diff mbox series

[v2,07/13] powerpc/eeh: Clean up pci_ers_result handling

Message ID e638159f9e6dfc4931f5164220741dd99bb4c0c7.1527217866.git.sbobroff@linux.ibm.com (mailing list archive)
State Accepted
Commit 30424e386a30d1160a0fdf47beafe8b116d0a8f7
Headers show
Series EEH refactoring 2 | expand

Commit Message

Sam Bobroff May 25, 2018, 3:11 a.m. UTC 
As EEH event handling progresses, a cumulative result of type
pci_ers_result is built up by (some of) the eeh_report_*() functions
using either:
	if (rc == PCI_ERS_RESULT_NEED_RESET) *res = rc;
	if (*res == PCI_ERS_RESULT_NONE) *res = rc;
or:
	if ((*res == PCI_ERS_RESULT_NONE) ||
	    (*res == PCI_ERS_RESULT_RECOVERED)) *res = rc;
	if (*res == PCI_ERS_RESULT_DISCONNECT &&
	    rc == PCI_ERS_RESULT_NEED_RESET) *res = rc;
(Where *res is the accumulator.)

However, the intent is not immediately clear and the result in some
situations is order dependent.

Address this by assigning a priority to each result value, and always
merging to the highest priority. This renders the intent clear, and
provides a stable value for all orderings.

Signed-off-by: Sam Bobroff <sbobroff@linux.ibm.com>
---

Comments

Michael Ellerman June 1, 2018, 3:40 p.m. UTC | #1 
Sam Bobroff <sbobroff@linux.ibm.com> writes:

> As EEH event handling progresses, a cumulative result of type
> pci_ers_result is built up by (some of) the eeh_report_*() functions
> using either:
> 	if (rc == PCI_ERS_RESULT_NEED_RESET) *res = rc;
> 	if (*res == PCI_ERS_RESULT_NONE) *res = rc;
> or:
> 	if ((*res == PCI_ERS_RESULT_NONE) ||
> 	    (*res == PCI_ERS_RESULT_RECOVERED)) *res = rc;
> 	if (*res == PCI_ERS_RESULT_DISCONNECT &&
> 	    rc == PCI_ERS_RESULT_NEED_RESET) *res = rc;
> (Where *res is the accumulator.)
>
> However, the intent is not immediately clear and the result in some
> situations is order dependent.
>
> Address this by assigning a priority to each result value, and always
> merging to the highest priority. This renders the intent clear, and
> provides a stable value for all orderings.
>
> Signed-off-by: Sam Bobroff <sbobroff@linux.ibm.com>
> ---
> ====== v1 -> v2: ======
>
> * Added the value, and missing newline, to some WARN()s.
> * Improved name of merge_result() to pci_ers_merge_result().
> * Adjusted the result priorities so that unknown doesn't overlap with _NONE.

These === markers seem to have confused patchwork, they ended up in the
patch, and then git put them in the changelog.

http://patchwork.ozlabs.org/patch/920194/

The usual format is just something like:

v2 - Added the value, and missing newline, to some WARN()s.
   - Improved name of merge_result() to pci_ers_merge_result().
   - Adjusted the result priorities so that unknown doesn't overlap with _NONE.

