mm: replace get_user_pages() write/force parameters with gup_flags

This removes the 'write' and 'force' from get_user_pages() and replaces
them with 'gup_flags' 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 <[e-mail]>
Acked-by: Christian König <[e-mail]>
Acked-by: Jesper Nilsson <[e-mail]>
Acked-by: Michal Hocko <[e-mail]>
Reviewed-by: Jan Kara <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

arch/cris/arch-v32/drivers/cryptocop.c

···
 	err = get_user_pages((unsigned long int)(oper.indata + prev_ix),
 			     noinpages,
 			     0,  /* read access only for in data */
-			     0, /* no force */
 			     inpages,
 			     NULL);
 
···
 	if (oper.do_cipher){
 		err = get_user_pages((unsigned long int)oper.cipher_outdata,
 				     nooutpages,
-				     1, /* write access for out data */
-				     0, /* no force */
+				     FOLL_WRITE, /* write access for out data */
 				     outpages,
 				     NULL);
 		up_read(&current->mm->mmap_sem);

arch/ia64/kernel/err_inject.c

···
 	u64 virt_addr=simple_strtoull(buf, NULL, 16);
 	int ret;
 
-	ret = get_user_pages(virt_addr, 1, VM_READ, 0, NULL, NULL);
+	ret = get_user_pages(virt_addr, 1, FOLL_WRITE, NULL, NULL);
 	if (ret<=0) {
 #ifdef ERR_INJ_DEBUG
 		printk("Virtual address %lx is not existing.\n",virt_addr);

arch/x86/mm/mpx.c

···
 {
 	long gup_ret;
 	int nr_pages = 1;
-	int force = 0;
 
-	gup_ret = get_user_pages((unsigned long)addr, nr_pages, write,
-			force, NULL, NULL);
+	gup_ret = get_user_pages((unsigned long)addr, nr_pages,
+			write ? FOLL_WRITE : 0,	NULL, NULL);
 	/*
 	 * get_user_pages() returns number of pages gotten.
 	 * 0 means we failed to fault in and get anything,

drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c

···
 int amdgpu_ttm_tt_get_user_pages(struct ttm_tt *ttm, struct page **pages)
 {
 	struct amdgpu_ttm_tt *gtt = (void *)ttm;
-	int write = !(gtt->userflags & AMDGPU_GEM_USERPTR_READONLY);
+	unsigned int flags = 0;
 	unsigned pinned = 0;
 	int r;
+
+	if (!(gtt->userflags & AMDGPU_GEM_USERPTR_READONLY))
+		flags |= FOLL_WRITE;
 
 	if (gtt->userflags & AMDGPU_GEM_USERPTR_ANONONLY) {
 		/* check that we only use anonymous memory
···
 		list_add(&guptask.list, &gtt->guptasks);
 		spin_unlock(&gtt->guptasklock);
 
-		r = get_user_pages(userptr, num_pages, write, 0, p, NULL);
+		r = get_user_pages(userptr, num_pages, flags, p, NULL);
 
 		spin_lock(&gtt->guptasklock);
 		list_del(&guptask.list);

drivers/gpu/drm/radeon/radeon_ttm.c

···
 		uint64_t userptr = gtt->userptr + pinned * PAGE_SIZE;
 		struct page **pages = ttm->pages + pinned;
 
-		r = get_user_pages(userptr, num_pages, write, 0, pages, NULL);
+		r = get_user_pages(userptr, num_pages, write ? FOLL_WRITE : 0,
+				   pages, NULL);
 		if (r < 0)
 			goto release_pages;
 

drivers/gpu/drm/via/via_dmablit.c

···
 	down_read(&current->mm->mmap_sem);
 	ret = get_user_pages((unsigned long)xfer->mem_addr,
 			     vsg->num_pages,
-			     (vsg->direction == DMA_FROM_DEVICE),
-			     0, vsg->pages, NULL);
+			     (vsg->direction == DMA_FROM_DEVICE) ? FOLL_WRITE : 0,
+			     vsg->pages, NULL);
 
 	up_read(&current->mm->mmap_sem);
 	if (ret != vsg->num_pages) {

drivers/infiniband/core/umem.c

···
 	unsigned long dma_attrs = 0;
 	struct scatterlist *sg, *sg_list_start;
 	int need_release = 0;
+	unsigned int gup_flags = FOLL_WRITE;
 
 	if (dmasync)
 		dma_attrs |= DMA_ATTR_WRITE_BARRIER;
···
 	if (ret)
 		goto out;
 
