NACK/CMT: [SRU][F:linux-bluefield][PATCH] netfilter: flowtable: Use rw sem as flow block lock

[Kelsey Skunberg]

This was re-sent to the mailing list to update the cherry picked to
backported. 

Daniel, please NACK old versions of your patches if you send updated
ones. It's also important to add version numbers in the subject if you
send a revised version. That way if we see v3, we know right away v2
is invalid. 

No reason to re-send this one; just a note for future patches. Thank
you!

-Kelsey

On 2021-05-11 21:05:26 , Daniel Jurgens wrote:
> From: Paul Blakey <paulb at mellanox.com>
> 
> BugLink: https://bugs.launchpad.net/bugs/1927251
> 
> Currently flow offload threads are synchronized by the flow block mutex.
> Use rw lock instead to increase flow insertion (read) concurrency.
> 
> Signed-off-by: Paul Blakey <paulb at mellanox.com>
> Reviewed-by: Oz Shlomo <ozsh at mellanox.com>
> Signed-off-by: Pablo Neira Ayuso <pablo at netfilter.org>
> (cherry picked from commit 422c032afcf57d5e8109a54912e22ffc53d99068)
> Signed-off-by: Daniel Jurgens <danielj at nvidia.com>
> 
> Conflicts:
> 	include/net/netfilter/nf_flow_table.h
> ---
>  include/net/netfilter/nf_flow_table.h |  2 +-
>  net/netfilter/nf_flow_table_core.c    | 11 +++++------
>  net/netfilter/nf_flow_table_offload.c |  4 ++--
>  3 files changed, 8 insertions(+), 9 deletions(-)
> 
> diff --git a/include/net/netfilter/nf_flow_table.h b/include/net/netfilter/nf_flow_table.h
> index 3a46b3c..e27b73f 100644
> --- a/include/net/netfilter/nf_flow_table.h
> +++ b/include/net/netfilter/nf_flow_table.h
> @@ -73,7 +73,7 @@ struct nf_flowtable {
>  	struct delayed_work		gc_work;
>  	unsigned int			flags;
>  	struct flow_block		flow_block;
> -	struct mutex			flow_block_lock; /* Guards flow_block */
> +	struct rw_semaphore		flow_block_lock; /* Guards flow_block */
>  	u32				flow_timeout;
>  	possible_net_t			net;
>  };
> diff --git a/net/netfilter/nf_flow_table_core.c b/net/netfilter/nf_flow_table_core.c
> index 5144e31..0c409aa 100644
> --- a/net/netfilter/nf_flow_table_core.c
> +++ b/net/netfilter/nf_flow_table_core.c
> @@ -398,7 +398,7 @@ int nf_flow_table_offload_add_cb(struct nf_flowtable *flow_table,
>  	struct flow_block_cb *block_cb;
>  	int err = 0;
>  
> -	mutex_lock(&flow_table->flow_block_lock);
> +	down_write(&flow_table->flow_block_lock);
>  	block_cb = flow_block_cb_lookup(block, cb, cb_priv);
>  	if (block_cb) {
>  		err = -EEXIST;
> @@ -414,7 +414,7 @@ int nf_flow_table_offload_add_cb(struct nf_flowtable *flow_table,
>  	list_add_tail(&block_cb->list, &block->cb_list);
>  
>  unlock:
> -	mutex_unlock(&flow_table->flow_block_lock);
> +	up_write(&flow_table->flow_block_lock);
>  	return err;
>  }
>  EXPORT_SYMBOL_GPL(nf_flow_table_offload_add_cb);
> @@ -425,13 +425,13 @@ void nf_flow_table_offload_del_cb(struct nf_flowtable *flow_table,
>  	struct flow_block *block = &flow_table->flow_block;
>  	struct flow_block_cb *block_cb;
>  
> -	mutex_lock(&flow_table->flow_block_lock);
> +	down_write(&flow_table->flow_block_lock);
>  	block_cb = flow_block_cb_lookup(block, cb, cb_priv);
>  	if (block_cb)
>  		list_del(&block_cb->list);
>  	else
>  		WARN_ON(true);
> -	mutex_unlock(&flow_table->flow_block_lock);
> +	up_write(&flow_table->flow_block_lock);
>  }
>  EXPORT_SYMBOL_GPL(nf_flow_table_offload_del_cb);
>  
> @@ -561,7 +561,7 @@ int nf_flow_table_init(struct nf_flowtable *flowtable)
>  
>  	INIT_DEFERRABLE_WORK(&flowtable->gc_work, nf_flow_offload_work_gc);
>  	flow_block_init(&flowtable->flow_block);
> -	mutex_init(&flowtable->flow_block_lock);
> +	init_rwsem(&flowtable->flow_block_lock);
>  
>  	err = rhashtable_init(&flowtable->rhashtable,
>  			      &nf_flow_offload_rhash_params);
> @@ -627,7 +627,6 @@ void nf_flow_table_free(struct nf_flowtable *flow_table)
>  		nf_flow_table_iterate(flow_table, nf_flow_offload_gc_step,
>  				      flow_table);
>  	rhashtable_destroy(&flow_table->rhashtable);
> -	mutex_destroy(&flow_table->flow_block_lock);
>  }
>  EXPORT_SYMBOL_GPL(nf_flow_table_free);
>  
> diff --git a/net/netfilter/nf_flow_table_offload.c b/net/netfilter/nf_flow_table_offload.c
> index 26a950d..46bffaa 100644
> --- a/net/netfilter/nf_flow_table_offload.c
> +++ b/net/netfilter/nf_flow_table_offload.c
> @@ -698,7 +698,7 @@ static int nf_flow_offload_tuple(struct nf_flowtable *flowtable,
>  	if (cmd == FLOW_CLS_REPLACE)
>  		cls_flow.rule = flow_rule->rule;
>  
> -	mutex_lock(&flowtable->flow_block_lock);
> +	down_read(&flowtable->flow_block_lock);
>  	list_for_each_entry(block_cb, block_cb_list, list) {
>  		err = block_cb->cb(TC_SETUP_CLSFLOWER, &cls_flow,
>  				   block_cb->cb_priv);
> @@ -707,7 +707,7 @@ static int nf_flow_offload_tuple(struct nf_flowtable *flowtable,
>  
>  		i++;
>  	}
> -	mutex_unlock(&flowtable->flow_block_lock);
> +	up_read(&flowtable->flow_block_lock);
>  
>  	if (cmd == FLOW_CLS_STATS)
>  		memcpy(stats, &cls_flow.stats, sizeof(*stats));
> -- 
> 1.8.3.1
> 
> 
> -- 
> kernel-team mailing list
> kernel-team at lists.ubuntu.com
> https://lists.ubuntu.com/mailman/listinfo/kernel-team