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Subject[PATCH 12/16] mm: consolidate the get_user_pages* implementations
Date
Always build mm/gup.c, and move the nommu versions and replace the
separate stubs for various functions by the default ones, with the _fast
version always falling back to the slow path because gup_fast_permitted
always returns false now if HAVE_FAST_GUP is not set, and we use the
nommu version of __get_user_pages while keeping all the wrappers common.

This also ensures the new put_user_pages* helpers are available for
nommu, as those are currently missing, which would create a problem as
soon as we actually grew users for it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
mm/Kconfig | 1 +
mm/Makefile | 4 +-
mm/gup.c | 476 +++++++++++++++++++++++++++++-----------------------
mm/nommu.c | 88 ----------
mm/util.c | 47 ------
5 files changed, 269 insertions(+), 347 deletions(-)

diff --git a/mm/Kconfig b/mm/Kconfig
index 98dffb0f2447..5c41409557da 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -133,6 +133,7 @@ config HAVE_MEMBLOCK_PHYS_MAP
bool

config HAVE_FAST_GUP
+ depends on MMU
bool

config ARCH_KEEP_MEMBLOCK
diff --git a/mm/Makefile b/mm/Makefile
index ac5e5ba78874..dc0746ca1109 100644
--- a/mm/Makefile
+++ b/mm/Makefile
@@ -22,7 +22,7 @@ KCOV_INSTRUMENT_mmzone.o := n
KCOV_INSTRUMENT_vmstat.o := n

mmu-y := nommu.o
-mmu-$(CONFIG_MMU) := gup.o highmem.o memory.o mincore.o \
+mmu-$(CONFIG_MMU) := highmem.o memory.o mincore.o \
mlock.o mmap.o mmu_gather.o mprotect.o mremap.o \
msync.o page_vma_mapped.o pagewalk.o \
pgtable-generic.o rmap.o vmalloc.o
@@ -39,7 +39,7 @@ obj-y := filemap.o mempool.o oom_kill.o fadvise.o \
mm_init.o mmu_context.o percpu.o slab_common.o \
compaction.o vmacache.o \
interval_tree.o list_lru.o workingset.o \
- debug.o $(mmu-y)
+ debug.o gup.o $(mmu-y)

# Give 'page_alloc' its own module-parameter namespace
page-alloc-y := page_alloc.o
diff --git a/mm/gup.c b/mm/gup.c
index a24f52292c7f..c8da7764de9c 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -134,6 +134,7 @@ void put_user_pages(struct page **pages, unsigned long npages)
}
EXPORT_SYMBOL(put_user_pages);

+#ifdef CONFIG_MMU
static struct page *no_page_table(struct vm_area_struct *vma,
unsigned int flags)
{
@@ -1099,86 +1100,6 @@ static __always_inline long __get_user_pages_locked(struct task_struct *tsk,
return pages_done;
}

