mm/gup: change GUP fast to use flags rather than a write 'bool'

To facilitate additional options to get_user_pages_fast() change the
singular write parameter to be gup_flags.

This patch does not change any functionality.  New functionality will
follow in subsequent patches.

Some of the get_user_pages_fast() call sites were unchanged because they
already passed FOLL_WRITE or 0 for the write parameter.

NOTE: It was suggested to change the ordering of the get_user_pages_fast()
arguments to ensure that callers were converted.  This breaks the current
GUP call site convention of having the returned pages be the final
parameter.  So the suggestion was rejected.

Link: http://lkml.kernel.org/r/20190328084422.29911-4-ira.weiny@intel.com
Link: http://lkml.kernel.org/r/20190317183438.2057-4-ira.weiny@intel.com
Signed-off-by: Ira Weiny <ira.weiny@intel.com>
Reviewed-by: Mike Marshall <hubcap@omnibond.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Hogan <jhogan@kernel.org>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Rich Felker <dalias@libc.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arch/mips/mm/gup.c

@@ -235,7 +235,7 @@ int __get_user_pages_fast(unsigned long start, int nr_pages, int write,
  * get_user_pages_fast() - pin user pages in memory
  * @start:	starting user address
  * @nr_pages:	number of pages from start to pin
- * @write:	whether pages will be written to
+ * @gup_flags:	flags modifying pin behaviour
  * @pages:	array that receives pointers to the pages pinned.
  *		Should be at least nr_pages long.
  *
@@ -247,8 +247,8 @@ int __get_user_pages_fast(unsigned long start, int nr_pages, int write,
  * requested. If nr_pages is 0 or negative, returns 0. If no pages
  * were pinned, returns -errno.
  */
-int get_user_pages_fast(unsigned long start, int nr_pages, int write,
-			struct page **pages)
+int get_user_pages_fast(unsigned long start, int nr_pages,
+			unsigned int gup_flags, struct page **pages)
 {
 	struct mm_struct *mm = current->mm;
 	unsigned long addr, len, end;
@@ -273,7 +273,8 @@ int get_user_pages_fast(unsigned long start, int nr_pages, int write,
 		next = pgd_addr_end(addr, end);
 		if (pgd_none(pgd))
 			goto slow;
-		if (!gup_pud_range(pgd, addr, next, write, pages, &nr))
+		if (!gup_pud_range(pgd, addr, next, gup_flags & FOLL_WRITE,
+				   pages, &nr))
 			goto slow;
 	} while (pgdp++, addr = next, addr != end);
 	local_irq_enable();
@@ -289,7 +290,7 @@ 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,
-				      pages, write ? FOLL_WRITE : 0);
+				      pages, gup_flags);
 
 	/* Have to be a bit careful with return values */
 	if (nr > 0) {

arch/powerpc/kvm/book3s_64_mmu_hv.c

@@ -600,7 +600,7 @@ int kvmppc_book3s_hv_page_fault(struct kvm_run *run, struct kvm_vcpu *vcpu,
 	/* If writing != 0, then the HPTE must allow writing, if we get here */
 	write_ok = writing;
 	hva = gfn_to_hva_memslot(memslot, gfn);
-	npages = get_user_pages_fast(hva, 1, writing, pages);
+	npages = get_user_pages_fast(hva, 1, writing ? FOLL_WRITE : 0, pages);
 	if (npages < 1) {
 		/* Check if it's an I/O mapping */
 		down_read(&current->mm->mmap_sem);
@@ -1193,7 +1193,7 @@ void *kvmppc_pin_guest_page(struct kvm *kvm, unsigned long gpa,
 	if (!memslot || (memslot->flags & KVM_MEMSLOT_INVALID))
 		goto err;
 	hva = gfn_to_hva_memslot(memslot, gfn);
-	npages = get_user_pages_fast(hva, 1, 1, pages);
+	npages = get_user_pages_fast(hva, 1, FOLL_WRITE, pages);
 	if (npages < 1)
 		goto err;
 	page = pages[0];

arch/powerpc/kvm/e500_mmu.c

@@ -783,7 +783,7 @@ int kvm_vcpu_ioctl_config_tlb(struct kvm_vcpu *vcpu,
 	if (!pages)
 		return -ENOMEM;
 
