| Message ID | 1457351357-13457-1-git-send-email-sudipm.mukherjee@gmail.com |
|---|---|
| State | Accepted |
| Headers | show |
On Mon, Mar 07, 2016 at 05:19:17PM +0530, Sudip Mukherjee wrote: > The variable p is a data structure which is used by the driver core > internally and it is not expected that busses will be directly accessing > these driver core internal only data. > > Signed-off-by: Sudip Mukherjee <sudip.mukherjee@codethink.co.uk> > --- > > Reference of Greg's comment about it at: > https://lkml.org/lkml/2016/3/5/171 > > drivers/i2c/i2c-core.c | 6 ++++-- > 1 file changed, 4 insertions(+), 2 deletions(-) > > diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c > index 2949ab3..2f31fb5 100644 > --- a/drivers/i2c/i2c-core.c > +++ b/drivers/i2c/i2c-core.c > @@ -73,6 +73,7 @@ static struct device_type i2c_client_type; > static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver); > > static struct static_key i2c_trace_msg = STATIC_KEY_INIT_FALSE; > +static bool is_registered; > > void i2c_transfer_trace_reg(void) > { > @@ -1529,7 +1530,7 @@ static int i2c_register_adapter(struct i2c_adapter *adap) > int res = 0; > > /* Can't register until after driver model init */ > - if (unlikely(WARN_ON(!i2c_bus_type.p))) { > + if (unlikely(WARN_ON(!is_registered))) { > res = -EAGAIN; > goto out_list; > } Minor nit, likely/unlikely should only be used on very "hot paths" where the difference if it is not included can be measured. the "register a device" path is not "hot" at all. That being said, the patch is fine with me: Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Monday 07 March 2016 10:27 PM, Greg KH wrote: > On Mon, Mar 07, 2016 at 05:19:17PM +0530, Sudip Mukherjee wrote: >> The variable p is a data structure which is used by the driver core >> internally and it is not expected that busses will be directly accessing >> these driver core internal only data. >> >> Signed-off-by: Sudip Mukherjee <sudip.mukherjee@codethink.co.uk> >> --- >> >> Reference of Greg's comment about it at: >> https://lkml.org/lkml/2016/3/5/171 >> >> drivers/i2c/i2c-core.c | 6 ++++-- >> 1 file changed, 4 insertions(+), 2 deletions(-) >> >> diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c >> index 2949ab3..2f31fb5 100644 >> --- a/drivers/i2c/i2c-core.c >> +++ b/drivers/i2c/i2c-core.c >> @@ -73,6 +73,7 @@ static struct device_type i2c_client_type; >> static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver); >> >> static struct static_key i2c_trace_msg = STATIC_KEY_INIT_FALSE; >> +static bool is_registered; >> >> void i2c_transfer_trace_reg(void) >> { >> @@ -1529,7 +1530,7 @@ static int i2c_register_adapter(struct i2c_adapter *adap) >> int res = 0; >> >> /* Can't register until after driver model init */ >> - if (unlikely(WARN_ON(!i2c_bus_type.p))) { >> + if (unlikely(WARN_ON(!is_registered))) { >> res = -EAGAIN; >> goto out_list; >> } > > Minor nit, likely/unlikely should only be used on very "hot paths" where > the difference if it is not included can be measured. the "register a > device" path is not "hot" at all. I can submit a patch afterwards to remove the "unlikely" if that is ok with Wolfram. regards sudip -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Mon, Mar 07, 2016 at 05:19:17PM +0530, Sudip Mukherjee wrote: > The variable p is a data structure which is used by the driver core > internally and it is not expected that busses will be directly accessing > these driver core internal only data. > > Signed-off-by: Sudip Mukherjee <sudip.mukherjee@codethink.co.uk> Removed the unlikely() and applied to for-next, thanks!
