Re: [PATCH] drivers: pnp: proc.c: Handle errors while attaching devices
On 21/04/28 02:30PM, Jaroslav Kysela wrote:
> Dne 28. 04. 21 v 14:21 Leon Romanovsky napsal(a):
> > On Wed, Apr 28, 2021 at 02:04:49PM +0200, Jaroslav Kysela wrote:
> >> Dne 26. 04. 21 v 19:50 bkkarthik napsal(a):
> >>> On 21/04/26 08:04AM, Leon Romanovsky wrote:
> On Sun, Apr 25, 2021 at 01:13:01AM +0530, Anupama K Patil wrote:
> > isapnp_proc_init() does not look at the return value from
> > isapnp_proc_attach_device(). Check for this return value in
> > isapnp_proc_detach_device().
> >
> > Cleanup in isapnp_proc_detach_device and
> > isapnp_proc_detach_bus() for cleanup.
> >
> > Changed sprintf() to the kernel-space function scnprintf() as it returns
> > the actual number of bytes written.
> >
> > Removed unnecessary variables de, e of type 'struct proc_dir_entry' to
> > save memory.
>
> What exactly do you fix for such an old code?
> >>>
> >>> I was not aware that this code is so old. This fix was made after
> >>> checkpatch reported assignment inside an if-statement.
> >>> Please ignore this patch if th change is not necessary as the code is
> >>> probably not being used anywhere :)
> >>>
> >>> Maybe the code has to be marked as obsolete in the MAINTAINERS file to
> >>> prevent patches being sent?
> >>>
>
> >
> > Suggested-by: Shuah Khan
> > Co-developed-by: B K Karthik
> > Signed-off-by: B K Karthik
> > Signed-off-by: Anupama K Patil
> > ---
> > drivers/pnp/isapnp/proc.c | 40 +--
> > 1 file changed, 30 insertions(+), 10 deletions(-)
> >
> > diff --git a/drivers/pnp/isapnp/proc.c b/drivers/pnp/isapnp/proc.c
> > index 785a796430fa..46ebc24175b7 100644
> > --- a/drivers/pnp/isapnp/proc.c
> > +++ b/drivers/pnp/isapnp/proc.c
> > @@ -54,34 +54,54 @@ static const struct proc_ops
> > isapnp_proc_bus_proc_ops = {
> > .proc_read = isapnp_proc_bus_read,
> > };
> >
> > +static int isapnp_proc_detach_device(struct pnp_dev *dev)
> > +{
> > + proc_remove(dev->procent);
> > + dev->procent = NULL;
> > + return 0;
> > +}
> > +
> > +static int isapnp_proc_detach_bus(struct pnp_card *bus)
> > +{
> > + proc_remove(bus->procdir);
> > + return 0;
> > +}
>
> Please don't add one line functions that are called only once and have
> return value that no one care about it.
> >>>
> >>> These were only intended for a clean-up job, the idea of this function
> >>> came from how PCI handles procfs.
> >>> Maybe those should be changed?
> >>
> >> Which code you refer? I see:
> >>
> >>for_each_pci_dev(dev)
> >> pci_proc_attach_device(dev);
> >
> > He talks about isapnp_proc_detach_*() functions.
>
> But only this patch introduced those functions. The pci_proc_init() code does
> not call pci_proc_detach_*() functions and ignores the allocation errors, too.
The changes in this patch make isapnp_proc_init() look at the return value of
isapnp_proc_attach_device() and call isapnp_proc_detach_device() if that
returns an error code.
> I don't think that this cleanup code is required.
Oh okay!
karthik
>
> Jaroslav
>
> --
> Jaroslav Kysela
> Linux Sound Maintainer; ALSA Project; Red Hat, Inc.
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Re: [PATCH] drivers: pnp: proc.c: Handle errors while attaching devices
Dne 28. 04. 21 v 14:21 Leon Romanovsky napsal(a):
> On Wed, Apr 28, 2021 at 02:04:49PM +0200, Jaroslav Kysela wrote:
>> Dne 26. 04. 21 v 19:50 bkkarthik napsal(a):
>>> On 21/04/26 08:04AM, Leon Romanovsky wrote:
On Sun, Apr 25, 2021 at 01:13:01AM +0530, Anupama K Patil wrote:
> isapnp_proc_init() does not look at the return value from
> isapnp_proc_attach_device(). Check for this return value in
> isapnp_proc_detach_device().
>
> Cleanup in isapnp_proc_detach_device and
> isapnp_proc_detach_bus() for cleanup.
>
> Changed sprintf() to the kernel-space function scnprintf() as it returns
> the actual number of bytes written.
>
> Removed unnecessary variables de, e of type 'struct proc_dir_entry' to
> save memory.
What exactly do you fix for such an old code?
