[PATCH V2 0/7] Add FOLL_LONGTERM to GUP fast and use it

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ira.weiny＠intel.com

13 Feb 2019 13 Feb '19

11:04 p.m.

From: Ira Weiny ira.weiny@intel.com

NOTE: This series depends on my clean up patch to remove the write parameter from gup_fast_permitted()[1]

HFI1, qib, and mthca, use get_user_pages_fast() due to it performance advantages. These pages can be held for a significant time. But get_user_pages_fast() does not protect against mapping of FS DAX pages.

Introduce FOLL_LONGTERM and use this flag in get_user_pages_fast() which retains the performance while also adding the FS DAX checks. XDP has also shown interest in using this functionality.[2]

In addition we change get_user_pages() to use the new FOLL_LONGTERM flag and remove the specialized get_user_pages_longterm call.

[1] https://lkml.org/lkml/2019/2/11/237 [2] https://lkml.org/lkml/2019/2/11/1789

Ira Weiny (7): mm/gup: Replace get_user_pages_longterm() with FOLL_LONGTERM mm/gup: Change write parameter to flags in fast walk mm/gup: Change GUP fast to use flags rather than a write 'bool' mm/gup: Add FOLL_LONGTERM capability to GUP fast IB/hfi1: Use the new FOLL_LONGTERM flag to get_user_pages_fast() IB/qib: Use the new FOLL_LONGTERM flag to get_user_pages_fast() IB/mthca: Use the new FOLL_LONGTERM flag to get_user_pages_fast()

-- 2.20.1

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ira.weiny＠intel.com

13 Feb 13 Feb

11:04 p.m.

New subject: [PATCH V2 1/7] mm/gup: Replace get_user_pages_longterm() with FOLL_LONGTERM

From: Ira Weiny ira.weiny@intel.com

Rather than have a separate get_user_pages_longterm() call, introduce FOLL_LONGTERM and change the longterm callers to use it.

This patch does not change any functionality.

FOLL_LONGTERM can only be supported with get_user_pages() as it requires vmas to determine if DAX is in use.

Signed-off-by: Ira Weiny ira.weiny@intel.com --- drivers/infiniband/core/umem.c | 5 +- drivers/infiniband/hw/qib/qib_user_pages.c | 8 +- drivers/infiniband/hw/usnic/usnic_uiom.c | 9 +- drivers/media/v4l2-core/videobuf-dma-sg.c | 6 +- drivers/vfio/vfio_iommu_type1.c | 3 +- include/linux/mm.h | 13 +- mm/gup.c | 138 ++++++++++++--------- mm/gup_benchmark.c | 5 +- 8 files changed, 101 insertions(+), 86 deletions(-)

diff --git a/drivers/infiniband/core/umem.c b/drivers/infiniband/core/umem.c index b69d3efa8712..120a40df91b4 100644 --- a/drivers/infiniband/core/umem.c +++ b/drivers/infiniband/core/umem.c @@ -185,10 +185,11 @@ struct ib_umem *ib_umem_get(struct ib_udata *udata, unsigned long addr,

while (npages) { down_read(&mm->mmap_sem); - ret = get_user_pages_longterm(cur_base, + ret = get_user_pages(cur_base, min_t(unsigned long, npages, PAGE_SIZE / sizeof (struct page *)), - gup_flags, page_list, vma_list); + gup_flags | FOLL_LONGTERM, + page_list, vma_list); if (ret < 0) { up_read(&mm->mmap_sem); goto umem_release; diff --git a/drivers/infiniband/hw/qib/qib_user_pages.c b/drivers/infiniband/hw/qib/qib_user_pages.c index ef8bcf366ddc..1b9368261035 100644 --- a/drivers/infiniband/hw/qib/qib_user_pages.c +++ b/drivers/infiniband/hw/qib/qib_user_pages.c @@ -114,10 +114,10 @@ int qib_get_user_pages(unsigned long start_page, size_t num_pages,

down_read(&current->mm->mmap_sem); for (got = 0; got < num_pages; got += ret) { - ret = get_user_pages_longterm(start_page + got * PAGE_SIZE, - num_pages - got, - FOLL_WRITE | FOLL_FORCE, - p + got, NULL); + ret = get_user_pages(start_page + got * PAGE_SIZE, + num_pages - got, + FOLL_LONGTERM | FOLL_WRITE | FOLL_FORCE, + p + got, NULL); if (ret < 0) { up_read(&current->mm->mmap_sem); goto bail_release; diff --git a/drivers/infiniband/hw/usnic/usnic_uiom.c b/drivers/infiniband/hw/usnic/usnic_uiom.c index 06862a6af185..1d9a182ac163 100644 --- a/drivers/infiniband/hw/usnic/usnic_uiom.c +++ b/drivers/infiniband/hw/usnic/usnic_uiom.c @@ -143,10 +143,11 @@ static int usnic_uiom_get_pages(unsigned long addr, size_t size, int writable, ret = 0;

while (npages) { - ret = get_user_pages_longterm(cur_base, - min_t(unsigned long, npages, - PAGE_SIZE / sizeof(struct page *)), - gup_flags, page_list, NULL); + ret = get_user_pages(cur_base, + min_t(unsigned long, npages, + PAGE_SIZE / sizeof(struct page *)), + gup_flags | FOLL_LONGTERM, + 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 08929c087e27..870a2a526e0b 100644 --- a/drivers/media/v4l2-core/videobuf-dma-sg.c +++ b/drivers/media/v4l2-core/videobuf-dma-sg.c @@ -186,12 +186,12 @@ static int videobuf_dma_init_user_locked(struct videobuf_dmabuf *dma, dprintk(1, "init user [0x%lx+0x%lx => %d pages]\n", data, size, dma->nr_pages);

