perf/arm-cmn: Fail DTC counter allocation correctly

Calling arm_cmn_event_clear() before all DTC indices are allocated is
wrong, and can lead to arm_cmn_event_add() erroneously clearing live
counters from full DTCs where allocation fails. Since the DTC counters
are only updated by arm_cmn_init_counter() after all DTC and DTM
allocations succeed, nothing actually needs cleaning up in this case
anyway, and it should just return directly as it did before.

Fixes: 7633ec2c262f ("perf/arm-cmn: Rework DTC counters (again)")
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Reviewed-by: Ilkka Koskinen <ilkka@os.amperecomputing.com>
Acked-by: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/ed589c0d8e4130dc68b8ad1625226d28bdc185d4.1702322847.git.robin.murphy@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

diff --git a/drivers/perf/arm-cmn.c b/drivers/perf/arm-cmn.c
index 014010d035882375e9c0381ebce08a80af48ddd5..847b0dc41293d2fa47689bf634b34aef60f6b1ab 100644 (file)
--- a/drivers/perf/arm-cmn.c
+++ b/drivers/perf/arm-cmn.c
@@ -1816,7 +1816,7 @@ static int arm_cmn_event_add(struct perf_event *event, int flags)
                        idx = 0;
                        while (cmn->dtc[j].counters[idx])
                                if (++idx == CMN_DT_NUM_COUNTERS)
-                                       goto free_dtms;
+                                       return -ENOSPC;
                }
                hw->dtc_idx[j] = idx;
        }