* Re: [PATCH] PCI: Mark expected switch fall-throughs
2019-03-20 18:27 [PATCH] PCI: Mark expected switch fall-throughs Gustavo A. R. Silva
@ 2019-03-20 19:24 ` Bjorn Helgaas
2019-03-20 19:33 ` Gustavo A. R. Silva
2019-03-20 19:27 ` [Xen-devel] " Andrew Cooper
` (2 subsequent siblings)
3 siblings, 1 reply; 8+ messages in thread
From: Bjorn Helgaas @ 2019-03-20 19:24 UTC (permalink / raw)
To: Gustavo A. R. Silva
Cc: Boris Ostrovsky, Juergen Gross, Stefano Stabellini,
Konrad Rzeszutek Wilk, linux-pci, linux-kernel, xen-devel,
Kees Cook
On Wed, Mar 20, 2019 at 01:27:15PM -0500, Gustavo A. R. Silva wrote:
> In preparation to enabling -Wimplicit-fallthrough, mark switch
> cases where we are expecting to fall through.
Does this fix all the remaining cases in drivers/pci? I'd like to fix
them all at once.
What's the best way to watch for new warnings being added? I fiddled
with "make W=2" etc but it didn't seem useful. Does the 0-day robot
warn when -Wimplicit-fallthrough warnings are added?
Bjorn
> This patch fixes the following warnings:
>
> drivers/pci/proc.c: In function ‘proc_bus_pci_ioctl’:
> drivers/pci/proc.c:216:6: warning: this statement may fall through [-Wimplicit-fallthrough=]
> if (arch_can_pci_mmap_wc()) {
> ^
> drivers/pci/proc.c:225:2: note: here
> default:
> ^~~~~~~
>
> drivers/pci/xen-pcifront.c: In function ‘pcifront_backend_changed’:
> drivers/pci/xen-pcifront.c:1105:6: warning: this statement may fall through [-Wimplicit-fallthrough=]
> if (xdev->state == XenbusStateClosed)
> ^
> drivers/pci/xen-pcifront.c:1108:2: note: here
> case XenbusStateClosing:
> ^~~~
>
> Notice that, in this particular case, the /* fall through */
> comment is placed at the very bottom of the case statement,
> which is what GCC is expecting to find.
>
> Warning level 3 was used: -Wimplicit-fallthrough=3
>
> This patch is part of the ongoing efforts to enable
> -Wimplicit-fallthrough.
>
> Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
> ---
> drivers/pci/proc.c | 1 +
> drivers/pci/xen-pcifront.c | 2 +-
> 2 files changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/pci/proc.c b/drivers/pci/proc.c
> index 6fa1627ce08d..445b51db75b0 100644
> --- a/drivers/pci/proc.c
> +++ b/drivers/pci/proc.c
> @@ -222,6 +222,7 @@ static long proc_bus_pci_ioctl(struct file *file, unsigned int cmd,
> }
> /* If arch decided it can't, fall through... */
> #endif /* HAVE_PCI_MMAP */
> + /* fall through */
> default:
> ret = -EINVAL;
> break;
> diff --git a/drivers/pci/xen-pcifront.c b/drivers/pci/xen-pcifront.c
> index eba6e33147a2..14cf0f41ecf0 100644
> --- a/drivers/pci/xen-pcifront.c
> +++ b/drivers/pci/xen-pcifront.c
> @@ -1104,7 +1104,7 @@ static void __ref pcifront_backend_changed(struct xenbus_device *xdev,
> case XenbusStateClosed:
> if (xdev->state == XenbusStateClosed)
> break;
> - /* Missed the backend's CLOSING state -- fallthrough */
> + /* fall through - Missed the backend's CLOSING state. */
> case XenbusStateClosing:
> dev_warn(&xdev->dev, "backend going away!\n");
> pcifront_try_disconnect(pdev);
> --
> 2.21.0
>
^ permalink raw reply [flat|nested] 8+ messages in thread* Re: [PATCH] PCI: Mark expected switch fall-throughs
2019-03-20 19:24 ` Bjorn Helgaas
@ 2019-03-20 19:33 ` Gustavo A. R. Silva
0 siblings, 0 replies; 8+ messages in thread
From: Gustavo A. R. Silva @ 2019-03-20 19:33 UTC (permalink / raw)
To: Bjorn Helgaas
Cc: Boris Ostrovsky, Juergen Gross, Stefano Stabellini,
Konrad Rzeszutek Wilk, linux-pci, linux-kernel, xen-devel,
Kees Cook
On 3/20/19 2:24 PM, Bjorn Helgaas wrote:
> On Wed, Mar 20, 2019 at 01:27:15PM -0500, Gustavo A. R. Silva wrote:
>> In preparation to enabling -Wimplicit-fallthrough, mark switch
>> cases where we are expecting to fall through.