- err = get_user_pages_longterm(data & PAGE_MASK, dma->nr_pages, - flags, dma->pages, NULL); + err = get_user_pages(data & PAGE_MASK, dma->nr_pages, + flags | FOLL_LONGTERM, dma->pages, NULL);

if (err != dma->nr_pages) { dma->nr_pages = (err >= 0) ? err : 0; - dprintk(1, "get_user_pages_longterm: err=%d [%d]\n", err, + dprintk(1, "get_user_pages: err=%d [%d]\n", err, dma->nr_pages); return err < 0 ? err : -EINVAL; } diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c index 73652e21efec..1500bd0bb6da 100644 --- a/drivers/vfio/vfio_iommu_type1.c +++ b/drivers/vfio/vfio_iommu_type1.c @@ -351,7 +351,8 @@ static int vaddr_get_pfn(struct mm_struct *mm, unsigned long vaddr,

down_read(&mm->mmap_sem); if (mm == current->mm) { - ret = get_user_pages_longterm(vaddr, 1, flags, page, vmas); + ret = get_user_pages(vaddr, 1, flags | FOLL_LONGTERM, page, + vmas); } else { ret = get_user_pages_remote(NULL, mm, vaddr, 1, flags, page, vmas, NULL); diff --git a/include/linux/mm.h b/include/linux/mm.h index 80bb6408fe73..05a105d9d4c3 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1536,18 +1536,6 @@ long get_user_pages_locked(unsigned long start, unsigned long nr_pages, unsigned int gup_flags, struct page **pages, int *locked); long get_user_pages_unlocked(unsigned long start, unsigned long nr_pages, struct page **pages, unsigned int gup_flags); -#ifdef CONFIG_FS_DAX -long get_user_pages_longterm(unsigned long start, unsigned long nr_pages, - unsigned int gup_flags, struct page **pages, - struct vm_area_struct **vmas); -#else -static inline long get_user_pages_longterm(unsigned long start, - unsigned long nr_pages, unsigned int gup_flags, - struct page **pages, struct vm_area_struct **vmas) -{ - return get_user_pages(start, nr_pages, gup_flags, pages, vmas); -} -#endif /* CONFIG_FS_DAX */

int get_user_pages_fast(unsigned long start, int nr_pages, int write, struct page **pages); @@ -2615,6 +2603,7 @@ struct page *follow_page(struct vm_area_struct *vma, unsigned long address, #define FOLL_REMOTE 0x2000 /* we are working on non-current tsk/mm */ #define FOLL_COW 0x4000 /* internal GUP flag */ #define FOLL_ANON 0x8000 /* don't do file mappings */ +#define FOLL_LONGTERM 0x10000 /* mapping is intended for a long term pin */

static inline int vm_fault_to_errno(vm_fault_t vm_fault, int foll_flags) { diff --git a/mm/gup.c b/mm/gup.c index b63e88eca31b..ee96eaff118c 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -1109,87 +1109,109 @@ long get_user_pages_remote(struct task_struct *tsk, struct mm_struct *mm, } EXPORT_SYMBOL(get_user_pages_remote);

-/* - * This is the same as get_user_pages_remote(), just with a - * less-flexible calling convention where we assume that the task - * and mm being operated on are the current task's and don't allow - * passing of a locked parameter. We also obviously don't pass - * FOLL_REMOTE in here. - */ -long get_user_pages(unsigned long start, unsigned long nr_pages, - unsigned int gup_flags, struct page **pages, - struct vm_area_struct **vmas) -{ - return __get_user_pages_locked(current, current->mm, start, nr_pages, - pages, vmas, NULL, - gup_flags | FOLL_TOUCH); -} -EXPORT_SYMBOL(get_user_pages); - #ifdef CONFIG_FS_DAX /* - * This is the same as get_user_pages() in that it assumes we are - * operating on the current task's mm, but it goes further to validate - * that the vmas associated with the address range are suitable for - * longterm elevated page reference counts. For example, filesystem-dax - * mappings are subject to the lifetime enforced by the filesystem and - * we need guarantees that longterm users like RDMA and V4L2 only - * establish mappings that have a kernel enforced revocation mechanism. + * __gup_longterm_locked() is a wrapper for __get_uer_pages_locked which + * allows us to process the FOLL_LONGTERM flag if present. + * + * __gup_longterm_locked() validates that the vmas associated with the address + * range are suitable for longterm elevated page reference counts. For example, + * filesystem-dax mappings are subject to the lifetime enforced by the + * filesystem and we need guarantees that longterm users like RDMA and V4L2 + * only establish mappings that have a kernel enforced revocation mechanism. * * "longterm" == userspace controlled elevated page count lifetime. * Contrast this to iov_iter_get_pages() usages which are transient. */ -long get_user_pages_longterm(unsigned long start, unsigned long nr_pages, - unsigned int gup_flags, struct page **pages, - struct vm_area_struct **vmas_arg) +static __always_inline long __gup_longterm_locked(struct task_struct *tsk, + struct mm_struct *mm, + unsigned long start, + unsigned long nr_pages, + struct page **pages, + struct vm_area_struct **vmas, + unsigned int flags) { - struct vm_area_struct **vmas = vmas_arg; + struct vm_area_struct **vmas_tmp = vmas; struct vm_area_struct *vma_prev = NULL; long rc, i;

- if (!pages) - return -EINVAL; - - if (!vmas) { - vmas = kcalloc(nr_pages, sizeof(struct vm_area_struct *), - GFP_KERNEL); - if (!vmas) - return -ENOMEM; + if (flags & FOLL_LONGTERM) { + if (!pages) + return -EINVAL; + + if (!vmas_tmp) { + vmas_tmp = kcalloc(nr_pages, + sizeof(struct vm_area_struct *), + GFP_KERNEL); + if (!vmas_tmp) + return -ENOMEM; + } }

- rc = get_user_pages(start, nr_pages, gup_flags, pages, vmas); + rc = __get_user_pages_locked(tsk, mm, start, nr_pages, pages, + vmas_tmp, NULL, flags);

