[v2,03/14] mm/gup: Check p4d presence before going on

Message ID	20240318200404.448346-4-peterx@redhat.com (mailing list archive)
State	New
Headers	show Return-Path: <owner-linux-mm@kvack.org> From: peterx@redhat.com To: linux-kernel@vger.kernel.org, linux-mm@kvack.org Cc: Andrew Morton <akpm@linux-foundation.org>, x86@kernel.org, Muchun Song <muchun.song@linux.dev>, Mike Rapoport <rppt@kernel.org>, Matthew Wilcox <willy@infradead.org>, sparclinux@vger.kernel.org, Jason Gunthorpe <jgg@nvidia.com>, linuxppc-dev@lists.ozlabs.org, Christophe Leroy <christophe.leroy@csgroup.eu>, linux-arm-kernel@lists.infradead.org, peterx@redhat.com Subject: [PATCH v2 03/14] mm/gup: Check p4d presence before going on Date: Mon, 18 Mar 2024 16:03:53 -0400 Message-ID: <20240318200404.448346-4-peterx@redhat.com> In-Reply-To: <20240318200404.448346-1-peterx@redhat.com> References: <20240318200404.448346-1-peterx@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset="US-ASCII"; x-default=true Sender: owner-linux-mm@kvack.org Precedence: bulk
Series	mm/treewide: Remove pXd_huge() API \| expand [v2,00/14] mm/treewide: Remove pXd_huge() API [v2,01/14] mm/hmm: Process pud swap entry without pud_huge() [v2,02/14] mm/gup: Cache p4d in follow_p4d_mask() [v2,03/14] mm/gup: Check p4d presence before going on [v2,04/14] mm/x86: Change pXd_huge() behavior to exclude swap entries [v2,06/14] mm/arm: Use macros to define pmd/pud helpers [v2,08/14] mm/arm64: Merge pXd_huge() and pXd_leaf() definitions [v2,09/14] mm/powerpc: Redefine pXd_huge() with pXd_leaf() [v2,10/14] mm/gup: Merge pXd huge mapping checks [v2,11/14] mm/treewide: Replace pXd_huge() with pXd_leaf() [v2,13/14] mm/arm: Remove pmd_thp_or_huge()

Message ID

20240318200404.448346-4-peterx@redhat.com (mailing list archive)

State

New

Headers

From: peterx@redhat.com
To: linux-kernel@vger.kernel.org,
	linux-mm@kvack.org
Cc: Andrew Morton <akpm@linux-foundation.org>,
	x86@kernel.org,
	Muchun Song <muchun.song@linux.dev>,
	Mike Rapoport <rppt@kernel.org>,
	Matthew Wilcox <willy@infradead.org>,
	sparclinux@vger.kernel.org,
	Jason Gunthorpe <jgg@nvidia.com>,
	linuxppc-dev@lists.ozlabs.org,
	Christophe Leroy <christophe.leroy@csgroup.eu>,
	linux-arm-kernel@lists.infradead.org,
	peterx@redhat.com
Subject: [PATCH v2 03/14] mm/gup: Check p4d presence before going on
Date: Mon, 18 Mar 2024 16:03:53 -0400
Message-ID: <20240318200404.448346-4-peterx@redhat.com>
In-Reply-To: <20240318200404.448346-1-peterx@redhat.com>
References: <20240318200404.448346-1-peterx@redhat.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
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Sender: owner-linux-mm@kvack.org
Precedence: bulk

Series

mm/treewide: Remove pXd_huge() API | expand

Commit Message

Peter Xu March 18, 2024, 8:03 p.m. UTC

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))))) {

[v2,03/14] mm/gup: Check p4d presence before going on

Commit Message

Patch