Re: [PATCH v2 15/16] dmaengine: bcm-sba-raid: Add debugfs support

[Vinod Koul]

On Thu, Sep 07, 2017 at 09:37:32PM +0200, Greg KH wrote:
> On Fri, Aug 18, 2017 at 10:56:13AM +0530, Vinod Koul wrote:
> > On Fri, Aug 18, 2017 at 10:33:54AM +0530, Anup Patel wrote:
> > > On Thu, Aug 17, 2017 at 1:31 PM, Vinod Koul  wrote:
> > > > On Tue, Aug 01, 2017 at 04:07:59PM +0530, Anup Patel wrote:
> > > > 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.
> > 
> > reported yes, bailing out on that err no..
> 
> Reported, no.  You should _never_ care about the return value of a
> debugfs call.  Never check it, just move on ad keep on going.  It
> doesn't matter.

Agreed that makes more sense. The driver was checking and bailing out, I
advised against that :)

-- 
~Vinod

Re: [PATCH v2 15/16] dmaengine: bcm-sba-raid: Add debugfs support

[Vinod Koul]

On Thu, Sep 07, 2017 at 09:37:32PM +0200, Greg KH wrote:
> On Fri, Aug 18, 2017 at 10:56:13AM +0530, Vinod Koul wrote:
> > On Fri, Aug 18, 2017 at 10:33:54AM +0530, Anup Patel wrote:
> > > On Thu, Aug 17, 2017 at 1:31 PM, Vinod Koul  wrote:
> > > > On Tue, Aug 01, 2017 at 04:07:59PM +0530, Anup Patel wrote:
> > > > 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.
> > 
> > reported yes, bailing out on that err no..
> 
> Reported, no.  You should _never_ care about the return value of a
> debugfs call.  Never check it, just move on ad keep on going.  It
> doesn't matter.

Agreed that makes more sense. The driver was checking and bailing out, I
advised against that :)

-- 
~Vinod

Re: [PATCH v2 15/16] dmaengine: bcm-sba-raid: Add debugfs support

[Greg KH]

On Fri, Aug 18, 2017 at 10:56:13AM +0530, Vinod Koul wrote:
> On Fri, Aug 18, 2017 at 10:33:54AM +0530, Anup Patel wrote:
> > On Thu, Aug 17, 2017 at 1:31 PM, Vinod Koul  wrote:
> > > On Tue, Aug 01, 2017 at 04:07:59PM +0530, Anup Patel wrote:
> > > 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.
> 
> reported yes, bailing out on that err no..

Reported, no.  You should _never_ care about the return value of a
debugfs call.  Never check it, just move on ad keep on going.  It
doesn't matter.

thanks,

greg k-h

Re: [PATCH v2 15/16] dmaengine: bcm-sba-raid: Add debugfs support

[Greg KH]

On Fri, Aug 18, 2017 at 10:56:13AM +0530, Vinod Koul wrote:
> On Fri, Aug 18, 2017 at 10:33:54AM +0530, Anup Patel wrote:
> > On Thu, Aug 17, 2017 at 1:31 PM, Vinod Koul  wrote:
> > > On Tue, Aug 01, 2017 at 04:07:59PM +0530, Anup Patel wrote:
> > > 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.
> 
> reported yes, bailing out on that err no..

Reported, no.  You should _never_ care about the return value of a
debugfs call.  Never check it, just move on ad keep on going.  It
doesn't matter.

thanks,

greg k-h

Re: [PATCH v2 15/16] dmaengine: bcm-sba-raid: Add debugfs support

[Anup Patel]

On Fri, Aug 18, 2017 at 10:56 AM, Vinod Koul  wrote:
> On Fri, Aug 18, 2017 at 10:33:54AM +0530, Anup Patel wrote:
>> On Thu, Aug 17, 2017 at 1:31 PM, Vinod Koul  wrote:
>> > On Tue, Aug 01, 2017 at 04:07:59PM +0530, Anup Patel wrote:
>> > 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.
>
> reported yes, bailing out on that err no..

OK, I will put dev_err() instead of bailing out.

Regards,
Anup

Re: [PATCH v2 15/16] dmaengine: bcm-sba-raid: Add debugfs support

[Anup Patel]

On Fri, Aug 18, 2017 at 10:56 AM, Vinod Koul  wrote:
> On Fri, Aug 18, 2017 at 10:33:54AM +0530, Anup Patel wrote:
>> On Thu, Aug 17, 2017 at 1:31 PM, Vinod Koul  wrote:
>> > On Tue, Aug 01, 2017 at 04:07:59PM +0530, Anup Patel wrote:
>> > 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.
>
> reported yes, bailing out on that err no..

OK, I will put dev_err() instead of bailing out.

