* io-mapping: Indicate mapping failure
@ 2020-07-21 14:16 Michael J. Ruhl
2020-07-21 14:16 ` Michael J. Ruhl
0 siblings, 1 reply; 9+ messages in thread
From: Michael J. Ruhl @ 2020-07-21 14:16 UTC (permalink / raw)
To: dri-devel
I found this when my system crashed long after the mapping failure.
The expected behavior should have been driver exit.
Since this is almost exclusively used for drm, I am posting to
the dri mailing list. Should this go to another list as well?
Thanks,
Mike
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^ permalink raw reply [flat|nested] 9+ messages in thread
* [PATCH] io-mapping: Indicate mapping failure
2020-07-21 14:16 io-mapping: Indicate mapping failure Michael J. Ruhl
@ 2020-07-21 14:16 ` Michael J. Ruhl
0 siblings, 0 replies; 9+ messages in thread
From: Michael J. Ruhl @ 2020-07-21 14:16 UTC (permalink / raw)
To: dri-devel
Cc: Michael J. Ruhl, Andrew Morton, Mike Rapoport, Andy Shevchenko,
Chris Wilson, stable
Sometimes it is good to know when your mapping failed.
Fixes: cafaf14a5d8f ("io-mapping: Always create a struct to hold metadata about the io-mapping"
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: stable@vger.kernel.org
Signed-off-by: Michael J. Ruhl <michael.j.ruhl@intel.com>
---
include/linux/io-mapping.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/include/linux/io-mapping.h b/include/linux/io-mapping.h
index 0beaa3eba155..5641e06cbcf7 100644
--- a/include/linux/io-mapping.h
+++ b/include/linux/io-mapping.h
@@ -118,7 +118,7 @@ io_mapping_init_wc(struct io_mapping *iomap,
iomap->prot = pgprot_noncached(PAGE_KERNEL);
#endif
- return iomap;
+ return iomap->iomem ? iomap : NULL;
}
static inline void
--
2.21.0
^ permalink raw reply related [flat|nested] 9+ messages in thread
* [PATCH] io-mapping: Indicate mapping failure
@ 2020-07-21 14:16 ` Michael J. Ruhl
0 siblings, 0 replies; 9+ messages in thread
From: Michael J. Ruhl @ 2020-07-21 14:16 UTC (permalink / raw)
To: dri-devel
Cc: Mike Rapoport, stable, Chris Wilson, Michael J. Ruhl,
Andrew Morton, Andy Shevchenko
Sometimes it is good to know when your mapping failed.
Fixes: cafaf14a5d8f ("io-mapping: Always create a struct to hold metadata about the io-mapping"
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: stable@vger.kernel.org
Signed-off-by: Michael J. Ruhl <michael.j.ruhl@intel.com>
---
include/linux/io-mapping.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/include/linux/io-mapping.h b/include/linux/io-mapping.h
index 0beaa3eba155..5641e06cbcf7 100644
--- a/include/linux/io-mapping.h
+++ b/include/linux/io-mapping.h
@@ -118,7 +118,7 @@ io_mapping_init_wc(struct io_mapping *iomap,
iomap->prot = pgprot_noncached(PAGE_KERNEL);
#endif
- return iomap;
+ return iomap->iomem ? iomap : NULL;
}
static inline void
--
2.21.0
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel
^ permalink raw reply related [flat|nested] 9+ messages in thread
* Re: [PATCH] io-mapping: Indicate mapping failure
2020-07-21 14:16 ` Michael J. Ruhl
@ 2020-07-21 14:47 ` Andy Shevchenko
-1 siblings, 0 replies; 9+ messages in thread
From: Andy Shevchenko @ 2020-07-21 14:47 UTC (permalink / raw)
To: Michael J. Ruhl
Cc: dri-devel, Andrew Morton, Mike Rapoport, Chris Wilson, stable
On Tue, Jul 21, 2020 at 10:16:41AM -0400, Michael J. Ruhl wrote:
> Sometimes it is good to know when your mapping failed.
Can you elaborate...
> Fixes: cafaf14a5d8f ("io-mapping: Always create a struct to hold metadata about the io-mapping"
...especially taking into account that Fixes implies regression / bug?
--
With Best Regards,
Andy Shevchenko
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH] io-mapping: Indicate mapping failure
@ 2020-07-21 14:47 ` Andy Shevchenko
0 siblings, 0 replies; 9+ messages in thread
From: Andy Shevchenko @ 2020-07-21 14:47 UTC (permalink / raw)
To: Michael J. Ruhl
Cc: Andrew Morton, Chris Wilson, stable, dri-devel, Mike Rapoport
On Tue, Jul 21, 2020 at 10:16:41AM -0400, Michael J. Ruhl wrote:
> Sometimes it is good to know when your mapping failed.
