kallsyms: Simplify update_iter_mod()

The logic in update_iter_mod() is overcomplicated and gets worse every
time another get_ksymbol_* function is added.

In preparation for adding another get_ksymbol_* function, simplify logic
in update_iter_mod().

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Tested-by: (ftrace changes only) Steven Rostedt (VMware) <rostedt@goodmis.org>
Acked-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: x86@kernel.org
Link: http://lkml.kernel.org/r/1528289651-4113-2-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/kernel/kallsyms.c b/kernel/kallsyms.c
index a23e21ada81b9dc6cbc8cd21c04805072bb98438..aa31aa07f2ef728e0f79fe334f7d6fcb43a91434 100644 (file)
--- a/kernel/kallsyms.c
+++ b/kernel/kallsyms.c
@@ -506,27 +506,24 @@ static void reset_iter(struct kallsym_iter *iter, loff_t new_pos)
        }
 }
 
+/*
+ * The end position (last + 1) of each additional kallsyms section is recorded
+ * in iter->pos_..._end as each section is added, and so can be used to
+ * determine which get_ksymbol_...() function to call next.
+ */
 static int update_iter_mod(struct kallsym_iter *iter, loff_t pos)
 {
        iter->pos = pos;
 
-       if (iter->pos_ftrace_mod_end > 0 &&
-           iter->pos_ftrace_mod_end < iter->pos)
-               return get_ksymbol_bpf(iter);
-
-       if (iter->pos_mod_end > 0 &&
-           iter->pos_mod_end < iter->pos) {
-               if (!get_ksymbol_ftrace_mod(iter))
-                       return get_ksymbol_bpf(iter);
+       if ((!iter->pos_mod_end || iter->pos_mod_end > pos) &&
+           get_ksymbol_mod(iter))
                return 1;
-       }
 
-       if (!get_ksymbol_mod(iter)) {
-               if (!get_ksymbol_ftrace_mod(iter))
-                       return get_ksymbol_bpf(iter);
-       }
+       if ((!iter->pos_ftrace_mod_end || iter->pos_ftrace_mod_end > pos) &&
+           get_ksymbol_ftrace_mod(iter))
+               return 1;
 
-       return 1;
+       return get_ksymbol_bpf(iter);
 }
 
 /* Returns false if pos at or past end of file. */