Re: [PATCH EDAC 03/13] ghes: add the needed hooks for EDAC error report

[Huang Ying <ying.huang@intel.com>]

On Thu, 2013-02-21 at 09:04 -0300, Mauro Carvalho Chehab wrote:
> Em Thu, 21 Feb 2013 09:26:07 +0800
> Huang Ying <ying.huang@intel.com> escreveu:
> 
> > Sorry for late!
> 
> Thanks for your comments. See my answers below.
> > 
> > On Fri, 2013-02-15 at 10:44 -0200, Mauro Carvalho Chehab wrote:
> > > In order to allow reporting errors via EDAC, add hooks for:
> > > 
> > > 1) register an EDAC driver;
> > > 2) unregister an EDAC driver;
> > > 3) report errors via EDAC.
> > > 
> > > As the EDAC driver will need to access the ghes structure, adds it
> > > as one of the parameters for ghes_do_proc.
> > > 
> > > Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
> > > ---
> > >  drivers/acpi/apei/ghes.c | 17 ++++++++++++++---
> > >  include/acpi/ghes.h      | 27 +++++++++++++++++++++++++++
> > >  2 files changed, 41 insertions(+), 3 deletions(-)
> > > 
> > > diff --git a/drivers/acpi/apei/ghes.c b/drivers/acpi/apei/ghes.c
> > > index 6d0e146..a21d7da 100644
> > > --- a/drivers/acpi/apei/ghes.c
> > > +++ b/drivers/acpi/apei/ghes.c
> > > @@ -409,7 +409,8 @@ static void ghes_clear_estatus(struct ghes *ghes)
> > >  	ghes->flags &= ~GHES_TO_CLEAR;
> > >  }
> > >  
> > > -static void ghes_do_proc(const struct acpi_hest_generic_status *estatus)
> > > +static void ghes_do_proc(struct ghes *ghes,
> > > +			 const struct acpi_hest_generic_status *estatus)
> > >  {
> > >  	int sev, sec_sev;
> > >  	struct acpi_hest_generic_data *gdata;
> > > @@ -421,6 +422,8 @@ static void ghes_do_proc(const struct acpi_hest_generic_status *estatus)
> > >  				 CPER_SEC_PLATFORM_MEM)) {
> > >  			struct cper_sec_mem_err *mem_err;
> > >  			mem_err = (struct cper_sec_mem_err *)(gdata+1);
> > > +			ghes_edac_report_mem_error(ghes, sev, mem_err);
> > > +
> > >  #ifdef CONFIG_X86_MCE
> > >  			apei_mce_report_mem_error(sev == GHES_SEV_CORRECTED,
> > >  						  mem_err);
> > > @@ -639,7 +642,7 @@ static int ghes_proc(struct ghes *ghes)
> > >  		if (ghes_print_estatus(NULL, ghes->generic, ghes->estatus))
> > >  			ghes_estatus_cache_add(ghes->generic, ghes->estatus);
> > >  	}
> > > -	ghes_do_proc(ghes->estatus);
> > > +	ghes_do_proc(ghes, ghes->estatus);
> > >  out:
> > >  	ghes_clear_estatus(ghes);
> > >  	return 0;
> > > @@ -732,7 +735,7 @@ static void ghes_proc_in_irq(struct irq_work *irq_work)
> > >  		estatus = GHES_ESTATUS_FROM_NODE(estatus_node);
> > >  		len = apei_estatus_len(estatus);
> > >  		node_len = GHES_ESTATUS_NODE_LEN(len);
> > > -		ghes_do_proc(estatus);
> > > +		ghes_do_proc(estatus_node->ghes, estatus);
> > >  		if (!ghes_estatus_cached(estatus)) {
> > >  			generic = estatus_node->generic;
> > >  			if (ghes_print_estatus(NULL, generic, estatus))
> > > @@ -821,6 +824,7 @@ static int ghes_notify_nmi(unsigned int cmd, struct pt_regs *regs)
> > >  		estatus_node = (void *)gen_pool_alloc(ghes_estatus_pool,
> > >  						      node_len);
> > >  		if (estatus_node) {
> > > +			estatus_node->ghes = ghes;
> > >  			estatus_node->generic = ghes->generic;
> > >  			estatus = GHES_ESTATUS_FROM_NODE(estatus_node);
> > >  			memcpy(estatus, ghes->estatus, len);
> > > @@ -942,6 +946,10 @@ static int ghes_probe(struct platform_device *ghes_dev)
> > >  	}
> > >  	platform_set_drvdata(ghes_dev, ghes);
> > >  
> > > +	rc = ghes_edac_register(ghes, &ghes_dev->dev);
> > > +	if (rc < 0)
> > > +		goto err;
> > > +
> > 
> > If ghes_edac_register() failed, we need to do some cleanup such as
> > unregister from hed etc.
> > 
> > Or just move ghes_edac_register() before switch?
> 
> Moving it to happen before the switch() looks the better. We need to unregister
> ghes_edac if IRQ fails.
> 
> > >  	return 0;
> > >  err:
