Thread (38 messages) 38 messages, 7 authors, 2016-10-20
STALE3538d

[PATCH 03/10] mm: replace get_user_pages_unlocked() write/force parameters with gup_flags

From: Lorenzo Stoakes <hidden>
Date: 2016-10-13 00:20:13
Also in: ceph-devel, dri-devel, intel-gfx, kvm, linux-alpha, linux-arm-kernel, linux-fbdev, linux-fsdevel, linux-media, linux-mips, linux-mm, linux-rdma, linux-s390, linux-samsung-soc, linux-scsi, linux-sh, lkml, netdev, sparclinux
Subsystem: ceph common code (libceph), framebuffer layer, ivtv video4linux driver, media input infrastructure (v4l/dvb), memory management, memory management - core, memory management - gup (get user pages), memory mapping, mips, s390 architecture, scsi subsystem, scsi tape driver, sparc + ultrasparc (sparc/sparc64), superh, the rest, x86 architecture (32-bit and 64-bit), x86 mm · Maintainers: Ilya Dryomov, Alex Markuze, Viacheslav Dubeyko, Helge Deller, Andy Walls, Mauro Carvalho Chehab, Andrew Morton, David Hildenbrand, Liam R. Howlett, Lorenzo Stoakes, Thomas Bogendoerfer, Heiko Carstens, Vasily Gorbik, Alexander Gordeev, "James E.J. Bottomley", "Martin K. Petersen", Kai Mäkisara, "David S. Miller", Andreas Larsson, Yoshinori Sato, Rich Felker, John Paul Adrian Glaubitz, Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen, Andy Lutomirski, Peter Zijlstra

This patch removes the write and force parameters from get_user_pages_unlocked()
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 <redacted>
---
 arch/mips/mm/gup.c                 |  2 +-
 arch/s390/mm/gup.c                 |  3 ++-
 arch/sh/mm/gup.c                   |  3 ++-
 arch/sparc/mm/gup.c                |  3 ++-
 arch/x86/mm/gup.c                  |  2 +-
 drivers/media/pci/ivtv/ivtv-udma.c |  4 ++--
 drivers/media/pci/ivtv/ivtv-yuv.c  |  5 +++--
 drivers/scsi/st.c                  |  5 ++---
 drivers/video/fbdev/pvr2fb.c       |  4 ++--
 include/linux/mm.h                 |  2 +-
 mm/gup.c                           | 14 ++++----------
 mm/nommu.c                         | 11 ++---------
 mm/util.c                          |  3 ++-
 net/ceph/pagevec.c                 |  2 +-
 14 files changed, 27 insertions(+), 36 deletions(-)
diff --git a/arch/mips/mm/gup.c b/arch/mips/mm/gup.c
index 42d124f..d8c3c15 100644
--- a/arch/mips/mm/gup.c
+++ b/arch/mips/mm/gup.c
@@ -287,7 +287,7 @@ int get_user_pages_fast(unsigned long start, int nr_pages, int write,
 	pages += nr;
 
 	ret = get_user_pages_unlocked(start, (end - start) >> PAGE_SHIFT,
-				      write, 0, pages);
+				      pages, write ? FOLL_WRITE : 0);
 
 	/* Have to be a bit careful with return values */
 	if (nr > 0) {
diff --git a/arch/s390/mm/gup.c b/arch/s390/mm/gup.c
index adb0c34..18d4107 100644
--- a/arch/s390/mm/gup.c
+++ b/arch/s390/mm/gup.c
@@ -266,7 +266,8 @@ int get_user_pages_fast(unsigned long start, int nr_pages, int write,
 	/* Try to get the remaining pages with get_user_pages */
 	start += nr << PAGE_SHIFT;
 	pages += nr;
-	ret = get_user_pages_unlocked(start, nr_pages - nr, write, 0, pages);
+	ret = get_user_pages_unlocked(start, nr_pages - nr, pages,
+				      write ? FOLL_WRITE : 0);
 	/* Have to be a bit careful with return values */
 	if (nr > 0)
 		ret = (ret < 0) ? nr : ret + nr;
diff --git a/arch/sh/mm/gup.c b/arch/sh/mm/gup.c
index 40fa6c8..063c298 100644
--- a/arch/sh/mm/gup.c
+++ b/arch/sh/mm/gup.c
@@ -258,7 +258,8 @@ int get_user_pages_fast(unsigned long start, int nr_pages, int write,
 		pages += nr;
 
 		ret = get_user_pages_unlocked(start,
-			(end - start) >> PAGE_SHIFT, write, 0, pages);
+			(end - start) >> PAGE_SHIFT, pages,
+			write ? FOLL_WRITE : 0);
 
