* [PATCH net RFC] ibmvnic: device remove has higher precedence over reset
@ 2021-01-19 19:33 Lijun Pan
2021-01-19 19:49 ` Uwe Kleine-König
0 siblings, 1 reply; 3+ messages in thread
From: Lijun Pan @ 2021-01-19 19:33 UTC (permalink / raw)
To: netdev
Cc: linuxppc-dev, drt, sukadev, mpe, julietk, benh, paulus, davem,
kuba, gregkh, kernel, Lijun Pan, Uwe Kleine-König
Returning -EBUSY in ibmvnic_remove() does not actually hold the
removal procedure since driver core doesn't care for the return
value (see __device_release_driver() in drivers/base/dd.c
calling dev->bus->remove()) though vio_bus_remove
(in arch/powerpc/platforms/pseries/vio.c) records the
return value and passes it on. [1]
During the device removal precedure, we should not schedule
any new reset, and rely on the flush_work and flush_delayed_work
to complete the pending resets, and specifically we need to
let __ibmvnic_reset() keep running while in REMOVING state since
flush_work and flush_delayed_work shall call __ibmvnic_reset finally.
[1] https://lore.kernel.org/linuxppc-dev/20210117101242.dpwayq6wdgfdzirl@pengutronix.de/T/#m48f5befd96bc9842ece2a3ad14f4c27747206a53
Reported-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Fixes: 7d7195a026ba ("ibmvnic: Do not process device remove during device reset")
Signed-off-by: Lijun Pan <ljp@linux.ibm.com>
---
drivers/net/ethernet/ibm/ibmvnic.c | 8 +-------
1 file changed, 1 insertion(+), 7 deletions(-)
diff --git a/drivers/net/ethernet/ibm/ibmvnic.c b/drivers/net/ethernet/ibm/ibmvnic.c
index aed985e08e8a..11f28fd03057 100644
--- a/drivers/net/ethernet/ibm/ibmvnic.c
+++ b/drivers/net/ethernet/ibm/ibmvnic.c
@@ -2235,8 +2235,7 @@ static void __ibmvnic_reset(struct work_struct *work)
while (rwi) {
spin_lock_irqsave(&adapter->state_lock, flags);
- if (adapter->state == VNIC_REMOVING ||
- adapter->state == VNIC_REMOVED) {
+ if (adapter->state == VNIC_REMOVED) {
spin_unlock_irqrestore(&adapter->state_lock, flags);
kfree(rwi);
rc = EBUSY;
@@ -5372,11 +5371,6 @@ static int ibmvnic_remove(struct vio_dev *dev)
unsigned long flags;
spin_lock_irqsave(&adapter->state_lock, flags);
- if (test_bit(0, &adapter->resetting)) {
- spin_unlock_irqrestore(&adapter->state_lock, flags);
- return -EBUSY;
- }
-
adapter->state = VNIC_REMOVING;
spin_unlock_irqrestore(&adapter->state_lock, flags);
--
2.22.0
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH net RFC] ibmvnic: device remove has higher precedence over reset
2021-01-19 19:33 [PATCH net RFC] ibmvnic: device remove has higher precedence over reset Lijun Pan
@ 2021-01-19 19:49 ` Uwe Kleine-König
2021-01-19 20:08 ` Lijun Pan
0 siblings, 1 reply; 3+ messages in thread
From: Uwe Kleine-König @ 2021-01-19 19:49 UTC (permalink / raw)
To: Lijun Pan
Cc: netdev, gregkh, julietk, mpe, paulus, kernel, benh, drt, kuba,
sukadev, linuxppc-dev, davem
[-- Attachment #1: Type: text/plain, Size: 2569 bytes --]
On Tue, Jan 19, 2021 at 01:33:13PM -0600, Lijun Pan wrote:
> Returning -EBUSY in ibmvnic_remove() does not actually hold the
> removal procedure since driver core doesn't care for the return
> value (see __device_release_driver() in drivers/base/dd.c
> calling dev->bus->remove()) though vio_bus_remove
> (in arch/powerpc/platforms/pseries/vio.c) records the
> return value and passes it on. [1]
>
> During the device removal precedure, we should not schedule
> any new reset, and rely on the flush_work and flush_delayed_work
> to complete the pending resets, and specifically we need to
> let __ibmvnic_reset() keep running while in REMOVING state since
> flush_work and flush_delayed_work shall call __ibmvnic_reset finally.
>
> [1] https://lore.kernel.org/linuxppc-dev/20210117101242.dpwayq6wdgfdzirl@pengutronix.de/T/#m48f5befd96bc9842ece2a3ad14f4c27747206a53
> Reported-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
> Fixes: 7d7195a026ba ("ibmvnic: Do not process device remove during device reset")
> Signed-off-by: Lijun Pan <ljp@linux.ibm.com>
> ---
> drivers/net/ethernet/ibm/ibmvnic.c | 8 +-------
> 1 file changed, 1 insertion(+), 7 deletions(-)
>
> diff --git a/drivers/net/ethernet/ibm/ibmvnic.c b/drivers/net/ethernet/ibm/ibmvnic.c
> index aed985e08e8a..11f28fd03057 100644
> --- a/drivers/net/ethernet/ibm/ibmvnic.c
> +++ b/drivers/net/ethernet/ibm/ibmvnic.c
> @@ -2235,8 +2235,7 @@ static void __ibmvnic_reset(struct work_struct *work)
> while (rwi) {
> spin_lock_irqsave(&adapter->state_lock, flags);
>
> - if (adapter->state == VNIC_REMOVING ||
> - adapter->state == VNIC_REMOVED) {
> + if (adapter->state == VNIC_REMOVED) {
I think you need to keep the check for VNIC_REMOVING. Otherwise you
don't prevent that a new reset being queued after ibmvnic_remove() set
the state to VNIC_REMOVING. Am I missing something?
