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authorChristoph Hellwig <hch@lst.de>2019-07-11 20:56:45 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2019-07-12 11:05:44 -0700
commit26f4c328079d78d6cd0462c53c14ec0b69f4748e (patch)
tree4383d175df563a0370612bd7d873e32d0d8463b0 /mm/gup.c
parentf455c854877dcce5d714b00203ea804bf601fb02 (diff)
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@lst.de Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Jason Gunthorpe <jgg@mellanox.com> Cc: Andrey Konovalov <andreyknvl@google.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: David Miller <davem@davemloft.net> Cc: James Hogan <jhogan@kernel.org> Cc: Khalid Aziz <khalid.aziz@oracle.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Paul Burton <paul.burton@mips.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Rich Felker <dalias@libc.org> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/gup.c')
-rw-r--r--mm/gup.c17
1 files changed, 7 insertions, 10 deletions
diff --git a/mm/gup.c b/mm/gup.c
index fc704dc37914..84891c06d485 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -2123,13 +2123,9 @@ static void gup_pgd_range(unsigned long addr, unsigned long end,
* 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 start, int nr_pages, int write,
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 start, int nr_pages, int write,
* 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 start, int nr_pages,
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();