cheers

>  arch/powerpc/kernel/eeh_driver.c | 36 ++++++++++++++++++++++++++----------
>  1 file changed, 26 insertions(+), 10 deletions(-)
>
> diff --git a/arch/powerpc/kernel/eeh_driver.c b/arch/powerpc/kernel/eeh_driver.c
> index 188d15c4fe3a..2d3cac584899 100644
> --- a/arch/powerpc/kernel/eeh_driver.c
> +++ b/arch/powerpc/kernel/eeh_driver.c
> @@ -39,6 +39,29 @@ struct eeh_rmv_data {
>  	int removed;
>  };
>  
> +static int eeh_result_priority(enum pci_ers_result result)
> +{
> +	switch (result) {
> +	case PCI_ERS_RESULT_NONE: return 1;
> +	case PCI_ERS_RESULT_NO_AER_DRIVER: return 2;
> +	case PCI_ERS_RESULT_RECOVERED: return 3;
> +	case PCI_ERS_RESULT_CAN_RECOVER: return 4;
> +	case PCI_ERS_RESULT_DISCONNECT: return 5;
> +	case PCI_ERS_RESULT_NEED_RESET: return 6;
> +	default:
> +		WARN_ONCE(1, "Unknown pci_ers_result value: %d\n", (int)result);
> +		return 0;
> +	}
> +};
> +
> +static enum pci_ers_result pci_ers_merge_result(enum pci_ers_result old,
> +						enum pci_ers_result new)
> +{
> +	if (eeh_result_priority(new) > eeh_result_priority(old))
> +		return new;
> +	return old;
> +}
> +
>  /**
>   * eeh_pcid_get - Get the PCI device driver
>   * @pdev: PCI device
> @@ -206,9 +229,7 @@ static void *eeh_report_error(struct eeh_dev *edev, void *userdata)
>  
>  	rc = driver->err_handler->error_detected(dev, pci_channel_io_frozen);
>  
> -	/* A driver that needs a reset trumps all others */
> -	if (rc == PCI_ERS_RESULT_NEED_RESET) *res = rc;
> -	if (*res == PCI_ERS_RESULT_NONE) *res = rc;
> +	*res = pci_ers_merge_result(*res, rc);
>  
>  	edev->in_error = true;
>  	pci_uevent_ers(dev, PCI_ERS_RESULT_NONE);
> @@ -249,9 +270,7 @@ static void *eeh_report_mmio_enabled(struct eeh_dev *edev, void *userdata)
>  
>  	rc = driver->err_handler->mmio_enabled(dev);
>  
> -	/* A driver that needs a reset trumps all others */
> -	if (rc == PCI_ERS_RESULT_NEED_RESET) *res = rc;
> -	if (*res == PCI_ERS_RESULT_NONE) *res = rc;
> +	*res = pci_ers_merge_result(*res, rc);
>  
>  out:
>  	eeh_pcid_put(dev);
> @@ -294,10 +313,7 @@ static void *eeh_report_reset(struct eeh_dev *edev, void *userdata)
>  		goto out;
>  
>  	rc = driver->err_handler->slot_reset(dev);
> -	if ((*res == PCI_ERS_RESULT_NONE) ||
> -	    (*res == PCI_ERS_RESULT_RECOVERED)) *res = rc;
> -	if (*res == PCI_ERS_RESULT_DISCONNECT &&
> -	     rc == PCI_ERS_RESULT_NEED_RESET) *res = rc;
> +	*res = pci_ers_merge_result(*res, rc);
>  
>  out:
>  	eeh_pcid_put(dev);
> -- 
> 2.16.1.74.g9b0b1f47b
Sam Bobroff June 4, 2018, 1:28 a.m. UTC | #2 
On Sat, Jun 02, 2018 at 01:40:46AM +1000, Michael Ellerman wrote:
> Sam Bobroff <sbobroff@linux.ibm.com> writes:
> 
> > As EEH event handling progresses, a cumulative result of type
> > pci_ers_result is built up by (some of) the eeh_report_*() functions
> > using either:
> > 	if (rc == PCI_ERS_RESULT_NEED_RESET) *res = rc;
> > 	if (*res == PCI_ERS_RESULT_NONE) *res = rc;
> > or:
> > 	if ((*res == PCI_ERS_RESULT_NONE) ||
> > 	    (*res == PCI_ERS_RESULT_RECOVERED)) *res = rc;
> > 	if (*res == PCI_ERS_RESULT_DISCONNECT &&
> > 	    rc == PCI_ERS_RESULT_NEED_RESET) *res = rc;
> > (Where *res is the accumulator.)
> >
> > However, the intent is not immediately clear and the result in some
> > situations is order dependent.
> >
> > Address this by assigning a priority to each result value, and always
> > merging to the highest priority. This renders the intent clear, and
> > provides a stable value for all orderings.
> >
> > Signed-off-by: Sam Bobroff <sbobroff@linux.ibm.com>
> > ---
> > ====== v1 -> v2: ======
> >
> > * Added the value, and missing newline, to some WARN()s.
> > * Improved name of merge_result() to pci_ers_merge_result().
> > * Adjusted the result priorities so that unknown doesn't overlap with _NONE.
> 
> These === markers seem to have confused patchwork, they ended up in the
> patch, and then git put them in the changelog.
> 
> http://patchwork.ozlabs.org/patch/920194/
> 
> The usual format is just something like:
> 
> v2 - Added the value, and missing newline, to some WARN()s.
>    - Improved name of merge_result() to pci_ers_merge_result().
>    - Adjusted the result priorities so that unknown doesn't overlap with _NONE.
> 
> cheers

Oh! I'll change it!

Sam.

