Merge branch 'zcrx-updates-6.19' into for-6.19/io_uring

Merge zcrx updates from Pavel:

"Zcrx updates for 6.19. It includes a bunch of small patches,
 IORING_REGISTER_ZCRX_CTRL and RQ flushing (Patches 4-5) and David's
 work on sharing zcrx b/w multiple io_uring instances."

Link: https://lore.kernel.org/io-uring/cover.1763029704.git.asml.silence@gmail.com/
Signed-off-by: Jens Axboe <axboe@kernel.dk>

* zcrx-updates-6.19:
  io_uring/zcrx: share an ifq between rings
  io_uring/zcrx: add io_fill_zcrx_offsets()
  io_uring/zcrx: export zcrx via a file
  io_uring/zcrx: move io_zcrx_scrub() and dependencies up
  io_uring/zcrx: count zcrx users
  io_uring/zcrx: add sync refill queue flushing
  io_uring/zcrx: introduce IORING_REGISTER_ZCRX_CTRL
  io_uring/zcrx: elide passing msg flags
  io_uring/zcrx: use folio_nr_pages() instead of shift operation
  io_uring/zcrx: convert to use netmem_desc

include/uapi/linux/io_uring.h

@@ -697,6 +697,9 @@ enum io_uring_register_op {
 	/* query various aspects of io_uring, see linux/io_uring/query.h */
 	IORING_REGISTER_QUERY			= 35,
 
+	/* auxiliary zcrx configuration, see enum zcrx_ctrl_op */
+	IORING_REGISTER_ZCRX_CTRL		= 36,
+
 	/* this goes last */
 	IORING_REGISTER_LAST,
 
@@ -1060,6 +1063,10 @@ struct io_uring_zcrx_area_reg {
 	__u64	__resv2[2];
 };
 
+enum zcrx_reg_flags {
+	ZCRX_REG_IMPORT	= 1,
+};
+
 /*
  * Argument for IORING_REGISTER_ZCRX_IFQ
  */
@@ -1078,6 +1085,33 @@ struct io_uring_zcrx_ifq_reg {
 	__u64	__resv[3];
 };
 
+enum zcrx_ctrl_op {
+	ZCRX_CTRL_FLUSH_RQ,
+	ZCRX_CTRL_EXPORT,
+
+	__ZCRX_CTRL_LAST,
+};
+
+struct zcrx_ctrl_flush_rq {
+	__u64		__resv[6];
+};
+
+struct zcrx_ctrl_export {
+	__u32		zcrx_fd;
+	__u32 		__resv1[11];
+};
+
+struct zcrx_ctrl {
+	__u32	zcrx_id;
+	__u32	op; /* see enum zcrx_ctrl_op */
+	__u64	__resv[2];
+
+	union {
+		struct zcrx_ctrl_export		zc_export;
+		struct zcrx_ctrl_flush_rq	zc_flush;
+	};
+};
+
 #ifdef __cplusplus
 }
 #endif

io_uring/net.c

@@ -110,7 +110,6 @@ enum sr_retry_flags {
 
 struct io_recvzc {
 	struct file			*file;
-	unsigned			msg_flags;
 	u16				flags;
 	u32				len;
 	struct io_zcrx_ifq		*ifq;
@@ -1253,8 +1252,7 @@ int io_recvzc_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 
 	zc->len = READ_ONCE(sqe->len);
 	zc->flags = READ_ONCE(sqe->ioprio);
-	zc->msg_flags = READ_ONCE(sqe->msg_flags);
-	if (zc->msg_flags)
+	if (READ_ONCE(sqe->msg_flags))
 		return -EINVAL;
 	if (zc->flags & ~(IORING_RECVSEND_POLL_FIRST | IORING_RECV_MULTISHOT))
 		return -EINVAL;
@@ -1283,8 +1281,7 @@ int io_recvzc(struct io_kiocb *req, unsigned int issue_flags)
 		return -ENOTSOCK;
 
