On Fri, Oct 09, 2020 at 09:55:12PM +0200, Pavel Reichl wrote:
> Refactor xfs_isilocked() to use newly introduced __xfs_rwsem_islocked().
> __xfs_rwsem_islocked() is a helper function which encapsulates checking
> state of rw_semaphores hold by inode.
>
> Signed-off-by: Pavel Reichl <preichl@xxxxxxxxxx>
> Suggested-by: Dave Chinner <dchinner@xxxxxxxxxx>
> Suggested-by: Eric Sandeen <sandeen@xxxxxxxxxx>
> Suggested-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
> Reviewed-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
> ---
> fs/xfs/xfs_inode.c | 48 ++++++++++++++++++++++++++++++++++++++--------
> fs/xfs/xfs_inode.h | 21 +++++++++++++-------
> 2 files changed, 54 insertions(+), 15 deletions(-)
>
> diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
> index c06129cffba9..7c1ceb4df4ec 100644
> --- a/fs/xfs/xfs_inode.c
> +++ b/fs/xfs/xfs_inode.c
> @@ -345,9 +345,43 @@ xfs_ilock_demote(
> }
>
> #if defined(DEBUG) || defined(XFS_WARN)
> -int
> +static inline bool
> +__xfs_rwsem_islocked(
> + struct rw_semaphore *rwsem,
> + int lock_flags)
> +{
> + int arg;
> +
> + if (!debug_locks)
> + return rwsem_is_locked(rwsem);
> +
> + if (lock_flags & (1 << XFS_SHARED_LOCK_SHIFT)) {
> + /*
> + * The caller could be asking if we have (shared | excl)
> + * access to the lock. Ask lockdep if the rwsem is
> + * locked either for read or write access.
> + *
> + * The caller could also be asking if we have only
> + * shared access to the lock. Holding a rwsem
> + * write-locked implies read access as well, so the
> + * request to lockdep is the same for this case.
> + */
> + arg = -1;
> + } else {
> + /*
> + * The caller is asking if we have only exclusive access
> + * to the lock. Ask lockdep if the rwsem is locked for
> + * write access.
> + */
> + arg = 0;
> + }
> +
> + return lockdep_is_held_type(rwsem, arg);
Why not write this as:
if (lock_flags & (1 << XFS_SHARED_LOCK_SHIFT)) {
...
return lockdep_is_held_type(rwsem, 1);
}
...
return lockdep_is_held_type(rwsem, 0);
}
which seems a lot easier to read compare to the strange arg variable.
Otherwise this looks good to me:
Reviewed-by: Christoph Hellwig <hch@xxxxxx>