>>>
>>> I was not aware that this code is so old. This fix was made after
>>> checkpatch reported assignment inside an if-statement.
>>> Please ignore this patch if th change is not necessary as the code is
>>> probably not being used anywhere :)
>>>
>>> Maybe the code has to be marked as obsolete in the MAINTAINERS file to
>>> prevent patches being sent?
>>>
>
> Suggested-by: Shuah Khan
> Co-developed-by: B K Karthik
> Signed-off-by: B K Karthik
> Signed-off-by: Anupama K Patil
> ---
> drivers/pnp/isapnp/proc.c | 40 +--
> 1 file changed, 30 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/pnp/isapnp/proc.c b/drivers/pnp/isapnp/proc.c
> index 785a796430fa..46ebc24175b7 100644
> --- a/drivers/pnp/isapnp/proc.c
> +++ b/drivers/pnp/isapnp/proc.c
> @@ -54,34 +54,54 @@ static const struct proc_ops isapnp_proc_bus_proc_ops
> = {
> .proc_read = isapnp_proc_bus_read,
> };
>
> +static int isapnp_proc_detach_device(struct pnp_dev *dev)
> +{
> + proc_remove(dev->procent);
> + dev->procent = NULL;
> + return 0;
> +}
> +
> +static int isapnp_proc_detach_bus(struct pnp_card *bus)
> +{
> + proc_remove(bus->procdir);
> + return 0;
> +}
Please don't add one line functions that are called only once and have
return value that no one care about it.
>>>
>>> These were only intended for a clean-up job, the idea of this function came
>>> from how PCI handles procfs.
>>> Maybe those should be changed?
>>
>> Which code you refer? I see:
>>
>>for_each_pci_dev(dev)
>> pci_proc_attach_device(dev);
>
> He talks about isapnp_proc_detach_*() functions.
But only this patch introduced those functions. The pci_proc_init() code does
not call pci_proc_detach_*() functions and ignores the allocation errors, too.
I don't think that this cleanup code is required.
Jaroslav
--
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Re: [PATCH] drivers: pnp: proc.c: Handle errors while attaching devices
On 21/04/28 03:21PM, Leon Romanovsky wrote:
> On Wed, Apr 28, 2021 at 02:04:49PM +0200, Jaroslav Kysela wrote:
> > Dne 26. 04. 21 v 19:50 bkkarthik napsal(a):
> > > On 21/04/26 08:04AM, Leon Romanovsky wrote:
> > >> On Sun, Apr 25, 2021 at 01:13:01AM +0530, Anupama K Patil wrote:
> > >>> isapnp_proc_init() does not look at the return value from
> > >>> isapnp_proc_attach_device(). Check for this return value in
> > >>> isapnp_proc_detach_device().
> > >>>
> > >>> Cleanup in isapnp_proc_detach_device and
> > >>> isapnp_proc_detach_bus() for cleanup.
> > >>>
> > >>> Changed sprintf() to the kernel-space function scnprintf() as it returns
> > >>> the actual number of bytes written.
> > >>>
> > >>> Removed unnecessary variables de, e of type 'struct proc_dir_entry' to
> > >>> save memory.
> > >>
> > >> What exactly do you fix for such an old code?
> > >
> > > I was not aware that this code is so old. This fix was made after
> > > checkpatch reported assignment inside an if-statement.
> > > Please ignore this patch if th change is not necessary as the code is
> > > probably not being used anywhere :)
> > >
> > > Maybe the code has to be marked as obsolete in the MAINTAINERS file to
> > > prevent patches being sent?
> > >
> > >>
> > >>>
> > >>> Suggested-by: Shuah Khan
> > >>> Co-developed-by: B K Karthik
> > >>> Signed-off-by: B K Karthik
> > >>> Signed-off-by: Anupama K Patil
> > >>> ---
> > >>> drivers/pnp/isapnp/proc.c | 40 +--
> > >>> 1 file changed, 30 insertions(+), 10 deletions(-)
> > >>>
> > >>> diff --git a/drivers/pnp/isapnp/proc.c b/drivers/pnp/isapnp/proc.c
> > >>> index 785a796430fa..46ebc24175b7 100644
> > >>> --- a/drivers/pnp/isapnp/proc.c
> > >>> +++ b/drivers/pnp/isapnp/proc.c
> > >>> @@ -54,34 +54,54 @@ static const struct proc_ops
> > >>> isapnp_proc_bus_proc_ops = {
> > >>> .proc_read = isapnp_proc_bus_read,
> > >>> };
> > >>>
> > >>> +static int isapnp_proc_detach_device(struct pnp_dev *dev)
> > >>> +{
> > >>> + proc_remove(dev->procent);
> > >>> + dev->procent = NULL;
> > >>> + return 0;
> > >>> +}
> > >>> +
> > >>> +static int isapnp_proc_detach_bus(struct pnp_card *bus)
> > >>> +{
> > >>> + proc_remove(bus->procdir);
> > >>> + return 0;
> > >>> +}
> > >>
> > >> Please don't add one line functions that are called only once and have
> > >> return value that no one care about it.
