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 <lstoakes@gmail.com>
Acked-by: Christian König <christian.koenig@amd.com>
Acked-by: Jesper Nilsson <jesper.nilsson@axis.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

4 files changed, 12 insertions, 4 deletions

diff --git a/drivers/infiniband/core/umem.c b/drivers/infiniband/core/umem.c
index c68746ce6624..224ad274ea0b 100644
--- a/drivers/infiniband/core/umem.c
+++ b/drivers/infiniband/core/umem.c
@@ -94,6 +94,7 @@ struct ib_umem *ib_umem_get(struct ib_ucontext *context, unsigned long addr,
 	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;
@@ -183,6 +184,9 @@ struct ib_umem *ib_umem_get(struct ib_ucontext *context, unsigned long addr,
 	if (ret)
 		goto out;
 
+	if (!umem->writable)
+		gup_flags |= FOLL_FORCE;
+
 	need_release = 1;
 	sg_list_start = umem->sg_head.sgl;
 
@@ -190,7 +194,7 @@ struct ib_umem *ib_umem_get(struct ib_ucontext *context, unsigned long addr,
 		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;
diff --git a/drivers/infiniband/hw/mthca/mthca_memfree.c b/drivers/infiniband/hw/mthca/mthca_memfree.c
index 6c00d04b8b28..c6fe89d79248 100644
--- a/drivers/infiniband/hw/mthca/mthca_memfree.c
+++ b/drivers/infiniband/hw/mthca/mthca_memfree.c
@@ -472,7 +472,7 @@ int mthca_map_user_db(struct mthca_dev *dev, struct mthca_uar *uar,
 		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;
 
diff --git a/drivers/infiniband/hw/qib/qib_user_pages.c b/drivers/infiniband/hw/qib/qib_user_pages.c
index 2d2b94fd3633..75f08624ac05 100644
--- a/drivers/infiniband/hw/qib/qib_user_pages.c
+++ b/drivers/infiniband/hw/qib/qib_user_pages.c
@@ -67,7 +67,8 @@ static int __qib_get_user_pages(unsigned long start_page, size_t num_pages,
 
 	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;
diff --git a/drivers/infiniband/hw/usnic/usnic_uiom.c b/drivers/infiniband/hw/usnic/usnic_uiom.c
index a0b6ebee4d8a..1ccee6ea5bc3 100644
--- a/drivers/infiniband/hw/usnic/usnic_uiom.c
+++ b/drivers/infiniband/hw/usnic/usnic_uiom.c
@@ -111,6 +111,7 @@ static int usnic_uiom_get_pages(unsigned long addr, size_t size, int writable,
 	int i;
 	int flags;
 	dma_addr_t pa;
+	unsigned int gup_flags;
 
 	if (!can_do_mlock())
 		return -EPERM;
@@ -135,6 +136,8 @@ static int usnic_uiom_get_pages(unsigned long addr, size_t size, int writable,
 
 	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;
 
@@ -142,7 +145,7 @@ static int usnic_uiom_get_pages(unsigned long addr, size_t size, int writable,
 		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;