* [PATCH v1 1/1] PCI/ERR: don't clobber status after reset_link()
@ 2020-10-09 2:52 Hedi Berriche
2020-10-09 3:46 ` Raj, Ashok
0 siblings, 1 reply; 4+ messages in thread
From: Hedi Berriche @ 2020-10-09 2:52 UTC (permalink / raw)
To: Kuppuswamy Sathyanarayanan
Cc: linux-pci, linux-kernel, Hedi Berriche, Russ Anderson,
Bjorn Helgaas, Ashok Raj, Keith Busch, Joerg Roedel, stable
Commit 6d2c89441571 ("PCI/ERR: Update error status after reset_link()")
changed pcie_do_recovery() so that status is updated with the return
value from reset_link(); this was to fix the problem where we would
wrongly report recovery failure, despite a successful reset_link(),
whenever the initial error status is PCI_ERS_RESULT_DISCONNECT or
PCI_ERS_RESULT_NO_AER_DRIVER.
Unfortunately this breaks the flow of pcie_do_recovery() as it prevents
the actions needed when the initial error is PCI_ERS_RESULT_CAN_RECOVER
or PCI_ERS_RESULT_NEED_RESET from taking place which causes error
recovery to fail.
Don't clobber status after reset_link() to restore the intended flow in
pcie_do_recovery().
Fix the original problem by saving the return value from reset_link()
and use it later on to decide whether error recovery should be deemed
successful in the scenarios where the initial error status is
PCI_ERS_RESULT_{DISCONNECT,NO_AER_DRIVER}.
Fixes: 6d2c89441571 ("PCI/ERR: Update error status after reset_link()")
Signed-off-by: Hedi Berriche <hedi.berriche@hpe.com>
Cc: Russ Anderson <rja@hpe.com>
Cc: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Ashok Raj <ashok.raj@intel.com>
Cc: Keith Busch <keith.busch@intel.com>
Cc: Joerg Roedel <jroedel@suse.com>
Cc: stable@kernel.org # v5.7+
---
drivers/pci/pcie/err.c | 13 ++++++++++---
1 file changed, 10 insertions(+), 3 deletions(-)
diff --git a/drivers/pci/pcie/err.c b/drivers/pci/pcie/err.c
index c543f419d8f9..dbd0b56bd6c1 100644
--- a/drivers/pci/pcie/err.c
+++ b/drivers/pci/pcie/err.c
@@ -150,7 +150,7 @@ pci_ers_result_t pcie_do_recovery(struct pci_dev *dev,
pci_channel_state_t state,
pci_ers_result_t (*reset_link)(struct pci_dev *pdev))
{
- pci_ers_result_t status = PCI_ERS_RESULT_CAN_RECOVER;
+ pci_ers_result_t post_reset_status, status = PCI_ERS_RESULT_CAN_RECOVER;
struct pci_bus *bus;
/*
@@ -165,8 +165,8 @@ pci_ers_result_t pcie_do_recovery(struct pci_dev *dev,
pci_dbg(dev, "broadcast error_detected message\n");
if (state == pci_channel_io_frozen) {
pci_walk_bus(bus, report_frozen_detected, &status);
- status = reset_link(dev);
- if (status != PCI_ERS_RESULT_RECOVERED) {
+ post_reset_status = reset_link(dev);
+ if (post_reset_status != PCI_ERS_RESULT_RECOVERED) {
pci_warn(dev, "link reset failed\n");
goto failed;
}
@@ -174,6 +174,13 @@ pci_ers_result_t pcie_do_recovery(struct pci_dev *dev,
pci_walk_bus(bus, report_normal_detected, &status);
}
+ if ((status == PCI_ERS_RESULT_DISCONNECT ||
+ status == PCI_ERS_RESULT_NO_AER_DRIVER) &&
+ post_reset_status == PCI_ERS_RESULT_RECOVERED) {
+ /* error recovery succeeded thanks to reset_link() */
+ status = PCI_ERS_RESULT_RECOVERED;
+ }
+
if (status == PCI_ERS_RESULT_CAN_RECOVER) {
status = PCI_ERS_RESULT_RECOVERED;
pci_dbg(dev, "broadcast mmio_enabled message\n");
--
2.28.0
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [PATCH v1 1/1] PCI/ERR: don't clobber status after reset_link()
2020-10-09 2:52 [PATCH v1 1/1] PCI/ERR: don't clobber status after reset_link() Hedi Berriche
@ 2020-10-09 3:46 ` Raj, Ashok
2020-10-09 4:05 ` Hedi Berriche
0 siblings, 1 reply; 4+ messages in thread
From: Raj, Ashok @ 2020-10-09 3:46 UTC (permalink / raw)
To: Hedi Berriche
Cc: Kuppuswamy Sathyanarayanan, linux-pci, linux-kernel,
Russ Anderson, Bjorn Helgaas, Keith Busch, Joerg Roedel, stable,
Ashok Raj
On Fri, Oct 09, 2020 at 03:52:51AM +0100, Hedi Berriche wrote:
> Commit 6d2c89441571 ("PCI/ERR: Update error status after reset_link()")
> changed pcie_do_recovery() so that status is updated with the return
> value from reset_link(); this was to fix the problem where we would
> wrongly report recovery failure, despite a successful reset_link(),
> whenever the initial error status is PCI_ERS_RESULT_DISCONNECT or
> PCI_ERS_RESULT_NO_AER_DRIVER.
