From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755536Ab0INU2t (ORCPT ); Tue, 14 Sep 2010 16:28:49 -0400 Received: from hrndva-omtalb.mail.rr.com ([71.74.56.125]:46028 "EHLO hrndva-omtalb.mail.rr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755349Ab0INU2o (ORCPT ); Tue, 14 Sep 2010 16:28:44 -0400 X-Authority-Analysis: v=1.1 cv=8l6A00wGdfxWf8DimOOtudg6dZOi9rXZmlWhmOLJpog= c=1 sm=0 a=8zscghigsQMA:10 a=bbbx4UPp9XUA:10 a=OPBmh+XkhLl+Enan7BmTLg==:17 a=20KFwNOVAAAA:8 a=meVymXHHAAAA:8 a=e3wGGlKu-nvtmt4V_JQA:9 a=HybK2k321xJG8tzuhk0A:7 a=mTsfN4b4h77MWf7bwp-7v3HTw6UA:4 a=jEp0ucaQiEUA:10 a=jeBq3FmKZ4MA:10 a=OPBmh+XkhLl+Enan7BmTLg==:117 X-Cloudmark-Score: 0 X-Originating-IP: 67.242.120.143 Message-Id: <20100914202842.876447635@goodmis.org> User-Agent: quilt/0.48-1 Date: Tue, 14 Sep 2010 16:27:17 -0400 From: Steven Rostedt To: linux-kernel@vger.kernel.org Cc: Ingo Molnar , Andrew Morton Subject: [PATCH 3/4] tracing: Keep track of set_ftrace_filter position and allow lseek again References: <20100914202714.376849326@goodmis.org> Content-Disposition: inline; filename=0003-tracing-Keep-track-of-set_ftrace_filter-position-and.patch Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Steven Rostedt This patch keeps track of the index within the elements of set_ftrace_filter and if the position goes backwards, it nicely resets and starts from the beginning again. This allows for lseek and pread to work properly now. Signed-off-by: Steven Rostedt --- kernel/trace/ftrace.c | 34 ++++++++++++++++++++++++++-------- 1 files changed, 26 insertions(+), 8 deletions(-) diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index c8db0db..2d51166 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -1368,6 +1368,7 @@ enum { #define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */ struct ftrace_iterator { + loff_t pos; loff_t func_pos; struct ftrace_page *pg; struct dyn_ftrace *func; @@ -1385,9 +1386,8 @@ t_hash_next(struct seq_file *m, loff_t *pos) struct hlist_node *hnd = NULL; struct hlist_head *hhd; - WARN_ON(!(iter->flags & FTRACE_ITER_HASH)); - (*pos)++; + iter->pos = *pos; if (iter->probe) hnd = &iter->probe->node; @@ -1427,14 +1427,9 @@ static void *t_hash_start(struct seq_file *m, loff_t *pos) void *p = NULL; loff_t l; - if (!(iter->flags & FTRACE_ITER_HASH)) - iter->func_pos = *pos; - if (iter->func_pos > *pos) return NULL; - iter->flags |= FTRACE_ITER_HASH; - iter->hidx = 0; for (l = 0; l <= (*pos - iter->func_pos); ) { p = t_hash_next(m, &l); @@ -1444,6 +1439,9 @@ static void *t_hash_start(struct seq_file *m, loff_t *pos) if (!p) return NULL; + /* Only set this if we have an item */ + iter->flags |= FTRACE_ITER_HASH; + return iter; } @@ -1478,6 +1476,8 @@ t_next(struct seq_file *m, void *v, loff_t *pos) return t_hash_next(m, pos); (*pos)++; + iter->pos = *pos; + iter->func_pos = *pos; if (iter->flags & FTRACE_ITER_PRINTALL) return NULL; @@ -1517,6 +1517,13 @@ t_next(struct seq_file *m, void *v, loff_t *pos) return iter; } +static void reset_iter_read(struct ftrace_iterator *iter) +{ + iter->pos = 0; + iter->func_pos = 0; + iter->flags &= ~(FTRACE_ITER_PRINTALL & FTRACE_ITER_HASH); +} + static void *t_start(struct seq_file *m, loff_t *pos) { struct ftrace_iterator *iter = m->private; @@ -1525,6 +1532,12 @@ static void *t_start(struct seq_file *m, loff_t *pos) mutex_lock(&ftrace_lock); /* + * If an lseek was done, then reset and start from beginning. + */ + if (*pos < iter->pos) + reset_iter_read(iter); + + /* * For set_ftrace_filter reading, if we have the filter * off, we can short cut and just print out that all * functions are enabled. @@ -1541,6 +1554,11 @@ static void *t_start(struct seq_file *m, loff_t *pos) if (iter->flags & FTRACE_ITER_HASH) return t_hash_start(m, pos); + /* + * Unfortunately, we need to restart at ftrace_pages_start + * every time we let go of the ftrace_mutex. This is because + * those pointers can change without the lock. + */ iter->pg = ftrace_pages_start; iter->idx = 0; for (l = 0; l <= *pos; ) { @@ -2447,7 +2465,7 @@ static const struct file_operations ftrace_filter_fops = { .open = ftrace_filter_open, .read = seq_read, .write = ftrace_filter_write, - .llseek = no_llseek, + .llseek = ftrace_regex_lseek, .release = ftrace_filter_release, }; -- 1.7.1