Regards,
Anup

Re: [PATCH v2 15/16] dmaengine: bcm-sba-raid: Add debugfs support

[Vinod Koul]

On Fri, Aug 18, 2017 at 10:33:54AM +0530, Anup Patel wrote:
> On Thu, Aug 17, 2017 at 1:31 PM, Vinod Koul  wrote:
> > On Tue, Aug 01, 2017 at 04:07:59PM +0530, Anup Patel wrote:
> > 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.

reported yes, bailing out on that err no..

-- 
~Vinod

Re: [PATCH v2 15/16] dmaengine: bcm-sba-raid: Add debugfs support

[Vinod Koul]

On Fri, Aug 18, 2017 at 10:33:54AM +0530, Anup Patel wrote:
> On Thu, Aug 17, 2017 at 1:31 PM, Vinod Koul  wrote:
> > On Tue, Aug 01, 2017 at 04:07:59PM +0530, Anup Patel wrote:
> > 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.

reported yes, bailing out on that err no..

-- 
~Vinod

Re: [PATCH v2 15/16] dmaengine: bcm-sba-raid: Add debugfs support

[Anup Patel]

On Thu, Aug 17, 2017 at 1:31 PM, Vinod Koul  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 
>> Reviewed-by: Ray Jui 
>> Reviewed-by: Scott Branden 
>> ---
>>  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 
>> +#include 
>>  #include 
>>  #include 
>>  #include 
>> @@ -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(>reqs_lock, flags);
>> +
>> + list_for_each_entry(req, >reqs_free_list, node)
>> + free_count++;
>> +
>> + list_for_each_entry(req, >reqs_alloc_list, node)
>> + alloced_count++;
>> +
>> + list_for_each_entry(req, >reqs_pending_list, node)
>> + pending_count++;
>> +
>> + list_for_each_entry(req, >reqs_active_list, node)
>> + active_count++;
>> +
>> + list_for_each_entry(req, >reqs_aborted_list, node)
>> + aborted_count++;
>> +
>> + list_for_each_entry(req, >reqs_completed_list, node)
>> + completed_count++;
>> +
>> + spin_unlock_irqrestore(>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

Re: [PATCH v2 15/16] dmaengine: bcm-sba-raid: Add debugfs support

[Anup Patel]

On Thu, Aug 17, 2017 at 1:31 PM, Vinod Koul  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 
>> Reviewed-by: Ray Jui 
>> Reviewed-by: Scott Branden 
>> ---
>>  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 
>> +#include 
>>  #include 
>>  #include 
>>  #include 
>> @@ -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(>reqs_lock, flags);
>> +
>> + list_for_each_entry(req, >reqs_free_list, node)
>> + free_count++;
>> +
>> + list_for_each_entry(req, >reqs_alloc_list, node)
>> + alloced_count++;
>> +
>> + list_for_each_entry(req, >reqs_pending_list, node)
>> + pending_count++;
>> +
>> + list_for_each_entry(req, >reqs_active_list, node)
>> + active_count++;
>> +
>> + list_for_each_entry(req, >reqs_aborted_list, node)
>> + aborted_count++;
>> +
>> + list_for_each_entry(req, >reqs_completed_list, node)
>> + completed_count++;
>> +
>> + spin_unlock_irqrestore(>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

Re: [PATCH v2 15/16] dmaengine: bcm-sba-raid: Add debugfs support

[Vinod Koul]

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 
> Reviewed-by: Ray Jui 
> Reviewed-by: Scott Branden 
> ---
>  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 
> +#include 
>  #include 
>  #include 
>  #include 
> @@ -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(>reqs_lock, flags);
> +
> + list_for_each_entry(req, >reqs_free_list, node)
> + free_count++;
> +
> + list_for_each_entry(req, >reqs_alloc_list, node)
> + alloced_count++;
> +
> + list_for_each_entry(req, >reqs_pending_list, node)
> + pending_count++;
> +
> + list_for_each_entry(req, >reqs_active_list, node)
> + active_count++;
> +
> + list_for_each_entry(req, >reqs_aborted_list, node)
> + aborted_count++;
> +
> + list_for_each_entry(req, >reqs_completed_list, node)
> + completed_count++;
> +
> + spin_unlock_irqrestore(>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

Re: [PATCH v2 15/16] dmaengine: bcm-sba-raid: Add debugfs support

[Vinod Koul]

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 
> Reviewed-by: Ray Jui 
> Reviewed-by: Scott Branden 
> ---
>  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 
> +#include 
>  #include 
>  #include 
>  #include 
> @@ -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(>reqs_lock, flags);
> +
> + list_for_each_entry(req, >reqs_free_list, node)
> + free_count++;
> +
> + list_for_each_entry(req, >reqs_alloc_list, node)
> + alloced_count++;
> +
> + list_for_each_entry(req, >reqs_pending_list, node)
> + pending_count++;
> +
> + list_for_each_entry(req, >reqs_active_list, node)
> + active_count++;
> +
> + list_for_each_entry(req, >reqs_aborted_list, node)
> + aborted_count++;
> +
> + list_for_each_entry(req, >reqs_completed_list, node)
> + completed_count++;
> +
> + spin_unlock_irqrestore(>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