> > >  	if (ghes) {
> > > @@ -995,6 +1003,9 @@ static int ghes_remove(struct platform_device *ghes_dev)
> > >  	}
> > >  
> > >  	ghes_fini(ghes);
> > > +
> > > +	ghes_edac_unregister(ghes);
> > > +
> > >  	kfree(ghes);
> > >  
> > >  	platform_set_drvdata(ghes_dev, NULL);
> > > diff --git a/include/acpi/ghes.h b/include/acpi/ghes.h
> > > index 3eb8dc4..c6fef72 100644
> > > --- a/include/acpi/ghes.h
> > > +++ b/include/acpi/ghes.h
> > > @@ -22,11 +22,14 @@ struct ghes {
> > >  		struct timer_list timer;
> > >  		unsigned int irq;
> > >  	};
> > > +
> > > +	struct mem_ctl_info *mci;
> > 
> > Why we need this?  This is not used by ghes.[hc].
> 
> This will be needed by the EDAC driver, as the EDAC core has its own main
> struct, and such struct need to be recovered when reporting an error.
> 
> As this struct is not used by ghes, there's no need to even include the
> include/linux/edac.h, where this is declared, as gcc will just handle it
> as "void *" when compiling ghes.
> 
> I opted for this design as it is simpler, and costs just 8 bytes for each
> ghes struct, and no extra code is needed.
> 
> However, as you're not happy with it, I'm removing it from there, and adding
> a list at the edac driver, together with a mutex, to serialize its access,
> associating each ghes struct with their corresponding MC struct.
> 
> I'll post the patch replacing patch 05/13 soon.
> 
> > 
> > >  };
> > >  
> > >  struct ghes_estatus_node {
> > >  	struct llist_node llnode;
> > >  	struct acpi_hest_generic *generic;
> > > +	struct ghes *ghes;
> > >  };
> > >  
> > >  struct ghes_estatus_cache {
> > > @@ -43,3 +46,27 @@ enum {
> > >  	GHES_SEV_RECOVERABLE = 0x2,
> > >  	GHES_SEV_PANIC = 0x3,
> > >  };
> > > +
> > > +#ifdef CONFIG_EDAC_GHES
> > > +void ghes_edac_report_mem_error(struct ghes *ghes, int sev,
> > > +				struct cper_sec_mem_err *mem_err);
> > > +
> > > +int ghes_edac_register(struct ghes *ghes, struct device *dev);
> > > +
> > > +void ghes_edac_unregister(struct ghes *ghes);
> > > +
> > > +#else
> > > +static inline void ghes_edac_report_mem_error(struct ghes *ghes, int sev,
> > > +				       struct cper_sec_mem_err *mem_err)
> > > +{
> > > +}
> > > +
> > > +static inline int ghes_edac_register(struct ghes *ghes, struct device *dev)
> > > +{
> > > +	return 0;
> > > +}
> > > +
> > > +static inline void ghes_edac_unregister(struct ghes *ghes)
> > > +{
> > > +}
> > > +#endif
> > 
> > I think it is better to put the above declaration into module which
> > implement these functions instead of use these functions.
> 
> This is due to Linux Coding Style. See Documentation/SubmittingPatches,
> session 2, item 1:
> 
> 	2) #ifdefs are ugly
> 
> 	Code cluttered with ifdefs is difficult to read and maintain.  Don't do
> 	it.  Instead, put your ifdefs in a header, and conditionally define
> 	'static inline' functions, or macros, which are used in the code.
> 	Let the compiler optimize away the "no-op" case.
> 
> 	Simple example, of poor code:
> 
> 	        dev = alloc_etherdev (sizeof(struct funky_private));
>        	 if (!dev)
> 	                return -ENODEV;
> 	        #ifdef CONFIG_NET_FUNKINESS
> 	        init_funky_net(dev);
> 	        #endif
> 
> 	Cleaned-up example:
> 
> 	(in header)
> 	        #ifndef CONFIG_NET_FUNKINESS
> 	        static inline void init_funky_net (struct net_device *d) {}
> 	        #endif
> 
> 	(in the code itself)
> 	        dev = alloc_etherdev (sizeof(struct funky_private));
> 	        if (!dev)
> 	                return -ENODEV;
> 	        init_funky_net(dev);
> 
> There is also an advantage on taking this approach: this patch can have just
> the ghes changes, and will still compile fine, as CONFIG_EDAC_GHES is not
> defined yet. So, the patch becomes is simpler and easier to review.

