Message-ID: <20161019074429.GN29967@quack2.suse.cz>
Date:   Wed, 19 Oct 2016 09:44:29 +0200
From:   Jan Kara <jack@...e.cz>
To:     Lorenzo Stoakes <lstoakes@...il.com>
Cc:     linux-mm@...ck.org, 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
Subject: Re: [PATCH 06/10] mm: replace get_user_pages() write/force
 parameters with gup_flags

On Thu 13-10-16 01:20:16, Lorenzo Stoakes wrote:
> This patch removes the write and force parameters from get_user_pages() 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>

The patch looks good. You can add:

Reviewed-by: Jan Kara <jack@...e.cz>

								Honza

> ---
>  arch/cris/arch-v32/drivers/cryptocop.c                 |  4 +---
>  arch/ia64/kernel/err_inject.c                          |  2 +-
>  arch/x86/mm/mpx.c                                      |  5 ++---
>  drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c                |  7 +++++--
>  drivers/gpu/drm/radeon/radeon_ttm.c                    |  3 ++-
>  drivers/gpu/drm/via/via_dmablit.c                      |  4 ++--
>  drivers/infiniband/core/umem.c                         |  6 +++++-
>  drivers/infiniband/hw/mthca/mthca_memfree.c            |  2 +-
>  drivers/infiniband/hw/qib/qib_user_pages.c             |  3 ++-
>  drivers/infiniband/hw/usnic/usnic_uiom.c               |  5 ++++-
>  drivers/media/v4l2-core/videobuf-dma-sg.c              |  7 +++++--
>  drivers/misc/mic/scif/scif_rma.c                       |  3 +--
>  drivers/misc/sgi-gru/grufault.c                        |  2 +-
>  drivers/platform/goldfish/goldfish_pipe.c              |  3 ++-
>  drivers/rapidio/devices/rio_mport_cdev.c               |  3 ++-
>  .../vc04_services/interface/vchiq_arm/vchiq_2835_arm.c |  3 +--
>  .../vc04_services/interface/vchiq_arm/vchiq_arm.c      |  3 +--
>  drivers/virt/fsl_hypervisor.c                          |  4 ++--
>  include/linux/mm.h                                     |  2 +-
>  mm/gup.c                                               | 12 +++---------
>  mm/mempolicy.c                                         |  2 +-
>  mm/nommu.c                                             | 18 ++++--------------
>  22 files changed, 49 insertions(+), 54 deletions(-)
> 
> diff --git a/arch/cris/arch-v32/drivers/cryptocop.c b/arch/cris/arch-v32/drivers/cryptocop.c
> index b5698c8..099e170 100644
> --- a/arch/cris/arch-v32/drivers/cryptocop.c
> +++ b/arch/cris/arch-v32/drivers/cryptocop.c
> @@ -2722,7 +2722,6 @@ static int cryptocop_ioctl_process(struct inode *inode, struct file *filp, unsig
>  	err = get_user_pages((unsigned long int)(oper.indata + prev_ix),
>  			     noinpages,
>  			     0,  /* read access only for in data */
> -			     0, /* no force */
>  			     inpages,
>  			     NULL);
>  
> @@ -2736,8 +2735,7 @@ static int cryptocop_ioctl_process(struct inode *inode, struct file *filp, unsig
>  	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);
> diff --git a/arch/ia64/kernel/err_inject.c b/arch/ia64/kernel/err_inject.c
> index 09f8457..5ed0ea9 100644
> --- a/arch/ia64/kernel/err_inject.c
> +++ b/arch/ia64/kernel/err_inject.c
> @@ -142,7 +142,7 @@ store_virtual_to_phys(struct device *dev, struct device_attribute *attr,
>  	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);
> diff --git a/arch/x86/mm/mpx.c b/arch/x86/mm/mpx.c
> index 8047687..e4f8009 100644
> --- a/arch/x86/mm/mpx.c
> +++ b/arch/x86/mm/mpx.c
> @@ -544,10 +544,9 @@ static int mpx_resolve_fault(long __user *addr, int write)
>  {
>  	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,
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
> index 887483b..dcaf691 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
> @@ -555,10 +555,13 @@ struct amdgpu_ttm_tt {
>  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
>  		   to prevent problems with writeback */
> @@ -581,7 +584,7 @@ int amdgpu_ttm_tt_get_user_pages(struct ttm_tt *ttm, struct page **pages)
>  		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);
> diff --git a/drivers/gpu/drm/radeon/radeon_ttm.c b/drivers/gpu/drm/radeon/radeon_ttm.c
> index 4552682..3de5e6e 100644
> --- a/drivers/gpu/drm/radeon/radeon_ttm.c
> +++ b/drivers/gpu/drm/radeon/radeon_ttm.c
> @@ -566,7 +566,8 @@ static int radeon_ttm_tt_pin_userptr(struct ttm_tt *ttm)
>  		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;
>  
> diff --git a/drivers/gpu/drm/via/via_dmablit.c b/drivers/gpu/drm/via/via_dmablit.c
> index 7e2a12c..1a3ad76 100644
> --- a/drivers/gpu/drm/via/via_dmablit.c
> +++ b/drivers/gpu/drm/via/via_dmablit.c
> @@ -241,8 +241,8 @@ via_lock_all_dma_pages(drm_via_sg_info_t *vsg,  drm_via_dmablit_t *xfer)
>  	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) {
> diff --git a/drivers/infiniband/core/umem.c b/drivers/infiniband/core/umem.c
