Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755273AbbESJOA (ORCPT ); Tue, 19 May 2015 05:14:00 -0400 Received: from szxga02-in.huawei.com ([119.145.14.65]:26710 "EHLO szxga02-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932276AbbESJNg (ORCPT ); Tue, 19 May 2015 05:13:36 -0400 From: Wang Long To: , , , CC: , , , , , , , , , Subject: [PATCH v2 09/17] tracing: Add seq_buf_get_buf() and seq_buf_commit() helper functions Date: Tue, 19 May 2015 09:08:54 +0000 Message-ID: <1432026542-123571-10-git-send-email-long.wanglong@huawei.com> X-Mailer: git-send-email 1.8.3.4 In-Reply-To: <1432026542-123571-1-git-send-email-long.wanglong@huawei.com> References: <1432026542-123571-1-git-send-email-long.wanglong@huawei.com> MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [10.107.197.200] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3295 Lines: 108 From: "Steven Rostedt (Red Hat)" commit 01cb06a4c229908d239149017049fdd1fca1dd51 upstream. Add two helper functions; seq_buf_get_buf() and seq_buf_commit() that are used by seq_buf_path(). This makes the code similar to the seq_file: seq_path() function, and will help to be able to consolidate the functions between seq_file and trace_seq. Link: http://lkml.kernel.org/r/20141104160222.644881406@goodmis.org Link: http://lkml.kernel.org/r/20141114011412.977571447@goodmis.org Tested-by: Jiri Kosina Acked-by: Jiri Kosina Reviewed-by: Petr Mladek [wanglong: backport to 3.10 stable] Signed-off-by: Wang Long Signed-off-by: Steven Rostedt --- include/linux/seq_buf.h | 41 +++++++++++++++++++++++++++++++++++++++++ kernel/trace/seq_buf.c | 7 +++---- 2 files changed, 44 insertions(+), 4 deletions(-) diff --git a/include/linux/seq_buf.h b/include/linux/seq_buf.h index 0800a24..12c6428 100644 --- a/include/linux/seq_buf.h +++ b/include/linux/seq_buf.h @@ -70,6 +70,47 @@ static inline unsigned int seq_buf_used(struct seq_buf *s) return min(s->len, s->size); } +/** + * seq_buf_get_buf - get buffer to write arbitrary data to + * @s: the seq_buf handle + * @bufp: the beginning of the buffer is stored here + * + * Return the number of bytes available in the buffer, or zero if + * there's no space. + */ +static inline size_t seq_buf_get_buf(struct seq_buf *s, char **bufp) +{ + WARN_ON(s->len > s->size + 1); + + if (s->len < s->size) { + *bufp = s->buffer + s->len; + return s->size - s->len; + } + + *bufp = NULL; + return 0; +} + +/** + * seq_buf_commit - commit data to the buffer + * @s: the seq_buf handle + * @num: the number of bytes to commit + * + * Commit @num bytes of data written to a buffer previously acquired + * by seq_buf_get. To signal an error condition, or that the data + * didn't fit in the available space, pass a negative @num value. + */ +static inline void seq_buf_commit(struct seq_buf *s, int num) +{ + if (num < 0) { + seq_buf_set_overflow(s); + } else { + /* num must be negative on overflow */ + BUG_ON(s->len + num > s->size); + s->len += num; + } +} + extern __printf(2, 3) int seq_buf_printf(struct seq_buf *s, const char *fmt, ...); extern __printf(2, 0) diff --git a/kernel/trace/seq_buf.c b/kernel/trace/seq_buf.c index c53f1d5..086f594 100644 --- a/kernel/trace/seq_buf.c +++ b/kernel/trace/seq_buf.c @@ -293,8 +293,8 @@ int seq_buf_putmem_hex(struct seq_buf *s, const void *mem, */ int seq_buf_path(struct seq_buf *s, const struct path *path, const char *esc) { - char *buf = s->buffer + s->len; - size_t size = seq_buf_buffer_left(s); + char *buf; + size_t size = seq_buf_get_buf(s, &buf); int res = -1; WARN_ON(s->size == 0); @@ -307,8 +307,7 @@ int seq_buf_path(struct seq_buf *s, const struct path *path, const char *esc) res = end - buf; } } - if (res > 0) - s->len += res; + seq_buf_commit(s, res); return res; } -- 1.8.3.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/