 	len = zc->len;
-	ret = io_zcrx_recv(req, zc->ifq, sock, zc->msg_flags | MSG_DONTWAIT,
-			   issue_flags, &zc->len);
+	ret = io_zcrx_recv(req, zc->ifq, sock, 0, issue_flags, &zc->len);
 	if (len && zc->len == 0) {
 		io_req_set_res(req, 0, 0);
 

io_uring/register.c

@@ -815,6 +815,9 @@ static int __io_uring_register(struct io_ring_ctx *ctx, unsigned opcode,
 	case IORING_REGISTER_QUERY:
 		ret = io_query(ctx, arg, nr_args);
 		break;
+	case IORING_REGISTER_ZCRX_CTRL:
+		ret = io_zcrx_ctrl(ctx, arg, nr_args);
+		break;
 	default:
 		ret = -EINVAL;
 		break;

io_uring/zcrx.c

@@ -8,6 +8,7 @@
 #include <linux/netdevice.h>
 #include <linux/rtnetlink.h>
 #include <linux/skbuff_ref.h>
+#include <linux/anon_inodes.h>
 
 #include <net/page_pool/helpers.h>
 #include <net/page_pool/memory_provider.h>
@@ -170,7 +171,7 @@ static unsigned long io_count_account_pages(struct page **pages, unsigned nr_pag
 		if (folio == last_folio)
 			continue;
 		last_folio = folio;
-		res += 1UL << folio_order(folio);
+		res += folio_nr_pages(folio);
 	}
 	return res;
 }
@@ -344,6 +345,13 @@ static void io_zcrx_get_niov_uref(struct net_iov *niov)
 	atomic_inc(io_get_user_counter(niov));
 }
 
+static void io_fill_zcrx_offsets(struct io_uring_zcrx_offsets *offsets)
+{
+	offsets->head = offsetof(struct io_uring, head);
+	offsets->tail = offsetof(struct io_uring, tail);
+	offsets->rqes = ALIGN(sizeof(struct io_uring), L1_CACHE_BYTES);
+}
+
 static int io_allocate_rbuf_ring(struct io_ring_ctx *ctx,
 				 struct io_zcrx_ifq *ifq,
 				 struct io_uring_zcrx_ifq_reg *reg,
@@ -355,7 +363,8 @@ static int io_allocate_rbuf_ring(struct io_ring_ctx *ctx,
 	void *ptr;
 	int ret;
 
-	off = ALIGN(sizeof(struct io_uring), L1_CACHE_BYTES);
+	io_fill_zcrx_offsets(&reg->offsets);
+	off = reg->offsets.rqes;
 	size = off + sizeof(struct io_uring_zcrx_rqe) * reg->rq_entries;
 	if (size > rd->size)
 		return -EINVAL;
@@ -371,9 +380,6 @@ static int io_allocate_rbuf_ring(struct io_ring_ctx *ctx,
 	ifq->rq_ring = (struct io_uring *)ptr;
 	ifq->rqes = (struct io_uring_zcrx_rqe *)(ptr + off);
 
-	reg->offsets.head = offsetof(struct io_uring, head);
-	reg->offsets.tail = offsetof(struct io_uring, tail);
-	reg->offsets.rqes = off;
 	return 0;
 }
 
@@ -482,6 +488,7 @@ static struct io_zcrx_ifq *io_zcrx_ifq_alloc(struct io_ring_ctx *ctx)
 	spin_lock_init(&ifq->rq_lock);
 	mutex_init(&ifq->pp_lock);
 	refcount_set(&ifq->refs, 1);
+	refcount_set(&ifq->user_refs, 1);
 	return ifq;
 }
 
@@ -543,6 +550,57 @@ static void io_put_zcrx_ifq(struct io_zcrx_ifq *ifq)
 		io_zcrx_ifq_free(ifq);
 }
 
