From nobody Wed Feb 11 20:04:00 2026 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 457CEC77B6F for ; Tue, 11 Apr 2023 14:39:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229727AbjDKOjP (ORCPT ); Tue, 11 Apr 2023 10:39:15 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53688 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229659AbjDKOjC (ORCPT ); Tue, 11 Apr 2023 10:39:02 -0400 Received: from mail-pj1-x1035.google.com (mail-pj1-x1035.google.com [IPv6:2607:f8b0:4864:20::1035]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B5E7A2683 for ; Tue, 11 Apr 2023 07:39:01 -0700 (PDT) Received: by mail-pj1-x1035.google.com with SMTP id 98e67ed59e1d1-246a1c48021so349309a91.3 for ; Tue, 11 Apr 2023 07:39:01 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; t=1681223941; x=1683815941; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to; bh=t3POXpBLOYkBNAqAT4V8Vzl8XKzx70OKFxmrdLGlI7U=; b=G1vyVng5aGWTk1Uq+ONgBFyZF/zKnJYI6UZMPEViRLwOA1kthwmJlZvq7JcygFc61l HlzEPjljVorrtzNSwZ3snpgIo85FrK8X3Cm5YwC1Y8D1hJ5AbaFE/jcAlhVdw6n/qj/d e6Ma4T/ZGuS8k5jNeuTDjeASqx/3qBEMRC8Ww= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; t=1681223941; x=1683815941; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=t3POXpBLOYkBNAqAT4V8Vzl8XKzx70OKFxmrdLGlI7U=; b=sMhtvJJLrW/xNxHzWPDkXAmxxlnAKPecg6HGvRKwFQWi9ATm9TVSyZmtySD8qU7jjC zZfRE4tC1cdTK4Wbx1m5nuKrWLUvp7eGTeB2Muy2pIJIuVSYrIAjeGgdEaxYKDjuxJJF LOUGrtPhqcKpKaWIziihgR7XhsY+mb2/bAEp+kMJztRCBl0RYaQIA0R0E3ngjSTJihCE f2OhrIpDtS0xQaFbH8KOZW8WmgeEDYJHTkJL6+khvYKo31E2k6VDMP87p1mFCPg/3cwy hFLvLao026rayzE/9kB+6kssYB3ZmM/t9FPkS5pYUoOVkNCZpvogrLr6dLwHxvbhtgub wYlw== X-Gm-Message-State: AAQBX9dKlNRaokpLuWQKOS1DXcC6zJNUOi1V4Sg/S6c2s9IzEntimHaS T1tSz+pk4uf7iB3PaushrQsCcQ== X-Google-Smtp-Source: AKy350bMuVL92dqZWO2yg0IrJyEZRI7Oi/TOcVmN0FZHJYilmGl32j1KaRME49/fg/vxl62XwxIPTA== X-Received: by 2002:aa7:9a41:0:b0:63a:38d2:d41f with SMTP id x1-20020aa79a41000000b0063a38d2d41fmr5346199pfj.29.1681223941186; Tue, 11 Apr 2023 07:39:01 -0700 (PDT) Received: from tigerii.tok.corp.google.com ([2401:fa00:8f:203:c8e3:b775:3b12:ac9e]) by smtp.gmail.com with ESMTPSA id k14-20020aa790ce000000b005abc0d426c4sm9897799pfk.54.2023.04.11.07.38.59 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 11 Apr 2023 07:39:00 -0700 (PDT) From: Sergey Senozhatsky To: Steven Rostedt , Petr Mladek Cc: Andrew Morton , Yosry Ahmed , linux-kernel@vger.kernel.org, Sergey Senozhatsky Subject: [PATCHv2] seq_buf: add seq_buf_do_printk() helper Date: Tue, 11 Apr 2023 23:38:52 +0900 Message-Id: <20230411143852.868524-1-senozhatsky@chromium.org> X-Mailer: git-send-email 2.40.0.577.gac1e443424-goog MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" Sometimes we use seq_buf to format a string buffer, which we then pass to printk(). However, in certain situations the seq_buf string buffer can get too big, exceeding the PRINTKRB_RECORD_MAX bytes limit, and causing printk() to truncate the string. Add a new seq_buf helper. This helper prints the seq_buf string buffer line by line, using \n as a delimiter, rather than passing the whole string buffer to printk() at once. Signed-off-by: Sergey Senozhatsky Reviewed-by: Petr Mladek --- include/linux/seq_buf.h | 2 ++ lib/seq_buf.c | 34 ++++++++++++++++++++++++++++++++++ 2 files changed, 36 insertions(+) diff --git a/include/linux/seq_buf.h b/include/linux/seq_buf.h index 5b31c5147969..515d7fcb9634 100644 --- a/include/linux/seq_buf.h +++ b/include/linux/seq_buf.h @@ -159,4 +159,6 @@ extern int seq_buf_bprintf(struct seq_buf *s, const char *fmt, const u32 *binary); #endif =20 +void seq_buf_do_printk(struct seq_buf *s, const char *lvl); + #endif /* _LINUX_SEQ_BUF_H */ diff --git a/lib/seq_buf.c b/lib/seq_buf.c index 0a68f7aa85d6..be7227d42b20 100644 --- a/lib/seq_buf.c +++ b/lib/seq_buf.c @@ -93,6 +93,40 @@ int seq_buf_printf(struct seq_buf *s, const char *fmt, .= ..) } EXPORT_SYMBOL_GPL(seq_buf_printf); =20 +/** + * seq_buf_do_printk - printk seq_buf line by line + * @s: seq_buf descriptor + * @lvl: printk level + * + * printk()-s a multi-line sequential buffer line by line. The function + * makes sure that the buffer in @s is nul terminated and safe to read + * as a string. + */ +void seq_buf_do_printk(struct seq_buf *s, const char *lvl) +{ + const char *start, *lf; + int len; + + if (s->size =3D=3D 0 || s->len =3D=3D 0) + return; + + seq_buf_terminate(s); + + start =3D s->buffer; + while ((lf =3D strchr(start, '\n'))) { + len =3D lf - start + 1; + printk("%s%.*s", lvl, len, start); + start =3D ++lf; + } + + /* No trailing LF */ + if (start < s->buffer + s->len) { + len =3D s->buffer + s->len - start; + printk("%s%.*s\n", lvl, len, start); + } +} +EXPORT_SYMBOL_GPL(seq_buf_do_printk); + #ifdef CONFIG_BINARY_PRINTF /** * seq_buf_bprintf - Write the printf string from binary arguments --=20 2.40.0.577.gac1e443424-goog