Can you elaborate...
> Fixes: cafaf14a5d8f ("io-mapping: Always create a struct to hold metadata about the io-mapping"
...especially taking into account that Fixes implies regression / bug?
--
With Best Regards,
Andy Shevchenko
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel
^ permalink raw reply [flat|nested] 9+ messages in thread
* RE: [PATCH] io-mapping: Indicate mapping failure
2020-07-21 14:47 ` Andy Shevchenko
@ 2020-07-21 15:00 ` Ruhl, Michael J
-1 siblings, 0 replies; 9+ messages in thread
From: Ruhl, Michael J @ 2020-07-21 15:00 UTC (permalink / raw)
To: Andy Shevchenko
Cc: dri-devel, Andrew Morton, Mike Rapoport, Chris Wilson, stable
>-----Original Message-----
>From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
>Sent: Tuesday, July 21, 2020 10:47 AM
>To: Ruhl, Michael J <michael.j.ruhl@intel.com>
>Cc: dri-devel@lists.freedesktop.org; Andrew Morton <akpm@linux-
>foundation.org>; Mike Rapoport <rppt@linux.ibm.com>; Chris Wilson
><chris@chris-wilson.co.uk>; stable@vger.kernel.org
>Subject: Re: [PATCH] io-mapping: Indicate mapping failure
>
>On Tue, Jul 21, 2020 at 10:16:41AM -0400, Michael J. Ruhl wrote:
>> Sometimes it is good to know when your mapping failed.
>
>Can you elaborate...
Sure, guess I was too glib. 😊
Currently the io_mapping_init_wc (the !ATOMIC_IOMAP version), function will
always return success.
If the setting of the iomem (from ioremap_wc) fails, the only way for the
caller to know is to check the value of iomap->iomem.
Since all of the callers expect a NULL return on error, and check for a NULL,
I felt this needed a fixes (i.e. unexpected behavior).
>> Fixes: cafaf14a5d8f ("io-mapping: Always create a struct to hold metadata
>about the io-mapping"
>
>...especially taking into account that Fixes implies regression / bug?
The failure (in my case a crash) is not revealed until the address is accessed
long after the init.
I will update the commit.
Mike
>--
>With Best Regards,
>Andy Shevchenko
>
^ permalink raw reply [flat|nested] 9+ messages in thread
* RE: [PATCH] io-mapping: Indicate mapping failure
@ 2020-07-21 15:00 ` Ruhl, Michael J
0 siblings, 0 replies; 9+ messages in thread
From: Ruhl, Michael J @ 2020-07-21 15:00 UTC (permalink / raw)
To: Andy Shevchenko
Cc: Andrew Morton, Chris Wilson, stable, dri-devel, Mike Rapoport
>-----Original Message-----
>From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
>Sent: Tuesday, July 21, 2020 10:47 AM
>To: Ruhl, Michael J <michael.j.ruhl@intel.com>
>Cc: dri-devel@lists.freedesktop.org; Andrew Morton <akpm@linux-
>foundation.org>; Mike Rapoport <rppt@linux.ibm.com>; Chris Wilson
><chris@chris-wilson.co.uk>; stable@vger.kernel.org
>Subject: Re: [PATCH] io-mapping: Indicate mapping failure
>
>On Tue, Jul 21, 2020 at 10:16:41AM -0400, Michael J. Ruhl wrote:
>> Sometimes it is good to know when your mapping failed.
>
>Can you elaborate...
Sure, guess I was too glib. 😊
Currently the io_mapping_init_wc (the !ATOMIC_IOMAP version), function will
always return success.
If the setting of the iomem (from ioremap_wc) fails, the only way for the
caller to know is to check the value of iomap->iomem.
Since all of the callers expect a NULL return on error, and check for a NULL,
I felt this needed a fixes (i.e. unexpected behavior).
>> Fixes: cafaf14a5d8f ("io-mapping: Always create a struct to hold metadata
>about the io-mapping"
>
>...especially taking into account that Fixes implies regression / bug?
The failure (in my case a crash) is not revealed until the address is accessed
long after the init.
I will update the commit.