> index c68746c..224ad27 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 6c00d04..c6fe89d 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 2d2b94f..75f0862 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 a0b6ebe..1ccee6e 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;
> diff --git a/drivers/media/v4l2-core/videobuf-dma-sg.c b/drivers/media/v4l2-core/videobuf-dma-sg.c
> index f300f06..1db0af6 100644
> --- a/drivers/media/v4l2-core/videobuf-dma-sg.c
> +++ b/drivers/media/v4l2-core/videobuf-dma-sg.c
> @@ -156,6 +156,7 @@ static int videobuf_dma_init_user_locked(struct videobuf_dmabuf *dma,
>  {
>  	unsigned long first, last;
>  	int err, rw = 0;
> +	unsigned int flags = FOLL_FORCE;
>  
>  	dma->direction = direction;
>  	switch (dma->direction) {
> @@ -178,12 +179,14 @@ static int videobuf_dma_init_user_locked(struct videobuf_dmabuf *dma,
>  	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;
> diff --git a/drivers/misc/mic/scif/scif_rma.c b/drivers/misc/mic/scif/scif_rma.c
> index e0203b1..f806a44 100644
> --- a/drivers/misc/mic/scif/scif_rma.c
> +++ b/drivers/misc/mic/scif/scif_rma.c
> @@ -1396,8 +1396,7 @@ int __scif_pin_pages(void *addr, size_t len, int *out_prot,
>  		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);
> diff --git a/drivers/misc/sgi-gru/grufault.c b/drivers/misc/sgi-gru/grufault.c
> index a2d97b9..6fb773d 100644
> --- a/drivers/misc/sgi-gru/grufault.c
> +++ b/drivers/misc/sgi-gru/grufault.c
> @@ -198,7 +198,7 @@ static int non_atomic_pte_lookup(struct vm_area_struct *vma,
>  #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);
> diff --git a/drivers/platform/goldfish/goldfish_pipe.c b/drivers/platform/goldfish/goldfish_pipe.c
> index 07462d7..1aba2c7 100644
> --- a/drivers/platform/goldfish/goldfish_pipe.c
> +++ b/drivers/platform/goldfish/goldfish_pipe.c
> @@ -309,7 +309,8 @@ static ssize_t goldfish_pipe_read_write(struct file *filp, char __user *buffer,
>  		 * 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;
> diff --git a/drivers/rapidio/devices/rio_mport_cdev.c b/drivers/rapidio/devices/rio_mport_cdev.c
> index 436dfe8..9013a58 100644
> --- a/drivers/rapidio/devices/rio_mport_cdev.c
> +++ b/drivers/rapidio/devices/rio_mport_cdev.c
> @@ -892,7 +892,8 @@ rio_dma_transfer(struct file *filp, u32 transfer_mode,
>  		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);
>  
> diff --git a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_2835_arm.c b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_2835_arm.c
> index c29040f..1091b9f 100644
> --- a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_2835_arm.c
> +++ b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_2835_arm.c
> @@ -423,8 +423,7 @@ create_pagelist(char __user *buf, size_t count, unsigned short type,
>  		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);
> diff --git a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c
> index e11c0e0..7b6cd4d 100644
> --- a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c
> +++ b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c
> @@ -1477,8 +1477,7 @@ dump_phys_mem(void *virt_addr, uint32_t num_bytes)
>  		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);
> diff --git a/drivers/virt/fsl_hypervisor.c b/drivers/virt/fsl_hypervisor.c
> index 60bdad3..150ce2a 100644
> --- a/drivers/virt/fsl_hypervisor.c
> +++ b/drivers/virt/fsl_hypervisor.c
> @@ -245,8 +245,8 @@ static long ioctl_memcpy(struct fsl_hv_ioctl_memcpy __user *p)
>  	/* 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) {
> diff --git a/include/linux/mm.h b/include/linux/mm.h
> index 5ff084f6..686a477 100644
> --- a/include/linux/mm.h
> +++ b/include/linux/mm.h
> @@ -1279,7 +1279,7 @@ long get_user_pages_remote(struct task_struct *tsk, struct mm_struct *mm,
>  			    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);
> diff --git a/mm/gup.c b/mm/gup.c
> index 7a0d033..dc91303 100644
> --- a/mm/gup.c
> +++ b/mm/gup.c
> @@ -977,18 +977,12 @@ EXPORT_SYMBOL(get_user_pages_remote);
>   * 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);
>  
> diff --git a/mm/mempolicy.c b/mm/mempolicy.c
> index ad1c96a..0b859af 100644
> --- a/mm/mempolicy.c
> +++ b/mm/mempolicy.c
> @@ -850,7 +850,7 @@ static int lookup_node(unsigned long addr)
>  	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);
> diff --git a/mm/nommu.c b/mm/nommu.c
> index 842cfdd..70cb844 100644
> --- a/mm/nommu.c
> +++ b/mm/nommu.c
> @@ -160,18 +160,11 @@ long __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
>   * - 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);
>  
> @@ -179,10 +172,7 @@ long get_user_pages_locked(unsigned long start, unsigned long nr_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);
>  
> -- 
> 2.10.0
> 
-- 
Jan Kara <jack@...e.com>
SUSE Labs, CR

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