> spin_unlock_irqrestore(&adapter->state_lock, flags);
> kfree(rwi);
> rc = EBUSY;
> @@ -5372,11 +5371,6 @@ static int ibmvnic_remove(struct vio_dev *dev)
> unsigned long flags;
>
> spin_lock_irqsave(&adapter->state_lock, flags);
> - if (test_bit(0, &adapter->resetting)) {
> - spin_unlock_irqrestore(&adapter->state_lock, flags);
> - return -EBUSY;
> - }
> -
> adapter->state = VNIC_REMOVING;
> spin_unlock_irqrestore(&adapter->state_lock, flags);
Best regards
Uwe
--
Pengutronix e.K. | Uwe Kleine-König |
Industrial Linux Solutions | https://www.pengutronix.de/ |
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^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH net RFC] ibmvnic: device remove has higher precedence over reset
2021-01-19 19:49 ` Uwe Kleine-König
@ 2021-01-19 20:08 ` Lijun Pan
0 siblings, 0 replies; 3+ messages in thread
From: Lijun Pan @ 2021-01-19 20:08 UTC (permalink / raw)
To: Uwe Kleine-König
Cc: Lijun Pan, netdev, gregkh, julietk, mpe, paulus, kernel, benh,
drt, Jakub Kicinski, sukadev, linuxppc-dev, davem
On Tue, Jan 19, 2021 at 1:56 PM Uwe Kleine-König
<u.kleine-koenig@pengutronix.de> wrote:
>
> On Tue, Jan 19, 2021 at 01:33:13PM -0600, Lijun Pan wrote:
> > Returning -EBUSY in ibmvnic_remove() does not actually hold the
> > removal procedure since driver core doesn't care for the return
> > value (see __device_release_driver() in drivers/base/dd.c
> > calling dev->bus->remove()) though vio_bus_remove
> > (in arch/powerpc/platforms/pseries/vio.c) records the
> > return value and passes it on. [1]
> >
> > During the device removal precedure, we should not schedule
> > any new reset, and rely on the flush_work and flush_delayed_work
> > to complete the pending resets, and specifically we need to
> > let __ibmvnic_reset() keep running while in REMOVING state since
> > flush_work and flush_delayed_work shall call __ibmvnic_reset finally.
> >
> > [1] https://lore.kernel.org/linuxppc-dev/20210117101242.dpwayq6wdgfdzirl@pengutronix.de/T/#m48f5befd96bc9842ece2a3ad14f4c27747206a53
> > Reported-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
> > Fixes: 7d7195a026ba ("ibmvnic: Do not process device remove during device reset")
> > Signed-off-by: Lijun Pan <ljp@linux.ibm.com>
> > ---
> > drivers/net/ethernet/ibm/ibmvnic.c | 8 +-------
> > 1 file changed, 1 insertion(+), 7 deletions(-)
> >
> > diff --git a/drivers/net/ethernet/ibm/ibmvnic.c b/drivers/net/ethernet/ibm/ibmvnic.c
> > index aed985e08e8a..11f28fd03057 100644
> > --- a/drivers/net/ethernet/ibm/ibmvnic.c
> > +++ b/drivers/net/ethernet/ibm/ibmvnic.c
> > @@ -2235,8 +2235,7 @@ static void __ibmvnic_reset(struct work_struct *work)
> > while (rwi) {
> > spin_lock_irqsave(&adapter->state_lock, flags);
> >
> > - if (adapter->state == VNIC_REMOVING ||
> > - adapter->state == VNIC_REMOVED) {
> > + if (adapter->state == VNIC_REMOVED) {
>
> I think you need to keep the check for VNIC_REMOVING. Otherwise you
> don't prevent that a new reset being queued after ibmvnic_remove() set
> the state to VNIC_REMOVING. Am I missing something?
I leave the checking for REMOVING there in ibmvnic_reset, which is the
function to schedule/queue up the resets.
Here I delete the REMOVING in __ibmvnic_reset to let it run and finish.
Otherwise flush_work will not do anything if __ibmvnic_reset() just return
doing nothing.
I can explain it in the commit message.
>
> > spin_unlock_irqrestore(&adapter->state_lock, flags);
> > kfree(rwi);
> > rc = EBUSY;
> > @@ -5372,11 +5371,6 @@ static int ibmvnic_remove(struct vio_dev *dev)
> > unsigned long flags;
> >
> > spin_lock_irqsave(&adapter->state_lock, flags);
> > - if (test_bit(0, &adapter->resetting)) {
> > - spin_unlock_irqrestore(&adapter->state_lock, flags);
> > - return -EBUSY;
> > - }
> > -
> > adapter->state = VNIC_REMOVING;
> > spin_unlock_irqrestore(&adapter->state_lock, flags);
>
> Best regards
> Uwe
>
> --
> Pengutronix e.K. | Uwe Kleine-König |
> Industrial Linux Solutions | https://www.pengutronix.de/ |
^ permalink raw reply [flat|nested] 3+ messages in thread
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2021-01-19 19:33 [PATCH net RFC] ibmvnic: device remove has higher precedence over reset Lijun Pan
2021-01-19 19:49 ` Uwe Kleine-König
2021-01-19 20:08 ` Lijun Pan
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