Commit db1e1adf authored by Olivier Langlois's avatar Olivier Langlois Committed by Jens Axboe
Browse files

io_uring/napi: Use lock guards 



Convert napi locks to use the shiny new Scope-Based Resource Management
machinery.

Signed-off-by: default avatarOlivier Langlois <olivier@trillion01.com>
Link: https://lore.kernel.org/r/2680ca47ee183cfdb89d1a40c84d349edeb620ab.1728828877.git.olivier@trillion01.com


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent a5e26f49

io_uring/napi.c

+21 −19
Original line number Diff line number Diff line
@@ -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();

	scoped_guard(rcu) {

		e = io_napi_hash_find(hash_list, napi_id);

		if (e) {

			WRITE_ONCE(e->timeout, jiffies + NAPI_TIMEOUT);

		rcu_read_unlock();

			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();

	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);

	rcu_read_unlock();

		} 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();

	scoped_guard(rcu) {

		is_stale = __io_napi_do_busy_loop(ctx, NULL);

	rcu_read_unlock();

	}



	io_napi_remove_stale(ctx, is_stale);

	return 1;