diff options
| author | Kirill A. Shutemov <kirill.shutemov@linux.intel.com> | 2017-03-16 18:26:51 +0300 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2017-03-18 09:48:02 +0100 |
| commit | 0005d20b2ff1e501e186b3b3bc587085ac305fdc (patch) | |
| tree | b0f05c1dc037f034e533ead0a56eeeb9dd5f0b23 /mm/gup.c | |
| parent | e7884f8ead4a301b04687a3238527b06feef8ea0 (diff) | |
mm/gup: Move page table entry dereference into helper function
This is a preparation patch for the transition of x86 to the generic GUP_fast()
implementation.
On x86 PAE, page table entry is larger than sizeof(long) and we would
need to provide a helper that can read the entry atomically.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Aneesh Kumar K . V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dann Frazier <dann.frazier@canonical.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Steve Capper <steve.capper@linaro.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-arch@vger.kernel.org
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/20170316152655.37789-4-kirill.shutemov@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'mm/gup.c')
| -rw-r--r-- | mm/gup.c | 20 |
1 files changed, 12 insertions, 8 deletions
@@ -1189,6 +1189,17 @@ struct page *get_dump_page(unsigned long addr) */ #ifdef CONFIG_HAVE_GENERIC_RCU_GUP +#ifndef gup_get_pte +/* + * We assume that the PTE can be read atomically. If this is not the case for + * your architecture, please provide the helper. + */ +static inline pte_t gup_get_pte(pte_t *ptep) +{ + return READ_ONCE(*ptep); +} +#endif + #ifdef __HAVE_ARCH_PTE_SPECIAL static int gup_pte_range(pmd_t pmd, unsigned long addr, unsigned long end, int write, struct page **pages, int *nr) @@ -1198,14 +1209,7 @@ static int gup_pte_range(pmd_t pmd, unsigned long addr, unsigned long end, ptem = ptep = pte_offset_map(&pmd, addr); do { - /* - * In the line below we are assuming that the pte can be read - * atomically. If this is not the case for your architecture, - * please wrap this in a helper function! - * - * for an example see gup_get_pte in arch/x86/mm/gup.c - */ - pte_t pte = READ_ONCE(*ptep); + pte_t pte = gup_get_pte(ptep); struct page *head, *page; /* |