-/*
- * We can leverage the VM_FAULT_RETRY functionality in the page fault
- * paths better by using either get_user_pages_locked() or
- * get_user_pages_unlocked().
- *
- * get_user_pages_locked() is suitable to replace the form:
- *
- * down_read(&mm->mmap_sem);
- * do_something()
- * get_user_pages(tsk, mm, ..., pages, NULL);
- * up_read(&mm->mmap_sem);
- *
- * to:
- *
- * int locked = 1;
- * down_read(&mm->mmap_sem);
- * do_something()
- * get_user_pages_locked(tsk, mm, ..., pages, &locked);
- * if (locked)
- * up_read(&mm->mmap_sem);
- */
-long get_user_pages_locked(unsigned long start, unsigned long nr_pages,
- unsigned int gup_flags, struct page **pages,
- int *locked)
-{
- /*
- * FIXME: Current FOLL_LONGTERM behavior is incompatible with
- * FAULT_FLAG_ALLOW_RETRY because of the FS DAX check requirement on
- * vmas. As there are no users of this flag in this call we simply
- * disallow this option for now.
- */
- if (WARN_ON_ONCE(gup_flags & FOLL_LONGTERM))
- return -EINVAL;
-
- return __get_user_pages_locked(current, current->mm, start, nr_pages,
- pages, NULL, locked,
- gup_flags | FOLL_TOUCH);
-}
-EXPORT_SYMBOL(get_user_pages_locked);
-
-/*
- * 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.
- */
-long get_user_pages_unlocked(unsigned long start, unsigned long nr_pages,
- struct page **pages, unsigned int gup_flags)
-{
- struct mm_struct *mm = current->mm;
- int locked = 1;
- long ret;
-
- /*
- * FIXME: Current FOLL_LONGTERM behavior is incompatible with
- * FAULT_FLAG_ALLOW_RETRY because of the FS DAX check requirement on
- * vmas. As there are no users of this flag in this call we simply
- * disallow this option for now.
- */
- if (WARN_ON_ONCE(gup_flags & FOLL_LONGTERM))
- return -EINVAL;
-
- down_read(&mm->mmap_sem);
- ret = __get_user_pages_locked(current, mm, start, nr_pages, pages, NULL,
- &locked, gup_flags | FOLL_TOUCH);
- if (locked)
- up_read(&mm->mmap_sem);
- return ret;
-}
-EXPORT_SYMBOL(get_user_pages_unlocked);
-
/*
* get_user_pages_remote() - pin user pages in memory
* @tsk: the task_struct to use for page fault accounting, or
@@ -1255,6 +1176,199 @@ long get_user_pages_remote(struct task_struct *tsk, struct mm_struct *mm,
}
EXPORT_SYMBOL(get_user_pages_remote);