Thanks for your explanation.  I agree to keep this in header file.

My original suggestion is that it may be better to move this from ghes.h
to some place like "ghes_edac.h", because these functions are
implemented in "ghes_edac.c" instead of ghes.c.

> If I would do it otherwise, I would need to fold patch 5 to avoid breaking
> git bisect.
> 
> Regards,
> Mauro
> 
> Patch with the changes enclosed.
> 
> -
> 
> [PATCH EDACv2 03/13] ghes: add the needed hooks for EDAC error report
> 
> In order to allow reporting errors via EDAC, add hooks for:
> 
> 1) register an EDAC driver;
> 2) unregister an EDAC driver;
> 3) report errors via EDAC.
> 
> As the EDAC driver will need to access the ghes structure, adds it
> as one of the parameters for ghes_do_proc.
> 
> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
> 
> diff --git a/drivers/acpi/apei/ghes.c b/drivers/acpi/apei/ghes.c
> index 6d0e146..19092dc 100644
> --- a/drivers/acpi/apei/ghes.c
> +++ b/drivers/acpi/apei/ghes.c
> @@ -409,7 +409,8 @@ static void ghes_clear_estatus(struct ghes *ghes)
>  	ghes->flags &= ~GHES_TO_CLEAR;
>  }
>  
> -static void ghes_do_proc(const struct acpi_hest_generic_status *estatus)
> +static void ghes_do_proc(struct ghes *ghes,
> +			 const struct acpi_hest_generic_status *estatus)
>  {
>  	int sev, sec_sev;
>  	struct acpi_hest_generic_data *gdata;
> @@ -421,6 +422,8 @@ static void ghes_do_proc(const struct acpi_hest_generic_status *estatus)
>  				 CPER_SEC_PLATFORM_MEM)) {
>  			struct cper_sec_mem_err *mem_err;
>  			mem_err = (struct cper_sec_mem_err *)(gdata+1);
> +			ghes_edac_report_mem_error(ghes, sev, mem_err);
> +
>  #ifdef CONFIG_X86_MCE
>  			apei_mce_report_mem_error(sev == GHES_SEV_CORRECTED,
>  						  mem_err);
> @@ -639,7 +642,7 @@ static int ghes_proc(struct ghes *ghes)
>  		if (ghes_print_estatus(NULL, ghes->generic, ghes->estatus))
>  			ghes_estatus_cache_add(ghes->generic, ghes->estatus);
>  	}
> -	ghes_do_proc(ghes->estatus);
> +	ghes_do_proc(ghes, ghes->estatus);
>  out:
>  	ghes_clear_estatus(ghes);
>  	return 0;
> @@ -732,7 +735,7 @@ static void ghes_proc_in_irq(struct irq_work *irq_work)
>  		estatus = GHES_ESTATUS_FROM_NODE(estatus_node);
>  		len = apei_estatus_len(estatus);
>  		node_len = GHES_ESTATUS_NODE_LEN(len);
> -		ghes_do_proc(estatus);
> +		ghes_do_proc(estatus_node->ghes, estatus);
>  		if (!ghes_estatus_cached(estatus)) {
>  			generic = estatus_node->generic;
>  			if (ghes_print_estatus(NULL, generic, estatus))
> @@ -821,6 +824,7 @@ static int ghes_notify_nmi(unsigned int cmd, struct pt_regs *regs)
>  		estatus_node = (void *)gen_pool_alloc(ghes_estatus_pool,
>  						      node_len);
>  		if (estatus_node) {
> +			estatus_node->ghes = ghes;
>  			estatus_node->generic = ghes->generic;
>  			estatus = GHES_ESTATUS_FROM_NODE(estatus_node);
>  			memcpy(estatus, ghes->estatus, len);
> @@ -899,6 +903,11 @@ static int ghes_probe(struct platform_device *ghes_dev)
>  		ghes = NULL;
>  		goto err;
>  	}
> +
> +	rc = ghes_edac_register(ghes, &ghes_dev->dev);
> +	if (rc < 0)
> +		goto err;
> +
>  	switch (generic->notify.type) {
>  	case ACPI_HEST_NOTIFY_POLLED:
>  		ghes->timer.function = ghes_poll_func;
> @@ -911,13 +920,13 @@ static int ghes_probe(struct platform_device *ghes_dev)
>  		if (acpi_gsi_to_irq(generic->notify.vector, &ghes->irq)) {
>  			pr_err(GHES_PFX "Failed to map GSI to IRQ for generic hardware error source: %d\n",
>  			       generic->header.source_id);
> -			goto err;
> +			goto err2;
>  		}
>  		if (request_irq(ghes->irq, ghes_irq_func,
>  				0, "GHES IRQ", ghes)) {
>  			pr_err(GHES_PFX "Failed to register IRQ for generic hardware error source: %d\n",
>  			       generic->header.source_id);
> -			goto err;
> +			goto err2;
>  		}
>  		break;
>  	case ACPI_HEST_NOTIFY_SCI:
> @@ -943,6 +952,8 @@ static int ghes_probe(struct platform_device *ghes_dev)
>  	platform_set_drvdata(ghes_dev, ghes);
>  
>  	return 0;
> +err2:

