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 X-Spam-Level: X-Spam-Status: No, score=-15.2 required=3.0 tests=BAYES_00, BUG6152_INVALID_DATE_TZ_ABSURD,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, INVALID_DATE_TZ_ABSURD,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 72F3BC1B0D9 for ; Mon, 7 Dec 2020 22:21:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 50B5B23976 for ; Mon, 7 Dec 2020 22:21:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728081AbgLGWVM (ORCPT ); Mon, 7 Dec 2020 17:21:12 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57486 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727942AbgLGWVE (ORCPT ); Mon, 7 Dec 2020 17:21:04 -0500 Received: from galois.linutronix.de (Galois.linutronix.de [IPv6:2a0a:51c0:0:12e:550::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A5F3EC061793 for ; Mon, 7 Dec 2020 14:20:23 -0800 (PST) From: John Ogness DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1607379621; 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=4cjdwuUZXyhbLW+Gtg3A2qyd0nc89zig5cOMQo+9MUI=; b=T+dAI4LyCSQKZuxOlr4hRv+9Y3ICW4IT8m14esL2SKlk7yWVExy2szbiRvyH4kFI4doxx8 ivcz48Og0Ur6Ba9DEmL+cpe/8CVj1iBSD9XVUXMaK7a2XsHyfinAyxiJfNGdLnw14vtta0 3b11dojRmP+87yXLpMEMY31Lm3G5igolMAru++Fyd0Qbt1r+4GxfXyoFRoYoOYcSPSCtJL puEXnLtSg0J0nKkWwOPWsa1JvcD03CUlOgasyUAsEdLoPZ2oq+Jga/3zNnWvfFUQ0oJ0w0 6YspbsQ/ew8ReK1YRdxEMqwuta72d6Z1NZ1w3QzB/0YOzgwWxeZLexCfZE8gFQ== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1607379621; 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=4cjdwuUZXyhbLW+Gtg3A2qyd0nc89zig5cOMQo+9MUI=; b=BiEA4333PhdroYg67T4XF4eQ1XuyVDG6rU1KtRmikLaTBhNXLil94cbFrDPLjdsL5sBHbg GT82NN/6feHGJjAA== To: Petr Mladek Cc: Sergey Senozhatsky , Sergey Senozhatsky , Steven Rostedt , Linus Torvalds , Greg Kroah-Hartman , Thomas Gleixner , linux-kernel@vger.kernel.org Subject: [PATCH next v3 1/3] printk: inline log_output(),log_store() in vprintk_store() Date: Mon, 7 Dec 2020 23:26:18 +0106 Message-Id: <20201207222020.2923-2-john.ogness@linutronix.de> In-Reply-To: <20201207222020.2923-1-john.ogness@linutronix.de> References: <20201207222020.2923-1-john.ogness@linutronix.de> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org In preparation for removing logbuf_lock, inline log_output() and log_store() into vprintk_store(). This will simplify dealing with the various code branches and fallbacks that are possible. Signed-off-by: John Ogness Reviewed-by: Petr Mladek Reviewed-by: Sergey Senozhatsky --- kernel/printk/printk.c | 145 +++++++++++++++++++---------------------- 1 file changed, 67 insertions(+), 78 deletions(-) diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c index f279d4fbd9dd..bf5fd2be3a05 100644 --- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c @@ -491,52 +491,6 @@ static void truncate_msg(u16 *text_len, u16 *trunc_msg_len) *trunc_msg_len = 0; } -/* insert record into the buffer, discard old ones, update heads */ -static int log_store(u32 caller_id, int facility, int level, - enum log_flags flags, u64 ts_nsec, - const struct dev_printk_info *dev_info, - const char *text, u16 text_len) -{ - struct prb_reserved_entry e; - struct printk_record r; - u16 trunc_msg_len = 0; - - prb_rec_init_wr(&r, text_len); - - if (!prb_reserve(&e, prb, &r)) { - /* truncate the message if it is too long for empty buffer */ - truncate_msg(&text_len, &trunc_msg_len); - prb_rec_init_wr(&r, text_len + trunc_msg_len); - /* survive when the log buffer is too small for trunc_msg */ - if (!prb_reserve(&e, prb, &r)) - return 0; - } - - /* fill message */ - memcpy(&r.text_buf[0], text, text_len); - if (trunc_msg_len) - memcpy(&r.text_buf[text_len], trunc_msg, trunc_msg_len); - r.info->text_len = text_len + trunc_msg_len; - r.info->facility = facility; - r.info->level = level & 7; - r.info->flags = flags & 0x1f; - if (ts_nsec > 0) - r.info->ts_nsec = ts_nsec; - else - r.info->ts_nsec = local_clock(); - r.info->caller_id = caller_id; - if (dev_info) - memcpy(&r.info->dev_info, dev_info, sizeof(r.info->dev_info)); - - /* A message without a trailing newline can be continued. */ - if (!