-	ret = get_user_pages_fast(cfg->array, num_pages, 1, pages);
+	ret = get_user_pages_fast(cfg->array, num_pages, FOLL_WRITE, pages);
 	if (ret < 0)
 		goto free_pages;
 

arch/s390/kvm/interrupt.c

@@ -2376,7 +2376,7 @@ static int kvm_s390_adapter_map(struct kvm *kvm, unsigned int id, __u64 addr)
 		ret = -EFAULT;
 		goto out;
 	}
-	ret = get_user_pages_fast(map->addr, 1, 1, &map->page);
+	ret = get_user_pages_fast(map->addr, 1, FOLL_WRITE, &map->page);
 	if (ret < 0)
 		goto out;
 	BUG_ON(ret != 1);

arch/sh/mm/gup.c

@@ -204,7 +204,7 @@ int __get_user_pages_fast(unsigned long start, int nr_pages, int write,
  * get_user_pages_fast() - pin user pages in memory
  * @start:	starting user address
  * @nr_pages:	number of pages from start to pin
- * @write:	whether pages will be written to
+ * @gup_flags:	flags modifying pin behaviour
  * @pages:	array that receives pointers to the pages pinned.
  *		Should be at least nr_pages long.
  *
@@ -216,8 +216,8 @@ int __get_user_pages_fast(unsigned long start, int nr_pages, int write,
  * requested. If nr_pages is 0 or negative, returns 0. If no pages
  * were pinned, returns -errno.
  */
-int get_user_pages_fast(unsigned long start, int nr_pages, int write,
-			struct page **pages)
+int get_user_pages_fast(unsigned long start, int nr_pages,
+			unsigned int gup_flags, struct page **pages)
 {
 	struct mm_struct *mm = current->mm;
 	unsigned long addr, len, end;
@@ -241,7 +241,8 @@ int get_user_pages_fast(unsigned long start, int nr_pages, int write,
 		next = pgd_addr_end(addr, end);
 		if (pgd_none(pgd))
 			goto slow;
-		if (!gup_pud_range(pgd, addr, next, write, pages, &nr))
+		if (!gup_pud_range(pgd, addr, next, gup_flags & FOLL_WRITE,
+				   pages, &nr))
 			goto slow;
 	} while (pgdp++, addr = next, addr != end);
 	local_irq_enable();
@@ -261,7 +262,7 @@ int get_user_pages_fast(unsigned long start, int nr_pages, int write,
 
 		ret = get_user_pages_unlocked(start,
 			(end - start) >> PAGE_SHIFT, pages,
-			write ? FOLL_WRITE : 0);
+			gup_flags);
 
 		/* Have to be a bit careful with return values */
 		if (nr > 0) {

arch/sparc/mm/gup.c

@@ -245,8 +245,8 @@ int __get_user_pages_fast(unsigned long start, int nr_pages, int write,
 	return nr;
 }
 
-int get_user_pages_fast(unsigned long start, int nr_pages, int write,
-			struct page **pages)
+int get_user_pages_fast(unsigned long start, int nr_pages,
+			unsigned int gup_flags, struct page **pages)
 {
 	struct mm_struct *mm = current->mm;
 	unsigned long addr, len, end;
@@ -303,7 +303,8 @@ int get_user_pages_fast(unsigned long start, int nr_pages, int write,
 		next = pgd_addr_end(addr, end);
 		if (pgd_none(pgd))
 			goto slow;
-		if (!gup_pud_range(pgd, addr, next, write, pages, &nr))
+		if (!gup_pud_range(pgd, addr, next, gup_flags & FOLL_WRITE,
+				   pages, &nr))
 			goto slow;
 	} while (pgdp++, addr = next, addr != end);
 
@@ -324,7 +325,7 @@ int get_user_pages_fast(unsigned long start, int nr_pages, int write,
 
 		ret = get_user_pages_unlocked(start,
 			(end - start) >> PAGE_SHIFT, pages,
-			write ? FOLL_WRITE : 0);
+			gup_flags);
 
 		/* Have to be a bit careful with return values */
 		if (nr > 0) {

arch/x86/kvm/paging_tmpl.h

@@ -140,7 +140,7 @@ static int FNAME(cmpxchg_gpte)(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu,
 	pt_element_t *table;
 	struct page *page;
 
