On Thu, Aug 17, 2017 at 1:31 PM, Vinod Koul <vinod.k...@intel.com> wrote:
> 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.pa...@broadcom.com>
>> Reviewed-by: Ray Jui <ray....@broadcom.com>
>> Reviewed-by: Scott Branden <scott.bran...@broadcom.com>
>> ---
>> 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?
Yes, we are handling the case when debugfs is not available
and skipping debugfs gracefully.
If debugfs is available then failure of debugfs_create_dir()
should be reported.
Regards,
Anup