>
> Unfortunately this breaks the flow of pcie_do_recovery() as it prevents
What is the reference to "this breaks" above?
> the actions needed when the initial error is PCI_ERS_RESULT_CAN_RECOVER
> or PCI_ERS_RESULT_NEED_RESET from taking place which causes error
> recovery to fail.
>
> Don't clobber status after reset_link() to restore the intended flow in
> pcie_do_recovery().
>
> Fix the original problem by saving the return value from reset_link()
> and use it later on to decide whether error recovery should be deemed
> successful in the scenarios where the initial error status is
> PCI_ERS_RESULT_{DISCONNECT,NO_AER_DRIVER}.
I would rather rephrase the above to make it clear what is being proposed.
Since the description seems to talk about the old problem and new solution
all mixed up.
>
> Fixes: 6d2c89441571 ("PCI/ERR: Update error status after reset_link()")
> Signed-off-by: Hedi Berriche <hedi.berriche@hpe.com>
> Cc: Russ Anderson <rja@hpe.com>
> Cc: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
> Cc: Bjorn Helgaas <bhelgaas@google.com>
> Cc: Ashok Raj <ashok.raj@intel.com>
> Cc: Keith Busch <keith.busch@intel.com>
> Cc: Joerg Roedel <jroedel@suse.com>
>
> Cc: stable@kernel.org # v5.7+
> ---
> drivers/pci/pcie/err.c | 13 ++++++++++---
> 1 file changed, 10 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/pci/pcie/err.c b/drivers/pci/pcie/err.c
> index c543f419d8f9..dbd0b56bd6c1 100644
> --- a/drivers/pci/pcie/err.c
> +++ b/drivers/pci/pcie/err.c
> @@ -150,7 +150,7 @@ pci_ers_result_t pcie_do_recovery(struct pci_dev *dev,
> pci_channel_state_t state,
> pci_ers_result_t (*reset_link)(struct pci_dev *pdev))
> {
> - pci_ers_result_t status = PCI_ERS_RESULT_CAN_RECOVER;
> + pci_ers_result_t post_reset_status, status = PCI_ERS_RESULT_CAN_RECOVER;
why call it post_reset_status?
> struct pci_bus *bus;
>
> /*
> @@ -165,8 +165,8 @@ pci_ers_result_t pcie_do_recovery(struct pci_dev *dev,
> pci_dbg(dev, "broadcast error_detected message\n");
> if (state == pci_channel_io_frozen) {
> pci_walk_bus(bus, report_frozen_detected, &status);
> - status = reset_link(dev);
> - if (status != PCI_ERS_RESULT_RECOVERED) {
> + post_reset_status = reset_link(dev);
> + if (post_reset_status != PCI_ERS_RESULT_RECOVERED) {
> pci_warn(dev, "link reset failed\n");
> goto failed;
> }
> @@ -174,6 +174,13 @@ pci_ers_result_t pcie_do_recovery(struct pci_dev *dev,
> pci_walk_bus(bus, report_normal_detected, &status);
> }
>
> + if ((status == PCI_ERS_RESULT_DISCONNECT ||
> + status == PCI_ERS_RESULT_NO_AER_DRIVER) &&
> + post_reset_status == PCI_ERS_RESULT_RECOVERED) {
> + /* error recovery succeeded thanks to reset_link() */
> + status = PCI_ERS_RESULT_RECOVERED;
> + }
> +
> if (status == PCI_ERS_RESULT_CAN_RECOVER) {
> status = PCI_ERS_RESULT_RECOVERED;
> pci_dbg(dev, "broadcast mmio_enabled message\n");
> --
> 2.28.0
>
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH v1 1/1] PCI/ERR: don't clobber status after reset_link()
2020-10-09 3:46 ` Raj, Ashok
@ 2020-10-09 4:05 ` Hedi Berriche
2020-10-09 4:11 ` Hedi Berriche
0 siblings, 1 reply; 4+ messages in thread
From: Hedi Berriche @ 2020-10-09 4:05 UTC (permalink / raw)
To: Raj, Ashok
Cc: Kuppuswamy Sathyanarayanan, linux-pci, linux-kernel,
Russ Anderson, Bjorn Helgaas, Joerg Roedel, stable
On Fri, Oct 09, 2020 at 04:46 Raj, Ashok wrote:
Hi Ashok,
Thanks for looking into this.
