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* [PATCH 1/1] s390x/css: Fix css stsch detection to go beyond 8192 devices
@ 2026-08-14 15:17 Christian Borntraeger
  2026-08-14 15:19 ` Christian Borntraeger
  0 siblings, 1 reply; 2+ messages in thread
From: Christian Borntraeger @ 2026-08-14 15:17 UTC (permalink / raw)
  To: linux-btrfs, Qu Wenruo
  Cc: borntraeger, David Sterba, Chris Mason, Josef Bacik,
	linux-kernel, kvm, linux-s390

find_last_bit expects a size in bits and not in words. the calculation
limits the number of guest devices to 8192.  This probably does not
matter in reality, its wrong anyway.

Fixes: df1fe5bb49241 ("s390: Virtual channel subsystem support")
Signed-off-by: Christian Borntraeger <borntraeger@linux.ibm.com>
---
 hw/s390x/css.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/hw/s390x/css.c b/hw/s390x/css.c
index 3a67b670531..dedd39006bf 100644
--- a/hw/s390x/css.c
+++ b/hw/s390x/css.c
@@ -2023,8 +2023,7 @@ bool css_schid_final(int m, uint8_t cssid, uint8_t ssid, uint16_t schid)
         return true;
     }
     set = channel_subsys.css[real_cssid]->sch_set[ssid];
-    return schid > find_last_bit(set->schids_used,
-                                 (MAX_SCHID + 1) / sizeof(unsigned long));
+    return schid > find_last_bit(set->schids_used,(MAX_SCHID + 1));
 }
 
 unsigned int css_find_free_chpid(uint8_t cssid)
-- 
2.55.0


^ permalink raw reply	[flat|nested] 2+ messages in thread

* Re: [PATCH 1/1] s390x/css: Fix css stsch detection to go beyond 8192 devices
  2026-08-14 15:17 [PATCH 1/1] s390x/css: Fix css stsch detection to go beyond 8192 devices Christian Borntraeger
@ 2026-08-14 15:19 ` Christian Borntraeger
  0 siblings, 0 replies; 2+ messages in thread
From: Christian Borntraeger @ 2026-08-14 15:19 UTC (permalink / raw)
  To: linux-btrfs, Qu Wenruo
  Cc: David Sterba, Chris Mason, Josef Bacik, linux-kernel, kvm, linux-s390

Sorry for the noise, please ignore.

Am 14.08.26 um 17:17 schrieb Christian Borntraeger:
> find_last_bit expects a size in bits and not in words. the calculation
> limits the number of guest devices to 8192.  This probably does not
> matter in reality, its wrong anyway.
> 
> Fixes: df1fe5bb49241 ("s390: Virtual channel subsystem support")
> Signed-off-by: Christian Borntraeger <borntraeger@linux.ibm.com>
> ---
>   hw/s390x/css.c | 3 +--
>   1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/hw/s390x/css.c b/hw/s390x/css.c
> index 3a67b670531..dedd39006bf 100644
> --- a/hw/s390x/css.c
> +++ b/hw/s390x/css.c
> @@ -2023,8 +2023,7 @@ bool css_schid_final(int m, uint8_t cssid, uint8_t ssid, uint16_t schid)
>           return true;
>       }
>       set = channel_subsys.css[real_cssid]->sch_set[ssid];
> -    return schid > find_last_bit(set->schids_used,
> -                                 (MAX_SCHID + 1) / sizeof(unsigned long));
> +    return schid > find_last_bit(set->schids_used,(MAX_SCHID + 1));
>   }
>   
>   unsigned int css_find_free_chpid(uint8_t cssid)


^ permalink raw reply	[flat|nested] 2+ messages in thread

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