| Message ID | 20230331080605.42961-1-den-plotnikov@yandex-team.ru (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | qlcnic: check pci_reset_function result | expand |
On Fri, Mar 31, 2023 at 11:06:05AM +0300, Denis Plotnikov wrote: > Static code analyzer complains to unchecked return value. > It seems that pci_reset_function return something meaningful > only if "reset_methods" is set. > Even if reset_methods isn't used check the return value to avoid > possible bugs leading to undefined behavior in the future. > > Signed-off-by: Denis Plotnikov <den-plotnikov@yandex-team.ru> nit: The tree this patch is targeted at should be designated, probably net-next, so the '[PATCH net-next]' in the subject. > --- > drivers/net/ethernet/qlogic/qlcnic/qlcnic_ctx.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/drivers/net/ethernet/qlogic/qlcnic/qlcnic_ctx.c b/drivers/net/ethernet/qlogic/qlcnic/qlcnic_ctx.c > index 87f76bac2e463..39ecfc1a1dbd0 100644 > --- a/drivers/net/ethernet/qlogic/qlcnic/qlcnic_ctx.c > +++ b/drivers/net/ethernet/qlogic/qlcnic/qlcnic_ctx.c > @@ -628,7 +628,9 @@ int qlcnic_fw_create_ctx(struct qlcnic_adapter *dev) > int i, err, ring; > > if (dev->flags & QLCNIC_NEED_FLR) { > - pci_reset_function(dev->pdev); > + err = pci_reset_function(dev->pdev); > + if (err && err != -ENOTTY) Are you sure about the -ENOTTY part? It seems odd to me that an FLR would be required but reset is not supported. > + return err; > dev->flags &= ~QLCNIC_NEED_FLR; > } > > -- > 2.25.1 >
On 31.03.2023 20:52, Simon Horman wrote: > On Fri, Mar 31, 2023 at 11:06:05AM +0300, Denis Plotnikov wrote: >> Static code analyzer complains to unchecked return value. >> It seems that pci_reset_function return something meaningful >> only if "reset_methods" is set. >> Even if reset_methods isn't used check the return value to avoid >> possible bugs leading to undefined behavior in the future. >> >> Signed-off-by: Denis Plotnikov <den-plotnikov@yandex-team.ru> > nit: The tree this patch is targeted at should be designated, probably > net-next, so the '[PATCH net-next]' in the subject. > >> --- >> drivers/net/ethernet/qlogic/qlcnic/qlcnic_ctx.c | 4 +++- >> 1 file changed, 3 insertions(+), 1 deletion(-) >> >> diff --git a/drivers/net/ethernet/qlogic/qlcnic/qlcnic_ctx.c b/drivers/net/ethernet/qlogic/qlcnic/qlcnic_ctx.c >> index 87f76bac2e463..39ecfc1a1dbd0 100644 >> --- a/drivers/net/ethernet/qlogic/qlcnic/qlcnic_ctx.c >> +++ b/drivers/net/ethernet/qlogic/qlcnic/qlcnic_ctx.c >> @@ -628,7 +628,9 @@ int qlcnic_fw_create_ctx(struct qlcnic_adapter *dev) >> int i, err, ring; >> >> if (dev->flags & QLCNIC_NEED_FLR) { >> - pci_reset_function(dev->pdev); >> + err = pci_reset_function(dev->pdev); >> + if (err && err != -ENOTTY) > Are you sure about the -ENOTTY part? > > It seems odd to me that an FLR would be required but reset is not supported. No, I'm not sure. My logic is: if the reset method isn't set than pci_reset_function() returns -ENOTTY so treat that result as ok. pci_reset_function may return something different than -ENOTTY only if pci_reset_fn_methods[m].reset_fn is set. >> + return err; >> dev->flags &= ~QLCNIC_NEED_FLR; >> } >> >> -- >> 2.25.1 >>
+ Bjorn Helgaas and linux-pci, as this is about FLR On Mon, Apr 03, 2023 at 01:58:49PM +0300, Denis Plotnikov wrote: > > On 31.03.2023 20:52, Simon Horman wrote: > > On Fri, Mar 31, 2023 at 11:06:05AM +0300, Denis Plotnikov wrote: > > > Static code analyzer complains to unchecked return value. > > > It seems that pci_reset_function return something meaningful > > > only if "reset_methods" is set. > > > Even if reset_methods isn't used check the return value to avoid > > > possible bugs leading to undefined behavior in the future. > > > > > > Signed-off-by: Denis Plotnikov <den-plotnikov@yandex-team.ru> > > nit: The tree this patch is targeted at should be designated, probably > > net-next, so the '[PATCH net-next]' in the subject. > > > > > --- > > > drivers/net/ethernet/qlogic/qlcnic/qlcnic_ctx.c | 4 +++- > > > 1 file changed, 3 insertions(+), 1 deletion(-) > > > > > > diff --git a/drivers/net/ethernet/qlogic/qlcnic/qlcnic_ctx.c b/drivers/net/ethernet/qlogic/qlcnic/qlcnic_ctx.c > > > index 87f76bac2e463..39ecfc1a1dbd0 100644 > > > --- a/drivers/net/ethernet/qlogic/qlcnic/qlcnic_ctx.c > > > +++ b/drivers/net/ethernet/qlogic/qlcnic/qlcnic_ctx.c > > > @@ -628,7 +628,9 @@ int qlcnic_fw_create_ctx(struct qlcnic_adapter *dev) > > > int i, err, ring; > > > if (dev->flags & QLCNIC_NEED_FLR) { > > > - pci_reset_function(dev->pdev); > > > + err = pci_reset_function(dev->pdev); > > > + if (err && err != -ENOTTY) > > Are you sure about the -ENOTTY part? > > > > It seems odd to me that an FLR would be required but reset is not supported. > No, I'm not sure. My logic is: if the reset method isn't set than > pci_reset_function() returns -ENOTTY so treat that result as ok. > pci_reset_function may return something different than -ENOTTY only if > pci_reset_fn_methods[m].reset_fn is set. I see your reasoning: -ENOTTY means nothing happened, and probably that is ok. I think my main question is if that can ever happen. If that is unknown, then I think this conservative approach makes sense. Bjorn, do you happen to have any guidance here? > > > + return err; > > > dev->flags &= ~QLCNIC_NEED_FLR; > > > } > > > -- > > > 2.25.1 > > >
On Wed, Apr 05, 2023 at 03:04:39PM +0200, Simon Horman wrote: > On Mon, Apr 03, 2023 at 01:58:49PM +0300, Denis Plotnikov wrote: > > On 31.03.2023 20:52, Simon Horman wrote: > > > On Fri, Mar 31, 2023 at 11:06:05AM +0300, Denis Plotnikov wrote: > > > > Static code analyzer complains to unchecked return value. > > > > It seems that pci_reset_function return something meaningful > > > > only if "reset_methods" is set. > > > > Even if reset_methods isn't used check the return value to avoid > > > > possible bugs leading to undefined behavior in the future. > > > > > > > > Signed-off-by: Denis Plotnikov <den-plotnikov@yandex-team.ru> > > > nit: The tree this patch is targeted at should be designated, probably > > > net-next, so the '[PATCH net-next]' in the subject. > > > > > > > --- > > > > drivers/net/ethernet/qlogic/qlcnic/qlcnic_ctx.c | 4 +++- > > > > 1 file changed, 3 insertions(+), 1 deletion(-) > > > > > > > > diff --git a/drivers/net/ethernet/qlogic/qlcnic/qlcnic_ctx.c b/drivers/net/ethernet/qlogic/qlcnic/qlcnic_ctx.c > > > > index 87f76bac2e463..39ecfc1a1dbd0 100644 > > > > --- a/drivers/net/ethernet/qlogic/qlcnic/qlcnic_ctx.c > > > > +++ b/drivers/net/ethernet/qlogic/qlcnic/qlcnic_ctx.c > > > > @@ -628,7 +628,9 @@ int qlcnic_fw_create_ctx(struct qlcnic_adapter *dev) > > > > int i, err, ring; > > > > if (dev->flags & QLCNIC_NEED_FLR) { > > > > - pci_reset_function(dev->pdev); > > > > + err = pci_reset_function(dev->pdev); > > > > + if (err && err != -ENOTTY) > > > Are you sure about the -ENOTTY part? > > > > > > It seems odd to me that an FLR would be required but reset is not supported. > > No, I'm not sure. My logic is: if the reset method isn't set than > > pci_reset_function() returns -ENOTTY so treat that result as ok. > > pci_reset_function may return something different than -ENOTTY only if > > pci_reset_fn_methods[m].reset_fn is set. > > I see your reasoning: -ENOTTY means nothing happened, and probably that is ok. > I think my main question is if that can ever happen. > If that is unknown, then I think this conservative approach makes sense. The commit log mentions "reset_methods", which I don't think is really relevant here because reset_methods is an internal implementation detail. The point is that pci_reset_function() returns 0 if it was successful and a negative value if it failed. If the driver thinks the device needs to be reset, ignoring any negative return value seems like a mistake because the device was not reset. If the reset is required for a firmware update to take effect, maybe a diagnostic would be helpful if it fails, e.g., the other "Adapter initialization failed. Please reboot" messages. "QLCNIC_NEED_FLR" suggests that the driver expects an FLR (as opposed to other kinds of reset). If the driver knows that all qlcnic devices support FLR, it could use pcie_flr() directly. pci_reset_function() does have the possibility that the reset works on some devices but not all. Secondary Bus Reset fails if there are other functions on the same bus, e.g., a multi-function device. And there's some value in doing the reset the same way in all cases. So I would suggest something like: if (dev->flags & QLCNIC_NEED_FLR) { err = pcie_flr(dev->pdev); if (err) { dev_err(&pdev->dev, "Adapter reset failed (%d). Please reboot\n", err); return err; } dev->flags &= ~QLCNIC_NEED_FLR; } Or, if there are qlcnic devices that don't support FLR: if (dev->flags & QLCNIC_NEED_FLR) { err = pci_reset_function(dev->pdev); if (err) { dev_err(&pdev->dev, "Adapter reset failed (%d). Please reboot\n", err); return err; } dev->flags &= ~QLCNIC_NEED_FLR; } > > > > + return err; > > > > dev->flags &= ~QLCNIC_NEED_FLR; > > > > } > > > > -- > > > > 2.25.1 > > > >