>On Fri, Oct 09, 2020 at 03:52:51AM +0100, Hedi Berriche wrote:
>> Commit 6d2c89441571 ("PCI/ERR: Update error status after reset_link()")
>> changed pcie_do_recovery() so that status is updated with the return
>> value from reset_link(); this was to fix the problem where we would
>> wrongly report recovery failure, despite a successful reset_link(),
>> whenever the initial error status is PCI_ERS_RESULT_DISCONNECT or
>> PCI_ERS_RESULT_NO_AER_DRIVER.
>>
>> Unfortunately this breaks the flow of pcie_do_recovery() as it prevents
>
>What is the reference to "this breaks" above?
The code change introduced by commit 6d2c89441571; would
"this code change" instead of "this breaks"
work better? If not, I can also rephrase the whole paragraph along the following lines:
Commit 6d2c89441571 ("PCI/ERR: Update error status after reset_link()") breaks the flow
of pcie_do_recovery() as it prevents the actions needed when the initial error is
PCI_ERS_RESULT_CAN_RECOVER or PCI_ERS_RESULT_NEED_RESET from taking place which causes
error recovery to fail.
... and do away with the first paragraph.
>> the actions needed when the initial error is PCI_ERS_RESULT_CAN_RECOVER
>> or PCI_ERS_RESULT_NEED_RESET from taking place which causes error
>> recovery to fail.
>>
>> Don't clobber status after reset_link() to restore the intended flow in
>> pcie_do_recovery().
>>
>> Fix the original problem by saving the return value from reset_link()
>> and use it later on to decide whether error recovery should be deemed
>> successful in the scenarios where the initial error status is
>> PCI_ERS_RESULT_{DISCONNECT,NO_AER_DRIVER}.
>
>I would rather rephrase the above to make it clear what is being proposed.
>Since the description seems to talk about the old problem and new solution
>all mixed up.
OK; will do that to clarify that what's being proposed here is:
1. fix the regression introduced by commit 6d2c89441571
2. address the problem that commit 6d2c89441571 aimed to fix
>> Fixes: 6d2c89441571 ("PCI/ERR: Update error status after reset_link()")
>> Signed-off-by: Hedi Berriche <hedi.berriche@hpe.com>
>> Cc: Russ Anderson <rja@hpe.com>
>> Cc: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
>> Cc: Bjorn Helgaas <bhelgaas@google.com>
>> Cc: Ashok Raj <ashok.raj@intel.com>
>> Cc: Keith Busch <keith.busch@intel.com>
>> Cc: Joerg Roedel <jroedel@suse.com>
>>
>> Cc: stable@kernel.org # v5.7+
>> ---
>> drivers/pci/pcie/err.c | 13 ++++++++++---
>> 1 file changed, 10 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/pci/pcie/err.c b/drivers/pci/pcie/err.c
>> index c543f419d8f9..dbd0b56bd6c1 100644
>> --- a/drivers/pci/pcie/err.c
>> +++ b/drivers/pci/pcie/err.c
>> @@ -150,7 +150,7 @@ pci_ers_result_t pcie_do_recovery(struct pci_dev *dev,
>> pci_channel_state_t state,
>> pci_ers_result_t (*reset_link)(struct pci_dev *pdev))
>> {
>> - pci_ers_result_t status = PCI_ERS_RESULT_CAN_RECOVER;
>> + pci_ers_result_t post_reset_status, status = PCI_ERS_RESULT_CAN_RECOVER;
>
>why call it post_reset_status?
