The patch titled
Subject: mm: simplify gup_fast_permitted
has been added to the -mm tree. Its filename is
mm-simplify-gup_fast_permitted.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-simplify-gup_fast_permitted.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-simplify-gup_fast_permitted.patch
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*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
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------------------------------------------------------
From: Christoph Hellwig <hch@xxxxxx>
Subject: mm: simplify gup_fast_permitted
Pass in the already calculated end value instead of recomputing it, and
leave the end > start check in the callers instead of duplicating them in
the arch code.
Link: http://lkml.kernel.org/r/20190625143715.1689-3-hch@xxxxxx
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
Reviewed-by: Jason Gunthorpe <jgg@xxxxxxxxxxxx>
Cc: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
Cc: David Miller <davem@xxxxxxxxxxxxx>
Cc: James Hogan <jhogan@xxxxxxxxxx>
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>
---
arch/s390/include/asm/pgtable.h | 8 +-------
arch/x86/include/asm/pgtable_64.h | 8 +-------
mm/gup.c | 17 +++++++----------
3 files changed, 9 insertions(+), 24 deletions(-)
--- a/arch/s390/include/asm/pgtable.h~mm-simplify-gup_fast_permitted
+++ a/arch/s390/include/asm/pgtable.h
@@ -1270,14 +1270,8 @@ static inline pte_t *pte_offset(pmd_t *p
#define pte_offset_map(pmd, address) pte_offset_kernel(pmd, address)
#define pte_unmap(pte) do { } while (0)
-static inline bool gup_fast_permitted(unsigned long start, int nr_pages)
+static inline bool gup_fast_permitted(unsigned long start, unsigned long end)
{
- unsigned long len, end;
-
- len = (unsigned long) nr_pages << PAGE_SHIFT;
- end = start + len;
- if (end < start)
- return false;
return end <= current->mm->context.asce_limit;
}
#define gup_fast_permitted gup_fast_permitted
--- a/arch/x86/include/asm/pgtable_64.h~mm-simplify-gup_fast_permitted
+++ a/arch/x86/include/asm/pgtable_64.h
@@ -259,14 +259,8 @@ extern void init_extra_mapping_uc(unsign
extern void init_extra_mapping_wb(unsigned long phys, unsigned long size);
#define gup_fast_permitted gup_fast_permitted
-static inline bool gup_fast_permitted(unsigned long start, int nr_pages)
+static inline bool gup_fast_permitted(unsigned long start, unsigned long end)
{
- unsigned long len, end;
-
- len = (unsigned long)nr_pages << PAGE_SHIFT;
- end = start + len;
- if (end < start)
- return false;
if (end >> __VIRTUAL_MASK_SHIFT)
return false;
return true;
--- a/mm/gup.c~mm-simplify-gup_fast_permitted
+++ a/mm/gup.c
@@ -2123,13 +2123,9 @@ static void gup_pgd_range(unsigned long
* Check if it's allowed to use __get_user_pages_fast() for the range, or
* we need to fall back to the slow version:
*/
-bool gup_fast_permitted(unsigned long start, int nr_pages)
+static bool gup_fast_permitted(unsigned long start, unsigned long end)
{
- unsigned long len, end;
-
- len = (unsigned long) nr_pages << PAGE_SHIFT;
- end = start + len;
- return end >= start;
+ return true;
}
#endif
@@ -2150,6 +2146,8 @@ int __get_user_pages_fast(unsigned long
len = (unsigned long) nr_pages << PAGE_SHIFT;
end = start + len;
+ if (end <= start)
+ return 0;
if (unlikely(!access_ok((void __user *)start, len)))
return 0;
@@ -2165,7 +2163,7 @@ int __get_user_pages_fast(unsigned long
* block IPIs that come from THPs splitting.
*/
- if (gup_fast_permitted(start, nr_pages)) {
+ if (gup_fast_permitted(start, end)) {
local_irq_save(flags);
gup_pgd_range(start, end, write ? FOLL_WRITE : 0, pages, &nr);
local_irq_restore(flags);
@@ -2224,13 +2222,12 @@ int get_user_pages_fast(unsigned long st
len = (unsigned long) nr_pages << PAGE_SHIFT;
end = start + len;
- if (nr_pages <= 0)
+ if (end <= start)
return 0;
-
if (unlikely(!access_ok((void __user *)start, len)))
return -EFAULT;
- if (gup_fast_permitted(start, nr_pages)) {
+ if (gup_fast_permitted(start, end)) {
local_irq_disable();
gup_pgd_range(addr, end, gup_flags, pages, &nr);
local_irq_enable();
_
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
