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

[Daniel Jurgens]

> -----Original Message-----
> From: Kelsey Skunberg <kelsey.skunberg at canonical.com>
> Sent: Friday, May 28, 2021 7:41 PM
> Subject: CMT: [SRU][F:linux-bluefield][PATCH] netfilter: flowtable: Use rw
> sem as flow block lock
> 
> On 2021-05-19 00:43:25 , 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> (backported
> > from commit 422c032afcf57d5e8109a54912e22ffc53d99068)
> [danielj: minor context adjustments in header (for example)]
> > Signed-off-by: Daniel Jurgens <danielj at nvidia.com>
> 
> There was a prior version of this patch on the mailing list which Stefan
> reviewed. He requested a line like the above to please be added when
> applying.

Not clear if you want me to resubmit? Stefan said no need to. 

> 
> Thank you!
> 
> -Kelsey
> 
> >
> > ---
> >  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