- for (i = 0; i < rc; i++) { - struct vm_area_struct *vma = vmas[i]; + if (flags & FOLL_LONGTERM) { + for (i = 0; i < rc; i++) { + struct vm_area_struct *vma = vmas_tmp[i];

- if (vma == vma_prev) - continue; + if (vma == vma_prev) + continue;

- vma_prev = vma; + vma_prev = vma;

- if (vma_is_fsdax(vma)) - break; - } + if (vma_is_fsdax(vma)) + break; + }

- /* - * Either get_user_pages() failed, or the vma validation - * succeeded, in either case we don't need to put_page() before - * returning. - */ - if (i >= rc) - goto out; + /* + * Either get_user_pages() failed, or the vma validation + * succeeded, in either case we don't need to put_page() before + * returning. + */ + if (i >= rc) + goto out;

- for (i = 0; i < rc; i++) - put_page(pages[i]); - rc = -EOPNOTSUPP; + for (i = 0; i < rc; i++) + put_page(pages[i]); + rc = -EOPNOTSUPP; out: - if (vmas != vmas_arg) - kfree(vmas); + if (vmas_tmp != vmas) + kfree(vmas_tmp); + } + return rc; } -EXPORT_SYMBOL(get_user_pages_longterm); +#else /* !CONFIG_FS_DAX */ +static __always_inline long __gup_longterm_locked(struct task_struct *tsk, + struct mm_struct *mm, + unsigned long start, + unsigned long nr_pages, + struct page **pages, + struct vm_area_struct **vmas, + unsigned int flags) +{ + return __get_user_pages_locked(tsk, mm, start, nr_pages, pages, vmas, + NULL, flags); +} #endif /* CONFIG_FS_DAX */

+/* + * This is the same as get_user_pages_remote(), just with a + * less-flexible calling convention where we assume that the task + * and mm being operated on are the current task's and don't allow + * passing of a locked parameter. We also obviously don't pass + * FOLL_REMOTE in here. + */ +long get_user_pages(unsigned long start, unsigned long nr_pages, + unsigned int gup_flags, struct page **pages, + struct vm_area_struct **vmas) +{ + return __gup_longterm_locked(current, current->mm, start, nr_pages, + pages, vmas, gup_flags | FOLL_TOUCH); +} +EXPORT_SYMBOL(get_user_pages); + /** * populate_vma_page_range() - populate a range of pages in the vma. * @vma: target vma diff --git a/mm/gup_benchmark.c b/mm/gup_benchmark.c index 5b42d3d4b60a..c898e2e0d1e4 100644 --- a/mm/gup_benchmark.c +++ b/mm/gup_benchmark.c @@ -54,8 +54,9 @@ static int __gup_benchmark_ioctl(unsigned int cmd, pages + i); break; case GUP_LONGTERM_BENCHMARK: - nr = get_user_pages_longterm(addr, nr, gup->flags & 1, - pages + i, NULL); + nr = get_user_pages(addr, nr, + (gup->flags & 1) | FOLL_LONGTERM, + pages + i, NULL); break; case GUP_BENCHMARK: nr = get_user_pages(addr, nr, gup->flags & 1, pages + i,

-- 2.20.1

ira.weiny＠intel.com

11:04 p.m.

New subject: [PATCH V2 2/7] mm/gup: Change write parameter to flags in fast walk

From: Ira Weiny ira.weiny@intel.com

In order to support more options in the GUP fast walk, change the write parameter to flags throughout the call stack.

This patch does not change functionality and passes FOLL_WRITE where write was previously used.

Signed-off-by: Ira Weiny ira.weiny@intel.com --- mm/gup.c | 52 ++++++++++++++++++++++++++-------------------------- 1 file changed, 26 insertions(+), 26 deletions(-)

diff --git a/mm/gup.c b/mm/gup.c index ee96eaff118c..681388236106 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -1417,7 +1417,7 @@ static void undo_dev_pagemap(int *nr, int nr_start, struct page **pages)

#ifdef CONFIG_ARCH_HAS_PTE_SPECIAL static int gup_pte_range(pmd_t pmd, unsigned long addr, unsigned long end, - int write, struct page **pages, int *nr) + unsigned int flags, struct page **pages, int *nr) { struct dev_pagemap *pgmap = NULL; int nr_start = *nr, ret = 0; @@ -1435,7 +1435,7 @@ static int gup_pte_range(pmd_t pmd, unsigned long addr, unsigned long end, if (pte_protnone(pte)) goto pte_unmap;

- if (!pte_access_permitted(pte, write)) + if (!pte_access_permitted(pte, flags & FOLL_WRITE)) goto pte_unmap;

if (pte_devmap(pte)) { @@ -1487,7 +1487,7 @@ static int gup_pte_range(pmd_t pmd, unsigned long addr, unsigned long end, * useful to have gup_huge_pmd even if we can't operate on ptes. */ static int gup_pte_range(pmd_t pmd, unsigned long addr, unsigned long end, - int write, struct page **pages, int *nr) + unsigned int flags, struct page **pages, int *nr) { return 0; } @@ -1570,12 +1570,12 @@ static int __gup_device_huge_pud(pud_t pud, pud_t *pudp, unsigned long addr, #endif

static int gup_huge_pmd(pmd_t orig, pmd_t *pmdp, unsigned long addr, - unsigned long end, int write, struct page **pages, int *nr) + unsigned long end, unsigned int flags, struct page **pages, int *nr) { struct page *head, *page; int refs;

- if (!pmd_access_permitted(orig, write)) + if (!pmd_access_permitted(orig, flags & FOLL_WRITE)) return 0;

if (pmd_devmap(orig)) @@ -1608,12 +1608,12 @@ static int gup_huge_pmd(pmd_t orig, pmd_t *pmdp, unsigned long addr, }

static int gup_huge_pud(pud_t orig, pud_t *pudp, unsigned long addr, - unsigned long end, int write, struct page **pages, int *nr) + unsigned long end, unsigned int flags, struct page **pages, int *nr) { struct page *head, *page; int refs;

