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Subject[PATCH 02/10] ftrace: Separate out functionality from ftrace_location_range()
From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>

Create a new function called lookup_rec() from the functionality of
ftrace_location_range(). The difference between lookup_rec() is that it
returns the record that it finds, where as ftrace_location_range() returns
only if it found a match or not.

The lookup_rec() is static, and can be used for new functionality where
ftrace needs to find a record of a specific address.

Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
kernel/trace/ftrace.c | 38 +++++++++++++++++++++++---------------
1 file changed, 23 insertions(+), 15 deletions(-)

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 76e5de8c7822..b0e7f03919de 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -1541,6 +1541,26 @@ static int ftrace_cmp_recs(const void *a, const void *b)
return 0;
}

+static struct dyn_ftrace *lookup_rec(unsigned long start, unsigned long end)
+{
+ struct ftrace_page *pg;
+ struct dyn_ftrace *rec = NULL;
+ struct dyn_ftrace key;
+
+ key.ip = start;
+ key.flags = end; /* overload flags, as it is unsigned long */
+
+ for (pg = ftrace_pages_start; pg; pg = pg->next) {
+ if (end < pg->records[0].ip ||
+ start >= (pg->records[pg->index - 1].ip + MCOUNT_INSN_SIZE))
+ continue;
+ rec = bsearch(&key, pg->records, pg->index,
+ sizeof(struct dyn_ftrace),
+ ftrace_cmp_recs);
+ }
+ return rec;
+}
+
/**
* ftrace_location_range - return the first address of a traced location
* if it touches the given ip range
@@ -1555,23 +1575,11 @@ static int ftrace_cmp_recs(const void *a, const void *b)
*/
unsigned long ftrace_location_range(unsigned long start, unsigned long end)
{
- struct ftrace_page *pg;
struct dyn_ftrace *rec;
- struct dyn_ftrace key;

- key.ip = start;
- key.flags = end; /* overload flags, as it is unsigned long */
-
- for (pg = ftrace_pages_start; pg; pg = pg->next) {
- if (end < pg->records[0].ip ||
- start >= (pg->records[pg->index - 1].ip + MCOUNT_INSN_SIZE))
- continue;
- rec = bsearch(&key, pg->records, pg->index,
- sizeof(struct dyn_ftrace),
- ftrace_cmp_recs);
- if (rec)
- return rec->ip;
- }
+ rec = lookup_rec(start, end);
+ if (rec)
+ return rec->ip;

return 0;
}
--
2.23.0

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