Perhaps post_reset_status is not a great choice; would reset_result or reset_link_result be better?
Cheers,
Hedi.
>
>> struct pci_bus *bus;
>>
>> /*
>> @@ -165,8 +165,8 @@ pci_ers_result_t pcie_do_recovery(struct pci_dev *dev,
>> pci_dbg(dev, "broadcast error_detected message\n");
>> if (state == pci_channel_io_frozen) {
>> pci_walk_bus(bus, report_frozen_detected, &status);
>> - status = reset_link(dev);
>> - if (status != PCI_ERS_RESULT_RECOVERED) {
>> + post_reset_status = reset_link(dev);
>> + if (post_reset_status != PCI_ERS_RESULT_RECOVERED) {
>> pci_warn(dev, "link reset failed\n");
>> goto failed;
>> }
>> @@ -174,6 +174,13 @@ pci_ers_result_t pcie_do_recovery(struct pci_dev *dev,
>> pci_walk_bus(bus, report_normal_detected, &status);
>> }
>>
>> + if ((status == PCI_ERS_RESULT_DISCONNECT ||
>> + status == PCI_ERS_RESULT_NO_AER_DRIVER) &&
>> + post_reset_status == PCI_ERS_RESULT_RECOVERED) {
>> + /* error recovery succeeded thanks to reset_link() */
>> + status = PCI_ERS_RESULT_RECOVERED;
>> + }
>> +
>> if (status == PCI_ERS_RESULT_CAN_RECOVER) {
>> status = PCI_ERS_RESULT_RECOVERED;
>> pci_dbg(dev, "broadcast mmio_enabled message\n");
>> --
>> 2.28.0
>>
--
Be careful of reading health books, you might die of a misprint.
-- Mark Twain
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH v1 1/1] PCI/ERR: don't clobber status after reset_link()
2020-10-09 4:05 ` Hedi Berriche
@ 2020-10-09 4:11 ` Hedi Berriche
0 siblings, 0 replies; 4+ messages in thread
From: Hedi Berriche @ 2020-10-09 4:11 UTC (permalink / raw)
To: Raj, Ashok, Kuppuswamy Sathyanarayanan, linux-pci, linux-kernel,
Russ Anderson, Bjorn Helgaas, Joerg Roedel, stable
On Fri, Oct 09, 2020 at 05:09 Hedi Berriche wrote:
>On Fri, Oct 09, 2020 at 04:46 Raj, Ashok wrote:
>
>Hi Ashok,
>
>Thanks for looking into this.
>
>>On Fri, Oct 09, 2020 at 03:52:51AM +0100, Hedi Berriche wrote:
>>>Commit 6d2c89441571 ("PCI/ERR: Update error status after reset_link()")
>>>changed pcie_do_recovery() so that status is updated with the return
>>>value from reset_link(); this was to fix the problem where we would
>>>wrongly report recovery failure, despite a successful reset_link(),
>>>whenever the initial error status is PCI_ERS_RESULT_DISCONNECT or
>>>PCI_ERS_RESULT_NO_AER_DRIVER.
>>>
>>>Unfortunately this breaks the flow of pcie_do_recovery() as it prevents
>>
>>What is the reference to "this breaks" above?
>
>The code change introduced by commit 6d2c89441571; would
>
> "this code change" instead of "this breaks"
>
>work better? If not, I can also rephrase the whole paragraph along the following lines:
>
>Commit 6d2c89441571 ("PCI/ERR: Update error status after reset_link()") breaks the flow
>of pcie_do_recovery() as it prevents the actions needed when the initial error is
>PCI_ERS_RESULT_CAN_RECOVER or PCI_ERS_RESULT_NEED_RESET from taking place which causes
>error recovery to fail.
>
>... and do away with the first paragraph.
>
>>>the actions needed when the initial error is PCI_ERS_RESULT_CAN_RECOVER
>>>or PCI_ERS_RESULT_NEED_RESET from taking place which causes error
>>>recovery to fail.
>>>
>>>Don't clobber status after reset_link() to restore the intended flow in
>>>pcie_do_recovery().
>>>
>>>Fix the original problem by saving the return value from reset_link()
>>>and use it later on to decide whether error recovery should be deemed
>>>successful in the scenarios where the initial error status is
>>>PCI_ERS_RESULT_{DISCONNECT,NO_AER_DRIVER}.
