From nobody Wed Feb 11 18:14:05 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 AD714C77B61 for ; Tue, 11 Apr 2023 02:56:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229853AbjDKC4R (ORCPT ); Mon, 10 Apr 2023 22:56:17 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45276 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229485AbjDKC4P (ORCPT ); Mon, 10 Apr 2023 22:56:15 -0400 Received: from mail-pj1-x1034.google.com (mail-pj1-x1034.google.com [IPv6:2607:f8b0:4864:20::1034]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B2C0A1BC9 for ; Mon, 10 Apr 2023 19:56:14 -0700 (PDT) Received: by mail-pj1-x1034.google.com with SMTP id ie17-20020a17090b401100b00246d4b282eeso1710375pjb.2 for ; Mon, 10 Apr 2023 19:56:14 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; t=1681181774; x=1683773774; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to; bh=46R98SU833t0R10XzHYlOpO895zvMtz2LA3SFulzgmE=; b=GEklmf0n/S5DRaQJ693SPU4U4JpMCIAD+kogYccAJWVM99dOcntryBAAlulURVMXPf 67E6zvU1aOp86PwhjtBZv98Sd7SCmqLhlqN+DWdVOvw//Az+a7o5e8mi0vIq2/z6ANkB CqQgQ1d6tGvUGG9pK5xpq5iXRPMyYyafQKLT0= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; t=1681181774; x=1683773774; 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=46R98SU833t0R10XzHYlOpO895zvMtz2LA3SFulzgmE=; b=nrfMRiN9HS8bPzrDR96DeB5aY9ogAOmr4pfxRoC7xYKmK6ARPo4GEdDCnoXkOoE72I XN0EGj7ZFBCMDh/DtlRfjwh4U8SC0hEGXLRPdF84PWXqOzsvHXTFKyEEg8rtn9MTj6ow D61yvoAGENtnNt1+egil+Q5JsCPdhKNIsbVeIJRKxhk50lXaS6JV1JVWE3JlhF0Wd0rm kI7nphT9lSYoRC7ApzzwK764xN3DfCSeqdjDZ4324u7r3hB3ihK8hCnuR5pu30ilPDbM NSxPv7H9F+ktmjdiSebc1kCchs1F2Q8Pk1vnZXxZhyVSIpxOKfpRnDZBXW4VLwvStDe9 cMGw== X-Gm-Message-State: AAQBX9daWMC3jMwgmqZFHQ1+e4BqDnSzJvECkHb9I4PbH+ZGFi+8n/sy rJS74DPRrrzAxBT56aAftL1krQ== X-Google-Smtp-Source: AKy350b8czDvs//4crrZaUbUZPkhNDYPKeh6x3YDKO6c2ouQJ99nBKSnhnZVQswJ+3brzS0WTQqY3Q== X-Received: by 2002:a17:90b:4a52:b0:23f:c096:7129 with SMTP id lb18-20020a17090b4a5200b0023fc0967129mr17038301pjb.26.1681181774177; Mon, 10 Apr 2023 19:56:14 -0700 (PDT) Received: from tigerii.tok.corp.google.com ([2401:fa00:8f:203:5a35:4a16:21ec:1fcc]) by smtp.gmail.com with ESMTPSA id m17-20020a17090ade1100b00231227781d5sm5348982pjv.2.2023.04.10.19.56.12 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 10 Apr 2023 19:56:13 -0700 (PDT) From: Sergey Senozhatsky To: Steven Rostedt , Petr Mladek Cc: Andrew Morton , Yosry Ahmed , linux-kernel@vger.kernel.org, Sergey Senozhatsky Subject: [PATCH] seq_buf: add seq_buf_printk() helper Date: Tue, 11 Apr 2023 11:55:56 +0900 Message-Id: <20230411025556.751349-1-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 Tested-by: Yosry Ahmed --- include/linux/seq_buf.h | 2 ++ lib/seq_buf.c | 30 ++++++++++++++++++++++++++++++ 2 files changed, 32 insertions(+) diff --git a/include/linux/seq_buf.h b/include/linux/seq_buf.h index 5b31c5147969..80b78df89809 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_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..9d13004c2324 100644 --- a/lib/seq_buf.c +++ b/lib/seq_buf.c @@ -93,6 +93,36 @@ int seq_buf_printf(struct seq_buf *s, const char *fmt, .= ..) } EXPORT_SYMBOL_GPL(seq_buf_printf); =20 +/** + * seq_buf_printk - printk seq_buf line by line + * @s: seq_buf descriptor + * @lvl: printk level + * + * printk()-s a multi-line sequential buffer line by line + */ +void seq_buf_printk(struct seq_buf *s, const char *lvl) +{ + const char *start, *lf; + int len; + + if (s->size =3D=3D 0) + return; + + 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_printk); + #ifdef CONFIG_BINARY_PRINTF /** * seq_buf_bprintf - Write the printf string from binary arguments --=20 2.40.0.577.gac1e443424-goog