+/**
+ * populate_vma_page_range() - populate a range of pages in the vma.
+ * @vma: target vma
+ * @start: start address
+ * @end: end address
+ * @nonblocking:
+ *
+ * This takes care of mlocking the pages too if VM_LOCKED is set.
+ *
+ * return 0 on success, negative error code on error.
+ *
+ * vma->vm_mm->mmap_sem must be held.
+ *
+ * If @nonblocking is NULL, it may be held for read or write and will
+ * be unperturbed.
+ *
+ * If @nonblocking is non-NULL, it must held for read only and may be
+ * released. If it's released, *@nonblocking will be set to 0.
+ */
+long populate_vma_page_range(struct vm_area_struct *vma,
+ unsigned long start, unsigned long end, int *nonblocking)
+{
+ struct mm_struct *mm = vma->vm_mm;
+ unsigned long nr_pages = (end - start) / PAGE_SIZE;
+ int gup_flags;
+
+ VM_BUG_ON(start & ~PAGE_MASK);
+ VM_BUG_ON(end & ~PAGE_MASK);
+ VM_BUG_ON_VMA(start < vma->vm_start, vma);
+ VM_BUG_ON_VMA(end > vma->vm_end, vma);
+ VM_BUG_ON_MM(!rwsem_is_locked(&mm->mmap_sem), mm);
+
+ gup_flags = FOLL_TOUCH | FOLL_POPULATE | FOLL_MLOCK;
+ if (vma->vm_flags & VM_LOCKONFAULT)
+ gup_flags &= ~FOLL_POPULATE;
+ /*
+ * We want to touch writable mappings with a write fault in order
+ * to break COW, except for shared mappings because these don't COW
+ * and we would not want to dirty them for nothing.
+ */
+ if ((vma->vm_flags & (VM_WRITE | VM_SHARED)) == VM_WRITE)
+ gup_flags |= FOLL_WRITE;
+
+ /*
+ * We want mlock to succeed for regions that have any permissions
+ * other than PROT_NONE.
+ */
+ if (vma->vm_flags & (VM_READ | VM_WRITE | VM_EXEC))
+ gup_flags |= FOLL_FORCE;
+
+ /*
+ * We made sure addr is within a VMA, so the following will
+ * not result in a stack expansion that recurses back here.
+ */
+ return __get_user_pages(current, mm, start, nr_pages, gup_flags,
+ NULL, NULL, nonblocking);
+}
+
+/*
+ * __mm_populate - populate and/or mlock pages within a range of address space.
+ *
+ * This is used to implement mlock() and the MAP_POPULATE / MAP_LOCKED mmap
+ * flags. VMAs must be already marked with the desired vm_flags, and
+ * mmap_sem must not be held.
+ */
+int __mm_populate(unsigned long start, unsigned long len, int ignore_errors)
+{
+ struct mm_struct *mm = current->mm;
+ unsigned long end, nstart, nend;
+ struct vm_area_struct *vma = NULL;
+ int locked = 0;
+ long ret = 0;
+
+ end = start + len;
+
+ for (nstart = start; nstart < end; nstart = nend) {
+ /*
+ * We want to fault in pages for [nstart; end) address range.
+ * Find first corresponding VMA.
+ */
+ if (!locked) {
+ locked = 1;
+ down_read(&mm->mmap_sem);
+ vma = find_vma(mm, nstart);
+ } else if (nstart >= vma->vm_end)
+ vma = vma->vm_next;
+ if (!vma || vma->vm_start >= end)
+ break;
+ /*
+ * Set [nstart; nend) to intersection of desired address
+ * range with the first VMA. Also, skip undesirable VMA types.
+ */
+ nend = min(end, vma->vm_end);
+ if (vma->vm_flags & (VM_IO | VM_PFNMAP))
+ continue;
+ if (nstart < vma->vm_start)
+ nstart = vma->vm_start;
+ /*
+ * Now fault in a range of pages. populate_vma_page_range()
+ * double checks the vma flags, so that it won't mlock pages
+ * if the vma was already munlocked.
+ */
+ ret = populate_vma_page_range(vma, nstart, nend, &locked);
+ if (ret < 0) {
+ if (ignore_errors) {
+ ret = 0;
+ continue; /* continue at next VMA */
+ }
+ break;
+ }
+ nend = nstart + ret * PAGE_SIZE;
+ ret = 0;
+ }
+ if (locked)
+ up_read(&mm->mmap_sem);
+ return ret; /* 0 or negative error code */
+}
+
+/**
+ * get_dump_page() - pin user page in memory while writing it to core dump
+ * @addr: user address
+ *
+ * Returns struct page pointer of user page pinned for dump,
+ * to be freed afterwards by put_page().
+ *
+ * Returns NULL on any kind of failure - a hole must then be inserted into
+ * the corefile, to preserve alignment with its headers; and also returns
+ * NULL wherever the ZERO_PAGE, or an anonymous pte_none, has been found -
+ * allowing a hole to be left in the corefile to save diskspace.
+ *
+ * Called without mmap_sem, but after all other threads have been killed.
+ */
+#ifdef CONFIG_ELF_CORE
+struct page *get_dump_page(unsigned long addr)
+{
+ struct vm_area_struct *vma;
+ struct page *page;
+
+ if (__get_user_pages(current, current->mm, addr, 1,
+ FOLL_FORCE | FOLL_DUMP | FOLL_GET, &page, &vma,
+ NULL) < 1)
+ return NULL;
+ flush_cache_page(vma, addr, page_to_pfn(page));
+ return page;
+}
+#endif /* CONFIG_ELF_CORE */
+
+#else /* CONFIG_MMU */
+static long __get_user_pages_locked(struct task_struct *tsk,
+ struct mm_struct *mm, unsigned long start,
+ unsigned long nr_pages, struct page **pages,
+ struct vm_area_struct **vmas, int *locked,
+ unsigned int foll_flags)
+{
+ struct vm_area_struct *vma;
+ unsigned long vm_flags;
+ int i;
+
+ /* calculate required read or write permissions.
+ * If FOLL_FORCE is set, we only require the "MAY" flags.
+ */
+ vm_flags = (foll_flags & FOLL_WRITE) ?
+ (VM_WRITE | VM_MAYWRITE) : (VM_READ | VM_MAYREAD);
+ vm_flags &= (foll_flags & FOLL_FORCE) ?
+ (VM_MAYREAD | VM_MAYWRITE) : (VM_READ | VM_WRITE);
+
+ for (i = 0; i < nr_pages; i++) {
+ vma = find_vma(mm, start);
+ if (!vma)
+ goto finish_or_fault;
+
+ /* protect what we can, including chardevs */
+ if ((vma->vm_flags & (VM_IO | VM_PFNMAP)) ||
+ !(vm_flags & vma->vm_flags))
+ goto finish_or_fault;
+
+ if (pages) {
+ pages[i] = virt_to_page(start);
+ if (pages[i])
+ get_page(pages[i]);
+ }
+ if (vmas)
+ vmas[i] = vma;
+ start = (start + PAGE_SIZE) & PAGE_MASK;
+ }
+
+ return i;
+
+finish_or_fault:
+ return i ? : -EFAULT;
+}
+#endif /* !CONFIG_MMU */
+
#if defined(CONFIG_FS_DAX) || defined (CONFIG_CMA)
static bool check_dax_vmas(struct vm_area_struct **vmas, long nr_pages)
{
@@ -1416,7 +1530,7 @@ static long check_and_migrate_cma_pages(struct task_struct *tsk,
{
return nr_pages;
}
-#endif
+#endif /* CONFIG_CMA */

