[PATCH 8/9] [media] drm/exynos: Convert g2d_userptr_get_dma_addr() to use get_vaddr_frames()

[PATCH 8/9] [media] drm/exynos: Convert g2d_userptr_get_dma_addr() to use get_vaddr_frames()

[Mauro Carvalho Chehab]

From: Jan Kara <jack@suse.cz>

Convert g2d_userptr_get_dma_addr() to pin pages using get_vaddr_frames().
This removes the knowledge about vmas and mmap_sem locking from exynos
driver. Also it fixes a problem that the function has been mapping user
provided address without holding mmap_sem.

Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>

diff --git a/drivers/gpu/drm/exynos/exynos_drm_g2d.c b/drivers/gpu/drm/exynos/exynos_drm_g2d.c
index 81a250830808..810e1ee7c07d 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_g2d.c
+++ b/drivers/gpu/drm/exynos/exynos_drm_g2d.c
@@ -190,10 +190,8 @@ struct g2d_cmdlist_userptr {
 	dma_addr_t		dma_addr;
 	unsigned long		userptr;
 	unsigned long		size;
-	struct page		**pages;
-	unsigned int		npages;
+	struct frame_vector	*vec;
 	struct sg_table		*sgt;
-	struct vm_area_struct	*vma;
 	atomic_t		refcount;
 	bool			in_pool;
 	bool			out_of_list;
@@ -363,6 +361,7 @@ static void g2d_userptr_put_dma_addr(struct drm_device *drm_dev,
 {
 	struct g2d_cmdlist_userptr *g2d_userptr =
 					(struct g2d_cmdlist_userptr *)obj;
+	struct page **pages;
 
 	if (!obj)
 		return;
@@ -382,19 +381,21 @@ out:
 	exynos_gem_unmap_sgt_from_dma(drm_dev, g2d_userptr->sgt,
 					DMA_BIDIRECTIONAL);
 
-	exynos_gem_put_pages_to_userptr(g2d_userptr->pages,
-					g2d_userptr->npages,
-					g2d_userptr->vma);
+	pages = frame_vector_pages(g2d_userptr->vec);
+	if (!IS_ERR(pages)) {
+		int i;
 
-	exynos_gem_put_vma(g2d_userptr->vma);
+		for (i = 0; i < frame_vector_count(g2d_userptr->vec); i++)
+			set_page_dirty_lock(pages[i]);
+	}
+	put_vaddr_frames(g2d_userptr->vec);
+	frame_vector_destroy(g2d_userptr->vec);
 
 	if (!g2d_userptr->out_of_list)
 		list_del_init(&g2d_userptr->list);
 
 	sg_free_table(g2d_userptr->sgt);
 	kfree(g2d_userptr->sgt);
-
-	drm_free_large(g2d_userptr->pages);
 	kfree(g2d_userptr);
 }
 
@@ -408,9 +409,7 @@ static dma_addr_t *g2d_userptr_get_dma_addr(struct drm_device *drm_dev,
 	struct exynos_drm_g2d_private *g2d_priv = file_priv->g2d_priv;
 	struct g2d_cmdlist_userptr *g2d_userptr;
 	struct g2d_data *g2d;
-	struct page **pages;
 	struct sg_table	*sgt;
-	struct vm_area_struct *vma;
 	unsigned long start, end;
 	unsigned int npages, offset;
 	int ret;
@@ -456,65 +455,38 @@ static dma_addr_t *g2d_userptr_get_dma_addr(struct drm_device *drm_dev,
 		return ERR_PTR(-ENOMEM);
 
 	atomic_set(&g2d_userptr->refcount, 1);
+	g2d_userptr->size = size;
 
 	start = userptr & PAGE_MASK;
 	offset = userptr & ~PAGE_MASK;
 	end = PAGE_ALIGN(userptr + size);
 	npages = (end - start) >> PAGE_SHIFT;
-	g2d_userptr->npages = npages;
-
-	pages = drm_calloc_large(npages, sizeof(struct page *));
-	if (!pages) {
-		DRM_ERROR("failed to allocate pages.\n");
-		ret = -ENOMEM;
+	g2d_userptr->vec = frame_vector_create(npages);
+	if (!vec)
 		goto err_free;
-	}
 