- if (!pud_access_permitted(orig, write)) + if (!pud_access_permitted(orig, flags & FOLL_WRITE)) return 0;

if (pud_devmap(orig)) @@ -1646,13 +1646,13 @@ static int gup_huge_pud(pud_t orig, pud_t *pudp, unsigned long addr, }

static int gup_huge_pgd(pgd_t orig, pgd_t *pgdp, unsigned long addr, - unsigned long end, int write, + unsigned long end, unsigned int flags, struct page **pages, int *nr) { int refs; struct page *head, *page;

- if (!pgd_access_permitted(orig, write)) + if (!pgd_access_permitted(orig, flags & FOLL_WRITE)) return 0;

BUILD_BUG_ON(pgd_devmap(orig)); @@ -1683,7 +1683,7 @@ static int gup_huge_pgd(pgd_t orig, pgd_t *pgdp, unsigned long addr, }

static int gup_pmd_range(pud_t pud, unsigned long addr, unsigned long end, - int write, struct page **pages, int *nr) + unsigned int flags, struct page **pages, int *nr) { unsigned long next; pmd_t *pmdp; @@ -1705,7 +1705,7 @@ static int gup_pmd_range(pud_t pud, unsigned long addr, unsigned long end, if (pmd_protnone(pmd)) return 0;

- if (!gup_huge_pmd(pmd, pmdp, addr, next, write, + if (!gup_huge_pmd(pmd, pmdp, addr, next, flags, pages, nr)) return 0;

@@ -1715,9 +1715,9 @@ static int gup_pmd_range(pud_t pud, unsigned long addr, unsigned long end, * pmd format and THP pmd format */ if (!gup_huge_pd(__hugepd(pmd_val(pmd)), addr, - PMD_SHIFT, next, write, pages, nr)) + PMD_SHIFT, next, flags, pages, nr)) return 0; - } else if (!gup_pte_range(pmd, addr, next, write, pages, nr)) + } else if (!gup_pte_range(pmd, addr, next, flags, pages, nr)) return 0; } while (pmdp++, addr = next, addr != end);

@@ -1725,7 +1725,7 @@ static int gup_pmd_range(pud_t pud, unsigned long addr, unsigned long end, }

static int gup_pud_range(p4d_t p4d, unsigned long addr, unsigned long end, - int write, struct page **pages, int *nr) + unsigned int flags, struct page **pages, int *nr) { unsigned long next; pud_t *pudp; @@ -1738,14 +1738,14 @@ static int gup_pud_range(p4d_t p4d, unsigned long addr, unsigned long end, if (pud_none(pud)) return 0; if (unlikely(pud_huge(pud))) { - if (!gup_huge_pud(pud, pudp, addr, next, write, + if (!gup_huge_pud(pud, pudp, addr, next, flags, pages, nr)) return 0; } else if (unlikely(is_hugepd(__hugepd(pud_val(pud))))) { if (!gup_huge_pd(__hugepd(pud_val(pud)), addr, - PUD_SHIFT, next, write, pages, nr)) + PUD_SHIFT, next, flags, pages, nr)) return 0; - } else if (!gup_pmd_range(pud, addr, next, write, pages, nr)) + } else if (!gup_pmd_range(pud, addr, next, flags, pages, nr)) return 0; } while (pudp++, addr = next, addr != end);

@@ -1753,7 +1753,7 @@ static int gup_pud_range(p4d_t p4d, unsigned long addr, unsigned long end, }

static int gup_p4d_range(pgd_t pgd, unsigned long addr, unsigned long end, - int write, struct page **pages, int *nr) + unsigned int flags, struct page **pages, int *nr) { unsigned long next; p4d_t *p4dp; @@ -1768,9 +1768,9 @@ static int gup_p4d_range(pgd_t pgd, unsigned long addr, unsigned long end, BUILD_BUG_ON(p4d_huge(p4d)); if (unlikely(is_hugepd(__hugepd(p4d_val(p4d))))) { if (!gup_huge_pd(__hugepd(p4d_val(p4d)), addr, - P4D_SHIFT, next, write, pages, nr)) + P4D_SHIFT, next, flags, pages, nr)) return 0; - } else if (!gup_pud_range(p4d, addr, next, write, pages, nr)) + } else if (!gup_pud_range(p4d, addr, next, flags, pages, nr)) return 0; } while (p4dp++, addr = next, addr != end);

@@ -1778,7 +1778,7 @@ static int gup_p4d_range(pgd_t pgd, unsigned long addr, unsigned long end, }

static void gup_pgd_range(unsigned long addr, unsigned long end, - int write, struct page **pages, int *nr) + unsigned int flags, struct page **pages, int *nr) { unsigned long next; pgd_t *pgdp; @@ -1791,14 +1791,14 @@ static void gup_pgd_range(unsigned long addr, unsigned long end, if (pgd_none(pgd)) return; if (unlikely(pgd_huge(pgd))) { - if (!gup_huge_pgd(pgd, pgdp, addr, next, write, + if (!gup_huge_pgd(pgd, pgdp, addr, next, flags, pages, nr)) return; } else if (unlikely(is_hugepd(__hugepd(pgd_val(pgd))))) { if (!gup_huge_pd(__hugepd(pgd_val(pgd)), addr, - PGDIR_SHIFT, next, write, pages, nr)) + PGDIR_SHIFT, next, flags, pages, nr)) return; - } else if (!gup_p4d_range(pgd, addr, next, write, pages, nr)) + } else if (!gup_p4d_range(pgd, addr, next, flags, pages, nr)) return; } while (pgdp++, addr = next, addr != end); } @@ -1852,7 +1852,7 @@ int __get_user_pages_fast(unsigned long start, int nr_pages, int write,

if (gup_fast_permitted(start, nr_pages)) { local_irq_save(flags); - gup_pgd_range(start, end, write, pages, &nr); + gup_pgd_range(start, end, write ? FOLL_WRITE : 0, pages, &nr); local_irq_restore(flags); }

@@ -1894,7 +1894,7 @@ int get_user_pages_fast(unsigned long start, int nr_pages, int write,

if (gup_fast_permitted(start, nr_pages)) { local_irq_disable(); - gup_pgd_range(addr, end, write, pages, &nr); + gup_pgd_range(addr, end, write ? FOLL_WRITE : 0, pages, &nr); local_irq_enable(); ret = nr; }

-- 2.20.1

ira.weiny＠intel.com

11:04 p.m.