-	npages = get_user_pages_fast((unsigned long)ptep_user, 1, 1, &page);
+	npages = get_user_pages_fast((unsigned long)ptep_user, 1, FOLL_WRITE, &page);
 	/* Check if the user is doing something meaningless. */
 	if (unlikely(npages != 1))
 		return -EFAULT;

arch/x86/kvm/svm.c

@@ -1805,7 +1805,7 @@ static struct page **sev_pin_memory(struct kvm *kvm, unsigned long uaddr,
 		return NULL;
 
 	/* Pin the user virtual address. */
-	npinned = get_user_pages_fast(uaddr, npages, write ? FOLL_WRITE : 0, pages);
+	npinned = get_user_pages_fast(uaddr, npages, FOLL_WRITE, pages);
 	if (npinned != npages) {
 		pr_err("SEV: Failure locking %lu pages.\n", npages);
 		goto err;

drivers/fpga/dfl-afu-dma-region.c

@@ -102,7 +102,7 @@ static int afu_dma_pin_pages(struct dfl_feature_platform_data *pdata,
 		goto unlock_vm;
 	}
 
-	pinned = get_user_pages_fast(region->user_addr, npages, 1,
+	pinned = get_user_pages_fast(region->user_addr, npages, FOLL_WRITE,
 				     region->pages);
 	if (pinned < 0) {
 		ret = pinned;

drivers/gpu/drm/via/via_dmablit.c

@@ -243,7 +243,8 @@ via_lock_all_dma_pages(drm_via_sg_info_t *vsg,  drm_via_dmablit_t *xfer)
 	if (NULL == vsg->pages)
 		return -ENOMEM;
 	ret = get_user_pages_fast((unsigned long)xfer->mem_addr,
-			vsg->num_pages, vsg->direction == DMA_FROM_DEVICE,
+			vsg->num_pages,
+			vsg->direction == DMA_FROM_DEVICE ? FOLL_WRITE : 0,
 			vsg->pages);
 	if (ret != vsg->num_pages) {
 		if (ret < 0)

drivers/infiniband/hw/hfi1/user_pages.c

@@ -105,7 +105,8 @@ int hfi1_acquire_user_pages(struct mm_struct *mm, unsigned long vaddr, size_t np
 {
 	int ret;
 
-	ret = get_user_pages_fast(vaddr, npages, writable, pages);
+	ret = get_user_pages_fast(vaddr, npages, writable ? FOLL_WRITE : 0,
+				  pages);
 	if (ret < 0)
 		return ret;
 

drivers/misc/genwqe/card_utils.c

@@ -603,7 +603,7 @@ int genwqe_user_vmap(struct genwqe_dev *cd, struct dma_mapping *m, void *uaddr,
 	/* pin user pages in memory */
 	rc = get_user_pages_fast(data & PAGE_MASK, /* page aligned addr */
 				 m->nr_pages,
-				 m->write,		/* readable/writable */
+				 m->write ? FOLL_WRITE : 0,	/* readable/writable */
 				 m->page_list);	/* ptrs to pages */
 	if (rc < 0)
 		goto fail_get_user_pages;

drivers/misc/vmw_vmci/vmci_host.c

@@ -242,7 +242,7 @@ static int vmci_host_setup_notify(struct vmci_ctx *context,
 	/*
 	 * Lock physical page backing a given user VA.
 	 */
-	retval = get_user_pages_fast(uva, 1, 1, &context->notify_page);
+	retval = get_user_pages_fast(uva, 1, FOLL_WRITE, &context->notify_page);
 	if (retval != 1) {
 		context->notify_page = NULL;
 		return VMCI_ERROR_GENERIC;

drivers/misc/vmw_vmci/vmci_queue_pair.c

@@ -659,7 +659,8 @@ static int qp_host_get_user_memory(u64 produce_uva,
 	int err = VMCI_SUCCESS;
 
 	retval = get_user_pages_fast((uintptr_t) produce_uva,
-				     produce_q->kernel_if->num_pages, 1,
+				     produce_q->kernel_if->num_pages,
+				     FOLL_WRITE,
 				     produce_q->kernel_if->u.h.header_page);
 	if (retval < (int)produce_q->kernel_if->num_pages) {
 		pr_debug("get_user_pages_fast(produce) failed (retval=%d)",
@@ -671,7 +672,8 @@ static int qp_host_get_user_memory(u64 produce_uva,
 	}
 
 	retval = get_user_pages_fast((uintptr_t) consume_uva,
-				     consume_q->kernel_if->num_pages, 1,
+				     consume_q->kernel_if->num_pages,
+				     FOLL_WRITE,
 				     consume_q->kernel_if->u.h.header_page);
 	if (retval < (int)consume_q->kernel_if->num_pages) {
 		pr_debug("get_user_pages_fast(consume) failed (retval=%d)",

drivers/platform/goldfish/goldfish_pipe.c

@@ -274,7 +274,8 @@ static int pin_user_pages(unsigned long first_page,
 		*iter_last_page_size = last_page_size;
 	}
 