> > >
> > > These were only intended for a clean-up job, the idea of this function
> > > came from how PCI handles procfs.
> > > Maybe those should be changed?
> >
> > Which code you refer? I see:
> >
> >for_each_pci_dev(dev)
> > pci_proc_attach_device(dev);
>
> He talks about isapnp_proc_detach_*() functions.
Yes, pci_proc_detach_device() and pci_proc_detach_bus() are both one-line
functions as well.
I don't mean to question working code, we only tried to do something similar
here for ISA.
thanks,
karthik
>
> >
> >
> > The error codes are ignored, too. It does not harm, if proc entries are not
> > created (in this case - the system is unstable anyway). We should
> > concentrate
> > only to the wrong pointers usage.
> >
> > Jaroslav
> >
> > --
> > Jaroslav Kysela
> > Linux Sound Maintainer; ALSA Project; Red Hat, Inc.
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Re: [PATCH] drivers: pnp: proc.c: Handle errors while attaching devices
Dne 26. 04. 21 v 19:50 bkkarthik napsal(a):
> On 21/04/26 08:04AM, Leon Romanovsky wrote:
>> On Sun, Apr 25, 2021 at 01:13:01AM +0530, Anupama K Patil wrote:
>>> isapnp_proc_init() does not look at the return value from
>>> isapnp_proc_attach_device(). Check for this return value in
>>> isapnp_proc_detach_device().
>>>
>>> Cleanup in isapnp_proc_detach_device and
>>> isapnp_proc_detach_bus() for cleanup.
>>>
>>> Changed sprintf() to the kernel-space function scnprintf() as it returns
>>> the actual number of bytes written.
>>>
>>> Removed unnecessary variables de, e of type 'struct proc_dir_entry' to
>>> save memory.
>>
>> What exactly do you fix for such an old code?
>
> I was not aware that this code is so old. This fix was made after checkpatch
> reported assignment inside an if-statement.
> Please ignore this patch if th change is not necessary as the code is
> probably not being used anywhere :)
>
> Maybe the code has to be marked as obsolete in the MAINTAINERS file to
> prevent patches being sent?
>
>>
>>>
>>> Suggested-by: Shuah Khan
>>> Co-developed-by: B K Karthik
>>> Signed-off-by: B K Karthik
>>> Signed-off-by: Anupama K Patil
>>> ---
>>> drivers/pnp/isapnp/proc.c | 40 +--
>>> 1 file changed, 30 insertions(+), 10 deletions(-)
>>>
>>> diff --git a/drivers/pnp/isapnp/proc.c b/drivers/pnp/isapnp/proc.c
>>> index 785a796430fa..46ebc24175b7 100644
>>> --- a/drivers/pnp/isapnp/proc.c
>>> +++ b/drivers/pnp/isapnp/proc.c
>>> @@ -54,34 +54,54 @@ static const struct proc_ops isapnp_proc_bus_proc_ops =
>>> {
>>> .proc_read = isapnp_proc_bus_read,
>>> };
>>>
>>> +static int isapnp_proc_detach_device(struct pnp_dev *dev)
>>> +{
>>> + proc_remove(dev->procent);
>>> + dev->procent = NULL;
>>> + return 0;
>>> +}
>>> +
>>> +static int isapnp_proc_detach_bus(struct pnp_card *bus)
>>> +{
>>> + proc_remove(bus->procdir);
>>> + return 0;
>>> +}
>>
>> Please don't add one line functions that are called only once and have
>> return value that no one care about it.
>
> These were only intended for a clean-up job, the idea of this function came
> from how PCI handles procfs.
> Maybe those should be changed?
Which code you refer? I see:
for_each_pci_dev(dev)
pci_proc_attach_device(dev);
The error codes are ignored, too. It does not harm, if proc entries are not
created (in this case - the system is unstable anyway). We should concentrate
only to the wrong pointers usage.
Jaroslav
--
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Linux Sound Maintainer; ALSA Project; Red Hat, Inc.
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Re: [PATCH] drivers: pnp: proc.c: Handle errors while attaching devices
On 21/04/26 08:04AM, Leon Romanovsky wrote:
> On Sun, Apr 25, 2021 at 01:13:01AM +0530, Anupama K Patil wrote:
> > isapnp_proc_init() does not look at the return value from
> > isapnp_proc_attach_device(). Check for this return value in
> > isapnp_proc_detach_device().
> >
> > Cleanup in isapnp_proc_detach_device and
> > isapnp_proc_detach_bus() for cleanup.