New subject: [PATCH V2 3/7] mm/gup: Change GUP fast to use flags rather than a write 'bool'

From: Ira Weiny ira.weiny@intel.com

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.

diff --git a/arch/mips/mm/gup.c b/arch/mips/mm/gup.c index 0d14e0d8eacf..4c2b4483683c 100644 --- a/arch/mips/mm/gup.c +++ b/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) { diff --git a/arch/powerpc/kvm/book3s_64_mmu_hv.c b/arch/powerpc/kvm/book3s_64_mmu_hv.c index bd2dcfbf00cd..8fcb0a921e46 100644 --- a/arch/powerpc/kvm/book3s_64_mmu_hv.c +++ b/arch/powerpc/kvm/book3s_64_mmu_hv.c @@ -582,7 +582,7 @@ 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); @@ -1175,7 +1175,7 @@ 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]; diff --git a/arch/powerpc/kvm/e500_mmu.c b/arch/powerpc/kvm/e500_mmu.c index 24296f4cadc6..e0af53fd78c5 100644 --- a/arch/powerpc/kvm/e500_mmu.c +++ b/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;

diff --git a/arch/powerpc/mm/mmu_context_iommu.c b/arch/powerpc/mm/mmu_context_iommu.c index a712a650a8b6..acb0990c8364 100644 --- a/arch/powerpc/mm/mmu_context_iommu.c +++ b/arch/powerpc/mm/mmu_context_iommu.c @@ -190,7 +190,7 @@ static long mm_iommu_do_alloc(struct mm_struct *mm, unsigned long ua, for (i = 0; i < entries; ++i) { cur_ua = ua + (i << PAGE_SHIFT); if (1 != get_user_pages_fast(cur_ua, - 1/* pages */, 1/* iswrite */, &page)) { + 1/* pages */, FOLL_WRITE, &page)) { ret = -EFAULT; for (j = 0; j < i; ++j) put_page(pfn_to_page(mem->hpas[j] >> @@ -209,7 +209,7 @@ static long mm_iommu_do_alloc(struct mm_struct *mm, unsigned long ua, if (mm_iommu_move_page_from_cma(page)) goto populate; if (1 != get_user_pages_fast(cur_ua, - 1/* pages */, 1/* iswrite */, + 1/* pages */, FOLL_WRITE, &page)) { ret = -EFAULT; for (j = 0; j < i; ++j) diff --git a/arch/s390/kvm/interrupt.c b/arch/s390/kvm/interrupt.c index fcb55b02990e..69d9366b966c 100644 --- a/arch/s390/kvm/interrupt.c +++ b/arch/s390/kvm/interrupt.c @@ -2278,7 +2278,7 @@ 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); diff --git a/arch/s390/mm/gup.c b/arch/s390/mm/gup.c index 2809d11c7a28..0a6faf3d9960 100644 --- a/arch/s390/mm/gup.c +++ b/arch/s390/mm/gup.c @@ -265,7 +265,7 @@ 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. * @@ -277,22 +277,22 @@ 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) { int nr, ret;

might_sleep(); start &= PAGE_MASK; - nr = __get_user_pages_fast(start, nr_pages, write, pages); + nr = __get_user_pages_fast(start, nr_pages, gup_flags & FOLL_WRITE, + pages); if (nr == nr_pages) return nr;

/* 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, pages, - write ? FOLL_WRITE : 0); + ret = get_user_pages_unlocked(start, nr_pages - nr, pages, gup_flags); /* 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 3e27f6d1f1ec..277c882f7489 100644 --- a/arch/sh/mm/gup.c +++ b/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) { diff --git a/arch/sparc/mm/gup.c b/arch/sparc/mm/gup.c index aee6dba83d0e..1e770a517d4a 100644 --- a/arch/sparc/mm/gup.c +++ b/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) { diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h index 6bdca39829bc..08715034e315 100644 --- a/arch/x86/kvm/paging_tmpl.h +++ b/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; diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c index f13a3a24d360..173596a020cb 100644 --- a/arch/x86/kvm/svm.c +++ b/arch/x86/kvm/svm.c @@ -1803,7 +1803,7 @@ 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; diff --git a/drivers/fpga/dfl-afu-dma-region.c b/drivers/fpga/dfl-afu-dma-region.c index e18a786fc943..c438722bf4e1 100644 --- a/drivers/fpga/dfl-afu-dma-region.c +++ b/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; diff --git a/drivers/gpu/drm/via/via_dmablit.c b/drivers/gpu/drm/via/via_dmablit.c index 345bda4494e1..0c8b09602910 100644 --- a/drivers/gpu/drm/via/via_dmablit.c +++ b/drivers/gpu/drm/via/via_dmablit.c @@ -239,7 +239,8 @@ 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) diff --git a/drivers/infiniband/hw/hfi1/user_pages.c b/drivers/infiniband/hw/hfi1/user_pages.c index 24b592c6522e..78ccacaf97d0 100644 --- a/drivers/infiniband/hw/hfi1/user_pages.c +++ b/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;