>>
>>I would rather rephrase the above to make it clear what is being proposed.
>>Since the description seems to talk about the old problem and new solution
>>all mixed up.
>
>OK; will do that to clarify that what's being proposed here is:
>
> 1. fix the regression introduced by commit 6d2c89441571
> 2. address the problem that commit 6d2c89441571 aimed to fix
>
>>>Fixes: 6d2c89441571 ("PCI/ERR: Update error status after reset_link()")
>>>Signed-off-by: Hedi Berriche <hedi.berriche@hpe.com>
>>>Cc: Russ Anderson <rja@hpe.com>
>>>Cc: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
>>>Cc: Bjorn Helgaas <bhelgaas@google.com>
>>>Cc: Ashok Raj <ashok.raj@intel.com>
>>>Cc: Keith Busch <keith.busch@intel.com>
>>>Cc: Joerg Roedel <jroedel@suse.com>
>>>
>>>Cc: stable@kernel.org # v5.7+
>>>---
>>> drivers/pci/pcie/err.c | 13 ++++++++++---
>>> 1 file changed, 10 insertions(+), 3 deletions(-)
>>>
>>>diff --git a/drivers/pci/pcie/err.c b/drivers/pci/pcie/err.c
>>>index c543f419d8f9..dbd0b56bd6c1 100644
>>>--- a/drivers/pci/pcie/err.c
>>>+++ b/drivers/pci/pcie/err.c
>>>@@ -150,7 +150,7 @@ pci_ers_result_t pcie_do_recovery(struct pci_dev *dev,
>>> pci_channel_state_t state,
>>> pci_ers_result_t (*reset_link)(struct pci_dev *pdev))
>>> {
>>>- pci_ers_result_t status = PCI_ERS_RESULT_CAN_RECOVER;
>>>+ pci_ers_result_t post_reset_status, status = PCI_ERS_RESULT_CAN_RECOVER;
>>
>>why call it post_reset_status?
>
>Perhaps post_reset_status is not a great choice; would reset_result or reset_link_result be better?
... or just do this with a boolean instead as I had it in an earlier iteration of the patch before I
eventually opted to use an pci_ers_result_t.
Cheers,
Hedi.
>
>Cheers,
>Hedi.
>
>>
>>> struct pci_bus *bus;
>>>
>>> /*
>>>@@ -165,8 +165,8 @@ pci_ers_result_t pcie_do_recovery(struct pci_dev *dev,
>>> pci_dbg(dev, "broadcast error_detected message\n");
>>> if (state == pci_channel_io_frozen) {
>>> pci_walk_bus(bus, report_frozen_detected, &status);
>>>- status = reset_link(dev);
>>>- if (status != PCI_ERS_RESULT_RECOVERED) {
>>>+ post_reset_status = reset_link(dev);
>>>+ if (post_reset_status != PCI_ERS_RESULT_RECOVERED) {
>>> pci_warn(dev, "link reset failed\n");
>>> goto failed;
>>> }
>>>@@ -174,6 +174,13 @@ pci_ers_result_t pcie_do_recovery(struct pci_dev *dev,
>>> pci_walk_bus(bus, report_normal_detected, &status);
>>> }
>>>
>>>+ if ((status == PCI_ERS_RESULT_DISCONNECT ||
>>>+ status == PCI_ERS_RESULT_NO_AER_DRIVER) &&
>>>+ post_reset_status == PCI_ERS_RESULT_RECOVERED) {
>>>+ /* error recovery succeeded thanks to reset_link() */
>>>+ status = PCI_ERS_RESULT_RECOVERED;
>>>+ }
>>>+
>>> if (status == PCI_ERS_RESULT_CAN_RECOVER) {
>>> status = PCI_ERS_RESULT_RECOVERED;
>>> pci_dbg(dev, "broadcast mmio_enabled message\n");
>>>--
>>>2.28.0
>>>
>
>--
>Be careful of reading health books, you might die of a misprint.
> -- Mark Twain
--
Be careful of reading health books, you might die of a misprint.
-- Mark Twain
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2020-10-09 4:11 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
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2020-10-09 2:52 [PATCH v1 1/1] PCI/ERR: don't clobber status after reset_link() Hedi Berriche
2020-10-09 3:46 ` Raj, Ashok
2020-10-09 4:05 ` Hedi Berriche
2020-10-09 4:11 ` Hedi Berriche
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