/*
* __gup_longterm_locked() is a wrapper for __get_user_pages_locked which
@@ -1502,152 +1616,85 @@ long get_user_pages(unsigned long start, unsigned long nr_pages,
}
EXPORT_SYMBOL(get_user_pages);

-/**
- * populate_vma_page_range() - populate a range of pages in the vma.
- * @vma: target vma
- * @start: start address
- * @end: end address
- * @nonblocking:
- *
- * This takes care of mlocking the pages too if VM_LOCKED is set.
+/*
+ * We can leverage the VM_FAULT_RETRY functionality in the page fault
+ * paths better by using either get_user_pages_locked() or
+ * get_user_pages_unlocked().
*
- * return 0 on success, negative error code on error.
+ * get_user_pages_locked() is suitable to replace the form:
*
- * vma->vm_mm->mmap_sem must be held.
+ * down_read(&mm->mmap_sem);
+ * do_something()
+ * get_user_pages(tsk, mm, ..., pages, NULL);
+ * up_read(&mm->mmap_sem);
*
- * If @nonblocking is NULL, it may be held for read or write and will
- * be unperturbed.
+ * to:
*
- * If @nonblocking is non-NULL, it must held for read only and may be
- * released. If it's released, *@nonblocking will be set to 0.
+ * int locked = 1;
+ * down_read(&mm->mmap_sem);
+ * do_something()
+ * get_user_pages_locked(tsk, mm, ..., pages, &locked);
+ * if (locked)
+ * up_read(&mm->mmap_sem);
*/
-long populate_vma_page_range(struct vm_area_struct *vma,
- unsigned long start, unsigned long end, int *nonblocking)
+long get_user_pages_locked(unsigned long start, unsigned long nr_pages,
+ unsigned int gup_flags, struct page **pages,
+ int *locked)
{
- struct mm_struct *mm = vma->vm_mm;
- unsigned long nr_pages = (end - start) / PAGE_SIZE;
- int gup_flags;
-
- VM_BUG_ON(start & ~PAGE_MASK);
- VM_BUG_ON(end & ~PAGE_MASK);
- VM_BUG_ON_VMA(start < vma->vm_start, vma);
- VM_BUG_ON_VMA(end > vma->vm_end, vma);
- VM_BUG_ON_MM(!rwsem_is_locked(&mm->mmap_sem), mm);
-
- gup_flags = FOLL_TOUCH | FOLL_POPULATE | FOLL_MLOCK;
- if (vma->vm_flags & VM_LOCKONFAULT)
- gup_flags &= ~FOLL_POPULATE;
- /*
- * We want to touch writable mappings with a write fault in order
- * to break COW, except for shared mappings because these don't COW
- * and we would not want to dirty them for nothing.
- */
- if ((vma->vm_flags & (VM_WRITE | VM_SHARED)) == VM_WRITE)
- gup_flags |= FOLL_WRITE;
-
/*
- * We want mlock to succeed for regions that have any permissions
- * other than PROT_NONE.
+ * FIXME: Current FOLL_LONGTERM behavior is incompatible with
+ * FAULT_FLAG_ALLOW_RETRY because of the FS DAX check requirement on
+ * vmas. As there are no users of this flag in this call we simply
+ * disallow this option for now.
*/
- if (vma->vm_flags & (VM_READ | VM_WRITE | VM_EXEC))
- gup_flags |= FOLL_FORCE;
+ if (WARN_ON_ONCE(gup_flags & FOLL_LONGTERM))
+ return -EINVAL;