+static void io_zcrx_return_niov_freelist(struct net_iov *niov)
+{
+	struct io_zcrx_area *area = io_zcrx_iov_to_area(niov);
+
+	spin_lock_bh(&area->freelist_lock);
+	area->freelist[area->free_count++] = net_iov_idx(niov);
+	spin_unlock_bh(&area->freelist_lock);
+}
+
+static void io_zcrx_return_niov(struct net_iov *niov)
+{
+	netmem_ref netmem = net_iov_to_netmem(niov);
+
+	if (!niov->desc.pp) {
+		/* copy fallback allocated niovs */
+		io_zcrx_return_niov_freelist(niov);
+		return;
+	}
+	page_pool_put_unrefed_netmem(niov->desc.pp, netmem, -1, false);
+}
+
+static void io_zcrx_scrub(struct io_zcrx_ifq *ifq)
+{
+	struct io_zcrx_area *area = ifq->area;
+	int i;
+
+	if (!area)
+		return;
+
+	/* Reclaim back all buffers given to the user space. */
+	for (i = 0; i < area->nia.num_niovs; i++) {
+		struct net_iov *niov = &area->nia.niovs[i];
+		int nr;
+
+		if (!atomic_read(io_get_user_counter(niov)))
+			continue;
+		nr = atomic_xchg(io_get_user_counter(niov), 0);
+		if (nr && !page_pool_unref_netmem(net_iov_to_netmem(niov), nr))
+			io_zcrx_return_niov(niov);
+	}
+}
+
+static void zcrx_unregister(struct io_zcrx_ifq *ifq)
+{
+	if (refcount_dec_and_test(&ifq->user_refs)) {
+		io_close_queue(ifq);
+		io_zcrx_scrub(ifq);
+	}
+	io_put_zcrx_ifq(ifq);
+}
+
 struct io_mapped_region *io_zcrx_get_region(struct io_ring_ctx *ctx,
 					    unsigned int id)
 {
@@ -553,6 +611,112 @@ struct io_mapped_region *io_zcrx_get_region(struct io_ring_ctx *ctx,
 	return ifq ? &ifq->region : NULL;
 }
 