diff --git a/drivers/misc/genwqe/card_utils.c b/drivers/misc/genwqe/card_utils.c index 25265fd0fd6e..89cff9d1012b 100644 --- a/drivers/misc/genwqe/card_utils.c +++ b/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; diff --git a/drivers/misc/vmw_vmci/vmci_host.c b/drivers/misc/vmw_vmci/vmci_host.c index 997f92543dd4..422d08da3244 100644 --- a/drivers/misc/vmw_vmci/vmci_host.c +++ b/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; diff --git a/drivers/misc/vmw_vmci/vmci_queue_pair.c b/drivers/misc/vmw_vmci/vmci_queue_pair.c index 264f4ed8eef2..c5396ee32e51 100644 --- a/drivers/misc/vmw_vmci/vmci_queue_pair.c +++ b/drivers/misc/vmw_vmci/vmci_queue_pair.c @@ -666,7 +666,8 @@ 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)", @@ -678,7 +679,8 @@ 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)", diff --git a/drivers/platform/goldfish/goldfish_pipe.c b/drivers/platform/goldfish/goldfish_pipe.c index 321bc673c417..cef0133aa47a 100644 --- a/drivers/platform/goldfish/goldfish_pipe.c +++ b/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; diff --git a/drivers/rapidio/devices/rio_mport_cdev.c b/drivers/rapidio/devices/rio_mport_cdev.c index cbe467ff1aba..f681b3e9e970 100644 --- a/drivers/rapidio/devices/rio_mport_cdev.c +++ b/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) { diff --git a/drivers/sbus/char/oradax.c b/drivers/sbus/char/oradax.c index 6516bc3cb58b..790aa148670d 100644 --- a/drivers/sbus/char/oradax.c +++ b/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; diff --git a/drivers/scsi/st.c b/drivers/scsi/st.c index 7ff22d3f03e3..871b25914c07 100644 --- a/drivers/scsi/st.c +++ b/drivers/scsi/st.c @@ -4918,7 +4918,8 @@ 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) diff --git a/drivers/staging/gasket/gasket_page_table.c b/drivers/staging/gasket/gasket_page_table.c index 26755d9ca41d..f67fdf1d3817 100644 --- a/drivers/staging/gasket/gasket_page_table.c +++ b/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, diff --git a/drivers/tee/tee_shm.c b/drivers/tee/tee_shm.c index 0b9ab1d0dd45..49fd7312e2aa 100644 --- a/drivers/tee/tee_shm.c +++ b/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) { diff --git a/drivers/vfio/vfio_iommu_spapr_tce.c b/drivers/vfio/vfio_iommu_spapr_tce.c index c424913324e3..a4b10bb4086b 100644 --- a/drivers/vfio/vfio_iommu_spapr_tce.c +++ b/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)); diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c index 24a129fcdd61..72685b1659ff 100644 --- a/drivers/vhost/vhost.c +++ b/drivers/vhost/vhost.c @@ -1700,7 +1700,7 @@ 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); diff --git a/drivers/video/fbdev/pvr2fb.c b/drivers/video/fbdev/pvr2fb.c index 8a53d1de611d..41390c8e0f67 100644 --- a/drivers/video/fbdev/pvr2fb.c +++ b/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; diff --git a/drivers/virt/fsl_hypervisor.c b/drivers/virt/fsl_hypervisor.c index 8ba726e600e9..6446bcab4185 100644 --- a/drivers/virt/fsl_hypervisor.c +++ b/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 */ diff --git a/drivers/xen/gntdev.c b/drivers/xen/gntdev.c index 5efc5eee9544..7b47f1e6aab4 100644 --- a/drivers/xen/gntdev.c +++ b/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;

diff --git a/fs/orangefs/orangefs-bufmap.c b/fs/orangefs/orangefs-bufmap.c index 443bcd8c3c19..5a7c4fda682f 100644 --- a/fs/orangefs/orangefs-bufmap.c +++ b/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; diff --git a/include/linux/mm.h b/include/linux/mm.h index 05a105d9d4c3..8e1f3cd7482a 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1537,8 +1537,8 @@ 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 { diff --git a/kernel/futex.c b/kernel/futex.c index fdd312da0992..e10209946f8b 100644 --- a/kernel/futex.c +++ b/kernel/futex.c @@ -546,7 +546,7 @@ 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. diff --git a/lib/iov_iter.c b/lib/iov_iter.c index be4bd627caf0..6dbae0692719 100644 --- a/lib/iov_iter.c +++ b/lib/iov_iter.c @@ -1280,7 +1280,9 @@ 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; @@ -1361,7 +1363,8 @@ 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; diff --git a/mm/gup.c b/mm/gup.c index 681388236106..6f32d36b3c5b 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -1863,7 +1863,7 @@ 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. * @@ -1875,8 +1875,8 @@ 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) { unsigned long addr, len, end; int nr = 0, ret = 0; @@ -1894,7 +1894,7 @@ int get_user_pages_fast(unsigned long start, int nr_pages, int write,

if (gup_fast_permitted(start, nr_pages)) { local_irq_disable(); - gup_pgd_range(addr, end, write ? FOLL_WRITE : 0, pages, &nr); + gup_pgd_range(addr, end, gup_flags, pages, &nr); local_irq_enable(); ret = nr; } @@ -1905,7 +1905,7 @@ int get_user_pages_fast(unsigned long start, int nr_pages, int write, pages += nr;

ret = get_user_pages_unlocked(start, nr_pages - nr, pages, - write ? FOLL_WRITE : 0); + gup_flags);