>
> Does this fix all the remaining cases in drivers/pci? I'd like to fix
> them all at once.
>
These are actually the last ones.
> What's the best way to watch for new warnings being added? I fiddled
> with "make W=2" etc but it didn't seem useful. Does the 0-day robot
> warn when -Wimplicit-fallthrough warnings are added?
>
0-day robot doesn't know about these warnings yet. But it certainly
will once we finally enable -Wimplicit-fallthrough.
Add this to your Makefile to see the warnings:
KBUILD_CFLAGS += $(call cc-option,-Wimplicit-fallthrough=3,)
Thanks
--
Gustavo
> Bjorn
>
>> This patch fixes the following warnings:
>>
>> drivers/pci/proc.c: In function ‘proc_bus_pci_ioctl’:
>> drivers/pci/proc.c:216:6: warning: this statement may fall through [-Wimplicit-fallthrough=]
>> if (arch_can_pci_mmap_wc()) {
>> ^
>> drivers/pci/proc.c:225:2: note: here
>> default:
>> ^~~~~~~
>>
>> drivers/pci/xen-pcifront.c: In function ‘pcifront_backend_changed’:
>> drivers/pci/xen-pcifront.c:1105:6: warning: this statement may fall through [-Wimplicit-fallthrough=]
>> if (xdev->state == XenbusStateClosed)
>> ^
>> drivers/pci/xen-pcifront.c:1108:2: note: here
>> case XenbusStateClosing:
>> ^~~~
>>
>> Notice that, in this particular case, the /* fall through */
>> comment is placed at the very bottom of the case statement,
>> which is what GCC is expecting to find.
>>
>> Warning level 3 was used: -Wimplicit-fallthrough=3
>>
>> This patch is part of the ongoing efforts to enable
>> -Wimplicit-fallthrough.
>>
>> Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
>> ---
>> drivers/pci/proc.c | 1 +
>> drivers/pci/xen-pcifront.c | 2 +-
>> 2 files changed, 2 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/pci/proc.c b/drivers/pci/proc.c
>> index 6fa1627ce08d..445b51db75b0 100644
>> --- a/drivers/pci/proc.c
>> +++ b/drivers/pci/proc.c
>> @@ -222,6 +222,7 @@ static long proc_bus_pci_ioctl(struct file *file, unsigned int cmd,
>> }
>> /* If arch decided it can't, fall through... */
>> #endif /* HAVE_PCI_MMAP */
>> + /* fall through */
>> default:
>> ret = -EINVAL;
>> break;
>> diff --git a/drivers/pci/xen-pcifront.c b/drivers/pci/xen-pcifront.c
>> index eba6e33147a2..14cf0f41ecf0 100644
>> --- a/drivers/pci/xen-pcifront.c
>> +++ b/drivers/pci/xen-pcifront.c
>> @@ -1104,7 +1104,7 @@ static void __ref pcifront_backend_changed(struct xenbus_device *xdev,
>> case XenbusStateClosed:
>> if (xdev->state == XenbusStateClosed)
>> break;
>> - /* Missed the backend's CLOSING state -- fallthrough */
>> + /* fall through - Missed the backend's CLOSING state. */
>> case XenbusStateClosing:
>> dev_warn(&xdev->dev, "backend going away!\n");
>> pcifront_try_disconnect(pdev);
>> --
>> 2.21.0
>>
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [Xen-devel] [PATCH] PCI: Mark expected switch fall-throughs
2019-03-20 18:27 [PATCH] PCI: Mark expected switch fall-throughs Gustavo A. R. Silva
2019-03-20 19:24 ` Bjorn Helgaas
@ 2019-03-20 19:27 ` Andrew Cooper
2019-03-20 19:41 ` Gustavo A. R. Silva
2019-03-20 20:13 ` Bjorn Helgaas
2019-03-25 13:25 ` [Xen-devel] " Jan Beulich
3 siblings, 1 reply; 8+ messages in thread
From: Andrew Cooper @ 2019-03-20 19:27 UTC (permalink / raw)
To: Gustavo A. R. Silva, Bjorn Helgaas, Boris Ostrovsky,
Juergen Gross, Stefano Stabellini, Konrad Rzeszutek Wilk
Cc: linux-pci, linux-kernel, Kees Cook, xen-devel
On 20/03/2019 18:27, Gustavo A. R. Silva wrote:
> diff --git a/drivers/pci/proc.c b/drivers/pci/proc.c
> index 6fa1627ce08d..445b51db75b0 100644
> --- a/drivers/pci/proc.c
> +++ b/drivers/pci/proc.c
> @@ -222,6 +222,7 @@ static long proc_bus_pci_ioctl(struct file *file, unsigned int cmd,
> }
> /* If arch decided it can't, fall through... */
> #endif /* HAVE_PCI_MMAP */
> + /* fall through */
Surely it would be better to transpose the #endif and its previous line,
than to add a second fallthrough ?
