From db1e1adf6f993b1c2cef605d86eff709a8db5052 Mon Sep 17 00:00:00 2001 From: Olivier Langlois Date: Sun, 13 Oct 2024 14:29:02 -0400 Subject: [PATCH] io_uring/napi: Use lock guards Convert napi locks to use the shiny new Scope-Based Resource Management machinery. Signed-off-by: Olivier Langlois Link: https://lore.kernel.org/r/2680ca47ee183cfdb89d1a40c84d349edeb620ab.1728828877.git.olivier@trillion01.com Signed-off-by: Jens Axboe --- io_uring/napi.c | 40 +++++++++++++++++++++------------------- 1 file changed, 21 insertions(+), 19 deletions(-) diff --git a/io_uring/napi.c b/io_uring/napi.c index 5e2299e7ff8e..6d5fdd397f2f 100644 --- a/io_uring/napi.c +++ b/io_uring/napi.c @@ -49,14 +49,13 @@ int __io_napi_add_id(struct io_ring_ctx *ctx, unsigned int napi_id) hash_list = &ctx->napi_ht[hash_min(napi_id, HASH_BITS(ctx->napi_ht))]; - rcu_read_lock(); - e = io_napi_hash_find(hash_list, napi_id); - if (e) { - WRITE_ONCE(e->timeout, jiffies + NAPI_TIMEOUT); - rcu_read_unlock(); - return -EEXIST; + scoped_guard(rcu) { + e = io_napi_hash_find(hash_list, napi_id); + if (e) { + WRITE_ONCE(e->timeout, jiffies + NAPI_TIMEOUT); + return -EEXIST; + } } - rcu_read_unlock(); e = kmalloc(sizeof(*e), GFP_NOWAIT); if (!e) @@ -65,6 +64,10 @@ int __io_napi_add_id(struct io_ring_ctx *ctx, unsigned int napi_id) e->napi_id = napi_id; e->timeout = jiffies + NAPI_TIMEOUT; + /* + * guard(spinlock) is not used to manually unlock it before calling + * kfree() + */ spin_lock(&ctx->napi_lock); if (unlikely(io_napi_hash_find(hash_list, napi_id))) { spin_unlock(&ctx->napi_lock); @@ -82,7 +85,7 @@ static void __io_napi_remove_stale(struct io_ring_ctx *ctx) { struct io_napi_entry *e; - spin_lock(&ctx->napi_lock); + guard(spinlock)(&ctx->napi_lock); /* * list_for_each_entry_safe() is not required as long as: * 1. list_del_rcu() does not reset the deleted node next pointer @@ -96,7 +99,6 @@ static void __io_napi_remove_stale(struct io_ring_ctx *ctx) kfree_rcu(e, rcu); } } - spin_unlock(&ctx->napi_lock); } static inline void io_napi_remove_stale(struct io_ring_ctx *ctx, bool is_stale) @@ -168,11 +170,12 @@ static void io_napi_blocking_busy_loop(struct io_ring_ctx *ctx, if (list_is_singular(&ctx->napi_list)) loop_end_arg = iowq; - rcu_read_lock(); - do { - is_stale = __io_napi_do_busy_loop(ctx, loop_end_arg); - } while (!io_napi_busy_loop_should_end(iowq, start_time) && !loop_end_arg); - rcu_read_unlock(); + scoped_guard(rcu) { + do { + is_stale = __io_napi_do_busy_loop(ctx, loop_end_arg); + } while (!io_napi_busy_loop_should_end(iowq, start_time) && + !loop_end_arg); + } io_napi_remove_stale(ctx, is_stale); } @@ -203,13 +206,12 @@ void io_napi_free(struct io_ring_ctx *ctx) { struct io_napi_entry *e; - spin_lock(&ctx->napi_lock); + guard(spinlock)(&ctx->napi_lock); list_for_each_entry(e, &ctx->napi_list, list) { hash_del_rcu(&e->node); kfree_rcu(e, rcu); } INIT_LIST_HEAD_RCU(&ctx->napi_list); - spin_unlock(&ctx->napi_lock); } /* @@ -305,9 +307,9 @@ int io_napi_sqpoll_busy_poll(struct io_ring_ctx *ctx) if (list_empty_careful(&ctx->napi_list)) return 0; - rcu_read_lock(); - is_stale = __io_napi_do_busy_loop(ctx, NULL); - rcu_read_unlock(); + scoped_guard(rcu) { + is_stale = __io_napi_do_busy_loop(ctx, NULL); + } io_napi_remove_stale(ctx, is_stale); return 1;