> >
> > Changed sprintf() to the kernel-space function scnprintf() as it returns
> > the actual number of bytes written.
> >
> > Removed unnecessary variables de, e of type 'struct proc_dir_entry' to
> > save memory.
>
> What exactly do you fix for such an old code?
I was not aware that this code is so old. This fix was made after checkpatch
reported assignment inside an if-statement.
Please ignore this patch if th change is not necessary as the code is probably
not being used anywhere :)
Maybe the code has to be marked as obsolete in the MAINTAINERS file to prevent
patches being sent?
>
> >
> > Suggested-by: Shuah Khan
> > Co-developed-by: B K Karthik
> > Signed-off-by: B K Karthik
> > Signed-off-by: Anupama K Patil
> > ---
> > drivers/pnp/isapnp/proc.c | 40 +--
> > 1 file changed, 30 insertions(+), 10 deletions(-)
> >
> > diff --git a/drivers/pnp/isapnp/proc.c b/drivers/pnp/isapnp/proc.c
> > index 785a796430fa..46ebc24175b7 100644
> > --- a/drivers/pnp/isapnp/proc.c
> > +++ b/drivers/pnp/isapnp/proc.c
> > @@ -54,34 +54,54 @@ static const struct proc_ops isapnp_proc_bus_proc_ops =
> > {
> > .proc_read = isapnp_proc_bus_read,
> > };
> >
> > +static int isapnp_proc_detach_device(struct pnp_dev *dev)
> > +{
> > + proc_remove(dev->procent);
> > + dev->procent = NULL;
> > + return 0;
> > +}
> > +
> > +static int isapnp_proc_detach_bus(struct pnp_card *bus)
> > +{
> > + proc_remove(bus->procdir);
> > + return 0;
> > +}
>
> Please don't add one line functions that are called only once and have
> return value that no one care about it.
These were only intended for a clean-up job, the idea of this function came
from how PCI handles procfs.
Maybe those should be changed?
thanks,
karthik
>
> Thanks
>
> > +
> > static int isapnp_proc_attach_device(struct pnp_dev *dev)
> > {
> > struct pnp_card *bus = dev->card;
> > - struct proc_dir_entry *de, *e;
> > char name[16];
> >
> > - if (!(de = bus->procdir)) {
> > - sprintf(name, "%02x", bus->number);
> > - de = bus->procdir = proc_mkdir(name, isapnp_proc_bus_dir);
> > - if (!de)
> > + if (!bus->procdir) {
> > + scnprintf(name, 16, "%02x", bus->number);
> > + bus->procdir = proc_mkdir(name, isapnp_proc_bus_dir);
> > + if (!bus->procdir)
> > return -ENOMEM;
> > }
> > - sprintf(name, "%02x", dev->number);
> > - e = dev->procent = proc_create_data(name, S_IFREG | S_IRUGO, de,
> > + scnprintf(name, 16, "%02x", dev->number);
> > + dev->procent = proc_create_data(name, S_IFREG | S_IRUGO, bus->procdir,
> > &isapnp_proc_bus_proc_ops, dev);
> > - if (!e)
> > + if (!dev->procent) {
> > + isapnp_proc_detach_bus(bus);
> > return -ENOMEM;
> > - proc_set_size(e, 256);
> > + }
> > + proc_set_size(dev->procent, 256);
> > return 0;
> > }
> >
> > int __init isapnp_proc_init(void)
> > {
> > struct pnp_dev *dev;
> > + int dev_attach;
> >
> > isapnp_proc_bus_dir = proc_mkdir("bus/isapnp", NULL);
> > protocol_for_each_dev(&isapnp_protocol, dev) {
> > - isapnp_proc_attach_device(dev);
> > + dev_attach = isapnp_proc_attach_device(dev);
> > + if (!dev_attach) {
> > + pr_info("procfs: pnp: Unable to attach the device, not
> > enough memory");
> > + isapnp_proc_detach_device(dev);
> > + return -ENOMEM;
> > + }
> > }
> > return 0;
> > }
> > --
> > 2.25.1
> >
>
>
>
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Re: [PATCH] drivers: pnp: proc.c: Handle errors while attaching devices
On Thu, Apr 29, 2021 at 12:31:13AM -0400, Valdis Klētnieks wrote: > On Tue, 27 Apr 2021 07:26:27 +0300, Leon Romanovsky said: > > On Mon, Apr 26, 2021 at 11:20:32PM +0530, bkkarthik wrote: > > > These were only intended for a clean-up job, the idea of this function > > > came from how PCI handles procfs. > > > Maybe those should be changed? > > > > Probably, the CONFIG_PROC_FS around pci_proc_*() is not needed too. > > Will that actually build correctly if it's an embedded system or something > build with > CONFIG_PROC_FS=n? I'd expect that to die a horrid death while linking vmlinx > due > to stuff inside that #ifdef calling symbols only present with PROC_FS=m/y. We are talking about pci_proc_detach_device() and pci_proc_detach_bus() here. They will build perfectly without CONFIG_PROC_FS. Thanks ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Re: [PATCH] drivers: pnp: proc.c: Handle errors while attaching devices
