From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from gandalf.ozlabs.org (mail.ozlabs.org [IPv6:2404:9400:2221:ea00::3]) by passt.top (Postfix) with ESMTPS id 21B865A0279 for ; Mon, 19 Feb 2024 03:45:13 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gibson.dropbear.id.au; s=202312; t=1708310707; bh=QebmzTHOCRJ+twfhAFA3Sk/zK1sqLFOcIRA9hA5UWDk=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=QwdVpB35sCRGpgmlb4qCtQd2L65i+vqPZR3YsJOcgOPJb0cVQAOYjUkNMUZvhoXhe +gR+INkslTDOdLO7vXFIPj8yk6mkDFPGo4m2emcQH4AwBUXd++VWPLTdEdw296Ssyq 63YGq4X/aJBCd82ox8CR97qEpmP2dDO+tpDcs2YkMsqIgoBzozSzM0gZ2SYJq4/FAd Y/XyIMu6n7lngiaNiFEVqrzqLVFMbqHxl28iyLR60fk7pOiC2HUPONbYdE+iyxZpTF xj8LPgRAZuOVEIWrdPgCITDTdi+z+UBA0lwFRHtwVkYU5DtuD4KxjWSUHHUrbeFWNx rDxFRjLuLDarw== Received: by gandalf.ozlabs.org (Postfix, from userid 1007) id 4TdRhz6Fwnz4wcJ; Mon, 19 Feb 2024 13:45:07 +1100 (AEDT) Date: Mon, 19 Feb 2024 13:45:04 +1100 From: David Gibson To: Laurent Vivier Subject: Re: [PATCH v3 1/9] iov: add some functions to manage iovec Message-ID: References: <20240217150725.661467-1-lvivier@redhat.com> <20240217150725.661467-2-lvivier@redhat.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="o8l6NRW+q+hKxxbS" Content-Disposition: inline In-Reply-To: <20240217150725.661467-2-lvivier@redhat.com> Message-ID-Hash: YDHF3VOKJEFCKYRYDKISGW5I5CWHHOI3 X-Message-ID-Hash: YDHF3VOKJEFCKYRYDKISGW5I5CWHHOI3 X-MailFrom: dgibson@gandalf.ozlabs.org X-Mailman-Rule-Misses: dmarc-mitigation; no-senders; approved; emergency; loop; banned-address; member-moderation; nonmember-moderation; administrivia; implicit-dest; max-recipients; max-size; news-moderation; no-subject; digests; suspicious-header CC: passt-dev@passt.top X-Mailman-Version: 3.3.8 Precedence: list List-Id: Development discussion and patches for passt Archived-At: Archived-At: List-Archive: List-Archive: List-Help: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: --o8l6NRW+q+hKxxbS Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Sat, Feb 17, 2024 at 04:07:17PM +0100, Laurent Vivier wrote: > Introduce functions to copy to/from a buffer from/to an iovec array, > to compute data length in in bytes of an iovec and to copy memory from > an iovec to another. >=20 > iov_from_buf(), iov_to_buf(), iov_size(), iov_copy(). >=20 > Signed-off-by: Laurent Vivier Reviewed-by: David Gibson > --- >=20 > Notes: > v3: > - update copyright statement > (but keep it as proposed by Stefano) > - open code of iov_fill_from_buf()/iov_fill_to_buf() > into iov_frombuf()/iov_to_buf() > - coding style cleanup > - use size_t for the length of the vectors > =20 > v2: > - reorder added files in alphanetical order in Makefile > - update comments, cosmetic cleanup > - rename iov_from_buf_full/iov_to_buf_full to > iov_fill_from_buf/iov_fill_to_buf > - split loops that manage offset and bytes copy. > - move iov_from_buf()/iov_to_buf() to iov.c >=20 > Makefile | 8 +-- > iov.c | 171 +++++++++++++++++++++++++++++++++++++++++++++++++++++++ > iov.h | 29 ++++++++++ > 3 files changed, 204 insertions(+), 4 deletions(-) > create mode 100644 iov.c > create mode 100644 iov.h >=20 > diff --git a/Makefile b/Makefile > index af4fa87e7e13..156398b3844e 100644 > --- a/Makefile > +++ b/Makefile > @@ -45,16 +45,16 @@ FLAGS +=3D -DVERSION=3D\"$(VERSION)\" > FLAGS +=3D -DDUAL_STACK_SOCKETS=3D$(DUAL_STACK_SOCKETS) > =20 > PASST_SRCS =3D arch.c arp.c checksum.c conf.c dhcp.c dhcpv6.c flow.c icm= p.c \ > - igmp.c isolation.c lineread.c log.c mld.c ndp.c netlink.c packet.c \ > - passt.c pasta.c pcap.c pif.c port_fwd.c tap.c tcp.c tcp_splice.c udp.c \ > - util.c > + igmp.c iov.c isolation.c