On Wed, Apr 05, 2023 at 02:37:08PM -0500, Bjorn Helgaas wrote: > On Wed, Apr 05, 2023 at 03:04:39PM +0200, Simon Horman wrote: > > On Mon, Apr 03, 2023 at 01:58:49PM +0300, Denis Plotnikov wrote: > > > On 31.03.2023 20:52, Simon Horman wrote: > > > > On Fri, Mar 31, 2023 at 11:06:05AM +0300, Denis Plotnikov wrote: > > > > > Static code analyzer complains to unchecked return value. > > > > > It seems that pci_reset_function return something meaningful > > > > > only if "reset_methods" is set. > > > > > Even if reset_methods isn't used check the return value to avoid > > > > > possible bugs leading to undefined behavior in the future. > > > > > > > > > > Signed-off-by: Denis Plotnikov <den-plotnikov@yandex-team.ru> > > > > nit: The tree this patch is targeted at should be designated, probably > > > > net-next, so the '[PATCH net-next]' in the subject. > > > > > > > > > --- > > > > > drivers/net/ethernet/qlogic/qlcnic/qlcnic_ctx.c | 4 +++- > > > > > 1 file changed, 3 insertions(+), 1 deletion(-) > > > > > > > > > > diff --git a/drivers/net/ethernet/qlogic/qlcnic/qlcnic_ctx.c b/drivers/net/ethernet/qlogic/qlcnic/qlcnic_ctx.c > > > > > index 87f76bac2e463..39ecfc1a1dbd0 100644 > > > > > --- a/drivers/net/ethernet/qlogic/qlcnic/qlcnic_ctx.c > > > > > +++ b/drivers/net/ethernet/qlogic/qlcnic/qlcnic_ctx.c > > > > > @@ -628,7 +628,9 @@ int qlcnic_fw_create_ctx(struct qlcnic_adapter *dev) > > > > > int i, err, ring; > > > > > if (dev->flags & QLCNIC_NEED_FLR) { > > > > > - pci_reset_function(dev->pdev); > > > > > + err = pci_reset_function(dev->pdev); > > > > > + if (err && err != -ENOTTY) > > > > Are you sure about the -ENOTTY part? > > > > > > > > It seems odd to me that an FLR would be required but reset is not supported. > > > No, I'm not sure. My logic is: if the reset method isn't set than > > > pci_reset_function() returns -ENOTTY so treat that result as ok. > > > pci_reset_function may return something different than -ENOTTY only if > > > pci_reset_fn_methods[m].reset_fn is set. > > > > I see your reasoning: -ENOTTY means nothing happened, and probably that is ok. > > I think my main question is if that can ever happen. > > If that is unknown, then I think this conservative approach makes sense. > > The commit log mentions "reset_methods", which I don't think is really > relevant here because reset_methods is an internal implementation > detail. The point is that pci_reset_function() returns 0 if it was > successful and a negative value if it failed. > > If the driver thinks the device needs to be reset, ignoring any > negative return value seems like a mistake because the device was not > reset. > > If the reset is required for a firmware update to take effect, maybe a > diagnostic would be helpful if it fails, e.g., the other "Adapter > initialization failed. Please reboot" messages. > > "QLCNIC_NEED_FLR" suggests that the driver expects an FLR (as opposed > to other kinds of reset). If the driver knows that all qlcnic devices > support FLR, it could use pcie_flr() directly. > > pci_reset_function() does have the possibility that the reset works on > some devices but not all. Secondary Bus Reset fails if there are > other functions on the same bus, e.g., a multi-function device. And > there's some value in doing the reset the same way in all cases. > > So I would suggest something like: > > if (dev->flags & QLCNIC_NEED_FLR) { > err = pcie_flr(dev->pdev); > if (err) { > dev_err(&pdev->dev, "Adapter reset failed (%d). Please reboot\n", err); > return err; > } > dev->flags &= ~QLCNIC_NEED_FLR; > } > > Or, if there are qlcnic devices that don't support FLR: > > if (dev->flags & QLCNIC_NEED_FLR) { > err = pci_reset_function(dev->pdev); > if (err) { > dev_err(&pdev->dev, "Adapter reset failed (%d). Please reboot\n", err); > return err; > } > dev->flags &= ~QLCNIC_NEED_FLR; > } Thanks Bjorn, that is very helpful. I think that in order to move to option #1 some information would be needed from those familiar with the device(s). As it is a more invasive change - pci_reset_function -> pcie_flr. So my feeling is that, in lieu of such feedback, option #2 is a good improvement on the current code. OTOH, this driver is 'Supported' as opposed to 'Maintained'. So perhaps we can just use our best judgement and go for option #1.
