[RFC 2/6] io_uring/zcrx: move freelist lock to struct zcrx

[Pavel Begunkov <asml.silence@gmail.com>]

freelist_lock, which protects slow path allocations, is currently stored
in struct io_zcrx_area. Once we add support for multiple queues, we'll
need a lock in the zcrx ctx, move it there.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
---
 io_uring/zcrx.c | 14 +++++++-------
 io_uring/zcrx.h |  2 +-
 2 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/io_uring/zcrx.c b/io_uring/zcrx.c
index 3478040f2197..563bef1e724b 100644
--- a/io_uring/zcrx.c
+++ b/io_uring/zcrx.c
@@ -511,7 +511,6 @@ static int io_zcrx_create_area(struct io_zcrx_ifq *ifq,
 	/* we're only supporting one area per ifq for now */
 	area->area_id = 0;
 	area_reg->rq_area_token = (u64)area->area_id << IORING_ZCRX_AREA_SHIFT;
-	spin_lock_init(&area->freelist_lock);
 
 	ret = io_zcrx_append_area(ifq, area);
 	if (!ret)
@@ -532,6 +531,7 @@ static struct io_zcrx_ifq *io_zcrx_ifq_alloc(struct io_ring_ctx *ctx)
 
 	ifq->if_rxq = -1;
 	spin_lock_init(&ifq->rq.lock);
+	spin_lock_init(&ifq->alloc_lock);
 	mutex_init(&ifq->pp_lock);
 	refcount_set(&ifq->refs, 1);
 	refcount_set(&ifq->user_refs, 1);
@@ -603,8 +603,9 @@ static void io_put_zcrx_ifq(struct io_zcrx_ifq *ifq)
 static void io_zcrx_return_niov_freelist(struct net_iov *niov)
 {
 	struct io_zcrx_area *area = io_zcrx_iov_to_area(niov);
+	struct io_zcrx_ifq *ifq = area->ifq;
 
-	guard(spinlock_bh)(&area->freelist_lock);
+	guard(spinlock_bh)(&ifq->alloc_lock);
 	if (WARN_ON_ONCE(area->free_count >= area->nia.num_niovs))
 		return;
 	area->freelist[area->free_count++] = net_iov_idx(niov);
@@ -614,7 +615,7 @@ static struct net_iov *zcrx_get_free_niov(struct io_zcrx_area *area)
 {
 	unsigned niov_idx;
 
-	lockdep_assert_held(&area->freelist_lock);
+	lockdep_assert_held(&area->ifq->alloc_lock);
 
 	if (unlikely(!area->free_count))
 		return NULL;
@@ -1082,7 +1083,7 @@ static unsigned io_zcrx_refill_slow(struct page_pool *pp, struct io_zcrx_ifq *if
 	struct io_zcrx_area *area = ifq->area;
 	unsigned allocated = 0;
 
-	guard(spinlock_bh)(&area->freelist_lock);
+	guard(spinlock_bh)(&ifq->alloc_lock);
 
 	for (allocated = 0; allocated < to_alloc; allocated++) {
 		struct net_iov *niov = zcrx_get_free_niov(area);
@@ -1317,14 +1318,13 @@ static bool io_zcrx_queue_cqe(struct io_kiocb *req, struct net_iov *niov,
 
 static struct net_iov *io_alloc_fallback_niov(struct io_zcrx_ifq *ifq)
 {
-	struct io_zcrx_area *area = ifq->area;
 	struct net_iov *niov = NULL;
 
 	if (!ifq->kern_readable)
 		return NULL;
 
-	scoped_guard(spinlock_bh, &area->freelist_lock)
-		niov = zcrx_get_free_niov(area);
+	scoped_guard(spinlock_bh, &ifq->alloc_lock)
+		niov = zcrx_get_free_niov(ifq->area);
 
 	if (niov)
 		page_pool_fragment_netmem(net_iov_to_netmem(niov), 1);
diff --git a/io_uring/zcrx.h b/io_uring/zcrx.h
index 75e0a4e6ef6e..687ca7c9f45b 100644
--- a/io_uring/zcrx.h
+++ b/io_uring/zcrx.h
@@ -34,7 +34,6 @@ struct io_zcrx_area {
 	u16			area_id;
 
 	/* freelist */
-	spinlock_t		freelist_lock ____cacheline_aligned_in_smp;
 	u32			free_count;
 	u32			*freelist;
 
@@ -57,6 +56,7 @@ struct io_zcrx_ifq {
 	bool				kern_readable;
 
 	struct zcrx_rq			rq ____cacheline_aligned_in_smp;
+	spinlock_t			alloc_lock ____cacheline_aligned_in_smp;
 
 	u32				if_rxq;
 	struct device			*dev;
-- 
2.53.0