- /*
- * We made sure addr is within a VMA, so the following will
- * not result in a stack expansion that recurses back here.
- */
- return __get_user_pages(current, mm, start, nr_pages, gup_flags,
- NULL, NULL, nonblocking);
+ return __get_user_pages_locked(current, current->mm, start, nr_pages,
+ pages, NULL, locked,
+ gup_flags | FOLL_TOUCH);
}
+EXPORT_SYMBOL(get_user_pages_locked);

/*
- * __mm_populate - populate and/or mlock pages within a range of address space.
+ * get_user_pages_unlocked() is suitable to replace the form:
*
- * This is used to implement mlock() and the MAP_POPULATE / MAP_LOCKED mmap
- * flags. VMAs must be already marked with the desired vm_flags, and
- * mmap_sem must not be held.
+ * 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.
*/
-int __mm_populate(unsigned long start, unsigned long len, int ignore_errors)
+long get_user_pages_unlocked(unsigned long start, unsigned long nr_pages,
+ struct page **pages, unsigned int gup_flags)
{
struct mm_struct *mm = current->mm;
- unsigned long end, nstart, nend;
- struct vm_area_struct *vma = NULL;
- int locked = 0;
- long ret = 0;
+ int locked = 1;
+ long ret;

- end = start + len;
+ /*
+ * FIXME: Current FOLL_LONGTERM behavior is incompatible with
+ * FAULT_FLAG_ALLOW_RETRY because of the FS DAX check requirement on
+ * vmas. As there are no users of this flag in this call we simply
+ * disallow this option for now.
+ */
+ if (WARN_ON_ONCE(gup_flags & FOLL_LONGTERM))
+ return -EINVAL;

- for (nstart = start; nstart < end; nstart = nend) {
- /*
- * We want to fault in pages for [nstart; end) address range.
- * Find first corresponding VMA.
- */
- if (!locked) {
- locked = 1;
- down_read(&mm->mmap_sem);
- vma = find_vma(mm, nstart);
- } else if (nstart >= vma->vm_end)
- vma = vma->vm_next;
- if (!vma || vma->vm_start >= end)
- break;
- /*
- * Set [nstart; nend) to intersection of desired address
- * range with the first VMA. Also, skip undesirable VMA types.
- */
- nend = min(end, vma->vm_end);
- if (vma->vm_flags & (VM_IO | VM_PFNMAP))
- continue;
- if (nstart < vma->vm_start)
- nstart = vma->vm_start;
- /*
- * Now fault in a range of pages. populate_vma_page_range()
- * double checks the vma flags, so that it won't mlock pages
- * if the vma was already munlocked.
- */
- ret = populate_vma_page_range(vma, nstart, nend, &locked);
- if (ret < 0) {
- if (ignore_errors) {
- ret = 0;
- continue; /* continue at next VMA */
- }
- break;
- }
- nend = nstart + ret * PAGE_SIZE;
- ret = 0;
- }
+ down_read(&mm->mmap_sem);
+ ret = __get_user_pages_locked(current, mm, start, nr_pages, pages, NULL,
+ &locked, gup_flags | FOLL_TOUCH);
if (locked)
up_read(&mm->mmap_sem);
- return ret; /* 0 or negative error code */
-}
-
-/**
- * get_dump_page() - pin user page in memory while writing it to core dump
- * @addr: user address
- *
- * Returns struct page pointer of user page pinned for dump,
- * to be freed afterwards by put_page().
- *
- * Returns NULL on any kind of failure - a hole must then be inserted into
- * the corefile, to preserve alignment with its headers; and also returns
- * NULL wherever the ZERO_PAGE, or an anonymous pte_none, has been found -
- * allowing a hole to be left in the corefile to save diskspace.
- *
- * Called without mmap_sem, but after all other threads have been killed.
- */
-#ifdef CONFIG_ELF_CORE
-struct page *get_dump_page(unsigned long addr)
-{
- struct vm_area_struct *vma;
- struct page *page;
-
- if (__get_user_pages(current, current->mm, addr, 1,
- FOLL_FORCE | FOLL_DUMP | FOLL_GET, &page, &vma,
- NULL) < 1)
- return NULL;
- flush_cache_page(vma, addr, page_to_pfn(page));
- return page;
+ return ret;
}
-#endif /* CONFIG_ELF_CORE */
+EXPORT_SYMBOL(get_user_pages_unlocked);

