[Linux-kernel-mentees] [PATCH] net: xen-netback: hash.c: Use built-in RCU list checking

[Wei Liu]

On Wed, Jan 15, 2020 at 07:48:40PM +0530, madhuparnabhowmik04 at gmail.com wrote:
> From: Madhuparna Bhowmik <madhuparnabhowmik04 at gmail.com>
> 
> list_for_each_entry_rcu has built-in RCU and lock checking.
> Pass cond argument to list_for_each_entry_rcu.
> 
> Signed-off-by: Madhuparna Bhowmik <madhuparnabhowmik04 at gmail.com>

You seem to have dropped the second hunk which modified
xenvif_flush_hash, is that a mistake?

Wei.

> ---
>  drivers/net/xen-netback/hash.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/net/xen-netback/hash.c b/drivers/net/xen-netback/hash.c
> index 10d580c3dea3..3f9783f70a75 100644
> --- a/drivers/net/xen-netback/hash.c
> +++ b/drivers/net/xen-netback/hash.c
> @@ -51,7 +51,8 @@ static void xenvif_add_hash(struct xenvif *vif, const u8 *tag,
>  
>  	found = false;
>  	oldest = NULL;
> -	list_for_each_entry_rcu(entry, &vif->hash.cache.list, link) {
> +	list_for_each_entry_rcu(entry, &vif->hash.cache.list, link,
> +				lockdep_is_held(&vif->hash.cache.lock)) {
>  		/* Make sure we don't add duplicate entries */
>  		if (entry->len == len &&
>  		    memcmp(entry->tag, tag, len) == 0)
> -- 
> 2.17.1
>