The patch titled
Subject: mm: consolidate the get_user_pages* implementations
has been added to the -mm tree. Its filename is
mm-consolidate-the-get_user_pages-implementations.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-consolidate-the-get_user_pages-implementations.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-consolidate-the-get_user_pages-implementations.patch
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------------------------------------------------------
From: Christoph Hellwig <hch@xxxxxx>
Subject: mm: consolidate the get_user_pages* implementations
Always build mm/gup.c so that we don't have to provide separate nommu
stubs. Also merge the get_user_pages_fast and __get_user_pages_fast stubs
when HAVE_FAST_GUP into the main implementations, which will never call
the fast path if HAVE_FAST_GUP is not set.
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.
Link: http://lkml.kernel.org/r/20190625143715.1689-13-hch@xxxxxx
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
Cc: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
Cc: David Miller <davem@xxxxxxxxxxxxx>
Cc: James Hogan <jhogan@xxxxxxxxxx>
Cc: Jason Gunthorpe <jgg@xxxxxxxxxxxx>
Cc: Khalid Aziz <khalid.aziz@xxxxxxxxxx>
Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Cc: Nicholas Piggin <npiggin@xxxxxxxxx>
Cc: Paul Burton <paul.burton@xxxxxxxx>
Cc: Paul Mackerras <paulus@xxxxxxxxx>
Cc: Ralf Baechle <ralf@xxxxxxxxxxxxxx>
Cc: Rich Felker <dalias@xxxxxxxx>
Cc: Yoshinori Sato <ysato@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/Kconfig | 1
mm/Makefile | 4 +-
mm/gup.c | 67 +++++++++++++++++++++++++++++++++++---
mm/nommu.c | 88 --------------------------------------------------
mm/util.c | 47 --------------------------
5 files changed, 65 insertions(+), 142 deletions(-)
--- a/mm/gup.c~mm-consolidate-the-get_user_pages-implementations
+++ a/mm/gup.c
@@ -134,6 +134,7 @@ void put_user_pages(struct page **pages,
}
EXPORT_SYMBOL(put_user_pages);
+#ifdef CONFIG_MMU
static struct page *no_page_table(struct vm_area_struct *vma,
unsigned int flags)
{
@@ -1322,6 +1323,51 @@ struct page *get_dump_page(unsigned long
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)
@@ -1484,7 +1530,7 @@ static long check_and_migrate_cma_pages(
{
return nr_pages;
}
-#endif
+#endif /* CONFIG_CMA */
/*
* __gup_longterm_locked() is a wrapper for __get_user_pages_locked which
@@ -2160,6 +2206,12 @@ static void gup_pgd_range(unsigned long
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
/*
@@ -2177,6 +2229,9 @@ static bool gup_fast_permitted(unsigned
* 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)
@@ -2206,7 +2261,8 @@ int __get_user_pages_fast(unsigned long
* block IPIs that come from THPs splitting.
*/
- if (gup_fast_permitted(start, end)) {
+ if (IS_ENABLED(CONFIG_HAVE_FAST_GUP) &&
+ gup_fast_permitted(start, end)) {
local_irq_save(flags);
gup_pgd_range(start, end, write ? FOLL_WRITE : 0, pages, &nr);
local_irq_restore(flags);
@@ -2214,6 +2270,7 @@ int __get_user_pages_fast(unsigned long
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)
@@ -2270,7 +2327,8 @@ int get_user_pages_fast(unsigned long st
if (unlikely(!access_ok((void __user *)start, len)))
return -EFAULT;
- if (gup_fast_permitted(start, end)) {
+ if (IS_ENABLED(CONFIG_HAVE_FAST_GUP) &&
+ gup_fast_permitted(start, end)) {
local_irq_disable();
gup_pgd_range(addr, end, gup_flags, pages, &nr);
local_irq_enable();
@@ -2296,5 +2354,4 @@ int get_user_pages_fast(unsigned long st
return ret;
}
-
-#endif /* CONFIG_HAVE_GENERIC_GUP */
+EXPORT_SYMBOL_GPL(get_user_pages_fast);
--- a/mm/Kconfig~mm-consolidate-the-get_user_pages-implementations
+++ a/mm/Kconfig
@@ -133,6 +133,7 @@ config HAVE_MEMBLOCK_PHYS_MAP
bool
config HAVE_FAST_GUP
+ depends on MMU
bool
config ARCH_KEEP_MEMBLOCK
--- a/mm/Makefile~mm-consolidate-the-get_user_pages-implementations
+++ a/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.
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
--- a/mm/nommu.c~mm-consolidate-the-get_user_pages-implementations
+++ a/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
--- a/mm/util.c~mm-consolidate-the-get_user_pages-implementations
+++ a/mm/util.c
@@ -300,53 +300,6 @@ void arch_pick_mmap_layout(struct mm_str
}
#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)
_
Patches currently in -mm which might be from hch@xxxxxx are
mm-remove-the-account_page_dirtied-export.patch
mm-fix-an-overly-long-line-in-read_cache_page.patch
mm-dont-cast-readpage-to-filler_t-for-do_read_cache_page.patch
jffs2-pass-the-correct-prototype-to-read_cache_page.patch
9p-pass-the-correct-prototype-to-read_cache_page.patch
mm-use-untagged_addr-for-get_user_pages_fast-addresses.patch
mm-simplify-gup_fast_permitted.patch
mm-lift-the-x86_32-pae-version-of-gup_get_pte-to-common-code.patch
mips-use-the-generic-get_user_pages_fast-code.patch
sh-add-the-missing-pud_page-definition.patch
sh-use-the-generic-get_user_pages_fast-code.patch
sparc64-add-the-missing-pgd_page-definition.patch
sparc64-define-untagged_addr.patch
sparc64-use-the-generic-get_user_pages_fast-code.patch
mm-rename-config_have_generic_gup-to-config_have_fast_gup.patch
mm-reorder-code-blocks-in-gupc.patch
mm-consolidate-the-get_user_pages-implementations.patch
mm-validate-get_user_pages_fast-flags.patch
mm-move-the-powerpc-hugepd-code-to-mm-gupc.patch
mm-switch-gup_hugepte-to-use-try_get_compound_head.patch
mm-mark-the-page-referenced-in-gup_hugepte.patch
