From nobody Thu Dec 18 12:31:03 2025 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (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 68BF72153D8 for ; Wed, 6 Aug 2025 20:37:30 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.133.124 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1754512652; cv=none; b=HhkBVIHTb/ns+jArIOg+BygjAnD+fB9+e/Z3v133nV7TcO511rRwGHqzTJS1FLJpdIvhMS0WvQKa+FCn2QA7lYc/8qg3dfMHhPH/i7byZw04xMXDtf4xWSNzDfkp3DWF7Ls3B7r24sujbwEqT1dSoHo7a0Agsl0YfSO25/zKBGM= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1754512652; c=relaxed/simple; bh=iwlGvKhOI+i6VMNnthS81ctLD77v4aMMHF6SciyVTrI=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=lo2eRMzaUeASUWGSPkQVW0Pwv6xulW0IUVSikY+ExgI3gC28Tkv7r8UOxGiyDqs7vVZeAIAESfHiwRoWikQgjj+qVZFpP9KiM43+QZ1BNkiEz8yv8Wz3W9TQAefhgNkmKJ9TGK8JYdH8YPIo5vGgpPCP83aTwurAaTfTU9c2Vqc= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=ieFnWq7I; arc=none smtp.client-ip=170.10.133.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="ieFnWq7I" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1754512649; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=nWtz3qSueBra8NkVdEcoiYIsFsfLvyAM7VI8XyjxQXc=; b=ieFnWq7ID5fTVIMHRrkbn5SeM6lsZ5jwKIzcVZ1oI3gnB+EXnRiHHibI5PtuRQUh9TrXdE i48NYvAvc7fsZ93josMTS8wYRlNyKzLLJmbcKQw+9YJXjYRVaHNB6M4G4ENMQ4w+LwFcdw 9xsveb32WrHAZm4+mI2RAc8M3X4UNkM= Received: from mx-prod-mc-06.mail-002.prod.us-west-2.aws.redhat.com (ec2-35-165-154-97.us-west-2.compute.amazonaws.com [35.165.154.97]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-644-zdZ0tj3ZOWm2-1A-aEehfw-1; Wed, 06 Aug 2025 16:37:24 -0400 X-MC-Unique: zdZ0tj3ZOWm2-1A-aEehfw-1 X-Mimecast-MFC-AGG-ID: zdZ0tj3ZOWm2-1A-aEehfw_1754512639 Received: from mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.93]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 5F19E180034A; Wed, 6 Aug 2025 20:37:19 +0000 (UTC) Received: from warthog.procyon.org.com (unknown [10.42.28.17]) by mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id A294D1800447; Wed, 6 Aug 2025 20:37:16 +0000 (UTC) From: David Howells To: Steve French Cc: David Howells , Paulo Alcantara , Shyam Prasad N , Tom Talpey , Wang Zhaolong , Stefan Metzmacher , Mina Almasry , linux-cifs@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [RFC PATCH 01/31] iov_iter: Move ITER_DISCARD and ITER_XARRAY iteration out-of-line Date: Wed, 6 Aug 2025 21:36:22 +0100 Message-ID: <20250806203705.2560493-2-dhowells@redhat.com> In-Reply-To: <20250806203705.2560493-1-dhowells@redhat.com> References: <20250806203705.2560493-1-dhowells@redhat.com> 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 X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.93 Content-Type: text/plain; charset="utf-8" Move ITER_DISCARD and ITER_XARRAY iteration out-of-line in preparation of adding other iteration types which will also be out-of-line. Signed-off-by: David Howells --- include/linux/iov_iter.h | 77 +++----------------------------------- lib/iov_iter.c | 81 ++++++++++++++++++++++++++++++++++++++++ 2 files changed, 86 insertions(+), 72 deletions(-) diff --git a/include/linux/iov_iter.h b/include/linux/iov_iter.h index c4aa58032faf..0c47933df517 100644 --- a/include/linux/iov_iter.h +++ b/include/linux/iov_iter.h @@ -17,6 +17,9 @@ typedef size_t (*iov_step_f)(void *iter_base, size_t prog= ress, size_t len, typedef size_t (*iov_ustep_f)(void __user *iter_base, size_t progress, siz= e_t len, void *priv, void *priv2); =20 +size_t __iterate_and_advance2(struct iov_iter *iter, size_t len, void *pri= v, + void *priv2, iov_ustep_f ustep, iov_step_f step); + /* * Handle ITER_UBUF. */ @@ -195,72 +198,6 @@ size_t iterate_folioq(struct iov_iter *iter, size_t le= n, void *priv, void *priv2 return progress; } =20 -/* - * Handle ITER_XARRAY. - */ -static __always_inline -size_t iterate_xarray(struct iov_iter *iter, size_t len, void *priv, void = *priv2, - iov_step_f step) -{ - struct folio *folio; - size_t progress =3D 0; - loff_t start =3D iter->xarray_start + iter->iov_offset; - pgoff_t index =3D start / PAGE_SIZE; - XA_STATE(xas, iter->xarray, index); - - rcu_read_lock(); - xas_for_each(&xas, folio, ULONG_MAX) { - size_t remain, consumed, offset, part, flen; - - if (xas_retry(&xas, folio)) - continue; - if (WARN_ON(xa_is_value(folio))) - break; - if (WARN_ON(folio_test_hugetlb(folio))) - break; - - offset =3D offset_in_folio(folio, start + progress); - flen =3D min(folio_size(folio) - offset, len); - - while (flen) { - void *base =3D kmap_local_folio(folio, offset); - - part =3D min_t(size_t, flen, - PAGE_SIZE - offset_in_page(offset)); - remain =3D step(base, progress, part, priv, priv2); - kunmap_local(base); - - consumed =3D part - remain; - progress +=3D consumed; - len -=3D consumed; - - if (remain || len =3D=3D 0) - goto out; - flen -=3D consumed; - offset +=3D consumed; - } - } - -out: - rcu_read_unlock(); - iter->iov_offset +=3D progress; - iter->count -=3D progress; - return progress; -} - -/* - * Handle ITER_DISCARD. - */ -static __always_inline -size_t iterate_discard(struct iov_iter *iter, size_t len, void *priv, void= *priv2, - iov_step_f step) -{ - size_t progress =3D len; - - iter->count -=3D progress; - return progress; -} - /** * iterate_and_advance2 - Iterate over an iterator * @iter: The iterator to iterate over. @@ -306,9 +243,7 @@ size_t iterate_and_advance2(struct iov_iter *iter, size= _t len, void *priv, return iterate_kvec(iter, len, priv, priv2, step); if (iov_iter_is_folioq(iter)) return iterate_folioq(iter, len, priv, priv2, step); - if (iov_iter_is_xarray(iter)) - return iterate_xarray(iter, len, priv, priv2, step); - return iterate_discard(iter, len, priv, priv2, step); + return __iterate_and_advance2(iter, len, priv, priv2, ustep, step); } =20 /** @@ -370,9 +305,7 @@ size_t iterate_and_advance_kernel(struct iov_iter *iter= , size_t len, void *priv, return iterate_kvec(iter, len, priv, priv2, step); if (iov_iter_is_folioq(iter)) return iterate_folioq(iter, len, priv, priv2, step); - if (iov_iter_is_xarray(iter)) - return iterate_xarray(iter, len, priv, priv2, step); - return iterate_discard(iter, len, priv, priv2, step); + return __iterate_and_advance2(iter, len, priv, priv2, NULL, step); } =20 #endif /* _LINUX_IOV_ITER_H */ diff --git a/lib/iov_iter.c b/lib/iov_iter.c index f9193f952f49..53e58903fe75 100644 --- a/lib/iov_iter.c +++ b/lib/iov_iter.c @@ -1928,3 +1928,84 @@ ssize_t iov_iter_extract_pages(struct iov_iter *i, return -EFAULT; } EXPORT_SYMBOL_GPL(iov_iter_extract_pages); + +/* + * Handle ITER_XARRAY. + */ +static __always_inline +size_t iterate_xarray(struct iov_iter *iter, size_t len, void *priv, void = *priv2, + iov_step_f step) +{ + struct folio *folio; + size_t progress =3D 0; + loff_t start =3D iter->xarray_start + iter->iov_offset; + pgoff_t index =3D start / PAGE_SIZE; + XA_STATE(xas, iter->xarray, index); + + rcu_read_lock(); + xas_for_each(&xas, folio, ULONG_MAX) { + size_t remain, consumed, offset, part, flen; + + if (xas_retry(&xas, folio)) + continue; + if (WARN_ON(xa_is_value(folio))) + break; + if (WARN_ON(folio_test_hugetlb(folio))) + break; + + offset =3D offset_in_folio(folio, start + progress); + flen =3D min(folio_size(folio) - offset, len); + + while (flen) { + void *base =3D kmap_local_folio(folio, offset); + + part =3D min_t(size_t, flen, + PAGE_SIZE - offset_in_page(offset)); + remain =3D step(base, progress, part, priv, priv2); + kunmap_local(base); + + consumed =3D part - remain; + progress +=3D consumed; + len -=3D consumed; + + if (remain || len =3D=3D 0) + goto out; + flen -=3D consumed; + offset +=3D consumed; + } + } + +out: + rcu_read_unlock(); + iter->iov_offset +=3D progress; + iter->count -=3D progress; + return progress; +} + +/* + * Handle ITER_DISCARD. + */ +static __always_inline +size_t iterate_discard(struct iov_iter *iter, size_t len, void *priv, void= *priv2, + iov_step_f step) +{ + size_t progress =3D len; + + iter->count -=3D progress; + return progress; +} + +/* + * Out of line iteration for iterator types that don't need such fast hand= ling. + */ +size_t __iterate_and_advance2(struct iov_iter *iter, size_t len, void *pri= v, + void *priv2, iov_ustep_f ustep, iov_step_f step) +{ + if (iov_iter_is_discard(iter)) + return iterate_discard(iter, len, priv, priv2, step); + if (iov_iter_is_xarray(iter)) + return iterate_xarray(iter, len, priv, priv2, step); + WARN_ON(1); + return 0; +} +EXPORT_SYMBOL(__iterate_and_advance2);