[PATCH 03/21] call BLKTRACESETUP2 ioctl per default to setup a trace

[Johannes Thumshirn]

Call BLKTRACESETUP2 ioctl per default and if the kernel does not support
this ioctl because it is too old, fall back to calling BLKTRACESETUP.

Signed-off-by: Johannes Thumshirn <johannes.thumsh...@wdc.com>
---
 blktrace.c | 40 ++++++++++++++++++++++++++++++++++++----
 1 file changed, 36 insertions(+), 4 deletions(-)

diff --git a/blktrace.c b/blktrace.c
index 038b2cb..72562fd 100644
--- a/blktrace.c
+++ b/blktrace.c
@@ -279,7 +279,7 @@ static int max_cpus;
 static int ncpus;
 static cpu_set_t *online_cpus;
 static int pagesize;
-static int act_mask = ~0U;
+static unsigned long long act_mask = ~0U;
 static int kill_running_trace;
 static int stop_watch;
 static int piped_output;
@@ -1067,6 +1067,36 @@ static void close_client_connections(void)
        }
 }
 
+static int setup_buts2(void)
+{
+       struct list_head *p;
+       int ret = 0;
+
+       __list_for_each(p, &devpaths) {
+               struct blk_user_trace_setup2 buts2;
+               struct devpath *dpp = list_entry(p, struct devpath, head);
+
+               memset(&buts2, 0, sizeof(buts2));
+               buts2.buf_size = buf_size;
+               buts2.buf_nr = buf_nr;
+               buts2.act_mask = act_mask;
+
+               if (ioctl(dpp->fd, BLKTRACESETUP2, &buts2) >= 0) {
+                       dpp->ncpus = max_cpus;
+                       dpp->buts_name = strdup(buts2.name);
+                       dpp->setup_done = 1;
+                       if (dpp->stats)
+                               free(dpp->stats);
+                       dpp->stats = calloc(dpp->ncpus, sizeof(*dpp->stats));
+                       memset(dpp->stats, 0, dpp->ncpus * sizeof(*dpp->stats));
+               } else {
+                       ret++;
+               }
+       }
+
+       return ret;
+}
+
 static int setup_buts(void)
 {
        struct list_head *p;
@@ -2684,9 +2714,11 @@ static int run_tracers(void)
        if (net_mode == Net_client)
                printf("blktrace: connecting to %s\n", hostname);
 
-       if (setup_buts()) {
-               done = 1;
-               return 1;
+       if (setup_buts2()) {
+               if (setup_buts()) {
+                       done = 1;
+                       return 1;
+               }
        }
 
        if (use_tracer_devpaths()) {
-- 
2.51.0