for the page structures.
+ */
+int frame_vector_to_pages(struct frame_vector *vec)
+{
+ int i;
+ unsigned long *nums;
+ struct page **pages;
+
+ if (!vec->is_pfns)
+ return 0;
+ nums = frame_vector_pfns(vec);
+ for (i = 0; i < vec->nr_frames; i++)
+ if (!pfn_valid(nums[i]))
+ return -EINVAL;
+ pages = (struct page **)nums;
+ for (i = 0; i < vec->nr_frames; i++)
+ pages[i] = pfn_to_page(nums[i]);
+ vec->is_pfns = false;
+ return 0;
+}
+EXPORT_SYMBOL(frame_vector_to_pages);
+
+/**
+ * frame_vector_to_pfns - convert frame vector to contain pfns
+ * @vec: frame vector to convert
+ *
+ * Convert @vec to contain array of pfns.
+ */
+void frame_vector_to_pfns(struct frame_vector *vec)
+{
+ int i;
+ unsigned long *nums;
+ struct page **pages;
+
+ if (vec->is_pfns)
+ return;
+ pages = (struct page **)(vec->ptrs);
+ nums = (unsigned long *)pages;
+ for (i = 0; i < vec->nr_frames; i++)
+ nums[i] = page_to_pfn(pages[i]);
+ vec->is_pfns = true;
+}
+EXPORT_SYMBOL(frame_vector_to_pfns);
+
+/**
+ * frame_vector_create() - allocate & initialize structure for pinned pfns
+ * @nr_frames: number of pfns slots we should reserve
+ *
+ * Allocate and initialize struct pinned_pfns to be able to hold @nr_pfns
+ * pfns.
+ */
+struct frame_vector *frame_vector_create(unsigned int nr_frames)
+{
+ struct frame_vector *vec;
+ int size = sizeof(struct frame_vector) + sizeof(void *) * nr_frames;
+
+ if (WARN_ON_ONCE(nr_frames == 0))
+ return NULL;
+ /*
+ * This is absurdly high. It's here just to avoid strange effects when
+ * arithmetics overflows.
+ */
+ if (WARN_ON_ONCE(nr_frames > INT_MAX / sizeof(void *) / 2))
+ return NULL;
+ /*
+ * Avoid higher order allocations, use vmalloc instead. It should
+ * be rare anyway.
+ */
+ if (size <= PAGE_SIZE)
+ vec = kmalloc(size, GFP_KERNEL);
+ else
+ vec = vmalloc(size);
+ if (!vec)
+ return NULL;
+ vec->nr_allocated = nr_frames;
+ vec->nr_frames = 0;
+ return vec;
+}
+EXPORT_SYMBOL(frame_vector_create);
+
+/**
+ * frame_vector_destroy() - free memory allocated to carry frame vector
+ * @vec: Frame vector to free
+ *
+ * Free structure allocated by frame_vector_create() to carry frames.
+ */
+void frame_vector_destroy(struct frame_vector *vec)
+{
+ /* Make sure put_vaddr_frames() got called properly... */
+ VM_BUG_ON(vec->nr_frames > 0);
+ if (!is_vmalloc_addr(vec))
+ kfree(vec);
+ else
+ vfree(vec);
+}
+EXPORT_SYMBOL(frame_vector_destroy);
+
diff --git a/mm/gup.c b/mm/gup.c
index 9d7f4fde30cb..222d57e335f9 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -937,231 +937,6 @@ int __mm_populate(unsigned long start, unsigned long len, int ignore_errors)
return ret; /* 0 or negative error code */
}
-/*
- * get_vaddr_frames() - map virtual addresses to pfns
- * @start: starting user address
- * @nr_frames: number of pages / pfns from start to map
- * @write: whether pages will be written to by the caller
- * @force: whether to force write access even if user mapping is
- * readonly. See description of the same argument of
- get_user_pages().
- * @vec: structure which receives pages / pfns of the addresses mapped.
- * It should have space for at least nr_frames entries.
- *
- * This function maps virtual addresses from @start and fills @vec structure
- * with page frame numbers or page pointers to corresponding pages (choice
- * depends on the type of the vma underlying the virtual address). If @start
- * belongs to a normal vma, the function grabs reference to each of the pages
- * to pin them in memory. If @start belongs to VM_IO | VM_PFNMAP vma, we don't
- * touch page structures and the caller must make sure pfns aren't reused for
- * anything else while he is using them.
- *
- * The function returns number of pages mapped which may be less than
- * @nr_frames. In particular we stop mapping if there are more vmas of
- * different type underlying the specified range of virtual addresses.
- * When the function isn't able to map a single page, it returns error.
- *
- * This function takes care of grabbing mmap_sem as necessary.
- */
-int get_vaddr_frames(unsigned long start, unsigned int nr_frames,
- bool write, bool force, struct frame_vector *vec)
-{
- struct mm_struct *mm = current->mm;
- struct vm_area_struct *vma;
- int ret = 0;
- int err;
- int locked;
-
- if (nr_frames == 0)
- return 0;
-
- if (WARN_ON_ONCE(nr_frames > vec->nr_allocated))
- nr_frames = vec->nr_allocated;
-
- down_read(&mm->mmap_sem);
- locked = 1;
- vma = find_vma_intersection(mm, start, start + 1);
- if (!vma) {
- ret = -EFAULT;
- goto out;
- }
- if (!(vma->vm_flags & (VM_IO | VM_PFNMAP))) {
- vec->got_ref = true;
- vec->is_pfns = false;
- ret = get_user_pages_locked(current, mm, start, nr_frames,
- write, force, (struct page **)(vec->ptrs), &locked);
- goto out;
- }
-
- vec->got_ref = false;
- vec->is_pfns = true;
- do {
- unsigned long *nums = frame_vector_pfns(vec);
-
- while (ret < nr_frames && start + PAGE_SIZE <= vma->vm_end) {
- err = follow_pfn(vma, start, &nums[ret]);
- if (err) {
- if (ret == 0)
- ret = err;
- goto out;
- }
- start += PAGE_SIZE;
- ret++;
- }
- /*
- * We stop if we have enough pages or if VMA doesn't completely
- * cover the tail page.
