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Commit 26f4c328 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Linus Torvalds
Browse files

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: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarJason 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: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent f455c854

arch/s390/include/asm/pgtable.h

+1 −7
Original line number Original line Diff line number Diff line
@@ -1270,14 +1270,8 @@ static inline pte_t *pte_offset(pmd_t *pmd, unsigned long address) 
#define pte_offset_map(pmd, address) pte_offset_kernel(pmd, address)

#define pte_offset_map(pmd, address) pte_offset_kernel(pmd, address)

#define pte_unmap(pte) do { } while (0)

#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;

	return end <= current->mm->context.asce_limit;

}

}

#define gup_fast_permitted gup_fast_permitted

#define gup_fast_permitted gup_fast_permitted

arch/x86/include/asm/pgtable_64.h

+1 −7
Original line number Original line Diff line number Diff line
@@ -259,14 +259,8 @@ extern void init_extra_mapping_uc(unsigned long phys, unsigned long size); 
extern void init_extra_mapping_wb(unsigned long phys, unsigned long size);

extern void init_extra_mapping_wb(unsigned long phys, unsigned long size);





#define gup_fast_permitted gup_fast_permitted

#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)

	if (end >> __VIRTUAL_MASK_SHIFT)

		return false;

		return false;

	return true;

	return true;

mm/gup.c

+7 −10
Original line number Original line Diff line number Diff line
@@ -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

 * Check if it's allowed to use __get_user_pages_fast() for the range, or

 * we need to fall back to the slow version:

 * 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;

	return true;



	len = (unsigned long) nr_pages << PAGE_SHIFT;

	end = start + len;

	return end >= start;

}

}

#endif

#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;

	len = (unsigned long) nr_pages << PAGE_SHIFT;

	end = start + len;

	end = start + len;





	if (end <= start)

		return 0;

	if (unlikely(!access_ok((void __user *)start, len)))

	if (unlikely(!access_ok((void __user *)start, len)))

		return 0;

		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.

	 * block IPIs that come from THPs splitting.

	 */

	 */





	if (gup_fast_permitted(start, nr_pages)) {

	if (gup_fast_permitted(start, end)) {

		local_irq_save(flags);

		local_irq_save(flags);

		gup_pgd_range(start, end, write ? FOLL_WRITE : 0, pages, &nr);

		gup_pgd_range(start, end, write ? FOLL_WRITE : 0, pages, &nr);

		local_irq_restore(flags);

		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;

	len = (unsigned long) nr_pages << PAGE_SHIFT;

	end = start + len;

	end = start + len;





	if (nr_pages <= 0)

	if (end <= start)

		return 0;

		return 0;



	if (unlikely(!access_ok((void __user *)start, len)))

	if (unlikely(!access_ok((void __user *)start, len)))

		return -EFAULT;

		return -EFAULT;





	if (gup_fast_permitted(start, nr_pages)) {

	if (gup_fast_permitted(start, end)) {

		local_irq_disable();

		local_irq_disable();

		gup_pgd_range(addr, end, gup_flags, pages, &nr);

		gup_pgd_range(addr, end, gup_flags, pages, &nr);

		local_irq_enable();

		local_irq_enable();