 		/* Have to be a bit careful with return values */
 		if (nr > 0) {
diff --git a/arch/sparc/mm/gup.c b/arch/sparc/mm/gup.c
index 4e06750..cd0e32b 100644
--- a/arch/sparc/mm/gup.c
+++ b/arch/sparc/mm/gup.c
@@ -238,7 +238,8 @@ int get_user_pages_fast(unsigned long start, int nr_pages, int write,
 		pages += nr;
 
 		ret = get_user_pages_unlocked(start,
-			(end - start) >> PAGE_SHIFT, write, 0, pages);
+			(end - start) >> PAGE_SHIFT, pages,
+			write ? FOLL_WRITE : 0);
 
 		/* Have to be a bit careful with return values */
 		if (nr > 0) {
diff --git a/arch/x86/mm/gup.c b/arch/x86/mm/gup.c
index b8b6a60..0d4fb3e 100644
--- a/arch/x86/mm/gup.c
+++ b/arch/x86/mm/gup.c
@@ -435,7 +435,7 @@ int get_user_pages_fast(unsigned long start, int nr_pages, int write,
 
 		ret = get_user_pages_unlocked(start,
 					      (end - start) >> PAGE_SHIFT,
-					      write, 0, pages);
+					      pages, write ? FOLL_WRITE : 0);
 
 		/* Have to be a bit careful with return values */
 		if (nr > 0) {
diff --git a/drivers/media/pci/ivtv/ivtv-udma.c b/drivers/media/pci/ivtv/ivtv-udma.c
index 4769469..2c9232e 100644
--- a/drivers/media/pci/ivtv/ivtv-udma.c
+++ b/drivers/media/pci/ivtv/ivtv-udma.c
@@ -124,8 +124,8 @@ int ivtv_udma_setup(struct ivtv *itv, unsigned long ivtv_dest_addr,
 	}
 
 	/* Get user pages for DMA Xfer */
-	err = get_user_pages_unlocked(user_dma.uaddr, user_dma.page_count, 0,
-			1, dma->map);
+	err = get_user_pages_unlocked(user_dma.uaddr, user_dma.page_count,
+			dma->map, FOLL_FORCE);
 
 	if (user_dma.page_count != err) {
 		IVTV_DEBUG_WARN("failed to map user pages, returned %d instead of %d\n",
diff --git a/drivers/media/pci/ivtv/ivtv-yuv.c b/drivers/media/pci/ivtv/ivtv-yuv.c
index b094054..f7299d3 100644
--- a/drivers/media/pci/ivtv/ivtv-yuv.c
+++ b/drivers/media/pci/ivtv/ivtv-yuv.c
@@ -76,11 +76,12 @@ static int ivtv_yuv_prep_user_dma(struct ivtv *itv, struct ivtv_user_dma *dma,
 
 	/* Get user pages for DMA Xfer */
 	y_pages = get_user_pages_unlocked(y_dma.uaddr,
-			y_dma.page_count, 0, 1, &dma->map[0]);
+			y_dma.page_count, &dma->map[0], FOLL_FORCE);
 	uv_pages = 0; /* silence gcc. value is set and consumed only if: */
 	if (y_pages == y_dma.page_count) {
 		uv_pages = get_user_pages_unlocked(uv_dma.uaddr,
-				uv_dma.page_count, 0, 1, &dma->map[y_pages]);
+				uv_dma.page_count, &dma->map[y_pages],
+				FOLL_FORCE);
 	}
 
 	if (y_pages != y_dma.page_count || uv_pages != uv_dma.page_count) {
diff --git a/drivers/scsi/st.c b/drivers/scsi/st.c
index 7af5226..618422e 100644
--- a/drivers/scsi/st.c
+++ b/drivers/scsi/st.c
@@ -4922,9 +4922,8 @@ static int sgl_map_user_pages(struct st_buffer *STbp,
 	res = get_user_pages_unlocked(
 		uaddr,
 		nr_pages,
-		rw == READ,
-		0, /* don't force */
-		pages);
+		pages,
+		rw == READ ? FOLL_WRITE : 0); /* don't force */
 
 	/* Errors and no page mapped should return here */
 	if (res < nr_pages)
diff --git a/drivers/video/fbdev/pvr2fb.c b/drivers/video/fbdev/pvr2fb.c
index 3b1ca44..a2564ab 100644
--- a/drivers/video/fbdev/pvr2fb.c
+++ b/drivers/video/fbdev/pvr2fb.c
@@ -686,8 +686,8 @@ static ssize_t pvr2fb_write(struct fb_info *info, const char *buf,
 	if (!pages)
 		return -ENOMEM;
 
