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AJvYcCUOeH8oiL9dcoJ8NhxLfn+JElie4dmUmrXdckdMm5SEI2+ivywo24C9O5DEbBJRaDojNUR4nWIk5A==@kvack.org X-Gm-Message-State: AOJu0YymZRXNa1OqPu0sP88ldtOhFSZBHHNu+Wmr/q/mmp49E8npbUWm 8CQSqJ9n+nXELbd3See3vNcKISUYH/4bOOEcgTqCLbqhvbiUYfA6z0DM9f+YRi8= X-Google-Smtp-Source: AGHT+IGct1lfg7s+Av92JTuFI7wGr/k4q1ybIYiVEVcgmdImld0nRYlRbV5Vh9eNiEYSyV0nSbS/hA== X-Received: by 2002:a17:90a:7893:b0:2c9:635b:7271 with SMTP id 98e67ed59e1d1-2d5e9a24ea2mr1616047a91.21.1724228428100; Wed, 21 Aug 2024 01:20:28 -0700 (PDT) Received: from C02DW0BEMD6R.bytedance.net ([203.208.167.150]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-2d5eb9049b0sm1091453a91.17.2024.08.21.01.20.21 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 21 Aug 2024 01:20:27 -0700 (PDT) From: Qi Zheng To: david@redhat.com, hughd@google.com, willy@infradead.org, muchun.song@linux.dev, vbabka@kernel.org, akpm@linux-foundation.org, rppt@kernel.org, vishal.moola@gmail.com, peterx@redhat.com, ryan.roberts@arm.com Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-arm-kernel@lists.infradead.org, linuxppc-dev@lists.ozlabs.org, Qi Zheng Subject: [PATCH 09/14] mm: mremap: move_ptes() use pte_offset_map_maywrite_nolock() Date: Wed, 21 Aug 2024 16:18:52 +0800 Message-Id: <89bd1d48db1986ec83dcae228defa748f38238ff.1724226076.git.zhengqi.arch@bytedance.com> X-Mailer: git-send-email 2.24.3 (Apple Git-128) In-Reply-To: References: MIME-Version: 1.0 X-Rspamd-Server: rspam12 X-Rspamd-Queue-Id: 6A2261C001E X-Stat-Signature: nrjxyx4zniqoo9w19izbh3wjpiin47yq X-Rspam-User: X-HE-Tag: 1724228429-575899 X-HE-Meta: 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 gFwsi9w0 dW3rw9B6iTagvCzhStn3ga5F0io/ZGNwvGaej053H8DsujZYmszZCEKxrRmWTyiPXIZnWL7yKIPQl9d5kMB4556G52Kz2LU0NjdnUkRmnNUopKGxMtRDpvWDWR9BA2EFYlsyUcX7EQaHC3U/+hSZZ/Q3Cs70KLSCb9bheCB8SAmQq7Nd/90IOOswW+nfEe3DjUeT00KmTS+Fegq/XOIxrQ+fhyXeNVTmYCDIQMlc1OulNYZ2yz593f0C8cotmLnsS8vTq018kQTvDqtoPeHjb585jK1J4s/U9KHSzlEvI/VyrFa/3p4+WffQYu5z/V4w3wZAuD/rD0x+FdSRIFuLE4JTtQyVIfGs1BlB+qrhh3jZOWrye51o8VcO/YXZ686mcV6E1zdsUcNZQwIZf76ee+POz0sr99lB3lqEiQA0AdG/t0nYojEQ7ZvE3Dy7Ayh9KDViS X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: In move_ptes(), we may modify the new_pte after acquiring the new_ptl, so convert it to using pte_offset_map_maywrite_nolock(). But since we already hold the exclusive mmap_lock, there is no need to get pmdval to do pmd_same() check, just pass NULL to pmdvalp parameter. Signed-off-by: Qi Zheng --- mm/mremap.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/mm/mremap.c b/mm/mremap.c index e7ae140fc6409..33a0ccf79c32d 100644 --- a/mm/mremap.c +++ b/mm/mremap.c @@ -175,7 +175,12 @@ static int move_ptes(struct vm_area_struct *vma, pmd_t *old_pmd, err = -EAGAIN; goto out; } - new_pte = pte_offset_map_nolock(mm, new_pmd, new_addr, &new_ptl); + /* + * Use the maywrite version to indicate that new_pte will be modified, + * but since we hold the exclusive mmap_lock, there is no need to + * recheck pmd_same() after acquiring the new_ptl. + */ + new_pte = pte_offset_map_maywrite_nolock(mm, new_pmd, new_addr, NULL, &new_ptl); if (!new_pte) { pte_unmap_unlock(old_pte, old_ptl); err = -EAGAIN;