- */
- if (ret >= nr_frames || start < vma->vm_end)
- break;
- vma = find_vma_intersection(mm, start, start + 1);
- } while (vma && vma->vm_flags & (VM_IO | VM_PFNMAP));
-out:
- if (locked)
- up_read(&mm->mmap_sem);
- if (!ret)
- ret = -EFAULT;
- if (ret > 0)
- vec->nr_frames = ret;
- return ret;
-}
-EXPORT_SYMBOL(get_vaddr_frames);
-
-/**
- * put_vaddr_frames() - drop references to pages if get_vaddr_frames() acquired
- * them
- * @vec: frame vector to put
- *
- * Drop references to pages if get_vaddr_frames() acquired them. We also
- * invalidate the frame vector so that it is prepared for the next call into
- * get_vaddr_frames().
- */
-void put_vaddr_frames(struct frame_vector *vec)
-{
- int i;
- struct page **pages;
-
- if (!vec->got_ref)
- goto out;
- pages = frame_vector_pages(vec);
- /*
- * frame_vector_pages() might needed to do a conversion when
- * get_vaddr_frames() got pages but vec was later converted to pfns.
- * But it shouldn't really fail to convert pfns back...
- */
- if (WARN_ON(IS_ERR(pages)))
- goto out;
- for (i = 0; i < vec->nr_frames; i++)
- put_page(pages[i]);
- vec->got_ref = false;
-out:
- vec->nr_frames = 0;
-}
-EXPORT_SYMBOL(put_vaddr_frames);
-
-/**
- * frame_vector_to_pages - convert frame vector to contain page pointers
- * @vec: frame vector to convert
- *
- * Convert @vec to contain array of page pointers. If the conversion is
- * successful, return 0. Otherwise return an error. Note that we do not grab
- * page references for the page structures.
- */
-int frame_vector_to_pages(struct frame_vector *vec)
-{
- int i;
- unsigned long *nums;
- struct page **pages;
-
- if (!vec->is_pfns)
- return 0;
- nums = frame_vector_pfns(vec);
- for (i = 0; i < vec->nr_frames; i++)
- if (!pfn_valid(nums[i]))
- return -EINVAL;
- pages = (struct page **)nums;
- for (i = 0; i < vec->nr_frames; i++)
- pages[i] = pfn_to_page(nums[i]);
- vec->is_pfns = false;
- return 0;
-}
-EXPORT_SYMBOL(frame_vector_to_pages);
-
-/**
- * frame_vector_to_pfns - convert frame vector to contain pfns
- * @vec: frame vector to convert
- *
- * Convert @vec to contain array of pfns.
- */
-void frame_vector_to_pfns(struct frame_vector *vec)
-{
- int i;
- unsigned long *nums;
- struct page **pages;
-
- if (vec->is_pfns)
- return;
- pages = (struct page **)(vec->ptrs);
- nums = (unsigned long *)pages;
- for (i = 0; i < vec->nr_frames; i++)
- nums[i] = page_to_pfn(pages[i]);
- vec->is_pfns = true;
-}
-EXPORT_SYMBOL(frame_vector_to_pfns);
-
-/**
- * frame_vector_create() - allocate & initialize structure for pinned pfns
- * @nr_frames: number of pfns slots we should reserve
- *
- * Allocate and initialize struct pinned_pfns to be able to hold @nr_pfns
- * pfns.
- */
-struct frame_vector *frame_vector_create(unsigned int nr_frames)
-{
- struct frame_vector *vec;
- int size = sizeof(struct frame_vector) + sizeof(void *) * nr_frames;
-
- if (WARN_ON_ONCE(nr_frames == 0))
- return NULL;
- /*
- * This is absurdly high. It's here just to avoid strange effects when
- * arithmetics overflows.
- */
- if (WARN_ON_ONCE(nr_frames > INT_MAX / sizeof(void *) / 2))
- return NULL;
- /*
- * Avoid higher order allocations, use vmalloc instead. It should
- * be rare anyway.
- */
- if (size <= PAGE_SIZE)
- vec = kmalloc(size, GFP_KERNEL);
- else
- vec = vmalloc(size);
- if (!vec)
- return NULL;
- vec->nr_allocated = nr_frames;
- vec->nr_frames = 0;
- return vec;
-}
-EXPORT_SYMBOL(frame_vector_create);
-
-/**
- * frame_vector_destroy() - free memory allocated to carry frame vector
- * @vec: Frame vector to free
- *
- * Free structure allocated by frame_vector_create() to carry frames.
- */
-void frame_vector_destroy(struct frame_vector *vec)
-{
- /* Make sure put_vaddr_frames() got called properly... */
- VM_BUG_ON(vec->nr_frames > 0);
- if (!is_vmalloc_addr(vec))
- kfree(vec);
- else
- vfree(vec);
-}
-EXPORT_SYMBOL(frame_vector_destroy);
-
/**
* get_dump_page() - pin user page in memory while writing it to core dump
* @addr: user address
--
2.1.4
