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Date: Thu, 13 Oct 2016 01:20:15 +0100
From: Lorenzo Stoakes <lstoakes@...il.com>
To: linux-mm@...ck.org
Cc: Linus Torvalds <torvalds@...ux-foundation.org>,
Jan Kara <jack@...e.cz>, Hugh Dickins <hughd@...gle.com>,
Dave Hansen <dave.hansen@...ux.intel.com>,
Rik van Riel <riel@...hat.com>,
Mel Gorman <mgorman@...hsingularity.net>,
Andrew Morton <akpm@...ux-foundation.org>,
adi-buildroot-devel@...ts.sourceforge.net,
ceph-devel@...r.kernel.org, dri-devel@...ts.freedesktop.org,
intel-gfx@...ts.freedesktop.org, kvm@...r.kernel.org,
linux-alpha@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
linux-cris-kernel@...s.com, linux-fbdev@...r.kernel.org,
linux-fsdevel@...r.kernel.org, linux-ia64@...r.kernel.org,
linux-kernel@...r.kernel.org, linux-media@...r.kernel.org,
linux-mips@...ux-mips.org, linux-rdma@...r.kernel.org,
linux-s390@...r.kernel.org, linux-samsung-soc@...r.kernel.org,
linux-scsi@...r.kernel.org, linux-security-module@...r.kernel.org,
linux-sh@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org,
netdev@...r.kernel.org, sparclinux@...r.kernel.org, x86@...nel.org,
Lorenzo Stoakes <lstoakes@...il.com>
Subject: [PATCH 05/10] mm: replace get_vaddr_frames() write/force parameters with gup_flags
This patch removes the write and force parameters from get_vaddr_frames() and
replaces them with a gup_flags parameter to make the use of FOLL_FORCE explicit
in callers as use of this flag can result in surprising behaviour (and hence
bugs) within the mm subsystem.
Signed-off-by: Lorenzo Stoakes <lstoakes@...il.com>
---
drivers/gpu/drm/exynos/exynos_drm_g2d.c | 3 ++-
drivers/media/platform/omap/omap_vout.c | 2 +-
drivers/media/v4l2-core/videobuf2-memops.c | 6 +++++-
include/linux/mm.h | 2 +-
mm/frame_vector.c | 13 ++-----------
5 files changed, 11 insertions(+), 15 deletions(-)
diff --git a/drivers/gpu/drm/exynos/exynos_drm_g2d.c b/drivers/gpu/drm/exynos/exynos_drm_g2d.c
index aa92dec..fbd13fa 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_g2d.c
+++ b/drivers/gpu/drm/exynos/exynos_drm_g2d.c
@@ -488,7 +488,8 @@ static dma_addr_t *g2d_userptr_get_dma_addr(struct drm_device *drm_dev,
goto err_free;
}
- ret = get_vaddr_frames(start, npages, true, true, g2d_userptr->vec);
+ ret = get_vaddr_frames(start, npages, FOLL_FORCE | FOLL_WRITE,
+ g2d_userptr->vec);
if (ret != npages) {
DRM_ERROR("failed to get user pages from userptr.\n");
if (ret < 0)
diff --git a/drivers/media/platform/omap/omap_vout.c b/drivers/media/platform/omap/omap_vout.c
index e668dde..a31b95c 100644
--- a/drivers/media/platform/omap/omap_vout.c
+++ b/drivers/media/platform/omap/omap_vout.c
@@ -214,7 +214,7 @@ static int omap_vout_get_userptr(struct videobuf_buffer *vb, u32 virtp,
if (!vec)
return -ENOMEM;
- ret = get_vaddr_frames(virtp, 1, true, false, vec);
+ ret = get_vaddr_frames(virtp, 1, FOLL_WRITE, vec);
if (ret != 1) {
frame_vector_destroy(vec);
return -EINVAL;
diff --git a/drivers/media/v4l2-core/videobuf2-memops.c b/drivers/media/v4l2-core/videobuf2-memops.c
index 3c3b517..1cd322e 100644
--- a/drivers/media/v4l2-core/videobuf2-memops.c
+++ b/drivers/media/v4l2-core/videobuf2-memops.c
@@ -42,6 +42,10 @@ 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;
+
+ if (write)
+ flags |= FOLL_WRITE;
first = start >> PAGE_SHIFT;
last = (start + length - 1) >> PAGE_SHIFT;
@@ -49,7 +53,7 @@ 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, write, true, vec);
+ ret = get_vaddr_frames(start & PAGE_MASK, nr, flags, vec);
if (ret < 0)
goto out_destroy;
/* We accept only complete set of PFNs */
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 27ab538..5ff084f6 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1305,7 +1305,7 @@ struct frame_vector {
struct frame_vector *frame_vector_create(unsigned int nr_frames);
void frame_vector_destroy(struct frame_vector *vec);
int get_vaddr_frames(unsigned long start, unsigned int nr_pfns,
- bool write, bool force, struct frame_vector *vec);
+ unsigned int gup_flags, struct frame_vector *vec);
void put_vaddr_frames(struct frame_vector *vec);
int frame_vector_to_pages(struct frame_vector *vec);
void frame_vector_to_pfns(struct frame_vector *vec);
diff --git a/mm/frame_vector.c b/mm/frame_vector.c
index 81b6749..db77dcb 100644
--- a/mm/frame_vector.c
+++ b/mm/frame_vector.c
@@ -11,10 +11,7 @@
* 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().
+ * @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.
*
@@ -34,23 +31,17 @@
* 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)
+ unsigned int gup_flags, struct frame_vector *vec)
{
struct mm_struct *mm = current->mm;
struct vm_area_struct *vma;
int ret = 0;
int err;
int locked;
- unsigned int gup_flags = 0;
if (nr_frames == 0)
return 0;
- if (write)
- gup_flags |= FOLL_WRITE;
- if (force)
- gup_flags |= FOLL_FORCE;
-
if (WARN_ON_ONCE(nr_frames > vec->nr_allocated))
nr_frames = vec->nr_allocated;
--
2.10.0
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