[PATCH v2 15/16] dmaengine: bcm-sba-raid: Add debugfs support

[Anup Patel]

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 
Reviewed-by: Ray Jui 
Reviewed-by: Scott Branden 
---
 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 
+#include 
 #include 
 #include 
 #include 
@@ -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(>reqs_lock, flags);
+
+   list_for_each_entry(req, >reqs_free_list, node)
+   free_count++;
+
+   list_for_each_entry(req, >reqs_alloc_list, node)
+   alloced_count++;
+
+   list_for_each_entry(req, >reqs_pending_list, node)
+   pending_count++;
+
+   list_for_each_entry(req, >reqs_active_list, node)
+   active_count++;
+
+   list_for_each_entry(req, >reqs_aborted_list, node)
+   aborted_count++;
+
+   list_for_each_entry(req, >reqs_completed_list, node)
+   completed_count++;
+
+   spin_unlock_irqrestore(>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;
+   }
+
+   /* Create debugfs stats entry */
+   sba->stats = debugfs_create_devm_seqfile(sba->dev, "stats", sba->root,
+sba_debugfs_stats_show);
+   if (IS_ERR_OR_NULL(sba->stats)) {
+   ret = PTR_ERR_OR_ZERO(sba->stats);
+   goto fail_free_debugfs_root;
+   }
+skip_debugfs:
+
/* Register DMA device with Linux async framework */
ret = sba_async_register(sba);
if (ret)
-   goto fail_free_resources;
+   goto fail_free_debugfs_root;
 
/* Print device info */
dev_info(sba->dev, "%s using SBAv%d and %d mailbox channels",
@@ -1733,6 +1809,8 @@ static int sba_probe(struct platform_device *pdev)
 
return 0;
 
+fail_free_debugfs_root:
+   debugfs_remove_recursive(sba->root);
 fail_free_resources:
sba_freeup_channel_resources(sba);
 fail_free_mchans:
@@ -1748,6 +1826,8 @@ static int sba_remove(struct platform_device *pdev)
 
dma_async_device_unregister(>dma_dev);
 
+   debugfs_remove_recursive(sba->root);
+
sba_freeup_channel_resources(sba);
 
for (i = 0; i < sba->mchans_count; i++)
-- 
2.7.4

[PATCH v2 15/16] dmaengine: bcm-sba-raid: Add debugfs support

[Anup Patel]

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 
Reviewed-by: Ray Jui 
Reviewed-by: Scott Branden 
---
 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 
+#include 
 #include 
 #include 
 #include 
@@ -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(>reqs_lock, flags);
+
+   list_for_each_entry(req, >reqs_free_list, node)
+   free_count++;
+
+   list_for_each_entry(req, >reqs_alloc_list, node)
+   alloced_count++;
+
+   list_for_each_entry(req, >reqs_pending_list, node)
+   pending_count++;
+
+   list_for_each_entry(req, >reqs_active_list, node)
+   active_count++;
+
+   list_for_each_entry(req, >reqs_aborted_list, node)
+   aborted_count++;
+
+   list_for_each_entry(req, >reqs_completed_list, node)
+   completed_count++;
+
+   spin_unlock_irqrestore(>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;
+   }
+
+   /* Create debugfs stats entry */
+   sba->stats = debugfs_create_devm_seqfile(sba->dev, "stats", sba->root,
+sba_debugfs_stats_show);
+   if (IS_ERR_OR_NULL(sba->stats)) {
+   ret = PTR_ERR_OR_ZERO(sba->stats);
+   goto fail_free_debugfs_root;
+   }
+skip_debugfs:
+
/* Register DMA device with Linux async framework */
ret = sba_async_register(sba);
if (ret)
-   goto fail_free_resources;
+   goto fail_free_debugfs_root;
 
/* Print device info */
dev_info(sba->dev, "%s using SBAv%d and %d mailbox channels",
@@ -1733,6 +1809,8 @@ static int sba_probe(struct platform_device *pdev)
 
return 0;
 
+fail_free_debugfs_root:
+   debugfs_remove_recursive(sba->root);
 fail_free_resources:
sba_freeup_channel_resources(sba);
 fail_free_mchans:
@@ -1748,6 +1826,8 @@ static int sba_remove(struct platform_device *pdev)
 
dma_async_device_unregister(>dma_dev);
 
+   debugfs_remove_recursive(sba->root);
+
sba_freeup_channel_resources(sba);
 
for (i = 0; i < sba->mchans_count; i++)
-- 
2.7.4