Re: [PATCH v3 2/3] efi: don't use spinlocks for efi vars

[Matt Fleming <matt-mF/unelCI9GS6iBeEJttW/XRex20P6io@public.gmane.org>]

On Wed, 13 Jan, at 05:32:41PM, Sylvain Chouleur wrote:
> From: Sylvain Chouleur <sylvain.chouleur-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
> 
> All efivars operations are protected by a spinlock which prevents
> interruptions and preemption. This is too restricted, we just need a
> lock preventing concurency.
> The idea is to use a semaphore of count 1 and to have two ways of
> locking, depending on the context:
>  - In interrupt context, we call down_trylock(), if it fails we return
>  an error
>  - In normal context, we call down_interruptible()
> 
> We don't use a mutex here because the mutex_trylock() function must not
> be called from interrupt context, whereas the down_trylock() can.
> 
> Signed-off-by: Sylvain Chouleur <sylvain.chouleur-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
> ---
>  drivers/firmware/efi/efi-pstore.c |  36 +++++++---
>  drivers/firmware/efi/efivars.c    |  22 ++++--
>  drivers/firmware/efi/vars.c       | 145 +++++++++++++++++++++++---------------
>  fs/efivarfs/inode.c               |   5 +-
>  fs/efivarfs/super.c               |   9 ++-
>  include/linux/efi.h               |   6 +-
>  6 files changed, 149 insertions(+), 74 deletions(-)

Looks fine to me.