(flags & LOG_NEWLINE)) - prb_commit(&e); - else - prb_final_commit(&e); - - return (text_len + trunc_msg_len); -} - int dmesg_restrict = IS_ENABLED(CONFIG_SECURITY_DMESG_RESTRICT); static int syslog_action_restricted(int type) @@ -1907,44 +1861,28 @@ static inline u32 printk_caller_id(void) 0x80000000 + raw_smp_processor_id(); } -static size_t log_output(int facility, int level, enum log_flags lflags, - const struct dev_printk_info *dev_info, - char *text, size_t text_len) -{ - const u32 caller_id = printk_caller_id(); - - if (lflags & LOG_CONT) { - struct prb_reserved_entry e; - struct printk_record r; - - prb_rec_init_wr(&r, text_len); - if (prb_reserve_in_last(&e, prb, &r, caller_id, LOG_LINE_MAX)) { - memcpy(&r.text_buf[r.info->text_len], text, text_len); - r.info->text_len += text_len; - if (lflags & LOG_NEWLINE) { - r.info->flags |= LOG_NEWLINE; - prb_final_commit(&e); - } else { - prb_commit(&e); - } - return text_len; - } - } - - /* Store it in the record log */ - return log_store(caller_id, facility, level, lflags, 0, - dev_info, text, text_len); -} - /* Must be called under logbuf_lock. */ int vprintk_store(int facility, int level, const struct dev_printk_info *dev_info, const char *fmt, va_list args) { + const u32 caller_id = printk_caller_id(); static char textbuf[LOG_LINE_MAX]; - char *text = textbuf; - size_t text_len; + struct prb_reserved_entry e; enum log_flags lflags = 0; + struct printk_record r; + u16 trunc_msg_len = 0; + char *text = textbuf; + u16 text_len; + u64 ts_nsec; + + /* + * Since the duration of printk() can vary depending on the message + * and state of the ringbuffer, grab the timestamp now so that it is + * close to the call of printk(). This provides a more deterministic + * timestamp with respect to the caller. + */ + ts_nsec = local_clock(); /* * The printf needs to come first; we need the syslog @@ -1983,7 +1921,58 @@ int vprintk_store(int facility, int level, if (dev_info) lflags |= LOG_NEWLINE; - return log_output(facility, level, lflags, dev_info, text, text_len); + if (lflags & LOG_CONT) { + prb_rec_init_wr(&r, text_len); + if (prb_reserve_in_last(&e, prb, &r, caller_id, LOG_LINE_MAX)) { + memcpy(&r.text_buf[r.info->text_len], text, text_len); + r.info->text_len += text_len; + + if (lflags & LOG_NEWLINE) { + r.info->flags |= LOG_NEWLINE; + prb_final_commit(&e); + } else { + prb_commit(&e); + } + + return text_len; + } + } + + /* + * Explicitly initialize the record before every prb_reserve() call. + * prb_reserve_in_last() and prb_reserve() purposely invalidate the + * structure when they fail. + */ + prb_rec_init_wr(&r, text_len); + if (!prb_reserve(&e, prb, &r)) { + /* truncate the message if it is too long for empty buffer */ + truncate_msg(&text_len, &trunc_msg_len); + + prb_rec_init_wr(&r, text_len + trunc_msg_len); + if (!prb_reserve(&e, prb, &r)) + return 0; + } + + /* fill message */ + memcpy(&r.text_buf[0], text, text_len); + if (trunc_msg_len) + memcpy(&r.text_buf[text_len], trunc_msg, trunc_msg_len); + r.info->text_len = text_len + trunc_msg_len; + r.info->facility = facility; + r.info->level = level & 7; + r.info->flags = lflags & 0x1f; + r.info->ts_nsec = ts_nsec; + r.info->caller_id = caller_id; + if (dev_info) + memcpy(&r.info->dev_info, dev_info, sizeof(r.info->dev_info)); + + /* A message without a trailing newline can be continued. */ + if (!(lflags & LOG_NEWLINE)) + prb_commit(&e); + else + prb_final_commit(&e); + + return (text_len + trunc_msg_len); } asmlinkage int vprintk_emit(int facility, int level, -- 2.20.1