+	if (!umem->writable)
+		gup_flags |= FOLL_FORCE;
+
 	need_release = 1;
 	sg_list_start = umem->sg_head.sgl;
 
···
 		ret = get_user_pages(cur_base,
 				     min_t(unsigned long, npages,
 					   PAGE_SIZE / sizeof (struct page *)),
-				     1, !umem->writable, page_list, vma_list);
+				     gup_flags, page_list, vma_list);
 
 		if (ret < 0)
 			goto out;

drivers/infiniband/hw/mthca/mthca_memfree.c

···
 		goto out;
 	}
 
-	ret = get_user_pages(uaddr & PAGE_MASK, 1, 1, 0, pages, NULL);
+	ret = get_user_pages(uaddr & PAGE_MASK, 1, FOLL_WRITE, pages, NULL);
 	if (ret < 0)
 		goto out;
 

drivers/infiniband/hw/qib/qib_user_pages.c

···
 
 	for (got = 0; got < num_pages; got += ret) {
 		ret = get_user_pages(start_page + got * PAGE_SIZE,
-				     num_pages - got, 1, 1,
+				     num_pages - got,
+				     FOLL_WRITE | FOLL_FORCE,
 				     p + got, NULL);
 		if (ret < 0)
 			goto bail_release;

drivers/infiniband/hw/usnic/usnic_uiom.c

···
 	int i;
 	int flags;
 	dma_addr_t pa;
+	unsigned int gup_flags;
 
 	if (!can_do_mlock())
 		return -EPERM;
···
 
 	flags = IOMMU_READ | IOMMU_CACHE;
 	flags |= (writable) ? IOMMU_WRITE : 0;
+	gup_flags = FOLL_WRITE;
+	gup_flags |= (writable) ? 0 : FOLL_FORCE;
 	cur_base = addr & PAGE_MASK;
 	ret = 0;
 
···
 		ret = get_user_pages(cur_base,
 					min_t(unsigned long, npages,
 					PAGE_SIZE / sizeof(struct page *)),
-					1, !writable, page_list, NULL);
+					gup_flags, page_list, NULL);
 
 		if (ret < 0)
 			goto out;

drivers/media/v4l2-core/videobuf-dma-sg.c

···
 {
 	unsigned long first, last;
 	int err, rw = 0;
+	unsigned int flags = FOLL_FORCE;
 
 	dma->direction = direction;
 	switch (dma->direction) {
···
 	if (NULL == dma->pages)
 		return -ENOMEM;
 
+	if (rw == READ)
+		flags |= FOLL_WRITE;
+
 	dprintk(1, "init user [0x%lx+0x%lx => %d pages]\n",
 		data, size, dma->nr_pages);
 
 	err = get_user_pages(data & PAGE_MASK, dma->nr_pages,
-			     rw == READ, 1, /* force */
-			     dma->pages, NULL);
+			     flags, dma->pages, NULL);
 
 	if (err != dma->nr_pages) {
 		dma->nr_pages = (err >= 0) ? err : 0;

drivers/misc/mic/scif/scif_rma.c

···
 		pinned_pages->nr_pages = get_user_pages(
 				(u64)addr,
 				nr_pages,
-				!!(prot & SCIF_PROT_WRITE),
-				0,
+				(prot & SCIF_PROT_WRITE) ? FOLL_WRITE : 0,
 				pinned_pages->pages,
 				NULL);
 		up_write(&mm->mmap_sem);

drivers/misc/sgi-gru/grufault.c

···
 #else
 	*pageshift = PAGE_SHIFT;
 #endif
-	if (get_user_pages(vaddr, 1, write, 0, &page, NULL) <= 0)
+	if (get_user_pages(vaddr, 1, write ? FOLL_WRITE : 0, &page, NULL) <= 0)
 		return -EFAULT;
 	*paddr = page_to_phys(page);
 	put_page(page);

drivers/platform/goldfish/goldfish_pipe.c

···
 		 * much memory to the process.
 		 */
 		down_read(&current->mm->mmap_sem);
-		ret = get_user_pages(address, 1, !is_write, 0, &page, NULL);
+		ret = get_user_pages(address, 1, is_write ? 0 : FOLL_WRITE,
+				&page, NULL);
 		up_read(&current->mm->mmap_sem);
 		if (ret < 0)
 			break;