-	down_read(&current->mm->mmap_sem);
-	vma = find_vma(current->mm, userptr);
-	if (!vma) {
-		up_read(&current->mm->mmap_sem);
-		DRM_ERROR("failed to get vm region.\n");
-		ret = -EFAULT;
-		goto err_free_pages;
-	}
-
-	if (vma->vm_end < userptr + size) {
-		up_read(&current->mm->mmap_sem);
-		DRM_ERROR("vma is too small.\n");
-		ret = -EFAULT;
-		goto err_free_pages;
-	}
-
-	g2d_userptr->vma = exynos_gem_get_vma(vma);
-	if (!g2d_userptr->vma) {
-		up_read(&current->mm->mmap_sem);
-		DRM_ERROR("failed to copy vma.\n");
-		ret = -ENOMEM;
-		goto err_free_pages;
-	}
-
-	g2d_userptr->size = size;
-
-	ret = exynos_gem_get_pages_from_userptr(start & PAGE_MASK,
-						npages, pages, vma);
-	if (ret < 0) {
-		up_read(&current->mm->mmap_sem);
+	ret = get_vaddr_frames(start, npages, true, true, g2d_userptr->vec);
+	if (ret != npages) {
 		DRM_ERROR("failed to get user pages from userptr.\n");
-		goto err_put_vma;
+		if (ret < 0)
+			goto err_destroy_framevec;
+		ret = -EFAULT;
+		goto err_put_framevec;
+	}
+	if (frame_vector_to_pages(g2d_userptr->vec) < 0) {
+		ret = -EFAULT;
+		goto err_put_framevec;
 	}
-
-	up_read(&current->mm->mmap_sem);
-	g2d_userptr->pages = pages;
 
 	sgt = kzalloc(sizeof(*sgt), GFP_KERNEL);
 	if (!sgt) {
 		ret = -ENOMEM;
-		goto err_free_userptr;
+		goto err_put_framevec;
 	}
 
-	ret = sg_alloc_table_from_pages(sgt, pages, npages, offset,
-					size, GFP_KERNEL);
+	ret = sg_alloc_table_from_pages(sgt,
+					frame_vector_pages(g2d_userptr->vec),
+					npages, offset, size, GFP_KERNEL);
 	if (ret < 0) {
 		DRM_ERROR("failed to get sgt from pages.\n");
 		goto err_free_sgt;
@@ -549,16 +521,11 @@ err_sg_free_table:
 err_free_sgt:
 	kfree(sgt);
 
-err_free_userptr:
-	exynos_gem_put_pages_to_userptr(g2d_userptr->pages,
-					g2d_userptr->npages,
-					g2d_userptr->vma);
+err_put_framevec:
+	put_vaddr_frames(g2d_userptr->vec);
 
-err_put_vma:
-	exynos_gem_put_vma(g2d_userptr->vma);
-
-err_free_pages:
-	drm_free_large(pages);
+err_destroy_framevec:
+	frame_vector_destroy(g2d_userptr->vec);
 
 err_free:
 	kfree(g2d_userptr);
diff --git a/drivers/gpu/drm/exynos/exynos_drm_gem.c b/drivers/gpu/drm/exynos/exynos_drm_gem.c
index 0d5b9698d384..47068ae44ced 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_gem.c
+++ b/drivers/gpu/drm/exynos/exynos_drm_gem.c
@@ -378,103 +378,6 @@ int exynos_drm_gem_get_ioctl(struct drm_device *dev, void *data,
 	return 0;
 }
 
