[PATCH] net/mlx5: Fix failing fw tracer allocation on s390

[PATCH] net/mlx5: Fix failing fw tracer allocation on s390

[Niklas Schnelle]

On s390 FORCE_MAX_ZONEORDER is 9 instead of 11, thus a larger kzalloc()
allocation as done for the firmware tracer will always fail.

Looking at mlx5_fw_tracer_save_trace(), it is actually the driver itself
that copies the debug data into the trace array and there is no need for
the allocation to be contiguous in physical memory. We can therefor use
kvzalloc() instead of kzalloc() and get rid of the large contiguous
allcoation.

Fixes: f53aaa31cce7 ("net/mlx5: FW tracer, implement tracer logic")
Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com>
---
 drivers/net/ethernet/mellanox/mlx5/core/diag/fw_tracer.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/diag/fw_tracer.c b/drivers/net/ethernet/mellanox/mlx5/core/diag/fw_tracer.c
index c9c9b479bda5..5ce6ebbc7f10 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/diag/fw_tracer.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/diag/fw_tracer.c
@@ -935,7 +935,7 @@ struct mlx5_fw_tracer *mlx5_fw_tracer_create(struct mlx5_core_dev *dev)
 		return NULL;
 	}
 
-	tracer = kzalloc(sizeof(*tracer), GFP_KERNEL);
+	tracer = kvzalloc(sizeof(*tracer), GFP_KERNEL);
 	if (!tracer)
 		return ERR_PTR(-ENOMEM);
 
@@ -982,7 +982,7 @@ struct mlx5_fw_tracer *mlx5_fw_tracer_create(struct mlx5_core_dev *dev)
 	tracer->dev = NULL;
 	destroy_workqueue(tracer->work_queue);
 free_tracer:
-	kfree(tracer);
+	kvfree(tracer);
 	return ERR_PTR(err);
 }
 
@@ -1061,7 +1061,7 @@ void mlx5_fw_tracer_destroy(struct mlx5_fw_tracer *tracer)
 	mlx5_fw_tracer_destroy_log_buf(tracer);
 	flush_workqueue(tracer->work_queue);
 	destroy_workqueue(tracer->work_queue);
-	kfree(tracer);
+	kvfree(tracer);
 }
 
 static int fw_tracer_event(struct notifier_block *nb, unsigned long action, void *data)
-- 
2.17.1

Re: [PATCH] net/mlx5: Fix failing fw tracer allocation on s390

[Saeed Mahameed]

On Thu, 2020-04-09 at 09:46 +0200, Niklas Schnelle wrote:
> On s390 FORCE_MAX_ZONEORDER is 9 instead of 11, thus a larger
> kzalloc()
> allocation as done for the firmware tracer will always fail.
> 
> Looking at mlx5_fw_tracer_save_trace(), it is actually the driver
> itself
> that copies the debug data into the trace array and there is no need
> for
> the allocation to be contiguous in physical memory. We can therefor
> use
> kvzalloc() instead of kzalloc() and get rid of the large contiguous
> allcoation.
> 
> Fixes: f53aaa31cce7 ("net/mlx5: FW tracer, implement tracer logic")
> Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com>

Applied to net-mlx5, will be submitted to net in my next pull request.

Thanks,
Saeed.