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From:   Suzuki K Poulose <suzuki.poulose@arm.com>
To:     will@kernel.org, mathieu.poirier@linaro.org
Cc:     catalin.marinas@arm.com, anshuman.khandual@arm.com,
        mike.leach@linaro.org, leo.yan@linaro.org, maz@kernel.org,
        coresight@lists.linaro.org, linux-arm-kernel@lists.infradead.org,
        linux-kernel@vger.kernel.org,
        Suzuki K Poulose <suzuki.poulose@arm.com>
Subject: [PATCH v5 12/15] coresight: trbe: Make sure we have enough space
Date:   Thu, 14 Oct 2021 23:31:22 +0100
Message-Id: <20211014223125.2605031-13-suzuki.poulose@arm.com>
In-Reply-To: <20211014223125.2605031-1-suzuki.poulose@arm.com>
References: <20211014223125.2605031-1-suzuki.poulose@arm.com>
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The TRBE driver makes sure that there is enough space for a meaningful
run, otherwise pads the given space and restarts the offset calculation
once. But there is no guarantee that we may find space or hit "no space".
Make sure that we repeat the step until, either :
  - We have the minimum space
   OR
  - There is NO space at all.

Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Leo Yan <leo.yan@linaro.org>
Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
---
 drivers/hwtracing/coresight/coresight-trbe.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/hwtracing/coresight/coresight-trbe.c b/drivers/hwtracing/coresight/coresight-trbe.c
index 4a50309a892d..5fb9f49eab33 100644
--- a/drivers/hwtracing/coresight/coresight-trbe.c
+++ b/drivers/hwtracing/coresight/coresight-trbe.c
@@ -477,10 +477,14 @@ static unsigned long trbe_normal_offset(struct perf_output_handle *handle)
 	 * If the head is too close to the limit and we don't
 	 * have space for a meaningful run, we rather pad it
 	 * and start fresh.
+	 *
+	 * We might have to do this more than once to make sure
+	 * we have enough required space.
 	 */
-	if (limit && ((limit - head) < trbe_min_trace_buf_size(handle))) {
+	while (limit && ((limit - head) < trbe_min_trace_buf_size(handle))) {
 		trbe_pad_buf(handle, limit - head);
 		limit = __trbe_normal_offset(handle);
+		head = PERF_IDX2OFF(handle->head, buf);
 	}
 	return limit;
 }
-- 
2.25.4