On 06.04.2023 10:03, Simon Horman wrote: > On Wed, Apr 05, 2023 at 02:37:08PM -0500, Bjorn Helgaas wrote: >> On Wed, Apr 05, 2023 at 03:04:39PM +0200, Simon Horman wrote: >>> On Mon, Apr 03, 2023 at 01:58:49PM +0300, Denis Plotnikov wrote: >>>> On 31.03.2023 20:52, Simon Horman wrote: >>>>> On Fri, Mar 31, 2023 at 11:06:05AM +0300, Denis Plotnikov wrote: >>>>>> Static code analyzer complains to unchecked return value. >>>>>> It seems that pci_reset_function return something meaningful >>>>>> only if "reset_methods" is set. >>>>>> Even if reset_methods isn't used check the return value to avoid >>>>>> possible bugs leading to undefined behavior in the future. >>>>>> >>>>>> Signed-off-by: Denis Plotnikov <den-plotnikov@yandex-team.ru> >>>>> nit: The tree this patch is targeted at should be designated, probably >>>>> net-next, so the '[PATCH net-next]' in the subject. >>>>> >>>>>> --- >>>>>> drivers/net/ethernet/qlogic/qlcnic/qlcnic_ctx.c | 4 +++- >>>>>> 1 file changed, 3 insertions(+), 1 deletion(-) >>>>>> >>>>>> diff --git a/drivers/net/ethernet/qlogic/qlcnic/qlcnic_ctx.c b/drivers/net/ethernet/qlogic/qlcnic/qlcnic_ctx.c >>>>>> index 87f76bac2e463..39ecfc1a1dbd0 100644 >>>>>> --- a/drivers/net/ethernet/qlogic/qlcnic/qlcnic_ctx.c >>>>>> +++ b/drivers/net/ethernet/qlogic/qlcnic/qlcnic_ctx.c >>>>>> @@ -628,7 +628,9 @@ int qlcnic_fw_create_ctx(struct qlcnic_adapter *dev) >>>>>> int i, err, ring; >>>>>> if (dev->flags & QLCNIC_NEED_FLR) { >>>>>> - pci_reset_function(dev->pdev); >>>>>> + err = pci_reset_function(dev->pdev); >>>>>> + if (err && err != -ENOTTY) >>>>> Are you sure about the -ENOTTY part? >>>>> >>>>> It seems odd to me that an FLR would be required but reset is not supported. >>>> No, I'm not sure. My logic is: if the reset method isn't set than >>>> pci_reset_function() returns -ENOTTY so treat that result as ok. >>>> pci_reset_function may return something different than -ENOTTY only if >>>> pci_reset_fn_methods[m].reset_fn is set. >>> I see your reasoning: -ENOTTY means nothing happened, and probably that is ok. >>> I think my main question is if that can ever happen. >>> If that is unknown, then I think this conservative approach makes sense. >> The commit log mentions "reset_methods", which I don't think is really >> relevant here because reset_methods is an internal implementation >> detail. The point is that pci_reset_function() returns 0 if it was >> successful and a negative value if it failed. >> >> If the driver thinks the device needs to be reset, ignoring any >> negative return value seems like a mistake because the device was not >> reset. >> >> If the reset is required for a firmware update to take effect, maybe a >> diagnostic would be helpful if it fails, e.g., the other "Adapter >> initialization failed. Please reboot" messages. >> >> "QLCNIC_NEED_FLR" suggests that the driver expects an FLR (as opposed >> to other kinds of reset). If the driver knows that all qlcnic devices >> support FLR, it could use pcie_flr() directly. >> >> pci_reset_function() does have the possibility that the reset works on >> some devices but not all. Secondary Bus Reset fails if there are >> other functions on the same bus, e.g., a multi-function device. And >> there's some value in doing the reset the same way in all cases. >> >> So I would suggest something like: >> >> if (dev->flags & QLCNIC_NEED_FLR) { >> err = pcie_flr(dev->pdev); >> if (err) { >> dev_err(&pdev->dev, "Adapter reset failed (%d). Please reboot\n", err); >> return err; >> } >> dev->flags &= ~QLCNIC_NEED_FLR; >> } >> >> Or, if there are qlcnic devices that don't support FLR: >> >> if (dev->flags & QLCNIC_NEED_FLR) { >> err = pci_reset_function(dev->pdev); >> if (err) { >> dev_err(&pdev->dev, "Adapter reset failed (%d). Please reboot\n", err); >> return err; >> } >> dev->flags &= ~QLCNIC_NEED_FLR; >> } > Thanks Bjorn, > > that is very helpful. > > I think that in order to move to option #1 some information would be needed > from those familiar with the device(s). As it is a more invasive change - > pci_reset_function -> pcie_flr. > > So my feeling is that, in lieu of such feedback, option #2 is a good > improvement on the current code. > > OTOH, this driver is 'Supported' as opposed to 'Maintained'. > So perhaps we can just use our best judgement and go for option #1. So, it looks like option #2 is the safest choice as we do reset only if FLR is needed (when pci_reset_function() makes sense) If all agree with that I'll re-send the path