drivers/rapidio/devices/rio_mport_cdev.c

···
 		down_read(&current->mm->mmap_sem);
 		pinned = get_user_pages(
 				(unsigned long)xfer->loc_addr & PAGE_MASK,
-				nr_pages, dir == DMA_FROM_DEVICE, 0,
+				nr_pages,
+				dir == DMA_FROM_DEVICE ? FOLL_WRITE : 0,
 				page_list, NULL);
 		up_read(&current->mm->mmap_sem);
 

drivers/staging/vc04_services/interface/vchiq_arm/vchiq_2835_arm.c

···
 		actual_pages = get_user_pages(task, task->mm,
 				          (unsigned long)buf & ~(PAGE_SIZE - 1),
 					  num_pages,
-					  (type == PAGELIST_READ) /*Write */ ,
-					  0 /*Force */ ,
+					  (type == PAGELIST_READ) ? FOLL_WRITE : 0,
 					  pages,
 					  NULL /*vmas */);
 		up_read(&task->mm->mmap_sem);

drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c

···
 		current->mm,              /* mm */
 		(unsigned long)virt_addr, /* start */
 		num_pages,                /* len */
-		0,                        /* write */
-		0,                        /* force */
+		0,                        /* gup_flags */
 		pages,                    /* pages (array of page pointers) */
 		NULL);                    /* vmas */
 	up_read(&current->mm->mmap_sem);

drivers/virt/fsl_hypervisor.c

···
 	/* Get the physical addresses of the source buffer */
 	down_read(&current->mm->mmap_sem);
 	num_pinned = get_user_pages(param.local_vaddr - lb_offset,
-		num_pages, (param.source == -1) ? READ : WRITE,
-		0, pages, NULL);
+		num_pages, (param.source == -1) ? 0 : FOLL_WRITE,
+		pages, NULL);
 	up_read(&current->mm->mmap_sem);
 
 	if (num_pinned != num_pages) {

include/linux/mm.h

···
 			    int write, int force, struct page **pages,
 			    struct vm_area_struct **vmas);
 long get_user_pages(unsigned long start, unsigned long nr_pages,
-			    int write, int force, struct page **pages,
+			    unsigned int gup_flags, struct page **pages,
 			    struct vm_area_struct **vmas);
 long get_user_pages_locked(unsigned long start, unsigned long nr_pages,
 		    unsigned int gup_flags, struct page **pages, int *locked);

mm/gup.c

···
  * obviously don't pass FOLL_REMOTE in here.
  */
 long get_user_pages(unsigned long start, unsigned long nr_pages,
-		int write, int force, struct page **pages,
+		unsigned int gup_flags, struct page **pages,
 		struct vm_area_struct **vmas)
 {
-	unsigned int flags = FOLL_TOUCH;
-
-	if (write)
-		flags |= FOLL_WRITE;
-	if (force)
-		flags |= FOLL_FORCE;
-
 	return __get_user_pages_locked(current, current->mm, start, nr_pages,
-				       pages, vmas, NULL, false, flags);
+				       pages, vmas, NULL, false,
+				       gup_flags | FOLL_TOUCH);
 }
 EXPORT_SYMBOL(get_user_pages);
 

mm/mempolicy.c

···
 	struct page *p;
 	int err;
 
-	err = get_user_pages(addr & PAGE_MASK, 1, 0, 0, &p, NULL);
+	err = get_user_pages(addr & PAGE_MASK, 1, 0, &p, NULL);
 	if (err >= 0) {
 		err = page_to_nid(p);
 		put_page(p);

mm/nommu.c

···
  * - don't permit access to VMAs that don't support it, such as I/O mappings
  */
 long get_user_pages(unsigned long start, unsigned long nr_pages,
-		    int write, int force, struct page **pages,
+		    unsigned int gup_flags, struct page **pages,
 		    struct vm_area_struct **vmas)
 {
-	int flags = 0;
-
-	if (write)
-		flags |= FOLL_WRITE;
-	if (force)
-		flags |= FOLL_FORCE;
-
-	return __get_user_pages(current, current->mm, start, nr_pages, flags,
-				pages, vmas, NULL);
+	return __get_user_pages(current, current->mm, start, nr_pages,
+				gup_flags, pages, vmas, NULL);
 }
 EXPORT_SYMBOL(get_user_pages);
 
···
 			    unsigned int gup_flags, struct page **pages,
 			    int *locked)
 {
-	int write = gup_flags & FOLL_WRITE;
-	int force = gup_flags & FOLL_FORCE;
-
-	return get_user_pages(start, nr_pages, write, force, pages, NULL);
+	return get_user_pages(start, nr_pages, gup_flags, pages, NULL);
 }
 EXPORT_SYMBOL(get_user_pages_locked);