> 
> >  arch/powerpc/kernel/eeh_driver.c | 36 ++++++++++++++++++++++++++----------
> >  1 file changed, 26 insertions(+), 10 deletions(-)
> >
> > diff --git a/arch/powerpc/kernel/eeh_driver.c b/arch/powerpc/kernel/eeh_driver.c
> > index 188d15c4fe3a..2d3cac584899 100644
> > --- a/arch/powerpc/kernel/eeh_driver.c
> > +++ b/arch/powerpc/kernel/eeh_driver.c
> > @@ -39,6 +39,29 @@ struct eeh_rmv_data {
> >  	int removed;
> >  };
> >  
> > +static int eeh_result_priority(enum pci_ers_result result)
> > +{
> > +	switch (result) {
> > +	case PCI_ERS_RESULT_NONE: return 1;
> > +	case PCI_ERS_RESULT_NO_AER_DRIVER: return 2;
> > +	case PCI_ERS_RESULT_RECOVERED: return 3;
> > +	case PCI_ERS_RESULT_CAN_RECOVER: return 4;
> > +	case PCI_ERS_RESULT_DISCONNECT: return 5;
> > +	case PCI_ERS_RESULT_NEED_RESET: return 6;
> > +	default:
> > +		WARN_ONCE(1, "Unknown pci_ers_result value: %d\n", (int)result);
> > +		return 0;
> > +	}
> > +};
> > +
> > +static enum pci_ers_result pci_ers_merge_result(enum pci_ers_result old,
> > +						enum pci_ers_result new)
> > +{
> > +	if (eeh_result_priority(new) > eeh_result_priority(old))
> > +		return new;
> > +	return old;
> > +}
> > +
> >  /**
> >   * eeh_pcid_get - Get the PCI device driver
> >   * @pdev: PCI device
> > @@ -206,9 +229,7 @@ static void *eeh_report_error(struct eeh_dev *edev, void *userdata)
> >  
> >  	rc = driver->err_handler->error_detected(dev, pci_channel_io_frozen);
> >  
> > -	/* A driver that needs a reset trumps all others */
> > -	if (rc == PCI_ERS_RESULT_NEED_RESET) *res = rc;
> > -	if (*res == PCI_ERS_RESULT_NONE) *res = rc;
> > +	*res = pci_ers_merge_result(*res, rc);
> >  
> >  	edev->in_error = true;
> >  	pci_uevent_ers(dev, PCI_ERS_RESULT_NONE);
> > @@ -249,9 +270,7 @@ static void *eeh_report_mmio_enabled(struct eeh_dev *edev, void *userdata)
> >  
> >  	rc = driver->err_handler->mmio_enabled(dev);
> >  
> > -	/* A driver that needs a reset trumps all others */
> > -	if (rc == PCI_ERS_RESULT_NEED_RESET) *res = rc;
> > -	if (*res == PCI_ERS_RESULT_NONE) *res = rc;
> > +	*res = pci_ers_merge_result(*res, rc);
> >  
> >  out:
> >  	eeh_pcid_put(dev);
> > @@ -294,10 +313,7 @@ static void *eeh_report_reset(struct eeh_dev *edev, void *userdata)
> >  		goto out;
> >  
> >  	rc = driver->err_handler->slot_reset(dev);
> > -	if ((*res == PCI_ERS_RESULT_NONE) ||
> > -	    (*res == PCI_ERS_RESULT_RECOVERED)) *res = rc;
> > -	if (*res == PCI_ERS_RESULT_DISCONNECT &&
> > -	     rc == PCI_ERS_RESULT_NEED_RESET) *res = rc;
> > +	*res = pci_ers_merge_result(*res, rc);
> >  
> >  out:
> >  	eeh_pcid_put(dev);
> > -- 
> > 2.16.1.74.g9b0b1f47b
>
Michael Ellerman June 4, 2018, 9:43 a.m. UTC | #3 
Sam Bobroff <sbobroff@linux.ibm.com> writes:

> On Sat, Jun 02, 2018 at 01:40:46AM +1000, Michael Ellerman wrote:
>> Sam Bobroff <sbobroff@linux.ibm.com> writes:
>> 
>> > As EEH event handling progresses, a cumulative result of type
>> > pci_ers_result is built up by (some of) the eeh_report_*() functions
>> > using either:
>> > 	if (rc == PCI_ERS_RESULT_NEED_RESET) *res = rc;
>> > 	if (*res == PCI_ERS_RESULT_NONE) *res = rc;
>> > or:
>> > 	if ((*res == PCI_ERS_RESULT_NONE) ||
>> > 	    (*res == PCI_ERS_RESULT_RECOVERED)) *res = rc;
>> > 	if (*res == PCI_ERS_RESULT_DISCONNECT &&
>> > 	    rc == PCI_ERS_RESULT_NEED_RESET) *res = rc;
>> > (Where *res is the accumulator.)
>> >
>> > However, the intent is not immediately clear and the result in some
>> > situations is order dependent.
>> >
>> > Address this by assigning a priority to each result value, and always
>> > merging to the highest priority. This renders the intent clear, and
>> > provides a stable value for all orderings.
>> >
>> > Signed-off-by: Sam Bobroff <sbobroff@linux.ibm.com>
>> > ---
>> > ====== v1 -> v2: ======
>> >
>> > * Added the value, and missing newline, to some WARN()s.
>> > * Improved name of merge_result() to pci_ers_merge_result().
>> > * Adjusted the result priorities so that unknown doesn't overlap with _NONE.
>> 
>> These === markers seem to have confused patchwork, they ended up in the
>> patch, and then git put them in the changelog.
>> 
>> http://patchwork.ozlabs.org/patch/920194/
>> 
>> The usual format is just something like:
>> 
>> v2 - Added the value, and missing newline, to some WARN()s.
>>    - Improved name of merge_result() to pci_ers_merge_result().
>>    - Adjusted the result priorities so that unknown doesn't overlap with _NONE.
>> 
>> cheers
>
> Oh! I'll change it!

