Merge tag 'topic/iomem-mmap-vs-gup-2021-02-22' of git://anongit.freedesktop.org/drm/drm

Pull follow_pfn() updates from Daniel Vetter:
 "Fixes around VM_FPNMAP and follow_pfn:

   - replace mm/frame_vector.c by get_user_pages in misc/habana and
     drm/exynos drivers, then move that into media as it's sole user

   - close race in generic_access_phys

   - s390 pci ioctl fix of this series landed in 5.11 already

   - properly revoke iomem mappings (/dev/mem, pci files)"

* tag 'topic/iomem-mmap-vs-gup-2021-02-22' of git://anongit.freedesktop.org/drm/drm:
  PCI: Revoke mappings like devmem
  PCI: Also set up legacy files only after sysfs init
  sysfs: Support zapping of binary attr mmaps
  resource: Move devmem revoke code to resource framework
  /dev/mem: Only set filp->f_mapping
  PCI: Obey iomem restrictions for procfs mmap
  mm: Close race in generic_access_phys
  media: videobuf2: Move frame_vector into media subsystem
  mm/frame-vector: Use FOLL_LONGTERM
  misc/habana: Use FOLL_LONGTERM for userptr
  misc/habana: Stop using frame_vector helpers
  drm/exynos: Use FOLL_LONGTERM for g2d cmdlists
  drm/exynos: Stop using frame_vector helpers

4 files changed, 225 insertions, 3 deletions

diff --git a/drivers/media/common/videobuf2/Kconfig b/drivers/media/common/videobuf2/Kconfig
index edbc99ebba87..d2223a12c95f 100644
--- a/drivers/media/common/videobuf2/Kconfig
+++ b/drivers/media/common/videobuf2/Kconfig
@@ -9,7 +9,6 @@ config VIDEOBUF2_V4L2
 
 config VIDEOBUF2_MEMOPS
 	tristate
-	select FRAME_VECTOR
 
 config VIDEOBUF2_DMA_CONTIG
 	tristate
diff --git a/drivers/media/common/videobuf2/Makefile b/drivers/media/common/videobuf2/Makefile
index 77bebe8b202f..54306f8d096c 100644
--- a/drivers/media/common/videobuf2/Makefile
+++ b/drivers/media/common/videobuf2/Makefile
@@ -1,5 +1,6 @@
 # SPDX-License-Identifier: GPL-2.0
 videobuf2-common-objs := videobuf2-core.o
+videobuf2-common-objs += frame_vector.o
 
 ifeq ($(CONFIG_TRACEPOINTS),y)
   videobuf2-common-objs += vb2-trace.o
diff --git a/drivers/media/common/videobuf2/frame_vector.c b/drivers/media/common/videobuf2/frame_vector.c
new file mode 100644
index 000000000000..a0e65481a201
--- /dev/null
+++ b/drivers/media/common/videobuf2/frame_vector.c
@@ -0,0 +1,223 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/err.h>
+#include <linux/mm.h>
+#include <linux/slab.h>
+#include <linux/vmalloc.h>
+#include <linux/pagemap.h>
+#include <linux/sched.h>
+
+#include <media/frame_vector.h>
+
+/**
+ * get_vaddr_frames() - map virtual addresses to pfns
+ * @start:	starting user address
+ * @nr_frames:	number of pages / pfns from start to map
+ * @gup_flags:	flags modifying lookup behaviour
+ * @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_lock as necessary.
+ */
+int get_vaddr_frames(unsigned long start, unsigned int nr_frames,
+		     struct frame_vector *vec)
+{
+	struct mm_struct *mm = current->mm;
+	struct vm_area_struct *vma;
+	int ret = 0;
+	int err;
+
+	if (nr_frames == 0)
+		return 0;
+
+	if (WARN_ON_ONCE(nr_frames > vec->nr_allocated))
+		nr_frames = vec->nr_allocated;
+
+	start = untagged_addr(start);
+
+	ret = pin_user_pages_fast(start, nr_frames,
+				  FOLL_FORCE | FOLL_WRITE | FOLL_LONGTERM,
+				  (struct page **)(vec->ptrs));
+	if (ret > 0) {
+		vec->got_ref = true;
+		vec->is_pfns = false;
+		goto out_unlocked;
+	}
+
+	mmap_read_lock(mm);
+	vec->got_ref = false;
+	vec->is_pfns = true;
+	ret = 0;
+	do {
+		unsigned long *nums = frame_vector_pfns(vec);
+
+		vma = find_vma_intersection(mm, start, start + 1);
+		if (!vma)
+			break;
+
+		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++;
+		}
+		/* Bail out if VMA doesn't completely cover the tail page. */
+		if (start < vma->vm_end)
+			break;
+	} while (ret < nr_frames);
+out:
+	mmap_read_unlock(mm);
+out_unlocked:
+	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)
+{
+	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;
+
+	unpin_user_pages(pages, vec->nr_frames);
+	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.
+	 */
+	vec = kvmalloc(size, GFP_KERNEL);
+	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);
+	kvfree(vec);
+}
+EXPORT_SYMBOL(frame_vector_destroy);
diff --git a/drivers/media/common/videobuf2/videobuf2-memops.c b/drivers/media/common/videobuf2/videobuf2-memops.c
index 6e9e05153f4e..9dd6c27162f4 100644
--- a/drivers/media/common/videobuf2/videobuf2-memops.c
+++ b/drivers/media/common/videobuf2/videobuf2-memops.c
@@ -40,7 +40,6 @@ struct frame_vector *vb2_create_framevec(unsigned long start,
 	unsigned long first, last;
 	unsigned long nr;
 	struct frame_vector *vec;
-	unsigned int flags = FOLL_FORCE | FOLL_WRITE;
 
 	first = start >> PAGE_SHIFT;
 	last = (start + length - 1) >> PAGE_SHIFT;
@@ -48,7 +47,7 @@ struct frame_vector *vb2_create_framevec(unsigned long start,
 	vec = frame_vector_create(nr);
 	if (!vec)
 		return ERR_PTR(-ENOMEM);
-	ret = get_vaddr_frames(start & PAGE_MASK, nr, flags, vec);
+	ret = get_vaddr_frames(start & PAGE_MASK, nr, vec);
 	if (ret < 0)
 		goto out_destroy;
 	/* We accept only complete set of PFNs */