From: Christoph Hellwig <hch@lst.de>
To: Andrew Morton <akpm@linux-foundation.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Paul Burton <paul.burton@mips.com>,
James Hogan <jhogan@kernel.org>,
Yoshinori Sato <ysato@users.sourceforge.jp>,
Rich Felker <dalias@libc.org>,
"David S. Miller" <davem@davemloft.net>
Cc: Nicholas Piggin <npiggin@gmail.com>,
Khalid Aziz <khalid.aziz@oracle.com>,
Andrey Konovalov <andreyknvl@google.com>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Paul Mackerras <paulus@samba.org>,
Michael Ellerman <mpe@ellerman.id.au>,
linux-mips@vger.kernel.org, linux-sh@vger.kernel.org,
sparclinux@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
linux-mm@kvack.org, x86@kernel.org, linux-kernel@vger.kernel.org,
Jason Gunthorpe <jgg@mellanox.com>
Subject: [PATCH 02/16] mm: simplify gup_fast_permitted
Date: Tue, 25 Jun 2019 16:37:01 +0200 [thread overview]
Message-ID: <20190625143715.1689-3-hch@lst.de> (raw)
In-Reply-To: <20190625143715.1689-1-hch@lst.de>
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.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jason Gunthorpe <jgg@mellanox.com>
---
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(-)
diff --git a/arch/s390/include/asm/pgtable.h b/arch/s390/include/asm/pgtable.h
index 9f0195d5fa16..9b274fcaacb6 100644
--- a/arch/s390/include/asm/pgtable.h
+++ b/arch/s390/include/asm/pgtable.h
@@ -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_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
diff --git a/arch/x86/include/asm/pgtable_64.h b/arch/x86/include/asm/pgtable_64.h
index 0bb566315621..4990d26dfc73 100644
--- a/arch/x86/include/asm/pgtable_64.h
+++ b/arch/x86/include/asm/pgtable_64.h
@@ -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);
#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;
diff --git a/mm/gup.c b/mm/gup.c
index 6bb521db67ec..3237f33792e6 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();
--
2.20.1
next prev parent reply other threads:[~2019-06-25 14:38 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-25 14:36 switch the remaining architectures to use generic GUP v4 Christoph Hellwig
2019-06-25 14:37 ` [PATCH 01/16] mm: use untagged_addr() for get_user_pages_fast addresses Christoph Hellwig
2019-06-25 14:37 ` Christoph Hellwig [this message]
2019-06-25 14:37 ` [PATCH 03/16] mm: lift the x86_32 PAE version of gup_get_pte to common code Christoph Hellwig
2019-06-25 14:37 ` [PATCH 04/16] MIPS: use the generic get_user_pages_fast code Christoph Hellwig
2019-06-29 14:37 ` Guenter Roeck
2019-06-25 14:37 ` [PATCH 05/16] sh: add the missing pud_page definition Christoph Hellwig
2019-06-25 14:37 ` [PATCH 06/16] sh: use the generic get_user_pages_fast code Christoph Hellwig
2019-06-29 15:15 ` Guenter Roeck
2019-06-25 14:37 ` [PATCH 07/16] sparc64: add the missing pgd_page definition Christoph Hellwig
2019-06-25 14:37 ` [PATCH 08/16] sparc64: define untagged_addr() Christoph Hellwig
2019-06-25 14:37 ` [PATCH 09/16] sparc64: use the generic get_user_pages_fast code Christoph Hellwig
2019-06-25 14:37 ` [PATCH 10/16] mm: rename CONFIG_HAVE_GENERIC_GUP to CONFIG_HAVE_FAST_GUP Christoph Hellwig
2019-06-25 14:37 ` [PATCH 11/16] mm: reorder code blocks in gup.c Christoph Hellwig
2019-06-25 14:37 ` [PATCH 12/16] mm: consolidate the get_user_pages* implementations Christoph Hellwig
2019-06-25 14:37 ` [PATCH 13/16] mm: validate get_user_pages_fast flags Christoph Hellwig
2019-06-25 14:37 ` [PATCH 14/16] mm: move the powerpc hugepd code to mm/gup.c Christoph Hellwig
2019-06-25 19:37 ` Andrew Morton
2019-06-26 5:49 ` Christoph Hellwig
2019-06-25 14:37 ` [PATCH 15/16] mm: switch gup_hugepte to use try_get_compound_head Christoph Hellwig
2019-06-25 14:37 ` [PATCH 16/16] mm: mark the page referenced in gup_hugepte Christoph Hellwig
-- strict thread matches above, loose matches on Subject: below --
2019-06-11 14:40 switch the remaining architectures to use generic GUP v3 Christoph Hellwig
2019-06-11 14:40 ` [PATCH 02/16] mm: simplify gup_fast_permitted Christoph Hellwig
2019-06-21 13:40 ` Jason Gunthorpe
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