/* Have to be a bit careful with return values */ if (nr > 0) { diff --git a/mm/util.c b/mm/util.c index 1ea055138043..01ffe145c62b 100644 --- a/mm/util.c +++ b/mm/util.c @@ -306,7 +306,7 @@ EXPORT_SYMBOL_GPL(__get_user_pages_fast); * 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. * @@ -327,10 +327,10 @@ EXPORT_SYMBOL_GPL(__get_user_pages_fast); * get_user_pages_fast simply falls back to get_user_pages. */ int __weak get_user_pages_fast(unsigned long start, - int nr_pages, int write, struct page **pages) + int nr_pages, unsigned int gup_flags, + struct page **pages) { - return get_user_pages_unlocked(start, nr_pages, pages, - write ? FOLL_WRITE : 0); + return get_user_pages_unlocked(start, nr_pages, pages, gup_flags); } EXPORT_SYMBOL_GPL(get_user_pages_fast);

diff --git a/net/ceph/pagevec.c b/net/ceph/pagevec.c index d3736f5bffec..74cafc0142ea 100644 --- a/net/ceph/pagevec.c +++ b/net/ceph/pagevec.c @@ -27,7 +27,7 @@ struct page **ceph_get_direct_page_vector(const void __user *data, while (got < num_pages) { rc = get_user_pages_fast( (unsigned long)data + ((unsigned long)got * PAGE_SIZE), - num_pages - got, write_page, pages + got); + num_pages - got, write_page ? FOLL_WRITE : 0, pages + got); if (rc < 0) break; BUG_ON(rc == 0); diff --git a/net/rds/info.c b/net/rds/info.c index e367a97a18c8..03f6fd56d237 100644 --- a/net/rds/info.c +++ b/net/rds/info.c @@ -193,7 +193,7 @@ int rds_info_getsockopt(struct socket *sock, int optname, char __user *optval, ret = -ENOMEM; goto out; } - ret = get_user_pages_fast(start, nr_pages, 1, pages); + ret = get_user_pages_fast(start, nr_pages, FOLL_WRITE, pages); if (ret != nr_pages) { if (ret > 0) nr_pages = ret; diff --git a/net/rds/rdma.c b/net/rds/rdma.c index 182ab8430594..b340ed4fc43a 100644 --- a/net/rds/rdma.c +++ b/net/rds/rdma.c @@ -158,7 +158,8 @@ static int rds_pin_pages(unsigned long user_addr, unsigned int nr_pages, { int ret;

- ret = get_user_pages_fast(user_addr, nr_pages, write, pages); + ret = get_user_pages_fast(user_addr, nr_pages, write ? FOLL_WRITE : 0, + pages);

if (ret >= 0 && ret < nr_pages) { while (ret--)

-- 2.20.1

Jason Gunthorpe

11:11 p.m.

New subject: [PATCH V2 3/7] mm/gup: Change GUP fast to use flags rather than a write 'bool'

On Wed, Feb 13, 2019 at 03:04:51PM -0800, ira.weiny@intel.com wrote:

...

From: Ira Weiny ira.weiny@intel.com

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

So now we have:

long get_user_pages_unlocked(unsigned long start, unsigned long nr_pages, struct page **pages, unsigned int gup_flags);

and

int get_user_pages_fast(unsigned long start, int nr_pages, unsigned int gup_flags, struct page **pages)

Does this make any sense? At least the arguments should be in the same order, I think.

Also this comment: /* * get_user_pages_unlocked() is suitable to replace the form: * * down_read(&mm->mmap_sem); * get_user_pages(tsk, mm, ..., pages, NULL); * up_read(&mm->mmap_sem); * * with: * * get_user_pages_unlocked(tsk, mm, ..., pages); * * It is functionally equivalent to get_user_pages_fast so * get_user_pages_fast should be used instead if specific gup_flags * (e.g. FOLL_FORCE) are not required. */

Needs some attention as the recommendation is now nonsense.

Honestly a proper explanation of why two functions exist would be great at this point :)

Jason

Ira Weiny

11:52 p.m.

New subject: [PATCH V2 3/7] mm/gup: Change GUP fast to use flags rather than a write 'bool'

On Wed, Feb 13, 2019 at 04:11:10PM -0700, Jason Gunthorpe wrote:

...

On Wed, Feb 13, 2019 at 03:04:51PM -0800, ira.weiny@intel.com wrote:

...
From: Ira Weiny ira.weiny@intel.com

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

So now we have:

long get_user_pages_unlocked(unsigned long start, unsigned long nr_pages, struct page **pages, unsigned int gup_flags);

and

int get_user_pages_fast(unsigned long start, int nr_pages, unsigned int gup_flags, struct page **pages)

Does this make any sense? At least the arguments should be in the same order, I think.

Yes... and no. see below.

...

Also this comment: /*
get_user_pages_unlocked() is suitable to replace the form:
 down_read(&mm->mmap_sem);
 get_user_pages(tsk, mm, ..., pages, NULL);
 up_read(&mm->mmap_sem);
with:
 get_user_pages_unlocked(tsk, mm, ..., pages);
It is functionally equivalent to get_user_pages_fast so

get_user_pages_fast should be used instead if specific gup_flags

(e.g. FOLL_FORCE) are not required.
*/

Needs some attention as the recommendation is now nonsense.

IMO they are not functionally equivalent.

We can't remove *_unlocked() as it is used as both a helper for the arch specific *_fast() calls, _and_ in drivers. Again I don't know the history here but it could be that the drivers should never have used the call in the first place??? Or been converted at some point?

I could change the comment to be something like

/* * get_user_pages_unlocked() is only to be used by arch specific * get_user_pages_fast() calls. Drivers should be calling * get_user_pages_fast() */

Instead of the current comment.

And change the drivers to get_user_pages_fast().

However, I'm not sure if these drivers need the FOLL_TOUCH flag which *_unlocked() adds for them. And adding FOLL_TOUCH to *_fast() is not going to give the same functionality.

It _looks_ like we can add FOLL_TOUCH functionality to the fast path in the generic code. I'm not sure about the arch's.

If we did that then we can have those drivers use FOLL_TOUCH or not in *_fast() if they want/need.

...

Honestly a proper explanation of why two functions exist would be great at this point :)

I've not researched it. I do agree that there seems to be a lot of calls in this file and the differences are subtle.

Ira

...

Jason

ira.weiny＠intel.com

11:04 p.m.

New subject: [PATCH V2 4/7] mm/gup: Add FOLL_LONGTERM capability to GUP fast

From: Ira Weiny ira.weiny@intel.com

DAX pages were previously unprotected from longterm pins when users called get_user_pages_fast().

Use the new FOLL_LONGTERM flag to check for DEVMAP pages and fall back to regular GUP processing if a DEVMAP page is encountered.

