From: Pavel Begunkov <[email protected]> zcrx will need to have a pointer to an owning ctx to communicate different events. Reference the ctx while it's attached to zcrx, and rely on zcrx termination to drop the ctx to avoid circular ref deps.
Co-developed-by: Vishwanath Seshagiri <[email protected]> Signed-off-by: Pavel Begunkov <[email protected]> --- io_uring/zcrx.c | 39 +++++++++++++++++++++++++++++++-------- io_uring/zcrx.h | 3 +++ 2 files changed, 34 insertions(+), 8 deletions(-) diff --git a/io_uring/zcrx.c b/io_uring/zcrx.c index 3f9632e7790a..34faf90423f4 100644 --- a/io_uring/zcrx.c +++ b/io_uring/zcrx.c @@ -44,6 +44,17 @@ static inline struct io_zcrx_area *io_zcrx_iov_to_area(const struct net_iov *nio return container_of(owner, struct io_zcrx_area, nia); } +static bool zcrx_set_ring_ctx(struct io_zcrx_ifq *zcrx, + struct io_ring_ctx *ctx) +{ + guard(spinlock_bh)(&zcrx->ctx_lock); + if (zcrx->master_ctx) + return false; + percpu_ref_get(&ctx->refs); + zcrx->master_ctx = ctx; + return true; +} + static inline struct page *io_zcrx_iov_page(const struct net_iov *niov) { struct io_zcrx_area *area = io_zcrx_iov_to_area(niov); @@ -531,6 +542,7 @@ static struct io_zcrx_ifq *io_zcrx_ifq_alloc(struct io_ring_ctx *ctx) return NULL; ifq->if_rxq = -1; + spin_lock_init(&ifq->ctx_lock); spin_lock_init(&ifq->rq.lock); mutex_init(&ifq->pp_lock); refcount_set(&ifq->refs, 1); @@ -580,6 +592,8 @@ static void io_zcrx_ifq_free(struct io_zcrx_ifq *ifq) return; if (WARN_ON_ONCE(ifq->netdev != NULL)) return; + if (WARN_ON_ONCE(ifq->master_ctx)) + return; if (ifq->area) io_zcrx_free_area(ifq, ifq->area); @@ -656,17 +670,24 @@ static void io_zcrx_scrub(struct io_zcrx_ifq *ifq) } } -static void zcrx_unregister_user(struct io_zcrx_ifq *ifq) +static void zcrx_unregister_user(struct io_zcrx_ifq *ifq, struct io_ring_ctx *ctx) { + scoped_guard(spinlock_bh, &ifq->ctx_lock) { + if (ctx && ifq->master_ctx == ctx) { + ifq->master_ctx = NULL; + percpu_ref_put(&ctx->refs); + } + } + if (refcount_dec_and_test(&ifq->user_refs)) { io_close_queue(ifq); io_zcrx_scrub(ifq); } } -static void zcrx_unregister(struct io_zcrx_ifq *ifq) +static void zcrx_unregister(struct io_zcrx_ifq *ifq, struct io_ring_ctx *ctx) { - zcrx_unregister_user(ifq); + zcrx_unregister_user(ifq, ctx); io_put_zcrx_ifq(ifq); } @@ -686,7 +707,7 @@ static int zcrx_box_release(struct inode *inode, struct file *file) if (WARN_ON_ONCE(!ifq)) return -EFAULT; - zcrx_unregister(ifq); + zcrx_unregister(ifq, NULL); return 0; } @@ -711,7 +732,7 @@ static int zcrx_export(struct io_ring_ctx *ctx, struct io_zcrx_ifq *ifq, file = anon_inode_create_getfile("[zcrx]", &zcrx_box_fops, ifq, O_CLOEXEC, NULL); if (IS_ERR(file)) { - zcrx_unregister(ifq); + zcrx_unregister(ifq, NULL); return PTR_ERR(file); } @@ -787,7 +808,7 @@ static int import_zcrx(struct io_ring_ctx *ctx, scoped_guard(mutex, &ctx->mmap_lock) xa_erase(&ctx->zcrx_ctxs, id); err: - zcrx_unregister(ifq); + zcrx_unregister(ifq, ctx); return ret; } @@ -932,12 +953,14 @@ int io_register_zcrx(struct io_ring_ctx *ctx, ret = -EFAULT; goto err; } + + zcrx_set_ring_ctx(ifq, ctx); return 0; err: scoped_guard(mutex, &ctx->mmap_lock) xa_erase(&ctx->zcrx_ctxs, id); ifq_free: - zcrx_unregister(ifq); + zcrx_unregister(ifq, ctx); return ret; } @@ -967,7 +990,7 @@ void io_terminate_zcrx(struct io_ring_ctx *ctx) break; set_zcrx_entry_mark(ctx, id); id++; - zcrx_unregister_user(ifq); + zcrx_unregister_user(ifq, ctx); } } diff --git a/io_uring/zcrx.h b/io_uring/zcrx.h index 9e1a6a1b11e8..6b565d0bf6da 100644 --- a/io_uring/zcrx.h +++ b/io_uring/zcrx.h @@ -73,6 +73,9 @@ struct io_zcrx_ifq { */ struct mutex pp_lock; struct io_mapped_region rq_region; + + spinlock_t ctx_lock; + struct io_ring_ctx *master_ctx; }; #if defined(CONFIG_IO_URING_ZCRX) -- 2.53.0-Meta