On Tue, 27 Apr 2021 07:26:27 +0300, Leon Romanovsky said: > On Mon, Apr 26, 2021 at 11:20:32PM +0530, bkkarthik wrote: > > These were only intended for a clean-up job, the idea of this function came > > from how PCI handles procfs. > > Maybe those should be changed? > > Probably, the CONFIG_PROC_FS around pci_proc_*() is not needed too. Will that actually build correctly if it's an embedded system or something build with CONFIG_PROC_FS=n? I'd expect that to die a horrid death while linking vmlinx due to stuff inside that #ifdef calling symbols only present with PROC_FS=m/y. In general, inline ifdef's are frowned upon, so if you come across one in the kernel source, that's probably a *big* hint that either (a) refactoring the code to eliminate an inline ifdef was just too ugly to be allowed to live or (b) you *have* to put a guard around it because you're guaranteed a build failure otherwise. pgpz44CcAsPiA.pgp Description: PGP signature ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Re: [PATCH] drivers: pnp: proc.c: Handle errors while attaching devices
On Wed, Apr 28, 2021 at 02:04:49PM +0200, Jaroslav Kysela wrote:
> Dne 26. 04. 21 v 19:50 bkkarthik napsal(a):
> > On 21/04/26 08:04AM, Leon Romanovsky wrote:
> >> On Sun, Apr 25, 2021 at 01:13:01AM +0530, Anupama K Patil wrote:
> >>> isapnp_proc_init() does not look at the return value from
> >>> isapnp_proc_attach_device(). Check for this return value in
> >>> isapnp_proc_detach_device().
> >>>
> >>> Cleanup in isapnp_proc_detach_device and
> >>> isapnp_proc_detach_bus() for cleanup.
> >>>
> >>> Changed sprintf() to the kernel-space function scnprintf() as it returns
> >>> the actual number of bytes written.
> >>>
> >>> Removed unnecessary variables de, e of type 'struct proc_dir_entry' to
> >>> save memory.
> >>
> >> What exactly do you fix for such an old code?
> >
> > I was not aware that this code is so old. This fix was made after
> > checkpatch reported assignment inside an if-statement.
> > Please ignore this patch if th change is not necessary as the code is
> > probably not being used anywhere :)
> >
> > Maybe the code has to be marked as obsolete in the MAINTAINERS file to
> > prevent patches being sent?
> >
> >>
> >>>
> >>> Suggested-by: Shuah Khan
> >>> Co-developed-by: B K Karthik
> >>> Signed-off-by: B K Karthik
> >>> Signed-off-by: Anupama K Patil
> >>> ---
> >>> drivers/pnp/isapnp/proc.c | 40 +--
> >>> 1 file changed, 30 insertions(+), 10 deletions(-)
> >>>
> >>> diff --git a/drivers/pnp/isapnp/proc.c b/drivers/pnp/isapnp/proc.c
> >>> index 785a796430fa..46ebc24175b7 100644
> >>> --- a/drivers/pnp/isapnp/proc.c
> >>> +++ b/drivers/pnp/isapnp/proc.c
> >>> @@ -54,34 +54,54 @@ static const struct proc_ops isapnp_proc_bus_proc_ops
> >>> = {
> >>> .proc_read = isapnp_proc_bus_read,
> >>> };
> >>>
> >>> +static int isapnp_proc_detach_device(struct pnp_dev *dev)
> >>> +{
> >>> + proc_remove(dev->procent);
> >>> + dev->procent = NULL;
> >>> + return 0;
> >>> +}
> >>> +
> >>> +static int isapnp_proc_detach_bus(struct pnp_card *bus)
> >>> +{
> >>> + proc_remove(bus->procdir);
> >>> + return 0;
> >>> +}
> >>
> >> Please don't add one line functions that are called only once and have
> >> return value that no one care about it.
> >
> > These were only intended for a clean-up job, the idea of this function came
> > from how PCI handles procfs.
> > Maybe those should be changed?
>
> Which code you refer? I see:
>
>for_each_pci_dev(dev)
> pci_proc_attach_device(dev);
He talks about isapnp_proc_detach_*() functions.
>
>
> The error codes are ignored, too. It does not harm, if proc entries are not
> created (in this case - the system is unstable anyway). We should concentrate
> only to the wrong pointers usage.
>
> Jaroslav
>
> --
> Jaroslav Kysela
> Linux Sound Maintainer; ALSA Project; Red Hat, Inc.