+static int zcrx_box_release(struct inode *inode, struct file *file)
+{
+	struct io_zcrx_ifq *ifq = file->private_data;
+
+	if (WARN_ON_ONCE(!ifq))
+		return -EFAULT;
+	zcrx_unregister(ifq);
+	return 0;
+}
+
+static const struct file_operations zcrx_box_fops = {
+	.owner		= THIS_MODULE,
+	.release	= zcrx_box_release,
+};
+
+static int zcrx_export(struct io_ring_ctx *ctx, struct io_zcrx_ifq *ifq,
+		       struct zcrx_ctrl *ctrl, void __user *arg)
+{
+	struct zcrx_ctrl_export *ce = &ctrl->zc_export;
+	struct file *file;
+	int fd = -1;
+
+	if (!mem_is_zero(ce, sizeof(*ce)))
+		return -EINVAL;
+	fd = get_unused_fd_flags(O_CLOEXEC);
+	if (fd < 0)
+		return fd;
+
+	ce->zcrx_fd = fd;
+	if (copy_to_user(arg, ctrl, sizeof(*ctrl))) {
+		put_unused_fd(fd);
+		return -EFAULT;
+	}
+
+	refcount_inc(&ifq->refs);
+	refcount_inc(&ifq->user_refs);
+
+	file = anon_inode_create_getfile("[zcrx]", &zcrx_box_fops,
+					 ifq, O_CLOEXEC, NULL);
+	if (IS_ERR(file)) {
+		put_unused_fd(fd);
+		zcrx_unregister(ifq);
+		return PTR_ERR(file);
+	}
+
+	fd_install(fd, file);
+	return 0;
+}
+
+static int import_zcrx(struct io_ring_ctx *ctx,
+		       struct io_uring_zcrx_ifq_reg __user *arg,
+		       struct io_uring_zcrx_ifq_reg *reg)
+{
+	struct io_zcrx_ifq *ifq;
+	struct file *file;
+	int fd, ret;
+	u32 id;
+
+	if (!(ctx->flags & IORING_SETUP_DEFER_TASKRUN))
+		return -EINVAL;
+	if (!(ctx->flags & (IORING_SETUP_CQE32|IORING_SETUP_CQE_MIXED)))
+		return -EINVAL;
+	if (reg->if_rxq || reg->rq_entries || reg->area_ptr || reg->region_ptr)
+		return -EINVAL;
+
+	fd = reg->if_idx;
+	CLASS(fd, f)(fd);
+	if (fd_empty(f))
+		return -EBADF;
+
+	file = fd_file(f);
+	if (file->f_op != &zcrx_box_fops || !file->private_data)
+		return -EBADF;
+
+	ifq = file->private_data;
+	refcount_inc(&ifq->refs);
+	refcount_inc(&ifq->user_refs);
+
+	scoped_guard(mutex, &ctx->mmap_lock) {
+		ret = xa_alloc(&ctx->zcrx_ctxs, &id, NULL, xa_limit_31b, GFP_KERNEL);
+		if (ret)
+			goto err;
+	}
+
+	reg->zcrx_id = id;
+	io_fill_zcrx_offsets(&reg->offsets);
+	if (copy_to_user(arg, reg, sizeof(*reg))) {
+		ret = -EFAULT;
+		goto err_xa_erase;
+	}
+
+	scoped_guard(mutex, &ctx->mmap_lock) {
+		ret = -ENOMEM;
+		if (xa_store(&ctx->zcrx_ctxs, id, ifq, GFP_KERNEL))
+			goto err_xa_erase;
+	}
+
+	return 0;
+err_xa_erase:
+	scoped_guard(mutex, &ctx->mmap_lock)
+		xa_erase(&ctx->zcrx_ctxs, id);
+err:
+	zcrx_unregister(ifq);
+	return ret;
+}
+
 int io_register_zcrx_ifq(struct io_ring_ctx *ctx,
 			  struct io_uring_zcrx_ifq_reg __user *arg)
 {
@@ -578,11 +742,13 @@ int io_register_zcrx_ifq(struct io_ring_ctx *ctx,
 		return -EINVAL;
 	if (copy_from_user(&reg, arg, sizeof(reg)))
 		return -EFAULT;
-	if (copy_from_user(&rd, u64_to_user_ptr(reg.region_ptr), sizeof(rd)))
-		return -EFAULT;
 	if (!mem_is_zero(&reg.__resv, sizeof(reg.__resv)) ||
 	    reg.__resv2 || reg.zcrx_id)
 		return -EINVAL;
+	if (reg.flags & ZCRX_REG_IMPORT)
+		return import_zcrx(ctx, arg, &reg);
+	if (copy_from_user(&rd, u64_to_user_ptr(reg.region_ptr), sizeof(rd)))
+		return -EFAULT;
 	if (reg.if_rxq == -1 || !reg.rq_entries || reg.flags)
 		return -EINVAL;
 	if (reg.rq_entries > IO_RQ_MAX_ENTRIES) {
@@ -683,48 +849,6 @@ static struct net_iov *__io_zcrx_get_free_niov(struct io_zcrx_area *area)
 	return &area->nia.niovs[niov_idx];
 }
 