Thanks.

cheers
diff mbox series

Patch

====== v1 -> v2: ======
* Added the value, and missing newline, to some WARN()s.
* Improved name of merge_result() to pci_ers_merge_result().
* Adjusted the result priorities so that unknown doesn't overlap with _NONE.

 arch/powerpc/kernel/eeh_driver.c | 36 ++++++++++++++++++++++++++----------
 1 file changed, 26 insertions(+), 10 deletions(-)

diff --git a/arch/powerpc/kernel/eeh_driver.c b/arch/powerpc/kernel/eeh_driver.c
index 188d15c4fe3a..2d3cac584899 100644
--- a/arch/powerpc/kernel/eeh_driver.c
+++ b/arch/powerpc/kernel/eeh_driver.c
@@ -39,6 +39,29 @@  struct eeh_rmv_data {
 	int removed;
 };
 
+static int eeh_result_priority(enum pci_ers_result result)
+{
+	switch (result) {
+	case PCI_ERS_RESULT_NONE: return 1;
+	case PCI_ERS_RESULT_NO_AER_DRIVER: return 2;
+	case PCI_ERS_RESULT_RECOVERED: return 3;
+	case PCI_ERS_RESULT_CAN_RECOVER: return 4;
+	case PCI_ERS_RESULT_DISCONNECT: return 5;
+	case PCI_ERS_RESULT_NEED_RESET: return 6;
+	default:
+		WARN_ONCE(1, "Unknown pci_ers_result value: %d\n", (int)result);
+		return 0;
+	}
+};
+
+static enum pci_ers_result pci_ers_merge_result(enum pci_ers_result old,
+						enum pci_ers_result new)
+{
+	if (eeh_result_priority(new) > eeh_result_priority(old))
+		return new;
+	return old;
+}
+
 /**
  * eeh_pcid_get - Get the PCI device driver
  * @pdev: PCI device
@@ -206,9 +229,7 @@  static void *eeh_report_error(struct eeh_dev *edev, void *userdata)
 
 	rc = driver->err_handler->error_detected(dev, pci_channel_io_frozen);
 
-	/* A driver that needs a reset trumps all others */
-	if (rc == PCI_ERS_RESULT_NEED_RESET) *res = rc;
-	if (*res == PCI_ERS_RESULT_NONE) *res = rc;
+	*res = pci_ers_merge_result(*res, rc);
 
 	edev->in_error = true;
 	pci_uevent_ers(dev, PCI_ERS_RESULT_NONE);
@@ -249,9 +270,7 @@  static void *eeh_report_mmio_enabled(struct eeh_dev *edev, void *userdata)
 
 	rc = driver->err_handler->mmio_enabled(dev);
 
-	/* A driver that needs a reset trumps all others */
-	if (rc == PCI_ERS_RESULT_NEED_RESET) *res = rc;
-	if (*res == PCI_ERS_RESULT_NONE) *res = rc;
+	*res = pci_ers_merge_result(*res, rc);
 
 out:
 	eeh_pcid_put(dev);
@@ -294,10 +313,7 @@  static void *eeh_report_reset(struct eeh_dev *edev, void *userdata)
 		goto out;
 
 	rc = driver->err_handler->slot_reset(dev);
-	if ((*res == PCI_ERS_RESULT_NONE) ||
-	    (*res == PCI_ERS_RESULT_RECOVERED)) *res = rc;
-	if (*res == PCI_ERS_RESULT_DISCONNECT &&
-	     rc == PCI_ERS_RESULT_NEED_RESET) *res = rc;
+	*res = pci_ers_merge_result(*res, rc);
 
 out:
 	eeh_pcid_put(dev);