-struct vm_area_struct *exynos_gem_get_vma(struct vm_area_struct *vma)
-{
-	struct vm_area_struct *vma_copy;
-
-	vma_copy = kmalloc(sizeof(*vma_copy), GFP_KERNEL);
-	if (!vma_copy)
-		return NULL;
-
-	if (vma->vm_ops && vma->vm_ops->open)
-		vma->vm_ops->open(vma);
-
-	if (vma->vm_file)
-		get_file(vma->vm_file);
-
-	memcpy(vma_copy, vma, sizeof(*vma));
-
-	vma_copy->vm_mm = NULL;
-	vma_copy->vm_next = NULL;
-	vma_copy->vm_prev = NULL;
-
-	return vma_copy;
-}
-
-void exynos_gem_put_vma(struct vm_area_struct *vma)
-{
-	if (!vma)
-		return;
-
-	if (vma->vm_ops && vma->vm_ops->close)
-		vma->vm_ops->close(vma);
-
-	if (vma->vm_file)
-		fput(vma->vm_file);
-
-	kfree(vma);
-}
-
-int exynos_gem_get_pages_from_userptr(unsigned long start,
-						unsigned int npages,
-						struct page **pages,
-						struct vm_area_struct *vma)
-{
-	int get_npages;
-
-	/* the memory region mmaped with VM_PFNMAP. */
-	if (vma_is_io(vma)) {
-		unsigned int i;
-
-		for (i = 0; i < npages; ++i, start += PAGE_SIZE) {
-			unsigned long pfn;
-			int ret = follow_pfn(vma, start, &pfn);
-			if (ret)
-				return ret;
-
-			pages[i] = pfn_to_page(pfn);
-		}
-
-		if (i != npages) {
-			DRM_ERROR("failed to get user_pages.\n");
-			return -EINVAL;
-		}
-
-		return 0;
-	}
-
-	get_npages = get_user_pages(current, current->mm, start,
-					npages, 1, 1, pages, NULL);
-	get_npages = max(get_npages, 0);
-	if (get_npages != npages) {
-		DRM_ERROR("failed to get user_pages.\n");
-		while (get_npages)
-			put_page(pages[--get_npages]);
-		return -EFAULT;
-	}
-
-	return 0;
-}
-
-void exynos_gem_put_pages_to_userptr(struct page **pages,
-					unsigned int npages,
-					struct vm_area_struct *vma)
-{
-	if (!vma_is_io(vma)) {
-		unsigned int i;
-
-		for (i = 0; i < npages; i++) {
-			set_page_dirty_lock(pages[i]);
-
-			/*
-			 * undo the reference we took when populating
-			 * the table.
-			 */
-			put_page(pages[i]);
-		}
-	}
-}
-
 int exynos_gem_map_sgt_with_dma(struct drm_device *drm_dev,
 				struct sg_table *sgt,
 				enum dma_data_direction dir)
-- 
2.4.2

[PATCH 9/9] [media] mm: Move get_vaddr_frames() behind a config option

[Mauro Carvalho Chehab]

From: Jan Kara <jack@suse.cz>

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@linux-foundation.org>

Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>

 create mode 100644 mm/frame_vector.c

diff --git a/drivers/gpu/drm/exynos/Kconfig b/drivers/gpu/drm/exynos/Kconfig
index 0a6780367d28..fc678289cf79 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_VECTOR
 	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..217d613b0fe7 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_VECTOR
 	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 f7a01a72eb9e..f38f6e387f04 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_VECTOR
 
 config VIDEOBUF2_DMA_CONTIG
 	tristate
diff --git a/mm/Kconfig b/mm/Kconfig
index 390214da4546..2ca52e9986f0 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_VECTOR
+	bool
diff --git a/mm/Makefile b/mm/Makefile
index 98c4eaeabdcb..be5d5c866305 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_VECTOR) += frame_vector.o
diff --git a/mm/frame_vector.c b/mm/frame_vector.c
new file mode 100644
index 000000000000..31a2bd5f41d5
--- /dev/null
+++ b/mm/frame_vector.c
@@ -0,0 +1,232 @@
+#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
-- 
2.4.2

[PATCH 9/9] [media] mm: Move get_vaddr_frames() behind a config option

[Josh Triplett]

On Wed, Jun 10, 2015 at 06:20:52AM -0300, Mauro Carvalho Chehab wrote:
> From: Jan Kara <jack@suse.cz>
> 
> 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@linux-foundation.org>
> 
> Signed-off-by: Jan Kara <jack@suse.cz>
> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
> Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>

Seems sensible to me.