Suggest to rename it to err_edac_unreg or something like that.  Just a
suggestion.

Best Regards,
Huang Ying

> +	ghes_edac_unregister(ghes);
>  err:
>  	if (ghes) {
>  		ghes_fini(ghes);
> @@ -995,6 +1006,9 @@ static int ghes_remove(struct platform_device *ghes_dev)
>  	}
>  
>  	ghes_fini(ghes);
> +
> +	ghes_edac_unregister(ghes);
> +
>  	kfree(ghes);
>  
>  	platform_set_drvdata(ghes_dev, NULL);
> diff --git a/include/acpi/ghes.h b/include/acpi/ghes.h
> index 3eb8dc4..9015ec2 100644
> --- a/include/acpi/ghes.h
> +++ b/include/acpi/ghes.h
> @@ -27,6 +27,7 @@ struct ghes {
>  struct ghes_estatus_node {
>  	struct llist_node llnode;
>  	struct acpi_hest_generic *generic;
> +	struct ghes *ghes;
>  };
>  
>  struct ghes_estatus_cache {
> @@ -43,3 +44,27 @@ enum {
>  	GHES_SEV_RECOVERABLE = 0x2,
>  	GHES_SEV_PANIC = 0x3,
>  };
> +
> +#ifdef CONFIG_EDAC_GHES
> +void ghes_edac_report_mem_error(struct ghes *ghes, int sev,
> +				struct cper_sec_mem_err *mem_err);
> +
> +int ghes_edac_register(struct ghes *ghes, struct device *dev);
> +
> +void ghes_edac_unregister(struct ghes *ghes);
> +
> +#else
> +static inline void ghes_edac_report_mem_error(struct ghes *ghes, int sev,
> +				       struct cper_sec_mem_err *mem_err)
> +{
> +}
> +
> +static inline int ghes_edac_register(struct ghes *ghes, struct device *dev)
> +{
> +	return 0;
> +}
> +
> +static inline void ghes_edac_unregister(struct ghes *ghes)
> +{
> +}
> +#endif
>