/*
* Fast GUP
@@ -1682,7 +1729,7 @@ struct page *get_dump_page(unsigned long addr)
*
* This code is based heavily on the PowerPC implementation by Nick Piggin.
*/
-#ifdef CONFIG_HAVE_FAST_GUP
+#if defined(CONFIG_MMU) && defined(CONFIG_HAVE_FAST_GUP)
#ifdef CONFIG_GUP_GET_PTE_LOW_HIGH
/*
* WARNING: only to be used in the get_user_pages_fast() implementation.
@@ -2159,6 +2206,12 @@ static void gup_pgd_range(unsigned long addr, unsigned long end,
return;
} while (pgdp++, addr = next, addr != end);
}
+#else
+static inline void gup_pgd_range(unsigned long addr, unsigned long end,
+ unsigned int flags, struct page **pages, int *nr)
+{
+}
+#endif /* CONFIG_HAVE_FAST_GUP */

#ifndef gup_fast_permitted
/*
@@ -2167,7 +2220,7 @@ static void gup_pgd_range(unsigned long addr, unsigned long end,
*/
static bool gup_fast_permitted(unsigned long start, unsigned long end)
{
- return true;
+ return IS_ENABLED(CONFIG_HAVE_FAST_GUP) ? true : false;
}
#endif

@@ -2176,6 +2229,9 @@ static bool gup_fast_permitted(unsigned long start, unsigned long end)
* the regular GUP.
* Note a difference with get_user_pages_fast: this always returns the
* number of pages pinned, 0 if no pages were pinned.
+ *
+ * If the architecture does not support this function, simply return with no
+ * pages pinned.
*/
int __get_user_pages_fast(unsigned long start, int nr_pages, int write,
struct page **pages)
@@ -2213,6 +2269,7 @@ int __get_user_pages_fast(unsigned long start, int nr_pages, int write,

return nr;
}
+EXPORT_SYMBOL_GPL(__get_user_pages_fast);

static int __gup_longterm_unlocked(unsigned long start, int nr_pages,
unsigned int gup_flags, struct page **pages)
@@ -2295,5 +2352,4 @@ int get_user_pages_fast(unsigned long start, int nr_pages,

return ret;
}
-
-#endif /* CONFIG_HAVE_GENERIC_GUP */
+EXPORT_SYMBOL_GPL(get_user_pages_fast);
diff --git a/mm/nommu.c b/mm/nommu.c
index d8c02fbe03b5..07165ad2e548 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -111,94 +111,6 @@ unsigned int kobjsize(const void *objp)
return PAGE_SIZE << compound_order(page);
}