-static void io_zcrx_return_niov_freelist(struct net_iov *niov)
-{
-	struct io_zcrx_area *area = io_zcrx_iov_to_area(niov);
-
-	spin_lock_bh(&area->freelist_lock);
-	area->freelist[area->free_count++] = net_iov_idx(niov);
-	spin_unlock_bh(&area->freelist_lock);
-}
-
-static void io_zcrx_return_niov(struct net_iov *niov)
-{
-	netmem_ref netmem = net_iov_to_netmem(niov);
-
-	if (!niov->pp) {
-		/* copy fallback allocated niovs */
-		io_zcrx_return_niov_freelist(niov);
-		return;
-	}
-	page_pool_put_unrefed_netmem(niov->pp, netmem, -1, false);
-}
-
-static void io_zcrx_scrub(struct io_zcrx_ifq *ifq)
-{
-	struct io_zcrx_area *area = ifq->area;
-	int i;
-
-	if (!area)
-		return;
-
-	/* Reclaim back all buffers given to the user space. */
-	for (i = 0; i < area->nia.num_niovs; i++) {
-		struct net_iov *niov = &area->nia.niovs[i];
-		int nr;
-
-		if (!atomic_read(io_get_user_counter(niov)))
-			continue;
-		nr = atomic_xchg(io_get_user_counter(niov), 0);
-		if (nr && !page_pool_unref_netmem(net_iov_to_netmem(niov), nr))
-			io_zcrx_return_niov(niov);
-	}
-}
-
 void io_unregister_zcrx_ifqs(struct io_ring_ctx *ctx)
 {
 	struct io_zcrx_ifq *ifq;
@@ -741,10 +865,7 @@ void io_unregister_zcrx_ifqs(struct io_ring_ctx *ctx)
 		}
 		if (!ifq)
 			break;
-
-		io_close_queue(ifq);
-		io_zcrx_scrub(ifq);
-		io_put_zcrx_ifq(ifq);
+		zcrx_unregister(ifq);
 	}
 
 	xa_destroy(&ctx->zcrx_ctxs);
@@ -815,7 +936,7 @@ static void io_zcrx_ring_refill(struct page_pool *pp,
 		if (!page_pool_unref_and_test(netmem))
 			continue;
 
-		if (unlikely(niov->pp != pp)) {
+		if (unlikely(niov->desc.pp != pp)) {
 			io_zcrx_return_niov(niov);
 			continue;
 		}
@@ -941,6 +1062,97 @@ static const struct memory_provider_ops io_uring_pp_zc_ops = {
 	.uninstall		= io_pp_uninstall,
 };
 
+static unsigned zcrx_parse_rq(netmem_ref *netmem_array, unsigned nr,
+			      struct io_zcrx_ifq *zcrx)
+{
+	unsigned int mask = zcrx->rq_entries - 1;
+	unsigned int i;
+
+	guard(spinlock_bh)(&zcrx->rq_lock);
+
+	nr = min(nr, io_zcrx_rqring_entries(zcrx));
+	for (i = 0; i < nr; i++) {
+		struct io_uring_zcrx_rqe *rqe = io_zcrx_get_rqe(zcrx, mask);
+		struct net_iov *niov;
+
+		if (!io_parse_rqe(rqe, zcrx, &niov))
+			break;
+		netmem_array[i] = net_iov_to_netmem(niov);
+	}
+
+	smp_store_release(&zcrx->rq_ring->head, zcrx->cached_rq_head);
+	return i;
+}
+
+#define ZCRX_FLUSH_BATCH 32
+
+static void zcrx_return_buffers(netmem_ref *netmems, unsigned nr)
+{
+	unsigned i;
+
+	for (i = 0; i < nr; i++) {
+		netmem_ref netmem = netmems[i];
+		struct net_iov *niov = netmem_to_net_iov(netmem);
+
+		if (!io_zcrx_put_niov_uref(niov))
+			continue;
+		if (!page_pool_unref_and_test(netmem))
+			continue;
+		io_zcrx_return_niov(niov);
+	}
+}
+
+static int zcrx_flush_rq(struct io_ring_ctx *ctx, struct io_zcrx_ifq *zcrx,
+			 struct zcrx_ctrl *ctrl)
+{
+	struct zcrx_ctrl_flush_rq *frq = &ctrl->zc_flush;
+	netmem_ref netmems[ZCRX_FLUSH_BATCH];
+	unsigned total = 0;
+	unsigned nr;
+
+	if (!mem_is_zero(&frq->__resv, sizeof(frq->__resv)))
+		return -EINVAL;
+
+	do {
+		nr = zcrx_parse_rq(netmems, ZCRX_FLUSH_BATCH, zcrx);
+
+		zcrx_return_buffers(netmems, nr);
+		total += nr;
+
+		if (fatal_signal_pending(current))
+			break;
+		cond_resched();
+	} while (nr == ZCRX_FLUSH_BATCH && total < zcrx->rq_entries);
+
+	return 0;
+}
+
+int io_zcrx_ctrl(struct io_ring_ctx *ctx, void __user *arg, unsigned nr_args)
+{
+	struct zcrx_ctrl ctrl;
+	struct io_zcrx_ifq *zcrx;
+
+	if (nr_args)
+		return -EINVAL;
+	if (copy_from_user(&ctrl, arg, sizeof(ctrl)))
+		return -EFAULT;
+	if (!mem_is_zero(&ctrl.__resv, sizeof(ctrl.__resv)))
+		return -EFAULT;
+
+	zcrx = xa_load(&ctx->zcrx_ctxs, ctrl.zcrx_id);
+	if (!zcrx)
+		return -ENXIO;
+
+	switch (ctrl.op) {
+	case ZCRX_CTRL_FLUSH_RQ:
+		return zcrx_flush_rq(ctx, zcrx, &ctrl);
+	case ZCRX_CTRL_EXPORT:
+		return zcrx_export(ctx, zcrx, &ctrl, arg);
+	}
+
+	return -EOPNOTSUPP;
+}
+
 static bool io_zcrx_queue_cqe(struct io_kiocb *req, struct net_iov *niov,
 			      struct io_zcrx_ifq *ifq, int off, int len)
 {
@@ -1082,13 +1294,15 @@ static int io_zcrx_recv_frag(struct io_kiocb *req, struct io_zcrx_ifq *ifq,
 			     const skb_frag_t *frag, int off, int len)
 {
 	struct net_iov *niov;
+	struct page_pool *pp;
 