Since this patch makes the kernel smaller, can you include the delta
from bloat-o-meter between allnoconfig with and without this patch?

Also, I assume you've compile-tested the kernel with allyesconfig minus
the three options that now have "select FRAME_VECTOR", to make sure it
builds?

>  create mode 100644 mm/frame_vector.c
> 
> diff --git a/drivers/gpu/drm/exynos/Kconfig b/drivers/gpu/drm/exynos/Kconfig
> index 0a6780367d28..fc678289cf79 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_VECTOR
>  	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..217d613b0fe7 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_VECTOR
>  	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 f7a01a72eb9e..f38f6e387f04 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_VECTOR
>  
>  config VIDEOBUF2_DMA_CONTIG
>  	tristate
> diff --git a/mm/Kconfig b/mm/Kconfig
> index 390214da4546..2ca52e9986f0 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_VECTOR
> +	bool
> diff --git a/mm/Makefile b/mm/Makefile
> index 98c4eaeabdcb..be5d5c866305 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_VECTOR) += frame_vector.o
> diff --git a/mm/frame_vector.c b/mm/frame_vector.c
> new file mode 100644
> index 000000000000..31a2bd5f41d5
> --- /dev/null
> +++ b/mm/frame_vector.c
> @@ -0,0 +1,232 @@
> +#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
> -- 
> 2.4.2
> 

[PATCH 9/9] [media] mm: Move get_vaddr_frames() behind a config option

[Jan Kara]

On Wed 10-06-15 09:37:20, Josh Triplett wrote:
> On Wed, Jun 10, 2015 at 06:20:52AM -0300, Mauro Carvalho Chehab wrote:
> > From: Jan Kara <jack@suse.cz>
> > 
> > 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@linux-foundation.org>
> > 
> > Signed-off-by: Jan Kara <jack@suse.cz>
> > Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
> > Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
> 
> Seems sensible to me.
> 
> Since this patch makes the kernel smaller, can you include the delta
> from bloat-o-meter between allnoconfig with and without this patch?

The results are:

add/remove: 0/6 grow/shrink: 0/0 up/down: 0/-868 (-868)
function                                     old     new   delta
frame_vector_destroy                          55       -     -55
frame_vector_to_pfns                          56       -     -56
frame_vector_create                           81       -     -81
put_vaddr_frames                              93       -     -93
frame_vector_to_pages                         98       -     -98
get_vaddr_frames                             485       -    -485

I've added it to the changelog of the patch.

> Also, I assume you've compile-tested the kernel with allyesconfig minus
> the three options that now have "select FRAME_VECTOR", to make sure it
> builds?
  I did not because the config option VIDEOBUF2_MEMOPS is a virtual one
selected transitively by quite a few video drivers and I didn't bother with
tracking down all of them... But since that config option guards
compilation of the code I modified I'm pretty confident I got it right.

								Honza

> >  create mode 100644 mm/frame_vector.c
> > 
> > diff --git a/drivers/gpu/drm/exynos/Kconfig b/drivers/gpu/drm/exynos/Kconfig
> > index 0a6780367d28..fc678289cf79 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_VECTOR
> >  	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..217d613b0fe7 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_VECTOR
> >  	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 f7a01a72eb9e..f38f6e387f04 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_VECTOR
> >  
> >  config VIDEOBUF2_DMA_CONTIG
> >  	tristate
> > diff --git a/mm/Kconfig b/mm/Kconfig
> > index 390214da4546..2ca52e9986f0 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_VECTOR
> > +	bool
> > diff --git a/mm/Makefile b/mm/Makefile
> > index 98c4eaeabdcb..be5d5c866305 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_VECTOR) += frame_vector.o
> > diff --git a/mm/frame_vector.c b/mm/frame_vector.c
> > new file mode 100644
> > index 000000000000..31a2bd5f41d5
> > --- /dev/null
> > +++ b/mm/frame_vector.c
> > @@ -0,0 +1,232 @@
> > +#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
> > -- 
> > 2.4.2
> > 
-- 
Jan Kara <jack@suse.cz>
SUSE Labs, CR