On Tue, Aug 01, 2017 at 04:07:59PM +0530, Anup Patel wrote:
> This patch adds debugfs support to report stats via debugfs
> which in-turn will help debug hang or error situations.
>
> Signed-off-by: Anup Patel <anup.patel@xxxxxxxxxxxx>
> Reviewed-by: Ray Jui <ray.jui@xxxxxxxxxxxx>
> Reviewed-by: Scott Branden <scott.branden@xxxxxxxxxxxx>
> ---
> drivers/dma/bcm-sba-raid.c | 82 +++++++++++++++++++++++++++++++++++++++++++++-
> 1 file changed, 81 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/dma/bcm-sba-raid.c b/drivers/dma/bcm-sba-raid.c
> index f0a0e80..f9d110c 100644
> --- a/drivers/dma/bcm-sba-raid.c
> +++ b/drivers/dma/bcm-sba-raid.c
> @@ -36,6 +36,7 @@
> */
>
> #include <linux/bitops.h>
> +#include <linux/debugfs.h>
> #include <linux/dma-mapping.h>
> #include <linux/dmaengine.h>
> #include <linux/list.h>
> @@ -162,6 +163,9 @@ struct sba_device {
> struct list_head reqs_completed_list;
> struct list_head reqs_aborted_list;
> struct list_head reqs_free_list;
> + /* DebugFS directory entries */
> + struct dentry *root;
> + struct dentry *stats;
> };
>
> /* ====== Command helper routines ===== */
> @@ -486,6 +490,45 @@ static void sba_process_received_request(struct sba_device *sba,
> }
> }
>
> +static void sba_write_stats_in_seqfile(struct sba_device *sba,
> + struct seq_file *file)
> +{
> + unsigned long flags;
> + struct sba_request *req;
> + u32 free_count = 0, alloced_count = 0, pending_count = 0;
> + u32 active_count = 0, aborted_count = 0, completed_count = 0;
> +
> + spin_lock_irqsave(&sba->reqs_lock, flags);
> +
> + list_for_each_entry(req, &sba->reqs_free_list, node)
> + free_count++;
> +
> + list_for_each_entry(req, &sba->reqs_alloc_list, node)
> + alloced_count++;
> +
> + list_for_each_entry(req, &sba->reqs_pending_list, node)
> + pending_count++;
> +
> + list_for_each_entry(req, &sba->reqs_active_list, node)
> + active_count++;
> +
> + list_for_each_entry(req, &sba->reqs_aborted_list, node)
> + aborted_count++;
> +
> + list_for_each_entry(req, &sba->reqs_completed_list, node)
> + completed_count++;
> +
> + spin_unlock_irqrestore(&sba->reqs_lock, flags);
> +
> + seq_printf(file, "maximum requests = %d\n", sba->max_req);
> + seq_printf(file, "free requests = %d\n", free_count);
> + seq_printf(file, "alloced requests = %d\n", alloced_count);
> + seq_printf(file, "pending requests = %d\n", pending_count);
> + seq_printf(file, "active requests = %d\n", active_count);
> + seq_printf(file, "aborted requests = %d\n", aborted_count);
> + seq_printf(file, "completed requests = %d\n", completed_count);
> +}
> +
> /* ====== DMAENGINE callbacks ===== */
>
> static void sba_free_chan_resources(struct dma_chan *dchan)
> @@ -1451,6 +1494,19 @@ static void sba_receive_message(struct mbox_client *cl, void *msg)
> sba_process_received_request(sba, req);
> }
>
> +/* ====== Debugfs callbacks ====== */
> +
> +static int sba_debugfs_stats_show(struct seq_file *file, void *offset)
> +{
> + struct platform_device *pdev = to_platform_device(file->private);
> + struct sba_device *sba = platform_get_drvdata(pdev);
> +
> + /* Write stats in file */
> + sba_write_stats_in_seqfile(sba, file);
> +
> + return 0;
> +}
> +
> /* ====== Platform driver routines ===== */
>
> static int sba_prealloc_channel_resources(struct sba_device *sba)
> @@ -1721,10 +1777,30 @@ static int sba_probe(struct platform_device *pdev)
> if (ret)
> goto fail_free_mchans;
>
> + /* Check availability of debugfs */
> + if (!debugfs_initialized())
> + goto skip_debugfs;
> +
> + /* Create debugfs root entry */
> + sba->root = debugfs_create_dir(dev_name(sba->dev), NULL);
> + if (IS_ERR_OR_NULL(sba->root)) {
> + ret = PTR_ERR_OR_ZERO(sba->root);
> + goto fail_free_resources;
why fail, debugfs should be an optional thingy, why would you want to fail here?
--
~Vinod
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