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Re: [PATCH] drivers: pnp: proc.c: Handle errors while attaching devices
On Mon, Apr 26, 2021 at 11:20:32PM +0530, bkkarthik wrote:
> On 21/04/26 08:04AM, Leon Romanovsky wrote:
> > On Sun, Apr 25, 2021 at 01:13:01AM +0530, Anupama K Patil wrote:
> > > isapnp_proc_init() does not look at the return value from
> > > isapnp_proc_attach_device(). Check for this return value in
> > > isapnp_proc_detach_device().
> > >
> > > Cleanup in isapnp_proc_detach_device and
> > > isapnp_proc_detach_bus() for cleanup.
> > >
> > > Changed sprintf() to the kernel-space function scnprintf() as it returns
> > > the actual number of bytes written.
> > >
> > > Removed unnecessary variables de, e of type 'struct proc_dir_entry' to
> > > save memory.
<...>
> > > +static int isapnp_proc_detach_device(struct pnp_dev *dev)
> > > +{
> > > + proc_remove(dev->procent);
> > > + dev->procent = NULL;
> > > + return 0;
> > > +}
> > > +
> > > +static int isapnp_proc_detach_bus(struct pnp_card *bus)
> > > +{
> > > + proc_remove(bus->procdir);
> > > + return 0;
> > > +}
> >
> > Please don't add one line functions that are called only once and have
> > return value that no one care about it.
>
> These were only intended for a clean-up job, the idea of this function came
> from how PCI handles procfs.
> Maybe those should be changed?
Probably, the CONFIG_PROC_FS around pci_proc_*() is not needed too.
Thanks
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Re: [PATCH] drivers: pnp: proc.c: Handle errors while attaching devices
Hi
2021. április 24., szombat 21:43 keltezéssel, Anupama K Patil írta:
> isapnp_proc_init() does not look at the return value from
> isapnp_proc_attach_device(). Check for this return value in
> isapnp_proc_detach_device().
>
> Cleanup in isapnp_proc_detach_device and
> isapnp_proc_detach_bus() for cleanup.
>
> Changed sprintf() to the kernel-space function scnprintf() as it returns
> the actual number of bytes written.
>
> Removed unnecessary variables de, e of type 'struct proc_dir_entry' to
> save memory.
>
> Suggested-by: Shuah Khan
> Co-developed-by: B K Karthik
> Signed-off-by: B K Karthik
> Signed-off-by: Anupama K Patil
> ---
> drivers/pnp/isapnp/proc.c | 40 +--
> 1 file changed, 30 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/pnp/isapnp/proc.c b/drivers/pnp/isapnp/proc.c
> index 785a796430fa..46ebc24175b7 100644
> --- a/drivers/pnp/isapnp/proc.c
> +++ b/drivers/pnp/isapnp/proc.c
> @@ -54,34 +54,54 @@ static const struct proc_ops isapnp_proc_bus_proc_ops = {
> .proc_read = isapnp_proc_bus_read,
> };
>
> +static int isapnp_proc_detach_device(struct pnp_dev *dev)
> +{
> + proc_remove(dev->procent);
> + dev->procent = NULL;
> + return 0;
> +}
> +
> +static int isapnp_proc_detach_bus(struct pnp_card *bus)
> +{
> + proc_remove(bus->procdir);
Is there any reason for not setting `bus->procdir` to `NULL`
similarly to the previous function?
> + return 0;
> +}
> +
Is there any reason why the previous two functions return something? It doesn't
seem to be necessary.
> static int isapnp_proc_attach_device(struct pnp_dev *dev)
> {
> struct pnp_card *bus = dev->card;
> - struct proc_dir_entry *de, *e;
> char name[16];
>
> - if (!(de = bus->procdir)) {
> - sprintf(name, "%02x", bus->number);
> - de = bus->procdir = proc_mkdir(name, isapnp_proc_bus_dir);
> - if (!de)
> + if (!bus->procdir) {
> + scnprintf(name, 16, "%02x", bus->number);
I think `sizeof(name)` would be preferable to hard-coding 16.
> + bus->procdir = proc_mkdir(name, isapnp_proc_bus_dir);
> + if (!bus->procdir)
> return -ENOMEM;
> }
> - sprintf(name, "%02x", dev->number);
> - e = dev->procent = proc_create_data(name, S_IFREG | S_IRUGO, de,
> + scnprintf(name, 16, "%02x", dev->number);
Here as well.
> + dev->procent = proc_create_data(name, S_IFREG | S_IRUGO, bus->procdir,
> &isapnp_proc_bus_proc_ops, dev);
Please align the continuation properly.