~Andrew
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [Xen-devel] [PATCH] PCI: Mark expected switch fall-throughs
2019-03-20 19:27 ` [Xen-devel] " Andrew Cooper
@ 2019-03-20 19:41 ` Gustavo A. R. Silva
0 siblings, 0 replies; 8+ messages in thread
From: Gustavo A. R. Silva @ 2019-03-20 19:41 UTC (permalink / raw)
To: Andrew Cooper, Bjorn Helgaas, Boris Ostrovsky, Juergen Gross,
Stefano Stabellini, Konrad Rzeszutek Wilk
Cc: linux-pci, linux-kernel, Kees Cook, xen-devel
On 3/20/19 2:27 PM, Andrew Cooper wrote:
> On 20/03/2019 18:27, Gustavo A. R. Silva wrote:
>> diff --git a/drivers/pci/proc.c b/drivers/pci/proc.c
>> index 6fa1627ce08d..445b51db75b0 100644
>> --- a/drivers/pci/proc.c
>> +++ b/drivers/pci/proc.c
>> @@ -222,6 +222,7 @@ static long proc_bus_pci_ioctl(struct file *file, unsigned int cmd,
>> }
>> /* If arch decided it can't, fall through... */
>> #endif /* HAVE_PCI_MMAP */
>> + /* fall through */
>
> Surely it would be better to transpose the #endif and its previous line,
> than to add a second fallthrough ?
>
I agree. The thing is that, currently, GCC is expecting to find the
fall-through "annotations" at the very bottom of the case statement,
as I mentioned it in the changelog text.
That's the reason why I decided to left in place the original comment.
Thanks
--
Gustavo
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH] PCI: Mark expected switch fall-throughs
2019-03-20 18:27 [PATCH] PCI: Mark expected switch fall-throughs Gustavo A. R. Silva
2019-03-20 19:24 ` Bjorn Helgaas
2019-03-20 19:27 ` [Xen-devel] " Andrew Cooper
@ 2019-03-20 20:13 ` Bjorn Helgaas
2019-03-20 20:23 ` Gustavo A. R. Silva
2019-03-25 13:25 ` [Xen-devel] " Jan Beulich
3 siblings, 1 reply; 8+ messages in thread
From: Bjorn Helgaas @ 2019-03-20 20:13 UTC (permalink / raw)
To: Gustavo A. R. Silva
Cc: Boris Ostrovsky, Juergen Gross, Stefano Stabellini,
Konrad Rzeszutek Wilk, linux-pci, linux-kernel, xen-devel,
Kees Cook
On Wed, Mar 20, 2019 at 01:27:15PM -0500, Gustavo A. R. Silva wrote:
> In preparation to enabling -Wimplicit-fallthrough, mark switch
> cases where we are expecting to fall through.
>
> This patch fixes the following warnings:
>
> drivers/pci/proc.c: In function ‘proc_bus_pci_ioctl’:
> drivers/pci/proc.c:216:6: warning: this statement may fall through [-Wimplicit-fallthrough=]
> if (arch_can_pci_mmap_wc()) {
> ^
> drivers/pci/proc.c:225:2: note: here
> default:
> ^~~~~~~
>
> drivers/pci/xen-pcifront.c: In function ‘pcifront_backend_changed’:
> drivers/pci/xen-pcifront.c:1105:6: warning: this statement may fall through [-Wimplicit-fallthrough=]
> if (xdev->state == XenbusStateClosed)
> ^
> drivers/pci/xen-pcifront.c:1108:2: note: here
> case XenbusStateClosing:
> ^~~~
>
> Notice that, in this particular case, the /* fall through */
> comment is placed at the very bottom of the case statement,
> which is what GCC is expecting to find.
>
> Warning level 3 was used: -Wimplicit-fallthrough=3
>
> This patch is part of the ongoing efforts to enable
> -Wimplicit-fallthrough.
>
> Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Applied to pci/misc for v5.2, thanks!
