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Howlett" , Lorenzo Stoakes , Michal Hocko , Mike Rapoport , Muchun Song , Nikita Kalyazin , Oscar Salvador , Paolo Bonzini , Peter Xu , Sean Christopherson , Shuah Khan , Suren Baghdasaryan , Vlastimil Babka , linux-kernel@vger.kernel.org, kvm@vger.kernel.org, linux-kselftest@vger.kernel.org Subject: [PATCH RFC 11/17] userfaultfd: mfill_atomic() remove retry logic Date: Tue, 27 Jan 2026 21:29:30 +0200 Message-ID: <20260127192936.1250096-12-rppt@kernel.org> X-Mailer: git-send-email 2.51.0 In-Reply-To: <20260127192936.1250096-1-rppt@kernel.org> References: <20260127192936.1250096-1-rppt@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspamd-Server: rspam10 X-Rspamd-Queue-Id: 5B70140008 X-Stat-Signature: yuy6bibn13hpea98jfiq1ofbbk8r6udg X-Rspam-User: X-HE-Tag: 1769542257-308306 X-HE-Meta: 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 01H7SGvg 0RsV1520RQRbwxqLmKN1fnHZPDSCmdpqsyDHHgHRGCgNhFwtz2mvfhJMF2zWV9dpzSUmMm9cFJOKEdbDqAS9cdtnmcdvUzeo1+n3bC/Wrq5yaaU/bIDD43tt0sPxd5g5tndkuJBmS/JmSeFgLwDZqcWItb1nuU81f51RZxKYIco/ysaDDgJWb9kfK0NfeFk7LRdyAQhk1/0f8UpHQFbuogWpE+sG6+4Zr2WHLWHJl5f0hl6FFzqJWFx2PmkPD25l1CvPA4lHoc8uAIRo6ky/QlWJ4jN/h7XwlNWZsa3aTJJ/zY4LFE4iVlSdtl7wZXIrPDMZg 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: From: "Mike Rapoport (Microsoft)" Since __mfill_atomic_pte() handles the retry for both anonymous and shmem, there is no need to retry copying the date from the userspace in the loop in mfill_atomic(). Drop the retry logic from mfill_atomic(). Signed-off-by: Mike Rapoport (Microsoft) --- mm/userfaultfd.c | 24 ------------------------ 1 file changed, 24 deletions(-) diff --git a/mm/userfaultfd.c b/mm/userfaultfd.c index 54aa195237ba..1bd7631463c6 100644 --- a/mm/userfaultfd.c +++ b/mm/userfaultfd.c @@ -29,7 +29,6 @@ struct mfill_state { struct vm_area_struct *vma; unsigned long src_addr; unsigned long dst_addr; - struct folio *folio; pmd_t *pmd; }; @@ -889,7 +888,6 @@ static __always_inline ssize_t mfill_atomic(struct userfaultfd_ctx *ctx, VM_WARN_ON_ONCE(src_start + len <= src_start); VM_WARN_ON_ONCE(dst_start + len <= dst_start); -retry: err = mfill_get_vma(&state); if (err) goto out; @@ -916,26 +914,6 @@ static __always_inline ssize_t mfill_atomic(struct userfaultfd_ctx *ctx, err = mfill_atomic_pte(&state); cond_resched(); - if (unlikely(err == -ENOENT)) { - void *kaddr; - - mfill_put_vma(&state); - VM_WARN_ON_ONCE(!state.folio); - - kaddr = kmap_local_folio(state.folio, 0); - err = copy_from_user(kaddr, - (const void __user *)state.src_addr, - PAGE_SIZE); - kunmap_local(kaddr); - if (unlikely(err)) { - err = -EFAULT; - goto out; - } - flush_dcache_folio(state.folio); - goto retry; - } else - VM_WARN_ON_ONCE(state.folio); - if (!err) { state.dst_addr += PAGE_SIZE; state.src_addr += PAGE_SIZE; @@ -951,8 +929,6 @@ static __always_inline ssize_t mfill_atomic(struct userfaultfd_ctx *ctx, if (state.vma) mfill_put_vma(&state); out: - if (state.folio) - folio_put(state.folio); VM_WARN_ON_ONCE(copied < 0); VM_WARN_ON_ONCE(err > 0); VM_WARN_ON_ONCE(!copied && !err); -- 2.51.0