From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists1p.gnu.org (lists1p.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id D5450F34C4E for ; Mon, 13 Apr 2026 13:46:30 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists1p.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1wCHcE-0004zj-0P; Mon, 13 Apr 2026 09:46:14 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists1p.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1wCHcD-0004za-12 for qemu-devel@nongnu.org; Mon, 13 Apr 2026 09:46:13 -0400 Received: from mgamail.intel.com ([198.175.65.14]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1wCHcB-0002B8-2T for qemu-devel@nongnu.org; Mon, 13 Apr 2026 09:46:12 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1776087971; x=1807623971; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=7MG2x1Tpck0f/s3FRgTmVdtUJNJSEk2UYFSH4EpXP04=; b=JEEBKhg1mNrMasBylcYCSk4ua14iXtBF8RSQxvN+XBKh7IQfzGCmYztk Bk2jRX4JSEkxb7lhHKls5HahljNvlage3SWHn+0/D8PHzm2QYYv9WGErI QJEedV9jeTKI90MpN/nY5hc9Rh4tGfVgqk10I99hkoqyXtc5IvDMZACdX f92yZZRUohBR1qoSxvy89PHXXgE0FFInpxSnR7IIzLqsvRkasbsKkk1Ik cTgX/tNm0rgwwqzDshV9IXUIzdjwY9lUxBWcHkhmRffNLe603s0pLADxA 8f/41JVhPLRZY5meqvdM1jblgXKtGO4IpoubcltbDwcvTScfEfJ9QfRZp g==; X-CSE-ConnectionGUID: cpdLLcBOQuGeWD62R4hJmw== X-CSE-MsgGUID: hFBq0FW2SUuZaVFc/jp04w== X-IronPort-AV: E=McAfee;i="6800,10657,11758"; a="80885625" X-IronPort-AV: E=Sophos;i="6.23,177,1770624000"; d="scan'208";a="80885625" Received: from orviesa005.jf.intel.com ([10.64.159.145]) by orvoesa106.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 13 Apr 2026 06:46:11 -0700 X-CSE-ConnectionGUID: x3I1tAg6R8Cc1jAormWLEg== X-CSE-MsgGUID: QflxPTWTT1mZkJxiG56OOQ== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.23,177,1770624000"; d="scan'208";a="234770373" Received: from junjie-optiplex-micro-plus-7010.bj.intel.com ([10.238.152.98]) by orviesa005-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 13 Apr 2026 06:46:09 -0700 From: Junjie Cao To: qemu-devel@nongnu.org Cc: berrange@redhat.com, peterx@redhat.com, farosas@suse.de, junjie.cao@intel.com Subject: [PATCH v3 1/4] io/channel: introduce qio_channel_pread{v, }_all{, _eof}() Date: Tue, 14 Apr 2026 05:45:46 +0800 Message-ID: <20260413214549.926435-2-junjie.cao@intel.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260413214549.926435-1-junjie.cao@intel.com> References: <20260413214549.926435-1-junjie.cao@intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=198.175.65.14; envelope-from=junjie.cao@intel.com; helo=mgamail.intel.com X-Spam_score_int: -29 X-Spam_score: -3.0 X-Spam_bar: --- X-Spam_report: (-3.0 / 5.0 requ) BAYES_00=-1.9, DATE_IN_FUTURE_06_12=1.947, DKIMWL_WL_HIGH=-0.54, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_MED=-2.3, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, RCVD_IN_VALIDITY_SAFE_BLOCKED=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: qemu development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org qio_channel_pread() and qio_channel_preadv() perform a single positioned read and may return a short result. Callers that need all bytes currently have to open-code a retry loop or simply treat a short read as an error. Introduce four new helpers following the existing read_all / readv_all pattern: qio_channel_preadv_all_eof() -- retry loop; returns 1 on success, 0 on clean EOF, -1 on error. qio_channel_preadv_all() -- wraps _eof; treats early EOF as error; returns 0 / -1. qio_channel_pread_all_eof() -- single-buffer convenience wrapper around preadv_all_eof(). qio_channel_pread_all() -- single-buffer convenience wrapper around preadv_all(). These advance the file offset internally after each partial read. All four are marked coroutine_mixed_fn, consistent with the existing _all helpers. Suggested-by: Peter Xu Signed-off-by: Junjie Cao --- include/io/channel.h | 92 ++++++++++++++++++++++++++++++++++++++++++++ io/channel.c | 91 +++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 183 insertions(+) diff --git a/include/io/channel.h b/include/io/channel.h index 1b02350437..47af409ede 100644 --- a/include/io/channel.h +++ b/include/io/channel.h @@ -634,6 +634,98 @@ ssize_t qio_channel_preadv(QIOChannel *ioc, const struct iovec *iov, ssize_t qio_channel_pread(QIOChannel *ioc, void *buf, size_t buflen, off_t offset, Error **errp); +/** + * qio_channel_preadv_all_eof: + * @ioc: the channel object + * @iov: the array of memory regions to read data into + * @niov: the length of the @iov array + * @offset: the starting offset in the channel to read from + * @errp: pointer to a NULL-initialized error object + * + * Reads @iov, possibly blocking or (if the channel is non-blocking) + * yielding from the current coroutine multiple times until the entire + * content is read. If end-of-file occurs immediately it is not an + * error, but if it occurs after data has been read it will return + * an error rather than a short-read. Otherwise behaves as + * qio_channel_preadv(). + * + * Returns: 