 	if (unlikely(!skb_frag_is_net_iov(frag)))
 		return io_zcrx_copy_frag(req, ifq, frag, off, len);
 
 	niov = netmem_to_net_iov(frag->netmem);
-	if (!niov->pp || niov->pp->mp_ops != &io_uring_pp_zc_ops ||
-	    io_pp_to_ifq(niov->pp) != ifq)
+	pp = niov->desc.pp;
+
+	if (!pp || pp->mp_ops != &io_uring_pp_zc_ops || io_pp_to_ifq(pp) != ifq)
 		return -EFAULT;
 
 	if (!io_zcrx_queue_cqe(req, niov, ifq, off + skb_frag_off(frag), len))

io_uring/zcrx.h

@@ -55,6 +55,8 @@ struct io_zcrx_ifq {
 	struct net_device		*netdev;
 	netdevice_tracker		netdev_tracker;
 	refcount_t			refs;
+	/* counts userspace facing users like io_uring */
+	refcount_t			user_refs;
 
 	/*
 	 * Page pool and net configuration lock, can be taken deeper in the
@@ -65,6 +67,7 @@ struct io_zcrx_ifq {
 };
 
 #if defined(CONFIG_IO_URING_ZCRX)
+int io_zcrx_ctrl(struct io_ring_ctx *ctx, void __user *arg, unsigned nr_arg);
 int io_register_zcrx_ifq(struct io_ring_ctx *ctx,
 			 struct io_uring_zcrx_ifq_reg __user *arg);
 void io_unregister_zcrx_ifqs(struct io_ring_ctx *ctx);
@@ -93,6 +96,11 @@ static inline struct io_mapped_region *io_zcrx_get_region(struct io_ring_ctx *ct
 {
 	return NULL;
 }
+static inline int io_zcrx_ctrl(struct io_ring_ctx *ctx,
+				void __user *arg, unsigned nr_arg)
+{
+	return -EOPNOTSUPP;
+}
 #endif
 
 int io_recvzc(struct io_kiocb *req, unsigned int issue_flags);