On Mon, Mar 07, 2016 at 05:19:17PM +0530, Sudip Mukherjee wrote: > The variable p is a data structure which is used by the driver core > internally and it is not expected that busses will be directly accessing > these driver core internal only data. > > Signed-off-by: Sudip Mukherjee <sudip.mukherjee@codethink.co.uk> > --- > > Reference of Greg's comment about it at: > https://lkml.org/lkml/2016/3/5/171 > > drivers/i2c/i2c-core.c | 6 ++++-- > 1 file changed, 4 insertions(+), 2 deletions(-) > > diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c > index 2949ab3..2f31fb5 100644 > --- a/drivers/i2c/i2c-core.c > +++ b/drivers/i2c/i2c-core.c > @@ -73,6 +73,7 @@ static struct device_type i2c_client_type; > static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver); > > static struct static_key i2c_trace_msg = STATIC_KEY_INIT_FALSE; > +static bool is_registered; > > void i2c_transfer_trace_reg(void) > { > @@ -1529,7 +1530,7 @@ static int i2c_register_adapter(struct i2c_adapter *adap) > int res = 0; > > /* Can't register until after driver model init */ > - if (unlikely(WARN_ON(!i2c_bus_type.p))) { > + if (unlikely(WARN_ON(!is_registered))) { > res = -EAGAIN; > goto out_list; > } > @@ -1926,7 +1927,7 @@ int i2c_register_driver(struct module *owner, struct i2c_driver *driver) > int res; > > /* Can't register until after driver model init */ > - if (unlikely(WARN_ON(!i2c_bus_type.p))) > + if (unlikely(WARN_ON(!is_registered))) > return -EAGAIN; > > /* add the driver to the list of i2c drivers in the driver core */ > @@ -2118,6 +2119,7 @@ static int __init i2c_init(void) > if (IS_ENABLED(CONFIG_OF_DYNAMIC)) > WARN_ON(of_reconfig_notifier_register(&i2c_of_notifier)); > > + is_registered = true; > return 0; > > class_err: This doesn't work. I see a number of these WARN_ON()s trigger and I think the reason is that i2c_init() always fails now. The cause seems to be that i2c_init() calls i2c_add_driver(&dummy_driver), which will now always fail, because is_register is set to true *after* that call. There is no way I see I2C working at all after this patch. Thierry
> This doesn't work. I see a number of these WARN_ON()s trigger and I > think the reason is that i2c_init() always fails now. The cause seems to > be that i2c_init() calls i2c_add_driver(&dummy_driver), which will now > always fail, because is_register is set to true *after* that call. There > is no way I see I2C working at all after this patch. Same conclusion here. Too much trust applied to the original patch, mea culpa and sorry! Will send the fixup (tested!) in a minute.
On Mon, Mar 14, 2016 at 10:28:10AM +0100, Wolfram Sang wrote: > > > This doesn't work. I see a number of these WARN_ON()s trigger and I > > think the reason is that i2c_init() always fails now. The cause seems to > > be that i2c_init() calls i2c_add_driver(&dummy_driver), which will now > > always fail, because is_register is set to true *after* that call. There > > is no way I see I2C working at all after this patch. > > Same conclusion here. Too much trust applied to the original patch, mea > culpa and sorry! Will send the fixup (tested!) in a minute. No worries. There's nothing like good old runtime testing for making sure things really do work. =) Thierry
On Mon, Mar 14, 2016 at 10:28:10AM +0100, Wolfram Sang wrote: > > > This doesn't work. I see a number of these WARN_ON()s trigger and I > > think the reason is that i2c_init() always fails now. The cause seems to > > be that i2c_init() calls i2c_add_driver(&dummy_driver), which will now > > always fail, because is_register is set to true *after* that call. There > > is no way I see I2C working at all after this patch. > > Same conclusion here. Too much trust applied to the original patch, mea > culpa and sorry! Will send the fixup (tested!) in a minute. Sorry for the mess. Fengguang Wu did send me a warning, but since I was travelling i could not do much with it. Sorry again. regards sudip -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c index 2949ab3..2f31fb5 100644 --- a/drivers/i2c/i2c-core.c +++ b/drivers/i2c/i2c-core.c @@ -73,6 +73,7 @@ static struct device_type i2c_client_type; static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver); static struct static_key i2c_trace_msg = STATIC_KEY_INIT_FALSE; +static bool is_registered; void i2c_transfer_trace_reg(void) { @@ -1529,7 +1530,7 @@ static int i2c_register_adapter(struct i2c_adapter *adap) int res = 0; /* Can't register until after driver model init */ - if (unlikely(WARN_ON(!i2c_bus_type.p))) { + if (unlikely(WARN_ON(!is_registered))) { res = -EAGAIN; goto out_list; } @@ -1926,7 +1927,7 @@ int i2c_register_driver(struct module *owner, struct i2c_driver *driver) int res; /* Can't register until after driver model init */ - if (unlikely(WARN_ON(!i2c_bus_type.p))) + if (unlikely(WARN_ON(!is_registered))) return -EAGAIN; /* add the driver to the list of i2c drivers in the driver core */ @@ -2118,6 +2119,7 @@ static int __init i2c_init(void) if (IS_ENABLED(CONFIG_OF_DYNAMIC)) WARN_ON(of_reconfig_notifier_register(&i2c_of_notifier)); + is_registered = true; return 0; class_err:
The variable p is a data structure which is used by the driver core internally and it is not expected that busses will be directly accessing these driver core internal only data. Signed-off-by: Sudip Mukherjee <sudip.mukherjee@codethink.co.uk> --- Reference of Greg's comment about it at: https://lkml.org/lkml/2016/3/5/171 drivers/i2c/i2c-core.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)