First of all, it is an absolute requirement that each RX-queue have their own page_pool object/allocator. And this change is intendant to handle special case, where a single RX-queue can receive packets from two different net_devices. In order to protect against using same allocator for 2 different rx queues, add queue_index to xdp_mem_allocator to catch the obvious mistake where queue_index mismatch, as proposed by Jesper Dangaard Brouer. Adding this on xdp allocator level allows drivers with such dependency change the allocators w/o modifications. Signed-off-by: Ivan Khoronzhuk <ivan.khoronzhuk@xxxxxxxxxx> --- include/net/xdp_priv.h | 2 ++ net/core/xdp.c | 55 ++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 57 insertions(+) diff --git a/include/net/xdp_priv.h b/include/net/xdp_priv.h index 6a8cba6ea79a..9858a4057842 100644 --- a/include/net/xdp_priv.h +++ b/include/net/xdp_priv.h @@ -18,6 +18,8 @@ struct xdp_mem_allocator { struct rcu_head rcu; struct delayed_work defer_wq; unsigned long defer_warn; + unsigned long refcnt; + u32 queue_index; }; #endif /* __LINUX_NET_XDP_PRIV_H__ */ diff --git a/net/core/xdp.c b/net/core/xdp.c index 829377cc83db..4f0ddbb3717a 100644 --- a/net/core/xdp.c +++ b/net/core/xdp.c @@ -98,6 +98,18 @@ static bool __mem_id_disconnect(int id, bool force) WARN(1, "Request remove non-existing id(%d), driver bug?", id); return true; } + + /* to avoid calling hash lookup twice, decrement refcnt here till it + * reaches zero, then it can be called from workqueue afterwards. + */ + if (xa->refcnt) + xa->refcnt--; + + if (xa->refcnt) { + mutex_unlock(&mem_id_lock); + return true; + } + xa->disconnect_cnt++; /* Detects in-flight packet-pages for page_pool */ @@ -312,6 +324,33 @@ static bool __is_supported_mem_type(enum xdp_mem_type type) return true; } +static struct xdp_mem_allocator *xdp_allocator_find(void *allocator) +{ + struct xdp_mem_allocator *xae, *xa = NULL; + struct rhashtable_iter iter; + + if (!allocator) + return xa; + + rhashtable_walk_enter(mem_id_ht, &iter); + do { + rhashtable_walk_start(&iter); + + while ((xae = rhashtable_walk_next(&iter)) && !IS_ERR(xae)) { + if (xae->allocator == allocator) { + xa = xae; + break; + } + } + + rhashtable_walk_stop(&iter); + + } while (xae == ERR_PTR(-EAGAIN)); + rhashtable_walk_exit(&iter); + + return xa; +} + int xdp_rxq_info_reg_mem_model(struct xdp_rxq_info *xdp_rxq, enum xdp_mem_type type, void *allocator) { @@ -347,6 +386,20 @@ int xdp_rxq_info_reg_mem_model(struct xdp_rxq_info *xdp_rxq, } } + mutex_lock(&mem_id_lock); + xdp_alloc = xdp_allocator_find(allocator); + if (xdp_alloc) { + /* One allocator per queue is supposed only */ + if (xdp_alloc->queue_index != xdp_rxq->queue_index) + return -EINVAL; + + xdp_rxq->mem.id = xdp_alloc->mem.id; + xdp_alloc->refcnt++; + mutex_unlock(&mem_id_lock); + return 0; + } + mutex_unlock(&mem_id_lock); + xdp_alloc = kzalloc(sizeof(*xdp_alloc), gfp); if (!xdp_alloc) return -ENOMEM; @@ -360,6 +413,8 @@ int xdp_rxq_info_reg_mem_model(struct xdp_rxq_info *xdp_rxq, xdp_rxq->mem.id = id; xdp_alloc->mem = xdp_rxq->mem; xdp_alloc->allocator = allocator; + xdp_alloc->refcnt = 1; + xdp_alloc->queue_index = xdp_rxq->queue_index; /* Insert allocator into ID lookup table */ ptr = rhashtable_insert_slow(mem_id_ht, &id, &xdp_alloc->node); -- 2.17.1
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