1 if all bytes were read, 0 if end-of-file occurs + * without data, or -1 on error + */ +int coroutine_mixed_fn qio_channel_preadv_all_eof(QIOChannel *ioc, + const struct iovec *iov, + size_t niov, + off_t offset, + Error **errp); + +/** + * qio_channel_preadv_all: + * @ioc: the channel object + * @iov: the array of memory regions to read data into + * @niov: the length of the @iov array + * @offset: the starting offset in the channel to read from + * @errp: pointer to a NULL-initialized error object + * + * Reads @iov, possibly blocking or (if the channel is non-blocking) + * yielding from the current coroutine multiple times until the entire + * content is read. If end-of-file occurs before all requested data + * has been read, an error will be reported. Otherwise behaves as + * qio_channel_preadv(). + * + * Returns: 0 if all bytes were read, or -1 on error + */ +int coroutine_mixed_fn qio_channel_preadv_all(QIOChannel *ioc, + const struct iovec *iov, + size_t niov, + off_t offset, + Error **errp); + +/** + * qio_channel_pread_all_eof: + * @ioc: the channel object + * @buf: the memory region to read data into + * @buflen: the number of bytes to read into @buf + * @offset: the starting offset in the channel to read from + * @errp: pointer to a NULL-initialized error object + * + * Reads @buflen bytes, possibly blocking or (if the channel is + * non-blocking) yielding from the current coroutine multiple times + * until the entire content is read. If end-of-file occurs + * immediately it is not an error, but if it occurs after data has + * been read it will return an error rather than a short-read. + * Otherwise behaves as qio_channel_pread(). + * + * Returns: 1 if all bytes were read, 0 if end-of-file occurs + * without data, or -1 on error + */ +int coroutine_mixed_fn qio_channel_pread_all_eof(QIOChannel *ioc, + void *buf, + size_t buflen, + off_t offset, + Error **errp); + +/** + * qio_channel_pread_all: + * @ioc: the channel object + * @buf: the memory region to read data into + * @buflen: the number of bytes to read into @buf + * @offset: the starting offset in the channel to read from + * @errp: pointer to a NULL-initialized error object + * + * Reads @buflen bytes, possibly blocking or (if the channel is + * non-blocking) yielding from the current coroutine multiple times + * until the entire content is read. If end-of-file occurs before + * all requested data has been read, an error will be reported. + * Otherwise behaves as qio_channel_pread(). + * + * Returns: 0 if all bytes were read, or -1 on error + */ +int coroutine_mixed_fn qio_channel_pread_all(QIOChannel *ioc, + void *buf, + size_t buflen, + off_t offset, + Error **errp); + /** * qio_channel_shutdown: * @ioc: the channel object diff --git a/io/channel.c b/io/channel.c index cc02d997a4..52c1abfcbc 100644 --- a/io/channel.c +++ b/io/channel.c @@ -507,6 +507,97 @@ ssize_t qio_channel_pread(QIOChannel *ioc, void *buf, size_t buflen, return qio_channel_preadv(ioc, &iov, 1, offset, errp); } +int coroutine_mixed_fn qio_channel_preadv_all_eof(QIOChannel *ioc, + const struct iovec *iov, + size_t niov, + off_t offset, + Error **errp) +{ + int ret = -1; + struct iovec *local_iov = g_new(struct iovec, niov); + struct iovec *local_iov_head = local_iov; + unsigned int nlocal_iov = niov; + bool partial = false; + + nlocal_iov = iov_copy(local_iov, nlocal_iov, + iov, niov, + 0, iov_size(iov, niov)); + + while (nlocal_iov > 0) { + ssize_t len; + len = qio_channel_preadv(ioc, local_iov, nlocal_iov, offset, errp); + + if (len == QIO_CHANNEL_ERR_BLOCK) { + qio_channel_wait_cond(ioc, G_IO_IN); + continue; + } + + if (len == 0) { + if (!partial) { + ret = 0; + goto cleanup; + } + error_setg(errp, + "Unexpected end-of-file before all data were read"); + goto cleanup; + } + + if (len < 0) { + goto cleanup; + } + + partial = true; + offset += len; + iov_discard_front(&local_iov, &nlocal_iov, len); + } + + ret = 1; + + cleanup: + g_free(local_iov_head); + return ret; +} + +int coroutine_mixed_fn qio_channel_preadv_all(QIOChannel *ioc, + const struct iovec *iov, + size_t niov, + off_t offset, + Error **errp) +{ + int ret = qio_channel_preadv_all_eof(ioc, iov, niov, offset, errp); + + if (ret == 0) { + error_setg(errp, + "Unexpected end-of-file before all data were read"); + return -1; + } + if (ret == 1) { + return 0; + } + + return ret; +} + +int coroutine_mixed_fn qio_channel_pread_all_eof(QIOChannel *ioc, + void *buf, + size_t buflen, + off_t offset, + Error **errp) +{ + struct iovec iov = { .iov_base = buf, .iov_len = buflen }; + return qio_channel_preadv_all_eof(ioc, &iov, 1, offset, errp); +} + +int coroutine_mixed_fn qio_channel_pread_all(QIOChannel *ioc, + void *buf, + size_t buflen, + off_t offset, + Error **errp) +{ + struct iovec iov = { .iov_base = buf, .iov_len = buflen }; + return qio_channel_preadv_all(ioc, &iov, 1, offset, errp); +} + int qio_channel_shutdown(QIOChannel *ioc, QIOChannelShutdown how, Error **errp) -- 2.43.0