On Mon, 11 Jul, at 04:59:24PM, Ard Biesheuvel wrote:
> From: Sylvain Chouleur <sylvain.chouleur@xxxxxxxxx>
>
> All efivars operations are protected by a spinlock which prevents
> interruptions and preemption. This is too restricted, we just need a
> lock preventing concurrency.
> 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@xxxxxxxxx>
> [ardb: rebased onto v4.7-rc3]
> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
> ---
> drivers/firmware/efi/efi-pstore.c | 36 +++--
> drivers/firmware/efi/efivars.c | 22 +++-
> drivers/firmware/efi/vars.c | 137 ++++++++++++--------
> fs/efivarfs/inode.c | 5 +-
> fs/efivarfs/super.c | 9 +-
> include/linux/efi.h | 6 +-
> 6 files changed, 143 insertions(+), 72 deletions(-)
[...]
> @@ -545,10 +562,10 @@ EXPORT_SYMBOL_GPL(efivar_entry_remove);
> */
> static void efivar_entry_list_del_unlock(struct efivar_entry *entry)
> {
> - lockdep_assert_held(&efivars_lock);
> + lockdep_assert_held(&efivars_lock.lock);
>
> list_del(&entry->list);
> - spin_unlock_irq(&efivars_lock);
> + up(&efivars_lock);
> }
>
> /**
These LOCKDEP annotations are now incorrect because the spin lock
inside the semaphore is only held while acquiring the semaphore.
I can't see an equivalent assert for semaphores, so it's probably best
to just rip these out.
Other than that, this looks OK.
--
To unsubscribe from this list: send the line "unsubscribe linux-efi" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