Mike
>--
>With Best Regards,
>Andy Shevchenko
>
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH] io-mapping: Indicate mapping failure
2020-07-21 15:00 ` Ruhl, Michael J
@ 2020-07-21 15:06 ` Mike Rapoport
-1 siblings, 0 replies; 9+ messages in thread
From: Mike Rapoport @ 2020-07-21 15:06 UTC (permalink / raw)
To: Ruhl, Michael J
Cc: Andy Shevchenko, dri-devel, Andrew Morton, Chris Wilson, stable
On Tue, Jul 21, 2020 at 03:00:41PM +0000, Ruhl, Michael J wrote:
> >-----Original Message-----
> >From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> >Sent: Tuesday, July 21, 2020 10:47 AM
> >To: Ruhl, Michael J <michael.j.ruhl@intel.com>
> >Cc: dri-devel@lists.freedesktop.org; Andrew Morton <akpm@linux-
> >foundation.org>; Mike Rapoport <rppt@linux.ibm.com>; Chris Wilson
> ><chris@chris-wilson.co.uk>; stable@vger.kernel.org
> >Subject: Re: [PATCH] io-mapping: Indicate mapping failure
> >
> >On Tue, Jul 21, 2020 at 10:16:41AM -0400, Michael J. Ruhl wrote:
> >> Sometimes it is good to know when your mapping failed.
I was going to say it's always a good idea ;-)
> >Can you elaborate...
>
> Sure, guess I was too glib. 😊
>
> Currently the io_mapping_init_wc (the !ATOMIC_IOMAP version), function will
> always return success.
>
> If the setting of the iomem (from ioremap_wc) fails, the only way for the
> caller to know is to check the value of iomap->iomem.
>
> Since all of the callers expect a NULL return on error, and check for a NULL,
> I felt this needed a fixes (i.e. unexpected behavior).
>
> >> Fixes: cafaf14a5d8f ("io-mapping: Always create a struct to hold metadata
> >about the io-mapping"
> >
> >...especially taking into account that Fixes implies regression / bug?
>
> The failure (in my case a crash) is not revealed until the address is accessed
> long after the init.
>
> I will update the commit.
>
> Mike
>
> >--
> >With Best Regards,
> >Andy Shevchenko
> >
>
--
Sincerely yours,
Mike.
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH] io-mapping: Indicate mapping failure
@ 2020-07-21 15:06 ` Mike Rapoport
0 siblings, 0 replies; 9+ messages in thread
From: Mike Rapoport @ 2020-07-21 15:06 UTC (permalink / raw)
To: Ruhl, Michael J
Cc: Andrew Morton, Andy Shevchenko, stable, dri-devel, Chris Wilson
On Tue, Jul 21, 2020 at 03:00:41PM +0000, Ruhl, Michael J wrote:
> >-----Original Message-----
> >From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> >Sent: Tuesday, July 21, 2020 10:47 AM
> >To: Ruhl, Michael J <michael.j.ruhl@intel.com>
> >Cc: dri-devel@lists.freedesktop.org; Andrew Morton <akpm@linux-
> >foundation.org>; Mike Rapoport <rppt@linux.ibm.com>; Chris Wilson
> ><chris@chris-wilson.co.uk>; stable@vger.kernel.org
> >Subject: Re: [PATCH] io-mapping: Indicate mapping failure
> >
> >On Tue, Jul 21, 2020 at 10:16:41AM -0400, Michael J. Ruhl wrote:
> >> Sometimes it is good to know when your mapping failed.
I was going to say it's always a good idea ;-)
> >Can you elaborate...
>
> Sure, guess I was too glib. 😊
>
> Currently the io_mapping_init_wc (the !ATOMIC_IOMAP version), function will
> always return success.
>
> If the setting of the iomem (from ioremap_wc) fails, the only way for the
> caller to know is to check the value of iomap->iomem.
>
> Since all of the callers expect a NULL return on error, and check for a NULL,
> I felt this needed a fixes (i.e. unexpected behavior).
>
> >> Fixes: cafaf14a5d8f ("io-mapping: Always create a struct to hold metadata
> >about the io-mapping"
> >
> >...especially taking into account that Fixes implies regression / bug?
>
> The failure (in my case a crash) is not revealed until the address is accessed
> long after the init.
>
> I will update the commit.
>
> Mike
>
> >--
> >With Best Regards,
> >Andy Shevchenko
> >
>
--
Sincerely yours,
Mike.
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel
^ permalink raw reply [flat|nested] 9+ messages in thread
end of thread, other threads:[~2020-07-22 7:03 UTC | newest]
Thread overview: 9+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-07-21 14:16 io-mapping: Indicate mapping failure Michael J. Ruhl
2020-07-21 14:16 ` [PATCH] " Michael J. Ruhl
2020-07-21 14:16 ` Michael J. Ruhl
2020-07-21 14:47 ` Andy Shevchenko
2020-07-21 14:47 ` Andy Shevchenko
2020-07-21 15:00 ` Ruhl, Michael J
2020-07-21 15:00 ` Ruhl, Michael J
2020-07-21 15:06 ` Mike Rapoport
2020-07-21 15:06 ` Mike Rapoport
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