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net/tls: use RCU for the adder to the offload record list 

All modifications to TLS record list happen under the socket
lock. Since records form an ordered queue readers are only
concerned about elements being removed, additions can happen
concurrently.

Use RCU primitives to ensure the correct access types
(READ_ONCE/WRITE_ONCE).

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Dirk van der Merwe <dirk.vandermerwe@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Jakub Kicinski 2019-09-06 22:29:58 -07:00 committed by David S. Miller
parent 7ccd451912
commit d4774ac0d4
1 changed files with 13 additions and 8 deletions
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19
net/tls/tls_device.c
View File

@ -280,9 +280,7 @@ static int tls_push_record(struct sock *sk,
tls_append_frag(record, &dummy_tag_frag, prot->tag_size);
record->end_seq = tp->write_seq + record->len;
spin_lock_irq(&offload_ctx->lock);
list_add_tail(&record->list, &offload_ctx->records_list);
spin_unlock_irq(&offload_ctx->lock);
list_add_tail_rcu(&record->list, &offload_ctx->records_list);
offload_ctx->open_record = NULL;
if (test_bit(TLS_TX_SYNC_SCHED, &ctx->flags))
@ -535,12 +533,16 @@ struct tls_record_info *tls_get_record(struct tls_offload_context_tx *context,
/* if retransmit_hint is irrelevant start
* from the beggining of the list
*/
info = list_first_entry(&context->records_list,
info = list_first_entry_or_null(&context->records_list,
struct tls_record_info, list);
if (!info)
return NULL;
record_sn = context->unacked_record_sn;
}
list_for_each_entry_from(info, &context->records_list, list) {
/* We just need the _rcu for the READ_ONCE() */
rcu_read_lock();
list_for_each_entry_from_rcu(info, &context->records_list, list) {
if (before(seq, info->end_seq)) {
if (!context->retransmit_hint ||
after(info->end_seq,
@ -549,12 +551,15 @@ struct tls_record_info *tls_get_record(struct tls_offload_context_tx *context,
context->retransmit_hint = info;
}
*p_record_sn = record_sn;
return info;
goto exit_rcu_unlock;
}
record_sn++;
}
info = NULL;
return NULL;
exit_rcu_unlock:
rcu_read_unlock();
return info;
}
EXPORT_SYMBOL(tls_get_record);