From nobody Sun Feb 8 14:13:01 2026 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D0B5232695F; Tue, 27 Jan 2026 19:30:56 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769542256; cv=none; b=gcTlqUSIv6uYqdeYm6Tdg5fh2Ot2duKp++gyrFe/VnsNBBL2q/QH5caPFUQns+nyV5ghuqNXah+DZUkeAuG3vzOH/7Ye+eAe4/iipvwBnYOqxElPKvyUFIhh7DIRYuj7s4BNURaYRnZ2R7wPr+NfLb3PB3vA8dMmjPDX5Gi8VOU= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769542256; c=relaxed/simple; bh=dAICMUfnaufCCr/AJKZx+mvFFt/TvpVz3/Hz00SDDT0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=jhQ8iQcjnJLOpK5sENQAPiVamVwusXDkljlZ+dcRpiIXaf6rj48nCDpHGsWaNUxOi0QrZPOG7ZaMjvYms/ygcW0DOVMdT6tZjJd2CaioJt7L62fPUv20TIl8+9a+JePfBPsntUzILpT48e9QQoYocx2hRiDI0VUfwygFZbJOx5E= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=gwfokdNa; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="gwfokdNa" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B3A4CC116C6; Tue, 27 Jan 2026 19:30:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1769542256; bh=dAICMUfnaufCCr/AJKZx+mvFFt/TvpVz3/Hz00SDDT0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=gwfokdNanFjWz8h5LlR+icqZBH0klOoYnKAr1LNi95YICtl63fsrIcY8NnT+EiRGe yWtnqTwr+5yZpeYTvJL+8lRdpKwuDymh+P32EIO7DBV2T1c59DdkBL1R/WUsNWgMjo lwiKT5FEt89BPbSUwIaq5DpMdSJP8rTXn1u4K7DWOR24Jk6vMPpdim08J8mSngmaUC SPR+4MGDgZLIL7Ui9/esE9aoXfCdTxImkuayPuQIrY/yHzrePZ7E3MShe2i3YI3kJQ X9XKKQQ96ySvXVHKpmqecHcxy28t+t+LDSTtQZT/ngMyhyrkh3tbjgj2uPuiHiqjkZ T57CGZrW7YBBA== From: Mike Rapoport To: linux-mm@kvack.org Cc: Andrea Arcangeli , Andrew Morton , Axel Rasmussen , Baolin Wang , David Hildenbrand , Hugh Dickins , James Houghton , "Liam R. 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> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" 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; }; =20 @@ -889,7 +888,6 @@ static __always_inline ssize_t mfill_atomic(struct user= faultfd_ctx *ctx, VM_WARN_ON_ONCE(src_start + len <=3D src_start); VM_WARN_ON_ONCE(dst_start + len <=3D dst_start); =20 -retry: err =3D mfill_get_vma(&state); if (err) goto out; @@ -916,26 +914,6 @@ static __always_inline ssize_t mfill_atomic(struct use= rfaultfd_ctx *ctx, err =3D mfill_atomic_pte(&state); cond_resched(); =20 - if (unlikely(err =3D=3D -ENOENT)) { - void *kaddr; - - mfill_put_vma(&state); - VM_WARN_ON_ONCE(!state.folio); - - kaddr =3D kmap_local_folio(state.folio, 0); - err =3D copy_from_user(kaddr, - (const void __user *)state.src_addr, - PAGE_SIZE); - kunmap_local(kaddr); - if (unlikely(err)) { - err =3D -EFAULT; - goto out; - } - flush_dcache_folio(state.folio); - goto retry; - } else - VM_WARN_ON_ONCE(state.folio); - if (!err) { state.dst_addr +=3D PAGE_SIZE; state.src_addr +=3D PAGE_SIZE; @@ -951,8 +929,6 @@ static __always_inline ssize_t mfill_atomic(struct user= faultfd_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); --=20 2.51.0