On Thu, Apr 06, 2023 at 12:23:49PM +0300, Denis Plotnikov wrote: > > On 06.04.2023 10:03, Simon Horman wrote: > > On Wed, Apr 05, 2023 at 02:37:08PM -0500, Bjorn Helgaas wrote: > > > On Wed, Apr 05, 2023 at 03:04:39PM +0200, Simon Horman wrote: > > > > On Mon, Apr 03, 2023 at 01:58:49PM +0300, Denis Plotnikov wrote: > > > > > On 31.03.2023 20:52, Simon Horman wrote: > > > > > > On Fri, Mar 31, 2023 at 11:06:05AM +0300, Denis Plotnikov wrote: > > > > > > > Static code analyzer complains to unchecked return value. > > > > > > > It seems that pci_reset_function return something meaningful > > > > > > > only if "reset_methods" is set. > > > > > > > Even if reset_methods isn't used check the return value to avoid > > > > > > > possible bugs leading to undefined behavior in the future. > > > > > > > > > > > > > > Signed-off-by: Denis Plotnikov <den-plotnikov@yandex-team.ru> > > > > > > nit: The tree this patch is targeted at should be designated, probably > > > > > > net-next, so the '[PATCH net-next]' in the subject. > > > > > > > > > > > > > --- > > > > > > > drivers/net/ethernet/qlogic/qlcnic/qlcnic_ctx.c | 4 +++- > > > > > > > 1 file changed, 3 insertions(+), 1 deletion(-) > > > > > > > > > > > > > > diff --git a/drivers/net/ethernet/qlogic/qlcnic/qlcnic_ctx.c b/drivers/net/ethernet/qlogic/qlcnic/qlcnic_ctx.c > > > > > > > index 87f76bac2e463..39ecfc1a1dbd0 100644 > > > > > > > --- a/drivers/net/ethernet/qlogic/qlcnic/qlcnic_ctx.c > > > > > > > +++ b/drivers/net/ethernet/qlogic/qlcnic/qlcnic_ctx.c > > > > > > > @@ -628,7 +628,9 @@ int qlcnic_fw_create_ctx(struct qlcnic_adapter *dev) > > > > > > > int i, err, ring; > > > > > > > if (dev->flags & QLCNIC_NEED_FLR) { > > > > > > > - pci_reset_function(dev->pdev); > > > > > > > + err = pci_reset_function(dev->pdev); > > > > > > > + if (err && err != -ENOTTY) > > > > > > Are you sure about the -ENOTTY part? > > > > > > > > > > > > It seems odd to me that an FLR would be required but reset is not supported. > > > > > No, I'm not sure. My logic is: if the reset method isn't set than > > > > > pci_reset_function() returns -ENOTTY so treat that result as ok. > > > > > pci_reset_function may return something different than -ENOTTY only if > > > > > pci_reset_fn_methods[m].reset_fn is set. > > > > I see your reasoning: -ENOTTY means nothing happened, and probably that is ok. > > > > I think my main question is if that can ever happen. > > > > If that is unknown, then I think this conservative approach makes sense. > > > The commit log mentions "reset_methods", which I don't think is really > > > relevant here because reset_methods is an internal implementation > > > detail. The point is that pci_reset_function() returns 0 if it was > > > successful and a negative value if it failed. > > > > > > If the driver thinks the device needs to be reset, ignoring any > > > negative return value seems like a mistake because the device was not > > > reset. > > > > > > If the reset is required for a firmware update to take effect, maybe a > > > diagnostic would be helpful if it fails, e.g., the other "Adapter > > > initialization failed. Please reboot" messages. > > > > > > "QLCNIC_NEED_FLR" suggests that the driver expects an FLR (as opposed > > > to other kinds of reset). If the driver knows that all qlcnic devices > > > support FLR, it could use pcie_flr() directly. > > > > > > pci_reset_function() does have the possibility that the reset works on > > > some devices but not all. Secondary Bus Reset fails if there are > > > other functions on the same bus, e.g., a multi-function device. And > > > there's some value in doing the reset the same way in all cases. > > > > > > So I would suggest something like: > > > > > > if (dev->flags & QLCNIC_NEED_FLR) { > > > err = pcie_flr(dev->pdev); > > > if (err) { > > > dev_err(&pdev->dev, "Adapter reset failed (%d). Please reboot\n", err); > > > return err; > > > } > > > dev->flags &= ~QLCNIC_NEED_FLR; > > > } > > > > > > Or, if there are qlcnic devices that don't support FLR: > > > > > > if (dev->flags & QLCNIC_NEED_FLR) { > > > err = pci_reset_function(dev->pdev); > > > if (err) { > > > dev_err(&pdev->dev, "Adapter reset failed (%d). Please reboot\n", err); > > > return err; > > > } > > > dev->flags &= ~QLCNIC_NEED_FLR; > > > } > > Thanks Bjorn, > > > > that is very helpful. > > > > I think that in order to move to option #1 some information would be needed > > from those familiar with the device(s). As it is a more invasive change - > > pci_reset_function -> pcie_flr. > > > > So my feeling is that, in lieu of such feedback, option #2 is a good > > improvement on the current code. > > > > OTOH, this driver is 'Supported' as opposed to 'Maintained'. > > So perhaps we can just use our best judgement and go for option #1. > > So, it looks like option #2 is the safest choice as we do reset only if FLR > is needed (when pci_reset_function() makes sense) > > If all agree with that I'll re-send the path Yes. Maybe wait 24h, and if there is no further feedback go ahead with that plan?
On Thu, Apr 06, 2023 at 01:43:44PM +0200, Simon Horman wrote: > On Thu, Apr 06, 2023 at 12:23:49PM +0300, Denis Plotnikov wrote: > > > > On 06.04.2023 10:03, Simon Horman wrote: > > > On Wed, Apr 05, 2023 at 02:37:08PM -0500, Bjorn Helgaas wrote: > > > > On Wed, Apr 05, 2023 at 03:04:39PM +0200, Simon Horman wrote: > > > > > On Mon, Apr 03, 2023 at 01:58:49PM +0300, Denis Plotnikov wrote: > > > > > > On 31.03.2023 20:52, Simon Horman wrote: > > > > > > > On Fri, Mar 31, 2023 at 11:06:05AM +0300, Denis Plotnikov wrote: > > > > > > > > Static code analyzer complains to unchecked return value. > > > > > > > > It seems that pci_reset_function return something meaningful > > > > > > > > only if "reset_methods" is set. > > > > > > > > Even if reset_methods isn't used check the return value to avoid > > > > > > > > possible bugs leading to undefined behavior in the future. > > > > > > > > > > > > > > > > Signed-off-by: Denis Plotnikov <den-plotnikov@yandex-team.ru> > > > > > > > nit: The tree this patch is targeted at should be designated, probably > > > > > > > net-next, so the '[PATCH net-next]' in the subject. > > > > > > > > > > > > > > > --- > > > > > > > > drivers/net/ethernet/qlogic/qlcnic/qlcnic_ctx.c | 4 +++- > > > > > > > > 1 file changed, 3 insertions(+), 1 deletion(-) > > > > > > > > > > > > > > > > diff --git a/drivers/net/ethernet/qlogic/qlcnic/qlcnic_ctx.c b/drivers/net/ethernet/qlogic/qlcnic/qlcnic_ctx.c > > > > > > > > index 87f76bac2e463..39ecfc1a1dbd0 100644 > > > > > > > > --- a/drivers/net/ethernet/qlogic/qlcnic/qlcnic_ctx.c > > > > > > > > +++ b/drivers/net/ethernet/qlogic/qlcnic/qlcnic_ctx.c > > > > > > > > @@ -628,7 +628,9 @@ int qlcnic_fw_create_ctx(struct qlcnic_adapter *dev) > > > > > > > > int i, err, ring; > > > > > > > > if (dev->flags & QLCNIC_NEED_FLR) { > > > > > > > > - pci_reset_function(dev->pdev); > > > > > > > > + err = pci_reset_function(dev->pdev); > > > > > > > > + if (err && err != -ENOTTY) > > > > > > > Are you sure about the -ENOTTY part? > > > > > > > > > > > > > > It seems odd to me that an FLR would be required but reset is not supported. > > > > > > No, I'm not sure. My logic is: if the reset method isn't set than > > > > > > pci_reset_function() returns -ENOTTY so treat that result as ok. > > > > > > pci_reset_function may return something different than -ENOTTY only if > > > > > > pci_reset_fn_methods[m].reset_fn is set. > > > > > I see your reasoning: -ENOTTY means nothing happened, and probably that is ok. > > > > > I think my main question is if that can ever happen. > > > > > If that is unknown, then I think this conservative approach makes sense. > > > > The commit log mentions "reset_methods", which I don't think is really > > > > relevant here because reset_methods is an internal implementation > > > > detail. The point is that pci_reset_function() returns 0 if it was > > > > successful and a negative value if it failed. > > > > > > > > If the driver thinks the device needs