From: peterx@redhat.com
To: linux-kernel@vger.kernel.org, linux-mm@kvack.org
Cc: Muchun Song <muchun.song@linux.dev>,
Jason Gunthorpe <jgg@nvidia.com>,
x86@kernel.org, peterx@redhat.com,
Matthew Wilcox <willy@infradead.org>,
Mike Rapoport <rppt@kernel.org>,
sparclinux@vger.kernel.org,
Andrew Morton <akpm@linux-foundation.org>,
linuxppc-dev@lists.ozlabs.org,
linux-arm-kernel@lists.infradead.org
Subject: [PATCH 03/13] mm/gup: Check p4d presence before going on
Date: Wed, 13 Mar 2024 17:47:09 -0400 [thread overview]
Message-ID: <20240313214719.253873-4-peterx@redhat.com> (raw)
In-Reply-To: <20240313214719.253873-1-peterx@redhat.com>
From: Peter Xu <peterx@redhat.com>
Currently there should have no p4d swap entries so it may not matter much,
however this may help us to rule out swap entries in pXd_huge() API, which
will include p4d_huge(). The p4d_present() checks make it 100% clear that
we won't rely on p4d_huge() for swap entries.
Signed-off-by: Peter Xu <peterx@redhat.com>
---
mm/gup.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/mm/gup.c b/mm/gup.c
index 69a777f4fc5c..802987281b2f 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -776,7 +776,7 @@ static struct page *follow_p4d_mask(struct vm_area_struct *vma,
p4dp = p4d_offset(pgdp, address);
p4d = READ_ONCE(*p4dp);
- if (p4d_none(p4d))
+ if (!p4d_present(p4d))
return no_page_table(vma, flags);
BUILD_BUG_ON(p4d_huge(p4d));
if (unlikely(p4d_bad(p4d)))
@@ -3069,7 +3069,7 @@ static int gup_p4d_range(pgd_t *pgdp, pgd_t pgd, unsigned long addr, unsigned lo
p4d_t p4d = READ_ONCE(*p4dp);
next = p4d_addr_end(addr, end);
- if (p4d_none(p4d))
+ if (!p4d_present(p4d))
return 0;
BUILD_BUG_ON(p4d_huge(p4d));
if (unlikely(is_hugepd(__hugepd(p4d_val(p4d))))) {
--
2.44.0
next prev parent reply other threads:[~2024-03-13 21:51 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-13 21:47 [PATCH 00/13] mm/treewide: Remove pXd_huge() API peterx
2024-03-13 21:47 ` [PATCH 01/13] mm/hmm: Process pud swap entry without pud_huge() peterx
2024-03-13 21:47 ` [PATCH 02/13] mm/gup: Cache p4d in follow_p4d_mask() peterx
2024-03-13 21:47 ` peterx [this message]
2024-03-13 21:47 ` [PATCH 04/13] mm/x86: Change pXd_huge() behavior to exclude swap entries peterx
2024-03-13 21:47 ` [PATCH 05/13] mm/sparc: " peterx
2024-03-13 21:47 ` [PATCH 06/13] mm/arm: Use macros to define pmd/pud helpers peterx
2024-03-13 21:47 ` [PATCH 07/13] mm/arm: Redefine pmd_huge() with pmd_leaf() peterx
2024-03-13 21:47 ` [PATCH 08/13] mm/arm64: Merge pXd_huge() and pXd_leaf() definitions peterx
2024-03-13 21:47 ` [PATCH 09/13] mm/powerpc: Redefine pXd_huge() with pXd_leaf() peterx
2024-03-14 8:45 ` Christophe Leroy
2024-03-14 12:53 ` Peter Xu
2024-03-14 13:11 ` Christophe Leroy
2024-03-18 16:15 ` Jason Gunthorpe
2024-03-19 23:07 ` Christophe Leroy
2024-03-19 23:26 ` Jason Gunthorpe
2024-03-20 6:16 ` Christophe Leroy
2024-03-20 16:09 ` Peter Xu
2024-03-20 17:40 ` Christophe Leroy
2024-03-20 20:24 ` Peter Xu
2024-03-13 21:47 ` [PATCH 10/13] mm/gup: Merge pXd huge mapping checks peterx
2024-03-13 21:47 ` [PATCH 11/13] mm/treewide: Replace pXd_huge() with pXd_leaf() peterx
2024-03-14 8:50 ` Christophe Leroy
2024-03-14 12:59 ` Peter Xu
2024-03-18 16:16 ` Jason Gunthorpe
2024-03-13 21:47 ` [PATCH 12/13] mm/treewide: Remove pXd_huge() peterx
2024-03-14 8:56 ` Christophe Leroy
2024-03-14 14:08 ` Peter Xu
2024-03-13 21:47 ` [PATCH 13/13] mm: Document pXd_leaf() API peterx
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