On Fri, 15 Jul, at 09:36:30PM, 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, remove lockdep_assert_xxx() calls]
> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
> ---
> v3: remove lockdep_assert() calls: they are no longer appropriate now that we
> have switched to a semaphore
> v2: rebased onto v4.7-rc3
>
> 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, 139 insertions(+), 76 deletions(-)
[...]
> diff --git a/fs/efivarfs/inode.c b/fs/efivarfs/inode.c
> index 1d73fc6dba13..cbb50cadcffc 100644
> --- a/fs/efivarfs/inode.c
> +++ b/fs/efivarfs/inode.c
> @@ -105,7 +105,10 @@ static int efivarfs_create(struct inode *dir, struct dentry *dentry,
>
> inode->i_private = var;
>
> - efivar_entry_add(var, &efivarfs_list);
> + err = efivar_entry_add(var, &efivarfs_list);
> + if (err)
> + goto out;
> +
> d_instantiate(dentry, inode);
> dget(dentry);
> out:
Tobias, this patch requires the exact error path that was removed in
patch ("efivarfs: Eliminate dead code in efivarfs_create()").
Which unfortunately means I'm going to drop your patch from the queue.
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