Signed-off-by: Ira Weiny ira.weiny@intel.com --- mm/gup.c | 24 +++++++++++++++++++++--- 1 file changed, 21 insertions(+), 3 deletions(-)

diff --git a/mm/gup.c b/mm/gup.c index 6f32d36b3c5b..f7e759c523bb 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -1439,6 +1439,9 @@ static int gup_pte_range(pmd_t pmd, unsigned long addr, unsigned long end, goto pte_unmap;

if (pte_devmap(pte)) { + if (unlikely(flags & FOLL_LONGTERM)) + goto pte_unmap; + pgmap = get_dev_pagemap(pte_pfn(pte), pgmap); if (unlikely(!pgmap)) { undo_dev_pagemap(nr, nr_start, pages); @@ -1578,8 +1581,11 @@ static int gup_huge_pmd(pmd_t orig, pmd_t *pmdp, unsigned long addr, if (!pmd_access_permitted(orig, flags & FOLL_WRITE)) return 0;

- if (pmd_devmap(orig)) + if (pmd_devmap(orig)) { + if (unlikely(flags & FOLL_LONGTERM)) + return 0; return __gup_device_huge_pmd(orig, pmdp, addr, end, pages, nr); + }

refs = 0; page = pmd_page(orig) + ((addr & ~PMD_MASK) >> PAGE_SHIFT); @@ -1904,8 +1910,20 @@ int get_user_pages_fast(unsigned long start, int nr_pages, start += nr << PAGE_SHIFT; pages += nr;

- ret = get_user_pages_unlocked(start, nr_pages - nr, pages, - gup_flags); + if (gup_flags & FOLL_LONGTERM) { + down_read(&current->mm->mmap_sem); + ret = __gup_longterm_locked(current, current->mm, + start, nr_pages - nr, + pages, NULL, gup_flags); + up_read(&current->mm->mmap_sem); + } else { + /* + * retain FAULT_FOLL_ALLOW_RETRY optimization if + * possible + */ + ret = get_user_pages_unlocked(start, nr_pages - nr, + pages, gup_flags); + }

/* Have to be a bit careful with return values */ if (nr > 0) {

-- 2.20.1

ira.weiny＠intel.com

11:04 p.m.

New subject: [PATCH V2 5/7] IB/hfi1: Use the new FOLL_LONGTERM flag to get_user_pages_fast()

From: Ira Weiny ira.weiny@intel.com

Use the new FOLL_LONGTERM to get_user_pages_fast() to protect against FS DAX pages being mapped.

Signed-off-by: Ira Weiny ira.weiny@intel.com --- drivers/infiniband/hw/hfi1/user_pages.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/infiniband/hw/hfi1/user_pages.c b/drivers/infiniband/hw/hfi1/user_pages.c index 78ccacaf97d0..6a7f9cd5a94e 100644 --- a/drivers/infiniband/hw/hfi1/user_pages.c +++ b/drivers/infiniband/hw/hfi1/user_pages.c @@ -104,9 +104,11 @@ int hfi1_acquire_user_pages(struct mm_struct *mm, unsigned long vaddr, size_t np bool writable, struct page **pages) { int ret; + unsigned int gup_flags = writable ? FOLL_WRITE : 0;

- ret = get_user_pages_fast(vaddr, npages, writable ? FOLL_WRITE : 0, - pages); + gup_flags |= FOLL_LONGTERM; + + ret = get_user_pages_fast(vaddr, npages, gup_flags, pages); if (ret < 0) return ret;

-- 2.20.1

ira.weiny＠intel.com

11:04 p.m.

New subject: [PATCH V2 6/7] IB/qib: Use the new FOLL_LONGTERM flag to get_user_pages_fast()

From: Ira Weiny ira.weiny@intel.com

Use the new FOLL_LONGTERM to get_user_pages_fast() to protect against FS DAX pages being mapped.

Signed-off-by: Ira Weiny ira.weiny@intel.com --- drivers/infiniband/hw/qib/qib_user_sdma.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/infiniband/hw/qib/qib_user_sdma.c b/drivers/infiniband/hw/qib/qib_user_sdma.c index 31c523b2a9f5..b53cc0240e02 100644 --- a/drivers/infiniband/hw/qib/qib_user_sdma.c +++ b/drivers/infiniband/hw/qib/qib_user_sdma.c @@ -673,7 +673,7 @@ static int qib_user_sdma_pin_pages(const struct qib_devdata *dd, else j = npages;

- ret = get_user_pages_fast(addr, j, 0, pages); + ret = get_user_pages_fast(addr, j, FOLL_LONGTERM, pages); if (ret != j) { i = 0; j = ret;

-- 2.20.1

ira.weiny＠intel.com

11:04 p.m.

New subject: [PATCH V2 7/7] IB/mthca: Use the new FOLL_LONGTERM flag to get_user_pages_fast()

From: Ira Weiny ira.weiny@intel.com

Use the new FOLL_LONGTERM to get_user_pages_fast() to protect against FS DAX pages being mapped.

Signed-off-by: Ira Weiny ira.weiny@intel.com --- drivers/infiniband/hw/mthca/mthca_memfree.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/infiniband/hw/mthca/mthca_memfree.c b/drivers/infiniband/hw/mthca/mthca_memfree.c index 112d2f38e0de..8ff0e90d7564 100644 --- a/drivers/infiniband/hw/mthca/mthca_memfree.c +++ b/drivers/infiniband/hw/mthca/mthca_memfree.c @@ -472,7 +472,8 @@ int mthca_map_user_db(struct mthca_dev *dev, struct mthca_uar *uar, goto out; }

- ret = get_user_pages_fast(uaddr & PAGE_MASK, 1, FOLL_WRITE, pages); + ret = get_user_pages_fast(uaddr & PAGE_MASK, 1, + FOLL_WRITE | FOLL_LONGTERM, pages); if (ret < 0) goto out;

-- 2.20.1

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Ira Weiny
ira.weiny＠intel.com
Jason Gunthorpe