lineread.c log.c mld.c ndp.c netlink.c \ > + packet.c passt.c pasta.c pcap.c pif.c port_fwd.c tap.c tcp.c \ > + tcp_splice.c udp.c util.c > QRAP_SRCS =3D qrap.c > SRCS =3D $(PASST_SRCS) $(QRAP_SRCS) > =20 > MANPAGES =3D passt.1 pasta.1 qrap.1 > =20 > PASST_HEADERS =3D arch.h arp.h checksum.h conf.h dhcp.h dhcpv6.h flow.h \ > - flow_table.h icmp.h inany.h isolation.h lineread.h log.h ndp.h \ > + flow_table.h icmp.h inany.h iov.h isolation.h lineread.h log.h ndp.h \ > netlink.h packet.h passt.h pasta.h pcap.h pif.h port_fwd.h siphash.h \ > tap.h tcp.h tcp_conn.h tcp_splice.h udp.h util.h > HEADERS =3D $(PASST_HEADERS) seccomp.h > diff --git a/iov.c b/iov.c > new file mode 100644 > index 000000000000..1135f87e2f45 > --- /dev/null > +++ b/iov.c > @@ -0,0 +1,171 @@ > +// SPDX-License-Identifier: GPL-2.0-or-later > +/* > + * iov.h - helpers for using (partial) iovecs. > + * > + * Copyright Red Hat > + * Author: Laurent Vivier > + * > + * This file also contains code originally from QEMU include/qemu/iov.h > + * and licensed under the following terms: > + * > + * Copyright (C) 2010 Red Hat, Inc. > + * > + * Author(s): > + * Amit Shah > + * Michael Tokarev > + * > + * This work is licensed under the terms of the GNU GPL, version 2. See > + * the COPYING file in the top-level directory. > + * > + * Contributions after 2012-01-13 are licensed under the terms of the > + * GNU GPL, version 2 or (at your option) any later version. > + */ > +#include > + > +#include "util.h" > +#include "iov.h" > + > +/** > + * iov_from_buf - Copy data from a buffer to an I/O vector (struct iovec) > + * efficiently. > + * > + * @iov: Pointer to the array of struct iovec describing the > + * scatter/gather I/O vector. > + * @iov_cnt: Number of elements in the iov array. > + * @offset: Byte offset in the iov array where copying should start. > + * @buf: Pointer to the source buffer containing the data to copy. > + * @bytes: Total number of bytes to copy from buf to iov. > + * > + * Returns: The number of bytes successfully copied. > + */ > +size_t iov_from_buf(const struct iovec *iov, size_t iov_cnt, > + size_t offset, const void *buf, size_t bytes) > +{ > + unsigned int i; > + size_t copied; > + > + if (__builtin_constant_p(bytes) && iov_cnt && > + offset <=3D iov[0].iov_len && bytes <=3D iov[0].iov_len - offset) { > + memcpy((char *)iov[0].iov_base + offset, buf, bytes); > + return bytes; > + } > + > + /* skipping offset bytes in the iovec */ > + for (i =3D 0; offset >=3D iov[i].iov_len && i < iov_cnt; i++) > + offset -=3D iov[i].iov_len; > + > + /* copying data */ > + for (copied =3D 0; copied < bytes && i < iov_cnt; i++) { > + size_t len =3D MIN(iov[i].iov_len - offset, bytes - copied); > + > + memcpy((char *)iov[i].iov_base + offset, (char *)buf + copied, > + len); > + copied +=3D len; > + offset =3D 0; > + } > + > + return copied; > +} > + > +/** > + * iov_to_buf - Copy data from a scatter/gather I/O vector (struct iovec= ) to > + * a buffer efficiently. > + * > + * @iov: Pointer to the array of struct iovec describing the scatt= er/gather > + * I/O vector. > + * @iov_cnt: Number of elements in the iov array. > + * @offset: Offset within the first element of iov from where copying= should start. > + * @buf: Pointer to the destination buffer where data will be copi= ed. > + * @bytes: Total number of bytes to copy from iov to buf. > + * > + * Returns: The number of bytes successfully copied. > + */ > +size_t iov_to_buf(const struct iovec *iov, size_t iov_cnt, > + size_t offset, void *buf, size_t bytes) > +{ > + unsigned int i; > + size_t copied; > + > + if (__builtin_constant_p(bytes) && iov_cnt && > + offset <=3D iov[0].iov_len && bytes <=3D iov[0].iov_len - offset) { > + memcpy(buf, (char *)iov[0].iov_base + offset, bytes); > + return bytes; > + } > + > + /* skipping offset bytes in the iovec */ > + for (i =3D 0; offset >=3D iov[i].iov_len && i < iov_cnt; i++) > + offset -=3D iov[i].iov_len; > + > + /* copying data */ > + for (copied =3D 0; copied < bytes && i < iov_cnt; i++) { > + size_t len =3D MIN(iov[i].iov_len - offset, bytes - copied); > + memcpy((char *)buf + copied, (char *)iov[i].iov_base + offset, > + len); > + copied +=3D len; > + offset =3D 0; > + } > + > + return copied; > +} > + > +/** > + * iov_size - Calculate the total size of a scatter/gather I/O vector > + * (struct iovec). > + * > + * @iov: Pointer to the array of struct iovec describing the > + * scatter/gather I/O vector. > + * @iov_cnt: Number of elements in the iov array. > + * > + * Returns: The total size in bytes. > + */ > +size_t iov_size(const struct iovec *iov, size_t iov_cnt) > +{ > + unsigned int i; > + size_t len; > + > + for (i =3D 0, len =3D 0; i < iov_cnt; i++) > + len +=3D iov[i].iov_len; > + > + return len; > +} > + > +/** > + * iov_copy - Copy data from one scatter/gather I/O vector (struct iovec= ) to > + * another. > + * > + * @dst_iov: Pointer to the destination array of struct iovec descr= ibing > + * the scatter/gather I/O vector to copy to. > + * @dst_iov_cnt: Number of elements in the destination iov array. > + * @iov: Pointer to the source array of struct iovec describing > + * the scatter/gather I/O vector to copy from. > + * @iov_cnt: Number of elements in the source iov array. > + * @offset: Offset within the source iov from where copying should= start. > + * @bytes: Total number of bytes to copy from iov to dst_iov. > + * > + * Returns: The number of elements successfully copied to the dest= ination > + * iov array. > + */ > +unsigned iov_copy(struct iovec *dst_iov, size_t dst_iov_cnt, > + const struct iovec *iov, size_t iov_cnt, > + size_t offset, size_t bytes) > +{ > + unsigned int i, j; > + size_t len; > + > + /* skipping offset bytes in the iovec */ > + for (i =3D 0; offset >=3D iov[i].iov_len && i < iov_cnt; i++) > + offset -=3D iov[i].iov_len; > + > + /* copying data */ > + for (j =3D 0; i < iov_cnt && j < dst_iov_cnt && bytes; i++) { > + len =3D MIN(bytes, iov[i].iov_len - offset); > + > + dst_iov[j].iov_base =3D (char *)iov[i].iov_base + offset; > + dst_iov[j].iov_len =3D len; > + j++; > + bytes -=3D len; > + offset =3D 0; > + } > + > + return j; > +} > diff --git a/iov.h b/iov.h > new file mode 100644 > index 000000000000..ee35a75d0870 > --- /dev/null > +++ b/iov.h > @@ -0,0 +1,29 @@ > +// SPDX-License-Identifier: GPL-2.0-or-later > +/* > + * iov.c - helpers for using (partial) iovecs. > + * > + * Copyrigh Red Hat > + * Author: Laurent Vivier > + * > + * This file also contains code originally from QEMU include/qemu/iov.h: > + * > + * Author(s): > + * Amit Shah > + * Michael Tokarev > + */ > + > +#ifndef IOVEC_H > +#define IOVEC_H > + > +#include > +#include > + > +size_t iov_from_buf(const struct iovec *iov, size_t iov_cnt, > + size_t offset, const void *buf, size_t bytes); > +size_t iov_to_buf(const struct iovec *iov, size_t iov_cnt, > + size_t offset, void *buf, size_t bytes); > +size_t iov_size(const struct iovec *iov, size_t iov_cnt); > +unsigned iov_copy(struct iovec *dst_iov, size_t dst_iov_cnt, > + const struct iovec *iov, size_t iov_cnt, > + size_t offset, size_t bytes); > +#endif /* IOVEC_H */ --=20 David Gibson | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you. 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