* [PATCH] spi: fix bogus SPI bus number
@ 2017-10-17 10:44 Arnd Bergmann
[not found] ` <20171017104519.878892-1-arnd-r2nGTMty4D4@public.gmane.org>
0 siblings, 1 reply; 3+ messages in thread
From: Arnd Bergmann @ 2017-10-17 10:44 UTC (permalink / raw)
To: Mark Brown
Cc: Lucas Stach, Naresh Kamboju, Arnd Bergmann, Geert Uytterhoeven,
Andy Shevchenko, Rafael J. Wysocki,
linux-spi-u79uwXL29TY76Z2rM5mHXA,
linux-kernel-u79uwXL29TY76Z2rM5mHXA
lkft found a boot time regression on the Hikey board that has no
aliases entry for spi buses. of_alias_get_highest_id() here
returns -ENODEV, which is then used as the initial number for the
IDR allocation, and that in turn triggers a WARN_ON:
WARNING: CPU: 3 PID: 53 at include/linux/idr.h:113 spi_register_controller+0x890/0x940
This reworks the algorithm to turn any negative number into zero
again, restoring the original behavior for the Hikey case.
Fixes: 9ce70d49fa80 ("spi: fix IDR collision on systems with both fixed and dynamic SPI bus numbers")
Reported-by: Naresh Kamboju <naresh.kamboju-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
Link: https://lkft.validation.linaro.org/scheduler/job/48009#L3147
Signed-off-by: Arnd Bergmann <arnd-r2nGTMty4D4@public.gmane.org>
---
Not tested yet, please review carefully
---
drivers/spi/spi.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index 0483410e7cb3..4b6985ec962c 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -2116,9 +2116,11 @@ int spi_register_controller(struct spi_controller *ctlr)
}
if (ctlr->bus_num < 0) {
mutex_lock(&board_lock);
+ id = of_alias_get_highest_id("spi");
+ if (id < 0)
+ id = -1;
id = idr_alloc(&spi_master_idr, ctlr,
- of_alias_get_highest_id("spi") + 1,
- 0, GFP_KERNEL);
+ id + 1, 0, GFP_KERNEL);
mutex_unlock(&board_lock);
if (WARN(id < 0, "couldn't get idr"))
return id;
--
2.9.0
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^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] spi: fix bogus SPI bus number
[not found] ` <20171017104519.878892-1-arnd-r2nGTMty4D4@public.gmane.org>
@ 2017-10-17 12:20 ` Lucas Stach
2017-10-17 12:25 ` Mark Brown
1 sibling, 0 replies; 3+ messages in thread
From: Lucas Stach @ 2017-10-17 12:20 UTC (permalink / raw)
To: Arnd Bergmann, Mark Brown
Cc: Naresh Kamboju, Geert Uytterhoeven, Andy Shevchenko,
Rafael J. Wysocki, linux-spi-u79uwXL29TY76Z2rM5mHXA,
linux-kernel-u79uwXL29TY76Z2rM5mHXA
Am Dienstag, den 17.10.2017, 12:44 +0200 schrieb Arnd Bergmann:
> lkft found a boot time regression on the Hikey board that has no
> aliases entry for spi buses. of_alias_get_highest_id() here
> returns -ENODEV, which is then used as the initial number for the
> IDR allocation, and that in turn triggers a WARN_ON:
>
> WARNING: CPU: 3 PID: 53 at include/linux/idr.h:113
> spi_register_controller+0x890/0x940
>
> This reworks the algorithm to turn any negative number into zero
> again, restoring the original behavior for the Hikey case.
>
> Fixes: 9ce70d49fa80 ("spi: fix IDR collision on systems with both
> fixed and dynamic SPI bus numbers")
> Reported-by: Naresh Kamboju <naresh.kamboju-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
> Link: https://lkft.validation.linaro.org/scheduler/job/48009#L3147
> Signed-off-by: Arnd Bergmann <arnd-r2nGTMty4D4@public.gmane.org>
> ---
> Not tested yet, please review carefully
I've already sent a v2 of the borked patch, which Mark apparently
applied to his fix/idr branch.
Regards,
Lucas
> ---
> drivers/spi/spi.c | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
> index 0483410e7cb3..4b6985ec962c 100644
> --- a/drivers/spi/spi.c
> +++ b/drivers/spi/spi.c
> @@ -2116,9 +2116,11 @@ int spi_register_controller(struct
> spi_controller *ctlr)
> }
> if (ctlr->bus_num < 0) {
> mutex_lock(&board_lock);
> + id = of_alias_get_highest_id("spi");
> + if (id < 0)
> + id = -1;
> id = idr_alloc(&spi_master_idr, ctlr,
> - of_alias_get_highest_id("spi") + 1,
> - 0, GFP_KERNEL);
> + id + 1, 0, GFP_KERNEL);
> mutex_unlock(&board_lock);
> if (WARN(id < 0, "couldn't get idr"))
> return id;
--
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^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] spi: fix bogus SPI bus number
[not found] ` <20171017104519.878892-1-arnd-r2nGTMty4D4@public.gmane.org>
2017-10-17 12:20 ` Lucas Stach
@ 2017-10-17 12:25 ` Mark Brown
1 sibling, 0 replies; 3+ messages in thread
From: Mark Brown @ 2017-10-17 12:25 UTC (permalink / raw)
To: Arnd Bergmann
Cc: Lucas Stach, Naresh Kamboju, Geert Uytterhoeven, Andy Shevchenko,
Rafael J. Wysocki, linux-spi-u79uwXL29TY76Z2rM5mHXA,
linux-kernel-u79uwXL29TY76Z2rM5mHXA
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On Tue, Oct 17, 2017 at 12:44:50PM +0200, Arnd Bergmann wrote:
> lkft found a boot time regression on the Hikey board that has no
> aliases entry for spi buses. of_alias_get_highest_id() here
> returns -ENODEV, which is then used as the initial number for the
> IDR allocation, and that in turn triggers a WARN_ON:
This doesn't apply against current code, please check and resend.
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2017-10-17 10:44 [PATCH] spi: fix bogus SPI bus number Arnd Bergmann
[not found] ` <20171017104519.878892-1-arnd-r2nGTMty4D4@public.gmane.org>
2017-10-17 12:20 ` Lucas Stach
2017-10-17 12:25 ` Mark Brown
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