[PATCH v2 6/6] perf/x86/intel/bts: Use extended error reporting in event initialization

[Alexander Shishkin <alexander.shishkin@linux.intel.com>]

If intel_bts events would conflict with other events that are active in
the system, provide an extended error message to the user along with the
usual EBUSY.

Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
---
 arch/x86/kernel/cpu/perf_event_intel_bts.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kernel/cpu/perf_event_intel_bts.c b/arch/x86/kernel/cpu/perf_event_intel_bts.c
index 54690e8857..c6a8da8f5a 100644
--- a/arch/x86/kernel/cpu/perf_event_intel_bts.c
+++ b/arch/x86/kernel/cpu/perf_event_intel_bts.c
@@ -16,6 +16,8 @@
 
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 
+#define PERF_MODNAME	"perf/x86/intel/bts"
+
 #include <linux/bitops.h>
 #include <linux/types.h>
 #include <linux/slab.h>
@@ -492,7 +494,7 @@ static int bts_event_init(struct perf_event *event)
 		return -ENOENT;
 
 	if (x86_add_exclusive(x86_lbr_exclusive_bts))
-		return -EBUSY;
+		return perf_err(-EBUSY, "BTS conflicts with active events");
 
 	ret = x86_reserve_hardware();
 	if (ret) {
-- 
2.5.0