> ---
> drivers/pci/proc.c | 1 +
> drivers/pci/xen-pcifront.c | 2 +-
> 2 files changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/pci/proc.c b/drivers/pci/proc.c
> index 6fa1627ce08d..445b51db75b0 100644
> --- a/drivers/pci/proc.c
> +++ b/drivers/pci/proc.c
> @@ -222,6 +222,7 @@ static long proc_bus_pci_ioctl(struct file *file, unsigned int cmd,
> }
> /* If arch decided it can't, fall through... */
> #endif /* HAVE_PCI_MMAP */
> + /* fall through */
> default:
> ret = -EINVAL;
> break;
> diff --git a/drivers/pci/xen-pcifront.c b/drivers/pci/xen-pcifront.c
> index eba6e33147a2..14cf0f41ecf0 100644
> --- a/drivers/pci/xen-pcifront.c
> +++ b/drivers/pci/xen-pcifront.c
> @@ -1104,7 +1104,7 @@ static void __ref pcifront_backend_changed(struct xenbus_device *xdev,
> case XenbusStateClosed:
> if (xdev->state == XenbusStateClosed)
> break;
> - /* Missed the backend's CLOSING state -- fallthrough */
> + /* fall through - Missed the backend's CLOSING state. */
> case XenbusStateClosing:
> dev_warn(&xdev->dev, "backend going away!\n");
> pcifront_try_disconnect(pdev);
> --
> 2.21.0
>
^ permalink raw reply [flat|nested] 8+ messages in thread* Re: [PATCH] PCI: Mark expected switch fall-throughs
2019-03-20 20:13 ` Bjorn Helgaas
@ 2019-03-20 20:23 ` Gustavo A. R. Silva
0 siblings, 0 replies; 8+ messages in thread
From: Gustavo A. R. Silva @ 2019-03-20 20:23 UTC (permalink / raw)
To: Bjorn Helgaas
Cc: Boris Ostrovsky, Juergen Gross, Stefano Stabellini,
Konrad Rzeszutek Wilk, linux-pci, linux-kernel, xen-devel,
Kees Cook
On 3/20/19 3:13 PM, Bjorn Helgaas wrote:
> On Wed, Mar 20, 2019 at 01:27:15PM -0500, Gustavo A. R. Silva wrote:
[..]
>>
>> Warning level 3 was used: -Wimplicit-fallthrough=3
>>
>> This patch is part of the ongoing efforts to enable
>> -Wimplicit-fallthrough.
>>
>> Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
>
> Applied to pci/misc for v5.2, thanks!
>
Awesome!
Thanks
--
Gustavo
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [Xen-devel] [PATCH] PCI: Mark expected switch fall-throughs
2019-03-20 18:27 [PATCH] PCI: Mark expected switch fall-throughs Gustavo A. R. Silva
` (2 preceding siblings ...)
2019-03-20 20:13 ` Bjorn Helgaas
@ 2019-03-25 13:25 ` Jan Beulich
3 siblings, 0 replies; 8+ messages in thread
From: Jan Beulich @ 2019-03-25 13:25 UTC (permalink / raw)
To: Gustavo A.R.Silva
Cc: keescook, Bjorn Helgaas, Stefano Stabellini, xen-devel,
Boris Ostrovsky, Konrad Rzeszutek Wilk, Juergen Gross,
linux-kernel, linux-pci
>>> On 20.03.19 at 19:27, <gustavo@embeddedor.com> wrote:
> In preparation to enabling -Wimplicit-fallthrough, mark switch
> cases where we are expecting to fall through.
>
> This patch fixes the following warnings:
>
> drivers/pci/proc.c: In function ‘proc_bus_pci_ioctl’:
> drivers/pci/proc.c:216:6: warning: this statement may fall through
> [-Wimplicit-fallthrough=]
> if (arch_can_pci_mmap_wc()) {
> ^
> drivers/pci/proc.c:225:2: note: here
> default:
> ^~~~~~~
>
> drivers/pci/xen-pcifront.c: In function ‘pcifront_backend_changed’:
> drivers/pci/xen-pcifront.c:1105:6: warning: this statement may fall through
> [-Wimplicit-fallthrough=]
> if (xdev->state == XenbusStateClosed)
> ^
> drivers/pci/xen-pcifront.c:1108:2: note: here
> case XenbusStateClosing:
> ^~~~
>
> Notice that, in this particular case, the /* fall through */
> comment is placed at the very bottom of the case statement,
> which is what GCC is expecting to find.
>
> Warning level 3 was used: -Wimplicit-fallthrough=3
>
> This patch is part of the ongoing efforts to enable
> -Wimplicit-fallthrough.
None of the above explains why ...
> --- a/drivers/pci/xen-pcifront.c
> +++ b/drivers/pci/xen-pcifront.c
> @@ -1104,7 +1104,7 @@ static void __ref pcifront_backend_changed(struct xenbus_device *xdev,
> case XenbusStateClosed:
> if (xdev->state == XenbusStateClosed)
> break;
> - /* Missed the backend's CLOSING state -- fallthrough */
> + /* fall through - Missed the backend's CLOSING state. */
... the original comment here wasn't good enough.
Jan
^ permalink raw reply [flat|nested] 8+ messages in thread