On Wed, May 15 2019, Jakub Kicinski wrote:
> Since the bit_spin_lock() operations don't actually dereference
> the pointer, it's fine to forcefully drop the RCU annotation.
> This fixes 7 sparse warnings per include site.
>
> Fixes: 8f0db018006a ("rhashtable: use bit_spin_locks to protect hash bucket.")
> Signed-off-by: Jakub Kicinski <[email protected]>
> Reviewed-by: Simon Horman <[email protected]>
Hi, sorry for not responding to your initial post, but I'm otherwise
engaged this week and cannot give it any real time. I don't object to
this patch, but I'll try to have a proper look next week, if only to
find out how I didn't get the warnings, as I was testing with sparse.
Thanks,
NeilBrown
> ---
> include/linux/rhashtable.h | 12 ++++++------
> 1 file changed, 6 insertions(+), 6 deletions(-)
>
> diff --git a/include/linux/rhashtable.h b/include/linux/rhashtable.h
> index f7714d3b46bd..bea1e0440ab4 100644
> --- a/include/linux/rhashtable.h
> +++ b/include/linux/rhashtable.h
> @@ -325,27 +325,27 @@ static inline struct rhash_lock_head __rcu
> **rht_bucket_insert(
> */
>
> static inline void rht_lock(struct bucket_table *tbl,
> - struct rhash_lock_head **bkt)
> + struct rhash_lock_head __rcu **bkt)
> {
> local_bh_disable();
> - bit_spin_lock(0, (unsigned long *)bkt);
> + bit_spin_lock(0, (unsigned long __force *)bkt);
> lock_map_acquire(&tbl->dep_map);
> }
>
> static inline void rht_lock_nested(struct bucket_table *tbl,
> - struct rhash_lock_head **bucket,
> + struct rhash_lock_head __rcu **bkt,
> unsigned int subclass)
> {
> local_bh_disable();
> - bit_spin_lock(0, (unsigned long *)bucket);
> + bit_spin_lock(0, (unsigned long __force *)bkt);
> lock_acquire_exclusive(&tbl->dep_map, subclass, 0, NULL, _THIS_IP_);
> }
>
> static inline void rht_unlock(struct bucket_table *tbl,
> - struct rhash_lock_head **bkt)
> + struct rhash_lock_head __rcu **bkt)
> {
> lock_map_release(&tbl->dep_map);
> - bit_spin_unlock(0, (unsigned long *)bkt);
> + bit_spin_unlock(0, (unsigned long __force *)bkt);
> local_bh_enable();
> }
>
> --
> 2.21.0
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