to be reset, ignoring any > > > > negative return value seems like a mistake because the device was not > > > > reset. > > > > > > > > If the reset is required for a firmware update to take effect, maybe a > > > > diagnostic would be helpful if it fails, e.g., the other "Adapter > > > > initialization failed. Please reboot" messages. > > > > > > > > "QLCNIC_NEED_FLR" suggests that the driver expects an FLR (as opposed > > > > to other kinds of reset). If the driver knows that all qlcnic devices > > > > support FLR, it could use pcie_flr() directly. > > > > > > > > pci_reset_function() does have the possibility that the reset works on > > > > some devices but not all. Secondary Bus Reset fails if there are > > > > other functions on the same bus, e.g., a multi-function device. And > > > > there's some value in doing the reset the same way in all cases. > > > > > > > > So I would suggest something like: > > > > > > > > if (dev->flags & QLCNIC_NEED_FLR) { > > > > err = pcie_flr(dev->pdev); > > > > if (err) { > > > > dev_err(&pdev->dev, "Adapter reset failed (%d). Please reboot\n", err); > > > > return err; > > > > } > > > > dev->flags &= ~QLCNIC_NEED_FLR; > > > > } > > > > > > > > Or, if there are qlcnic devices that don't support FLR: > > > > > > > > if (dev->flags & QLCNIC_NEED_FLR) { > > > > err = pci_reset_function(dev->pdev); > > > > if (err) { > > > > dev_err(&pdev->dev, "Adapter reset failed (%d). Please reboot\n", err); > > > > return err; > > > > } > > > > dev->flags &= ~QLCNIC_NEED_FLR; > > > > } > > > Thanks Bjorn, > > > > > > that is very helpful. > > > > > > I think that in order to move to option #1 some information would be needed > > > from those familiar with the device(s). As it is a more invasive change - > > > pci_reset_function -> pcie_flr. > > > > > > So my feeling is that, in lieu of such feedback, option #2 is a good > > > improvement on the current code. > > > > > > OTOH, this driver is 'Supported' as opposed to 'Maintained'. > > > So perhaps we can just use our best judgement and go for option #1. > > > > So, it looks like option #2 is the safest choice as we do reset only if FLR > > is needed (when pci_reset_function() makes sense) > > > > If all agree with that I'll re-send the path > > Yes. Maybe wait 24h, and if there is no further feedback go ahead with that > plan? Perhaps a code comment, or the patch description could include some information about the reasoning above.
On 06.04.2023 14:43, Simon Horman wrote: > On Thu, Apr 06, 2023 at 12:23:49PM +0300, Denis Plotnikov wrote: >> On 06.04.2023 10:03, Simon Horman wrote: >>> On Wed, Apr 05, 2023 at 02:37:08PM -0500, Bjorn Helgaas wrote: >>>> On Wed, Apr 05, 2023 at 03:04:39PM +0200, Simon Horman wrote: >>>>> On Mon, Apr 03, 2023 at 01:58:49PM +0300, Denis Plotnikov wrote: >>>>>> On 31.03.2023 20:52, Simon Horman wrote: >>>>>>> On Fri, Mar 31, 2023 at 11:06:05AM +0300, Denis Plotnikov wrote: >>>>>>>> Static code analyzer complains to unchecked return value. >>>>>>>> It seems that pci_reset_function return something meaningful >>>>>>>> only if "reset_methods" is set. >>>>>>>> Even if reset_methods isn't used check the return value to avoid >>>>>>>> possible bugs leading to undefined behavior in the future. >>>>>>>> >>>>>>>> Signed-off-by: Denis Plotnikov <den-plotnikov@yandex-team.ru> >>>>>>> nit: The tree this patch is targeted at should be designated, probably >>>>>>> net-next, so the '[PATCH net-next]' in the subject. >>>>>>> >>>>>>>> --- >>>>>>>> drivers/net/ethernet/qlogic/qlcnic/qlcnic_ctx.c | 4 +++- >>>>>>>> 1 file changed, 3 insertions(+), 1 deletion(-) >>>>>>>> >>>>>>>> diff --git a/drivers/net/ethernet/qlogic/qlcnic/qlcnic_ctx.c b/drivers/net/ethernet/qlogic/qlcnic/qlcnic_ctx.c >>>>>>>> index 87f76bac2e463..39ecfc1a1dbd0 100644 >>>>>>>> --- a/drivers/net/ethernet/qlogic/qlcnic/qlcnic_ctx.c >>>>>>>> +++ b/drivers/net/ethernet/qlogic/qlcnic/qlcnic_ctx.c >>>>>>>> @@ -628,7 +628,9 @@ int qlcnic_fw_create_ctx(struct qlcnic_adapter *dev) >>>>>>>> int i, err, ring; >>>>>>>> if (dev->flags & QLCNIC_NEED_FLR) { >>>>>>>> - pci_reset_function(dev->pdev); >>>>>>>> + err = pci_reset_function(dev->pdev); >>>>>>>> + if (err && err != -ENOTTY) >>>>>>> Are you sure about the -ENOTTY part? >>>>>>> >>>>>>> It seems odd to me that an FLR would be required but reset is not supported. >>>>>> No, I'm not sure. My logic is: if the reset method isn't set than >>>>>> pci_reset_function() returns -ENOTTY so treat that result as ok. >>>>>> pci_reset_function may return something different than -ENOTTY only if >>>>>> pci_reset_fn_methods[m].reset_fn is set. >>>>> I see your reasoning: -ENOTTY means nothing happened, and probably that is ok. >>>>> I think my main question is if that can ever happen. >>>>> If that is unknown, then I think this conservative approach makes sense. >>>> The commit log mentions "reset_methods", which I don't think is really >>>> relevant here because reset_methods is an internal implementation >>>> detail. The point is that pci_reset_function() returns 0 if it was >>>> successful and a negative value if it failed. >>>> >>>> If the driver thinks the device needs to be reset, ignoring any >>>> negative return value seems like a mistake because the device was not >>>> reset. >>>> >>>> If the reset is required for a firmware update to take effect, maybe a >>>> diagnostic would be helpful if it fails, e.g., the other "Adapter >>>> initialization failed. Please reboot" messages. >>>> >>>> "QLCNIC_NEED_FLR" suggests that the driver expects an FLR (as opposed >>>> to other kinds of reset). If the driver knows that all qlcnic devices >>>> support FLR, it could use pcie_flr() directly. >>>> >>>> pci_reset_function() does have the possibility that the reset works on >>>> some devices but not all. Secondary Bus Reset fails if there are >>>> other functions on the same bus, e.g., a multi-function device. And >>>> there's some value in doing the reset the same way in all cases. >>>> >>>> So I would suggest something like: >>>> >>>> if (dev->flags & QLCNIC_NEED_FLR) { >>>> err = pcie_flr(dev->pdev); >>>> if (err) { >>>> dev_err(&pdev->dev, "Adapter reset failed (%d). Please reboot\n", err); >>>> return err; >>>> } >>>> dev->flags &= ~QLCNIC_NEED_FLR; >>>> } >>>> >>>> Or, if there are qlcnic devices that don't support FLR: >>>> >>>> if (dev->flags & QLCNIC_NEED_FLR) { >>>> err = pci_reset_function(dev->pdev); >>>> if (err) { >>>> dev_err(&pdev->dev, "Adapter reset failed (%d). Please reboot\n", err); >>>> return err; >>>> } >>>> dev->flags &= ~QLCNIC_NEED_FLR; >>>> } >>> Thanks Bjorn, >>> >>> that is very helpful. >>> >>> I think that in order to move to option #1 some information would be needed >>> from those familiar with the device(s). As it is a more invasive change - >>> pci_reset_function -> pcie_flr. >>> >>> So my feeling is that, in lieu of such feedback, option #2 is a good >>> improvement on the current code. >>> >>> OTOH, this driver is 'Supported' as opposed to 'Maintained'. >>> So perhaps we can just use our best judgement and go for option #1. >> So, it looks like option #2 is the safest choice as we do reset only if FLR >> is needed (when pci_reset_function() makes sense) >> >> If all agree with that I'll re-send the path > Yes. Maybe wait 24h, and if there is no further feedback go ahead with that > plan? Ok, will do so. Thanks!
diff --git a/drivers/net/ethernet/qlogic/qlcnic/qlcnic_ctx.c b/drivers/net/ethernet/qlogic/qlcnic/qlcnic_ctx.c index 87f76bac2e463..39ecfc1a1dbd0 100644 --- a/drivers/net/ethernet/qlogic/qlcnic/qlcnic_ctx.c +++ b/drivers/net/ethernet/qlogic/qlcnic/qlcnic_ctx.c @@ -628,7 +628,9 @@ int qlcnic_fw_create_ctx(struct qlcnic_adapter *dev) int i, err, ring; if (dev->flags & QLCNIC_NEED_FLR) { - pci_reset_function(dev->pdev); + err = pci_reset_function(dev->pdev); + if (err && err != -ENOTTY) + return err; dev->flags &= ~QLCNIC_NEED_FLR; }
Static code analyzer complains to unchecked return value. It seems that pci_reset_function return something meaningful only if "reset_methods" is set. Even if reset_methods isn't used check the return value to avoid possible bugs leading to undefined behavior in the future. Signed-off-by: Denis Plotnikov <den-plotnikov@yandex-team.ru> --- drivers/net/ethernet/qlogic/qlcnic/qlcnic_ctx.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)