perf evlist: Refactor mmap_pages parsing

Logic will be re-used for the out-pages argument for mmap based writes
in perf-record.

Signed-off-by: David Ahern <dsahern@gmail.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/1384267617-3446-4-git-send-email-dsahern@gmail.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 28 insertions, 11 deletions

diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
index fb4727d3df85..cb19044601bb 100644
--- a/tools/perf/util/evlist.c
+++ b/tools/perf/util/evlist.c
@@ -705,10 +705,9 @@ static size_t perf_evlist__mmap_size(unsigned long pages)
         return (pages + 1) * page_size;
 }
 
-int perf_evlist__parse_mmap_pages(const struct option *opt, const char *str,
-                                  int unset __maybe_unused)
+static long parse_pages_arg(const char *str, unsigned long min,
+                            unsigned long max)
 {
-        unsigned int *mmap_pages = opt->value;
         unsigned long pages, val;
         static struct parse_tag tags[] = {
                 { .tag  = 'B', .mult = 1       },
@@ -719,7 +718,7 @@ int perf_evlist__parse_mmap_pages(const struct option *opt, const char *str,
         };
 
         if (str == NULL)
-                return -1;
+                return -EINVAL;
 
         val = parse_tag_value(str, tags);
         if (val != (unsigned long) -1) {
@@ -729,20 +728,38 @@ int perf_evlist__parse_mmap_pages(const struct option *opt, const char *str,
                 /* we got pages count value */
                 char *eptr;
                 pages = strtoul(str, &eptr, 10);
-                if (*eptr != '\0') {
-                        pr_err("failed to parse --mmap_pages/-m value\n");
-                        return -1;
-                }
+                if (*eptr != '\0')
+                        return -EINVAL;
         }
 
-        if (pages < (1UL << 31) && !is_power_of_2(pages)) {
+        if ((pages == 0) && (min == 0)) {
+                /* leave number of pages at 0 */
+        } else if (pages < (1UL << 31) && !is_power_of_2(pages)) {
+                /* round pages up to next power of 2 */
                 pages = next_pow2(pages);
                 pr_info("rounding mmap pages size to %lu bytes (%lu pages)\n",
                         pages * page_size, pages);
         }
 
-        if (pages > UINT_MAX || pages > SIZE_MAX / page_size) {
-                pr_err("--mmap_pages/-m value too big\n");
+        if (pages > max)
+                return -EINVAL;
+
+        return pages;
+}
+
+int perf_evlist__parse_mmap_pages(const struct option *opt, const char *str,
+                                  int unset __maybe_unused)
+{
+        unsigned int *mmap_pages = opt->value;
+        unsigned long max = UINT_MAX;
+        long pages;
+
+        if (max < SIZE_MAX / page_size)
+                max = SIZE_MAX / page_size;
+
+        pages = parse_pages_arg(str, 1, max);
+        if (pages < 0) {
+                pr_err("Invalid argument for --mmap_pages/-m\n");
                 return -1;
         }