-static long __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
- unsigned long start, unsigned long nr_pages,
- unsigned int foll_flags, struct page **pages,
- struct vm_area_struct **vmas, int *nonblocking)
-{
- struct vm_area_struct *vma;
- unsigned long vm_flags;
- int i;
-
- /* calculate required read or write permissions.
- * If FOLL_FORCE is set, we only require the "MAY" flags.
- */
- vm_flags = (foll_flags & FOLL_WRITE) ?
- (VM_WRITE | VM_MAYWRITE) : (VM_READ | VM_MAYREAD);
- vm_flags &= (foll_flags & FOLL_FORCE) ?
- (VM_MAYREAD | VM_MAYWRITE) : (VM_READ | VM_WRITE);
-
- for (i = 0; i < nr_pages; i++) {
- vma = find_vma(mm, start);
- if (!vma)
- goto finish_or_fault;
-
- /* protect what we can, including chardevs */
- if ((vma->vm_flags & (VM_IO | VM_PFNMAP)) ||
- !(vm_flags & vma->vm_flags))
- goto finish_or_fault;
-
- if (pages) {
- pages[i] = virt_to_page(start);
- if (pages[i])
- get_page(pages[i]);
- }
- if (vmas)
- vmas[i] = vma;
- start = (start + PAGE_SIZE) & PAGE_MASK;
- }
-
- return i;
-
-finish_or_fault:
- return i ? : -EFAULT;
-}
-
-/*
- * get a list of pages in an address range belonging to the specified process
- * and indicate the VMA that covers each page
- * - this is potentially dodgy as we may end incrementing the page count of a
- * slab page or a secondary page from a compound page
- * - 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,
- unsigned int gup_flags, struct page **pages,
- struct vm_area_struct **vmas)
-{
- return __get_user_pages(current, current->mm, start, nr_pages,
- gup_flags, pages, vmas, NULL);
-}
-EXPORT_SYMBOL(get_user_pages);
-
-long get_user_pages_locked(unsigned long start, unsigned long nr_pages,
- unsigned int gup_flags, struct page **pages,
- int *locked)
-{
- return get_user_pages(start, nr_pages, gup_flags, pages, NULL);
-}
-EXPORT_SYMBOL(get_user_pages_locked);
-
-static long __get_user_pages_unlocked(struct task_struct *tsk,
- struct mm_struct *mm, unsigned long start,
- unsigned long nr_pages, struct page **pages,
- unsigned int gup_flags)
-{
- long ret;
- down_read(&mm->mmap_sem);
- ret = __get_user_pages(tsk, mm, start, nr_pages, gup_flags, pages,
- NULL, NULL);
- up_read(&mm->mmap_sem);
- return ret;
-}
-
-long get_user_pages_unlocked(unsigned long start, unsigned long nr_pages,
- struct page **pages, unsigned int gup_flags)
-{
- return __get_user_pages_unlocked(current, current->mm, start, nr_pages,
- pages, gup_flags);
-}
-EXPORT_SYMBOL(get_user_pages_unlocked);
-
/**
* follow_pfn - look up PFN at a user virtual address
* @vma: memory mapping
diff --git a/mm/util.c b/mm/util.c
index 91682a2090ee..d58f5b0eb669 100644
--- a/mm/util.c
+++ b/mm/util.c
@@ -300,53 +300,6 @@ void arch_pick_mmap_layout(struct mm_struct *mm, struct rlimit *rlim_stack)
}
#endif

-/*
- * Like get_user_pages_fast() except its IRQ-safe in that it won't fall
- * back to the regular GUP.
- * Note a difference with get_user_pages_fast: this always returns the
- * number of pages pinned, 0 if no pages were pinned.
- * If the architecture does not support this function, simply return with no
- * pages pinned.
- */
-int __weak __get_user_pages_fast(unsigned long start,
- int nr_pages, int write, struct page **pages)
-{
- return 0;
-}
-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
- * @gup_flags: flags modifying pin behaviour
- * @pages: array that receives pointers to the pages pinned.
- * Should be at least nr_pages long.
- *
- * get_user_pages_fast provides equivalent functionality to get_user_pages,
- * operating on current and current->mm, with force=0 and vma=NULL. However
- * unlike get_user_pages, it must be called without mmap_sem held.
- *
- * get_user_pages_fast may take mmap_sem and page table locks, so no
- * assumptions can be made about lack of locking. get_user_pages_fast is to be
- * implemented in a way that is advantageous (vs get_user_pages()) when the
- * user memory area is already faulted in and present in ptes. However if the
- * pages have to be faulted in, it may turn out to be slightly slower so
- * callers need to carefully consider what to use. On many architectures,
- * get_user_pages_fast simply falls back to get_user_pages.
- *
- * Return: number of pages pinned. This may be fewer than the number
- * requested. If nr_pages is 0 or negative, returns 0. If no pages
- * were pinned, returns -errno.
- */
-int __weak get_user_pages_fast(unsigned long start,
- int nr_pages, unsigned int gup_flags,
- struct page **pages)
-{
- return get_user_pages_unlocked(start, nr_pages, pages, gup_flags);
-}
-EXPORT_SYMBOL_GPL(get_user_pages_fast);
-
unsigned long vm_mmap_pgoff(struct file *file, unsigned long addr,
unsigned long len, unsigned long prot,
unsigned long flag, unsigned long pgoff)
--
2.20.1
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