-	ret = get_user_pages_unlocked((unsigned long)buf, nr_pages, WRITE,
-			0, pages);
+	ret = get_user_pages_unlocked((unsigned long)buf, nr_pages, pages,
+			FOLL_WRITE);
 
 	if (ret < nr_pages) {
 		nr_pages = ret;
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 2db98b6..6adc4bc 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1287,7 +1287,7 @@ long __get_user_pages_unlocked(struct task_struct *tsk, struct mm_struct *mm,
 			       unsigned long start, unsigned long nr_pages,
 			       struct page **pages, unsigned int gup_flags);
 long get_user_pages_unlocked(unsigned long start, unsigned long nr_pages,
-		    int write, int force, struct page **pages);
+		    struct page **pages, unsigned int gup_flags);
 int get_user_pages_fast(unsigned long start, int nr_pages, int write,
 			struct page **pages);
 
diff --git a/mm/gup.c b/mm/gup.c
index 3d620dd..cfcb014 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -897,17 +897,10 @@ EXPORT_SYMBOL(__get_user_pages_unlocked);
  * "force" parameter).
  */
 long get_user_pages_unlocked(unsigned long start, unsigned long nr_pages,
-			     int write, int force, struct page **pages)
+			     struct page **pages, unsigned int gup_flags)
 {
-	unsigned int flags = FOLL_TOUCH;
-
-	if (write)
-		flags |= FOLL_WRITE;
-	if (force)
-		flags |= FOLL_FORCE;
-
 	return __get_user_pages_unlocked(current, current->mm, start, nr_pages,
-					 pages, flags);
+					 pages, gup_flags | FOLL_TOUCH);
 }
 EXPORT_SYMBOL(get_user_pages_unlocked);
 
@@ -1525,7 +1518,8 @@ int get_user_pages_fast(unsigned long start, int nr_pages, int write,
 		start += nr << PAGE_SHIFT;
 		pages += nr;
 
-		ret = get_user_pages_unlocked(start, nr_pages - nr, write, 0, pages);
+		ret = get_user_pages_unlocked(start, nr_pages - nr, pages,
+				write ? FOLL_WRITE : 0);
 
 		/* Have to be a bit careful with return values */
 		if (nr > 0) {
diff --git a/mm/nommu.c b/mm/nommu.c
index 925dcc1..7e27add 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -197,17 +197,10 @@ long __get_user_pages_unlocked(struct task_struct *tsk, struct mm_struct *mm,
 EXPORT_SYMBOL(__get_user_pages_unlocked);
 
 long get_user_pages_unlocked(unsigned long start, unsigned long nr_pages,
-			     int write, int force, struct page **pages)
+			     struct page **pages, unsigned int gup_flags)
 {
-	unsigned int flags = 0;
-
-	if (write)
-		flags |= FOLL_WRITE;
-	if (force)
-		flags |= FOLL_FORCE;
-
 	return __get_user_pages_unlocked(current, current->mm, start, nr_pages,
-					 pages, flags);
+					 pages, gup_flags);
 }
 EXPORT_SYMBOL(get_user_pages_unlocked);
 
diff --git a/mm/util.c b/mm/util.c
index 662cddf..4c685bd 100644
--- a/mm/util.c
+++ b/mm/util.c
@@ -283,7 +283,8 @@ EXPORT_SYMBOL_GPL(__get_user_pages_fast);
 int __weak get_user_pages_fast(unsigned long start,
 				int nr_pages, int write, struct page **pages)
 {
-	return get_user_pages_unlocked(start, nr_pages, write, 0, pages);
+	return get_user_pages_unlocked(start, nr_pages, pages,
+				       write ? FOLL_WRITE : 0);
 }
 EXPORT_SYMBOL_GPL(get_user_pages_fast);
 
diff --git a/net/ceph/pagevec.c b/net/ceph/pagevec.c
index 00d2601..1a7c9a7 100644
--- a/net/ceph/pagevec.c
+++ b/net/ceph/pagevec.c
@@ -26,7 +26,7 @@ struct page **ceph_get_direct_page_vector(const void __user *data,
 	while (got < num_pages) {
 		rc = get_user_pages_unlocked(
 		    (unsigned long)data + ((unsigned long)got * PAGE_SIZE),
-		    num_pages - got, write_page, 0, pages + got);
+		    num_pages - got, pages + got, write_page ? FOLL_WRITE : 0);
 		if (rc < 0)
 			break;
 		BUG_ON(rc == 0);
-- 
2.10.0
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