From: Peter Zijlstra <peterz@infradead.org>
To: x86@kernel.org, willy@infradead.org
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
aarcange@redhat.com, kirill.shutemov@linux.intel.com,
jroedel@suse.de, peterz@infradead.org
Subject: [RFC][PATCH 6/9] mm/gup: Fix the lockless walkers
Date: Mon, 30 Nov 2020 12:27:11 +0100 [thread overview]
Message-ID: <20201130113603.145310991@infradead.org> (raw)
In-Reply-To: 20201130112705.900705277@infradead.org
On architectures where the PTE/PMD is larger than the native word size
(i386-PAE for example), READ_ONCE() can do the wrong thing. Use
pmdp_get_lockless() just like we use ptep_get_lockless().
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
kernel/events/core.c | 2 +-
mm/gup.c | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -7041,7 +7041,7 @@ static u64 perf_get_pgtable_size(struct
return pud_leaf_size(pud);
pmdp = pmd_offset_lockless(pudp, pud, addr);
- pmd = READ_ONCE(*pmdp);
+ pmd = pmdp_get_lockless(pmdp);
if (!pmd_present(pmd))
return 0;
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -2467,7 +2467,7 @@ static int gup_pmd_range(pud_t *pudp, pu
pmdp = pmd_offset_lockless(pudp, pud, addr);
do {
- pmd_t pmd = READ_ONCE(*pmdp);
+ pmd_t pmd = pmdp_get_lockless(pmdp);
next = pmd_addr_end(addr, end);
if (!pmd_present(pmd))
next prev parent reply other threads:[~2020-11-30 11:39 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-30 11:27 [RFC][PATCH 0/9] Clean up i386-PAE Peter Zijlstra
2020-11-30 11:27 ` [RFC][PATCH 1/9] mm: Update ptep_get_lockless()s comment Peter Zijlstra
2020-11-30 11:27 ` [RFC][PATCH 2/9] x86/mm/pae: Make pmd_t similar to pte_t Peter Zijlstra
2020-11-30 11:27 ` [RFC][PATCH 3/9] sh/mm: " Peter Zijlstra
2020-11-30 14:10 ` David Laight
2020-11-30 14:21 ` Peter Zijlstra
2020-11-30 11:27 ` [RFC][PATCH 4/9] mm: Fix pmd_read_atomic() Peter Zijlstra
2020-11-30 11:27 ` [RFC][PATCH 5/9] mm: Rename pmd_read_atomic() Peter Zijlstra
2020-11-30 15:31 ` Jason Gunthorpe
2020-12-01 8:57 ` Peter Zijlstra
2020-11-30 11:27 ` Peter Zijlstra [this message]
2020-11-30 11:27 ` [RFC][PATCH 7/9] x86/mm/pae: Dont (ab)use atomic64 Peter Zijlstra
2020-11-30 11:27 ` [RFC][PATCH 8/9] x86/mm/pae: Use WRITE_ONCE() Peter Zijlstra
2020-11-30 11:27 ` [RFC][PATCH 9/9] x86/mm/pae: Be consistent with pXXp_get_and_clear() Peter Zijlstra
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