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author | Steven Rostedt (VMware) <rostedt@goodmis.org> | 2017-03-29 22:45:18 -0400 |
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committer | Steven Rostedt (VMware) <rostedt@goodmis.org> | 2017-03-31 18:00:45 -0400 |
commit | 5bd84629a7a0e2462c28ca52e213ebe27fadfee8 (patch) | |
tree | 9fef370dae724a4822358278d0591ba5da1c3a4f /kernel | |
parent | 43ff926a0c3a0cfd6aa313c3232420f009ab43e8 (diff) | |
download | linux-5bd84629a7a0e2462c28ca52e213ebe27fadfee8.tar.gz linux-5bd84629a7a0e2462c28ca52e213ebe27fadfee8.tar.bz2 linux-5bd84629a7a0e2462c28ca52e213ebe27fadfee8.zip |
ftrace: Create separate t_func_next() to simplify the function / hash logic
I noticed that if I use dd to read the set_ftrace_filter file that the first
hash command is repeated.
# cd /sys/kernel/debug/tracing
# echo schedule > set_ftrace_filter
# echo do_IRQ >> set_ftrace_filter
# echo schedule:traceoff >> set_ftrace_filter
# echo do_IRQ:traceoff >> set_ftrace_filter
# cat set_ftrace_filter
schedule
do_IRQ
schedule:traceoff:unlimited
do_IRQ:traceoff:unlimited
# dd if=set_ftrace_filter bs=1
schedule
do_IRQ
schedule:traceoff:unlimited
schedule:traceoff:unlimited
do_IRQ:traceoff:unlimited
98+0 records in
98+0 records out
98 bytes copied, 0.00265011 s, 37.0 kB/s
This is due to the way t_start() calls t_next() as well as the seq_file
calls t_next() and the state is slightly different between the two. Namely,
t_start() will call t_next() with a local "pos" variable.
By separating out the function listing from t_next() into its own function,
we can have better control of outputting the functions and the hash of
triggers. This simplifies the code.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Diffstat (limited to 'kernel')
-rw-r--r-- | kernel/trace/ftrace.c | 45 |
1 files changed, 31 insertions, 14 deletions
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index d4b18ce9ba88..aff7a2c08387 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -3154,22 +3154,12 @@ t_hash_show(struct seq_file *m, struct ftrace_iterator *iter) } static void * -t_next(struct seq_file *m, void *v, loff_t *pos) +t_func_next(struct seq_file *m, loff_t *pos) { struct ftrace_iterator *iter = m->private; struct dyn_ftrace *rec = NULL; - if (unlikely(ftrace_disabled)) - return NULL; - - if (iter->flags & FTRACE_ITER_HASH) - return t_hash_next(m, pos); - (*pos)++; - iter->pos = iter->func_pos = *pos; - - if (iter->flags & FTRACE_ITER_PRINTALL) - return t_hash_start(m, pos); retry: if (iter->idx >= iter->pg->index) { @@ -3192,13 +3182,40 @@ t_next(struct seq_file *m, void *v, loff_t *pos) } if (!rec) - return t_hash_start(m, pos); + return NULL; + iter->pos = iter->func_pos = *pos; iter->func = rec; return iter; } +static void * +t_next(struct seq_file *m, void *v, loff_t *pos) +{ + struct ftrace_iterator *iter = m->private; + void *ret; + + if (unlikely(ftrace_disabled)) + return NULL; + + if (iter->flags & FTRACE_ITER_HASH) + return t_hash_next(m, pos); + + if (iter->flags & FTRACE_ITER_PRINTALL) { + /* next must increment pos, and t_hash_start does not */ + (*pos)++; + return t_hash_start(m, pos); + } + + ret = t_func_next(m, pos); + + if (!ret) + return t_hash_start(m, pos); + + return ret; +} + static void reset_iter_read(struct ftrace_iterator *iter) { iter->pos = 0; @@ -3250,13 +3267,13 @@ static void *t_start(struct seq_file *m, loff_t *pos) iter->pg = ftrace_pages_start; iter->idx = 0; for (l = 0; l <= *pos; ) { - p = t_next(m, p, &l); + p = t_func_next(m, &l); if (!p) break; } if (!p) - return NULL; + return t_hash_start(m, pos); return iter; } |