> - if (!e)
> + if (!dev->procent) {
> + isapnp_proc_detach_bus(bus);
I'm not sure if this should be here. If I'm not mistaken, the code
creates a procfs directory for a bus when it first sees a `pnp_dev` from that
bus.
This call removes the whole directory for the bus, and with that, the files of
those `pnp_dev`s which were successfully created earlier.
> return -ENOMEM;
> - proc_set_size(e, 256);
> + }
> + proc_set_size(dev->procent, 256);
> return 0;
> }
>
> int __init isapnp_proc_init(void)
> {
> struct pnp_dev *dev;
> + int dev_attach;
>
> isapnp_proc_bus_dir = proc_mkdir("bus/isapnp", NULL);
You could add a check to see if this `proc_mkdir()` call succeeds, and
possibly return early if it does not.
> protocol_for_each_dev(&isapnp_protocol, dev) {
> - isapnp_proc_attach_device(dev);
> + dev_attach = isapnp_proc_attach_device(dev);
> + if (!dev_attach) {
`isapnp_proc_attach_device()` returns 0 on success, so the condition should be
inverted.
And maybe `err` or something like that would be a better name than `dev_attach`.
> + pr_info("procfs: pnp: Unable to attach the device, not
> enough memory");
If I'm not mistaken, allocation failures are logged, so this is probably not
needed.
> + isapnp_proc_detach_device(dev);
I'm also not sure if this is needed here. If `isapnp_proc_attach_device()`
returns
an error, then `dev->procdir` could not have been "created". In other words,
if the execution reaches this point, `proc_create_data()` could not have
succeeded
because either it had not yet been called or it had failed.
> + return -ENOMEM;
It is usually preferable to return the error code you receive. E.g.:
err = isapnp_proc_attach_device(...);
if (err) {
...
return err;
}
> + }
> }
> return 0;
> }
> --
> 2.25.1
>
Regards,
Barnabás Pőcze
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Re: [PATCH] drivers: pnp: proc.c: Handle errors while attaching devices
On Sun, Apr 25, 2021 at 01:13:01AM +0530, Anupama K Patil wrote:
> isapnp_proc_init() does not look at the return value from
> isapnp_proc_attach_device(). Check for this return value in
> isapnp_proc_detach_device().
>
> Cleanup in isapnp_proc_detach_device and
> isapnp_proc_detach_bus() for cleanup.
>
> Changed sprintf() to the kernel-space function scnprintf() as it returns
> the actual number of bytes written.
>
> Removed unnecessary variables de, e of type 'struct proc_dir_entry' to
> save memory.
What exactly do you fix for such an old code?
>
> Suggested-by: Shuah Khan
> Co-developed-by: B K Karthik
> Signed-off-by: B K Karthik
> Signed-off-by: Anupama K Patil
> ---
> drivers/pnp/isapnp/proc.c | 40 +--
> 1 file changed, 30 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/pnp/isapnp/proc.c b/drivers/pnp/isapnp/proc.c
> index 785a796430fa..46ebc24175b7 100644
> --- a/drivers/pnp/isapnp/proc.c
> +++ b/drivers/pnp/isapnp/proc.c
> @@ -54,34 +54,54 @@ static const struct proc_ops isapnp_proc_bus_proc_ops = {
> .proc_read = isapnp_proc_bus_read,
> };
>
> +static int isapnp_proc_detach_device(struct pnp_dev *dev)
> +{
> + proc_remove(dev->procent);
> + dev->procent = NULL;
> + return 0;
> +}
> +
> +static int isapnp_proc_detach_bus(struct pnp_card *bus)
> +{
> + proc_remove(bus->procdir);
> + return 0;
> +}
Please don't add one line functions that are called only once and have
return value that no one care about it.
Thanks
> +
> static int isapnp_proc_attach_device(struct pnp_dev *dev)
> {
> struct pnp_card *bus = dev->card;
> - struct proc_dir_entry *de, *e;
> char name[16];
>
> - if (!(de = bus->procdir)) {
> - sprintf(name, "%02x", bus->number);
> - de = bus->procdir = proc_mkdir(name, isapnp_proc_bus_dir);
> - if (!de)
> + if (!bus->procdir) {
> + scnprintf(name, 16, "%02x", bus->number);
> + bus->procdir = proc_mkdir(name, isapnp_proc_bus_dir);
> + if (!bus->procdir)
> return -ENOMEM;
> }
> - sprintf(name, "%02x", dev->number);
> - e = dev->procent = proc_create_data(name, S_IFREG | S_IRUGO, de,
> + scnprintf(name, 16, "%02x", dev->number);
> + dev->procent = proc_create_data(name, S_IFREG | S_IRUGO, bus->procdir,
> &isapnp_proc_bus_proc_ops, dev);
> - if (!e)
> + if (!dev->procent) {
> + isapnp_proc_detach_bus(bus);
> return -ENOMEM;
> - proc_set_size(e, 256);
> + }
> + proc_set_size(dev->procent, 256);
> return 0;
> }
>
> int __init isapnp_proc_init(void)
> {
> struct pnp_dev *dev;
> + int dev_attach;
>
> isapnp_proc_bus_dir = proc_mkdir("bus/isapnp", NULL);
> protocol_for_each_dev(&isapnp_protocol, dev) {
> - isapnp_proc_attach_device(dev);
> + dev_attach = isapnp_proc_attach_device(dev);
> + if (!dev_attach) {
> + pr_info("procfs: pnp: Unable to attach the device, not
> enough memory");
> + isapnp_proc_detach_device(dev);
> + return -ENOMEM;
> + }
> }
> return 0;
> }
> --
> 2.25.1
>
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[PATCH] drivers: pnp: proc.c: Handle errors while attaching devices
isapnp_proc_init() does not look at the return value from
isapnp_proc_attach_device(). Check for this return value in
isapnp_proc_detach_device().
