[v2] firewire: core: call address handlers ouside RCU read-side critical section

[PATCH v2 0/4] firewire: core: call address handlers ouside RCU read-side critical section

Posted by Takashi Sakamoto 2 months ago

Hi,

This is an updated version of my previous patchset[1].

In the earlier version, XArray was used to collect FCP address handlers.
However, in typical system, only a few handlers are registered, and
using XArray for this purpose was unnecessarily complex and inefficient.
A simpler and faster approach is more appropriate here.

In this v2 patchset, the kernel stack is used initially to store up to 4
handlers. If more than 4 handlers are registered in the system, a buffer
is dynamically allocated from the kernel heap.

[1] https://lore.kernel.org/lkml/20250728015125.17825-1-o-takashi@sakamocchi.jp/

Takashi Sakamoto (4):
  firewire: core: use reference counting to invoke address handlers
    safely
  firewire: core: call handler for exclusive regions outside RCU
    read-side critical section
  firewire: core: call FCP address handlers outside RCU read-side
    critical section
  firewire: core: reallocate buffer for FCP address handlers when more
    than 4 are registered

 drivers/firewire/core-transaction.c | 91 +++++++++++++++++++++++++----
 include/linux/firewire.h            |  4 ++
 2 files changed, 85 insertions(+), 10 deletions(-)


base-commit: 7061835997daba9e73c723c85bd70bc4c44aef77
-- 
2.48.1

Re: [PATCH v2 0/4] firewire: core: call address handlers ouside RCU read-side critical section

Posted by Takashi Sakamoto 1 month, 3 weeks ago

On Sun, Aug 03, 2025 at 09:20:11PM +0900, Takashi Sakamoto wrote:
> Hi,
> 
> This is an updated version of my previous patchset[1].
> 
> In the earlier version, XArray was used to collect FCP address handlers.
> However, in typical system, only a few handlers are registered, and
> using XArray for this purpose was unnecessarily complex and inefficient.
> A simpler and faster approach is more appropriate here.
> 
> In this v2 patchset, the kernel stack is used initially to store up to 4
> handlers. If more than 4 handlers are registered in the system, a buffer
> is dynamically allocated from the kernel heap.
> 
> [1] https://lore.kernel.org/lkml/20250728015125.17825-1-o-takashi@sakamocchi.jp/
> 
> Takashi Sakamoto (4):
>   firewire: core: use reference counting to invoke address handlers
>     safely
>   firewire: core: call handler for exclusive regions outside RCU
>     read-side critical section
>   firewire: core: call FCP address handlers outside RCU read-side
>     critical section
>   firewire: core: reallocate buffer for FCP address handlers when more
>     than 4 are registered
> 
>  drivers/firewire/core-transaction.c | 91 +++++++++++++++++++++++++----
>  include/linux/firewire.h            |  4 ++
>  2 files changed, 85 insertions(+), 10 deletions(-)
> 
> 
> base-commit: 7061835997daba9e73c723c85bd70bc4c44aef77

Applied to for-linus branch.


Thanks

Takashi Sakamoto