File btreplay-machines-are-now-large-enough-that-holes-need-to-be-dealt-with.patch of Package blktrace.8516

From: Nathan Zimmer <nzimmer@sgi.com>
Date: Mon, 15 Apr 2013 09:53:33 -0500
Subject: btreplay: Machines are now large enough that holes need to be dealt
 with
Git-repo: git://git.kernel.dk/blktrace.git
Git-commit: 0c2df13d11dd91a1c3933dcc8faa98f2b59a5793
Patch-mainline: blktrace-1.1.0
References: bsc#934392

The current method fails if once we hit the first offlined cpu.  This
will correct that case.  However this still underreports the number cpus if
the last cpu are offlined.

Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Nathan Zimmer <nzimmer@sgi.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Acked-by: Jeff Mahoney <jeffm@suse.com>
---
 btreplay/btreplay.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/btreplay/btreplay.c b/btreplay/btreplay.c
index 20494e0..6f0ba63 100644
--- a/btreplay/btreplay.c
+++ b/btreplay/btreplay.c
@@ -502,6 +502,7 @@ static inline void start_iter(void)
  */
 static void get_ncpus(void)
 {
+	long last_cpu;
 	cpu_set_t cpus;
 
 	if (sched_getaffinity(getpid(), sizeof(cpus), &cpus)) {
@@ -509,12 +510,11 @@ static void get_ncpus(void)
 		/*NOTREACHED*/
 	}
 
-	/*
-	 * XXX This assumes (perhaps wrongly) that there are no /holes/ 
-	 * XXX in the mask.
-	 */
-	for (ncpus = 0; ncpus < CPU_SETSIZE && CPU_ISSET(ncpus, &cpus); ncpus++)
-		;
+	ncpus = -1;
+	for (last_cpu = 0; last_cpu < CPU_SETSIZE && CPU_ISSET(last_cpu, &cpus); last_cpu++)
+		if (CPU_ISSET( last_cpu, &cpus) ) 
+			ncpus = last_cpu;
+	ncpus++;
 	if (ncpus == 0) {
 		fatal(NULL, ERR_SYSCALL, "Insufficient number of CPUs\n");
 		/*NOTREACHED*/