Cleanup in isapnp_proc_detach_device and
isapnp_proc_detach_bus() for cleanup.
Changed sprintf() to the kernel-space function scnprintf() as it returns
the actual number of bytes written.
Removed unnecessary variables de, e of type 'struct proc_dir_entry' to
save memory.
Suggested-by: Shuah Khan
Co-developed-by: B K Karthik
Signed-off-by: B K Karthik
Signed-off-by: Anupama K Patil
---
drivers/pnp/isapnp/proc.c | 40 +--
1 file changed, 30 insertions(+), 10 deletions(-)
diff --git a/drivers/pnp/isapnp/proc.c b/drivers/pnp/isapnp/proc.c
index 785a796430fa..46ebc24175b7 100644
--- a/drivers/pnp/isapnp/proc.c
+++ b/drivers/pnp/isapnp/proc.c
@@ -54,34 +54,54 @@ static const struct proc_ops isapnp_proc_bus_proc_ops = {
.proc_read = isapnp_proc_bus_read,
};
+static int isapnp_proc_detach_device(struct pnp_dev *dev)
+{
+ proc_remove(dev->procent);
+ dev->procent = NULL;
+ return 0;
+}
+
+static int isapnp_proc_detach_bus(struct pnp_card *bus)
+{
+ proc_remove(bus->procdir);
+ return 0;
+}
+
static int isapnp_proc_attach_device(struct pnp_dev *dev)
{
struct pnp_card *bus = dev->card;
- struct proc_dir_entry *de, *e;
char name[16];
- if (!(de = bus->procdir)) {
- sprintf(name, "%02x", bus->number);
- de = bus->procdir = proc_mkdir(name, isapnp_proc_bus_dir);
- if (!de)
+ if (!bus->procdir) {
+ scnprintf(name, 16, "%02x", bus->number);
+ bus->procdir = proc_mkdir(name, isapnp_proc_bus_dir);
+ if (!bus->procdir)
return -ENOMEM;
}
- sprintf(name, "%02x", dev->number);
- e = dev->procent = proc_create_data(name, S_IFREG | S_IRUGO, de,
+ scnprintf(name, 16, "%02x", dev->number);
+ dev->procent = proc_create_data(name, S_IFREG | S_IRUGO, bus->procdir,
&isapnp_proc_bus_proc_ops, dev);
- if (!e)
+ if (!dev->procent) {
+ isapnp_proc_detach_bus(bus);
return -ENOMEM;
- proc_set_size(e, 256);
+ }
+ proc_set_size(dev->procent, 256);
return 0;
}
int __init isapnp_proc_init(void)
{
struct pnp_dev *dev;
+ int dev_attach;
isapnp_proc_bus_dir = proc_mkdir("bus/isapnp", NULL);
protocol_for_each_dev(&isapnp_protocol, dev) {
- isapnp_proc_attach_device(dev);
+ dev_attach = isapnp_proc_attach_device(dev);
+ if (!dev_attach) {
+ pr_info("procfs: pnp: Unable to attach the device, not
enough memory");
+ isapnp_proc_detach_device(dev);
+ return -ENOMEM;
+ }
}
return 0;
}
--
2.25.1
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Re: [PATCH] drivers: pnp: proc.c: Handle errors while attaching devices
On Sun, 25 Apr 2021 01:13:01 +0530, Anupama K Patil said:
> Changed sprintf() to the kernel-space function scnprintf() as it returns
> the actual number of bytes written.
> + if (!bus->procdir) {
> + scnprintf(name, 16, "%02x", bus->number);
> + scnprintf(name, 16, "%02x", dev->number);
Why do this when you don't *use* the number of bytes written, but instead ignore
the value returned?
For bonus points: Given the %02x format, under what conditions can it
return a value other than 2?
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