-	ret = get_user_pages_fast(first_page, requested_pages, !is_write,
+	ret = get_user_pages_fast(first_page, requested_pages,
+				  !is_write ? FOLL_WRITE : 0,
 				  pages);
 	if (ret <= 0)
 		return -EFAULT;

drivers/rapidio/devices/rio_mport_cdev.c

@@ -868,7 +868,9 @@ rio_dma_transfer(struct file *filp, u32 transfer_mode,
 
 		pinned = get_user_pages_fast(
 				(unsigned long)xfer->loc_addr & PAGE_MASK,
-				nr_pages, dir == DMA_FROM_DEVICE, page_list);
+				nr_pages,
+				dir == DMA_FROM_DEVICE ? FOLL_WRITE : 0,
+				page_list);
 
 		if (pinned != nr_pages) {
 			if (pinned < 0) {

drivers/sbus/char/oradax.c

@@ -437,7 +437,7 @@ static int dax_lock_page(void *va, struct page **p)
 
 	dax_dbg("uva %p", va);
 
-	ret = get_user_pages_fast((unsigned long)va, 1, 1, p);
+	ret = get_user_pages_fast((unsigned long)va, 1, FOLL_WRITE, p);
 	if (ret == 1) {
 		dax_dbg("locked page %p, for VA %p", *p, va);
 		return 0;

drivers/scsi/st.c

@@ -4922,7 +4922,8 @@ static int sgl_map_user_pages(struct st_buffer *STbp,
 
         /* Try to fault in all of the necessary pages */
         /* rw==READ means read from drive, write into memory area */
-	res = get_user_pages_fast(uaddr, nr_pages, rw == READ, pages);
+	res = get_user_pages_fast(uaddr, nr_pages, rw == READ ? FOLL_WRITE : 0,
+				  pages);
 
 	/* Errors and no page mapped should return here */
 	if (res < nr_pages)

drivers/staging/gasket/gasket_page_table.c

@@ -486,8 +486,8 @@ static int gasket_perform_mapping(struct gasket_page_table *pg_tbl,
 			ptes[i].dma_addr = pg_tbl->coherent_pages[0].paddr +
 					   off + i * PAGE_SIZE;
 		} else {
-			ret = get_user_pages_fast(page_addr - offset, 1, 1,
-						  &page);
+			ret = get_user_pages_fast(page_addr - offset, 1,
+						  FOLL_WRITE, &page);
 
 			if (ret <= 0) {
 				dev_err(pg_tbl->device,

drivers/tee/tee_shm.c

@@ -273,7 +273,7 @@ struct tee_shm *tee_shm_register(struct tee_context *ctx, unsigned long addr,
 		goto err;
 	}
 
-	rc = get_user_pages_fast(start, num_pages, 1, shm->pages);
+	rc = get_user_pages_fast(start, num_pages, FOLL_WRITE, shm->pages);
 	if (rc > 0)
 		shm->num_pages = rc;
 	if (rc != num_pages) {

drivers/vfio/vfio_iommu_spapr_tce.c

@@ -532,7 +532,8 @@ static int tce_iommu_use_page(unsigned long tce, unsigned long *hpa)
 	enum dma_data_direction direction = iommu_tce_direction(tce);
 
 	if (get_user_pages_fast(tce & PAGE_MASK, 1,
-			direction != DMA_TO_DEVICE, &page) != 1)
+			direction != DMA_TO_DEVICE ? FOLL_WRITE : 0,
+			&page) != 1)
 		return -EFAULT;
 
 	*hpa = __pa((unsigned long) page_address(page));

drivers/vhost/vhost.c

@@ -1704,7 +1704,7 @@ static int set_bit_to_user(int nr, void __user *addr)
 	int bit = nr + (log % PAGE_SIZE) * 8;
 	int r;
 
-	r = get_user_pages_fast(log, 1, 1, &page);
+	r = get_user_pages_fast(log, 1, FOLL_WRITE, &page);
 	if (r < 0)
 		return r;
 	BUG_ON(r != 1);

drivers/video/fbdev/pvr2fb.c

@@ -686,7 +686,7 @@ static ssize_t pvr2fb_write(struct fb_info *info, const char *buf,
 	if (!pages)
 		return -ENOMEM;
 
-	ret = get_user_pages_fast((unsigned long)buf, nr_pages, true, pages);
+	ret = get_user_pages_fast((unsigned long)buf, nr_pages, FOLL_WRITE, pages);
 	if (ret < nr_pages) {
 		nr_pages = ret;
 		ret = -EINVAL;

drivers/virt/fsl_hypervisor.c

@@ -244,7 +244,7 @@ static long ioctl_memcpy(struct fsl_hv_ioctl_memcpy __user *p)
 
 	/* Get the physical addresses of the source buffer */
 	num_pinned = get_user_pages_fast(param.local_vaddr - lb_offset,
-		num_pages, param.source != -1, pages);
+		num_pages, param.source != -1 ? FOLL_WRITE : 0, pages);
 
 	if (num_pinned != num_pages) {
 		/* get_user_pages() failed */

drivers/xen/gntdev.c

@@ -852,7 +852,7 @@ static int gntdev_get_page(struct gntdev_copy_batch *batch, void __user *virt,
 	unsigned long xen_pfn;
 	int ret;
 
-	ret = get_user_pages_fast(addr, 1, writeable, &page);
+	ret = get_user_pages_fast(addr, 1, writeable ? FOLL_WRITE : 0, &page);
 	if (ret < 0)
 		return ret;
 

fs/orangefs/orangefs-bufmap.c

@@ -269,7 +269,7 @@ orangefs_bufmap_map(struct orangefs_bufmap *bufmap,
 
 	/* map the pages */
 	ret = get_user_pages_fast((unsigned long)user_desc->ptr,
-			     bufmap->page_count, 1, bufmap->page_array);
+			     bufmap->page_count, FOLL_WRITE, bufmap->page_array);
 
 	if (ret < 0)
 		return ret;

include/linux/mm.h

@@ -1505,8 +1505,8 @@ long get_user_pages_locked(unsigned long start, unsigned long nr_pages,
 long get_user_pages_unlocked(unsigned long start, unsigned long nr_pages,
 		    struct page **pages, unsigned int gup_flags);
 
-int get_user_pages_fast(unsigned long start, int nr_pages, int write,
-			struct page **pages);
+int get_user_pages_fast(unsigned long start, int nr_pages,
+			unsigned int gup_flags, struct page **pages);
 
 /* Container for pinned pfns / pages */
 struct frame_vector {

kernel/futex.c

@@ -543,7 +543,7 @@ get_futex_key(u32 __user *uaddr, int fshared, union futex_key *key, enum futex_a
 	if (unlikely(should_fail_futex(fshared)))
 		return -EFAULT;
 
-	err = get_user_pages_fast(address, 1, 1, &page);
+	err = get_user_pages_fast(address, 1, FOLL_WRITE, &page);
 	/*
 	 * If write access is not required (eg. FUTEX_WAIT), try
 	 * and get read-only access.

lib/iov_iter.c

@@ -1293,7 +1293,9 @@ ssize_t iov_iter_get_pages(struct iov_iter *i,
 			len = maxpages * PAGE_SIZE;
 		addr &= ~(PAGE_SIZE - 1);
 		n = DIV_ROUND_UP(len, PAGE_SIZE);
-		res = get_user_pages_fast(addr, n, iov_iter_rw(i) != WRITE, pages);
+		res = get_user_pages_fast(addr, n,
+				iov_iter_rw(i) != WRITE ?  FOLL_WRITE : 0,
+				pages);
 		if (unlikely(res < 0))
 			return res;
 		return (res == n ? len : res * PAGE_SIZE) - *start;
@@ -1374,7 +1376,8 @@ ssize_t iov_iter_get_pages_alloc(struct iov_iter *i,
 		p = get_pages_array(n);
 		if (!p)
 			return -ENOMEM;
-		res = get_user_pages_fast(addr, n, iov_iter_rw(i) != WRITE, p);
+		res = get_user_pages_fast(addr, n,
+				iov_iter_rw(i) != WRITE ?  FOLL_WRITE : 0, p);
 		if (unlikely(res < 0)) {
 			kvfree(p);
 			return res;