// SPDX-License-Identifier: GPL-2.0 #include "io_uring.h"#include "napi.h" #ifdef CONFIG_NET_RX_BUSY_POLL /* Timeout for cleanout of stale entries. */#define NAPI_TIMEOUT		(60 * SEC_CONVERSION) struct io_napi_entry {	unsigned int		napi_id;	struct list_head	list; 	unsigned long		timeout;	struct hlist_node	node; 	struct rcu_head		rcu;}; static struct io_napi_entry *io_napi_hash_find(struct hlist_head *hash_list,					       unsigned int napi_id){	struct io_napi_entry *e; 	hlist_for_each_entry_rcu(e, hash_list, node) {		if (e->napi_id != napi_id)			continue;		e->timeout = jiffies + NAPI_TIMEOUT;		return e;	} 	return NULL;} void __io_napi_add(struct io_ring_ctx *ctx, struct socket *sock){	struct hlist_head *hash_list;	unsigned int napi_id;	struct sock *sk;	struct io_napi_entry *e; 	sk = sock->sk;	if (!sk)		return; 	napi_id = READ_ONCE(sk->sk_napi_id); 	/* Non-NAPI IDs can be rejected. */	if (napi_id < MIN_NAPI_ID)		return; 	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) {		e->timeout = jiffies + NAPI_TIMEOUT;		rcu_read_unlock();		return;	}	rcu_read_unlock(); 	e = kmalloc(sizeof(*e), GFP_NOWAIT);	if (!e)		return; 	e->napi_id = napi_id;	e->timeout = jiffies + NAPI_TIMEOUT; 	spin_lock(&ctx->napi_lock);	if (unlikely(io_napi_hash_find(hash_list, napi_id))) {		spin_unlock(&ctx->napi_lock);		kfree(e);		return;	} 	hlist_add_tail_rcu(&e->node, hash_list);	list_add_tail(&e->list, &ctx->napi_list);	spin_unlock(&ctx->napi_lock);} static void __io_napi_remove_stale(struct io_ring_ctx *ctx){	struct io_napi_entry *e;	unsigned int i; 	spin_lock(&ctx->napi_lock);	hash_for_each(ctx->napi_ht, i, e, node) {		if (time_after(jiffies, e->timeout)) {			list_del(&e->list);			hash_del_rcu(&e->node);			kfree_rcu(e, rcu);		}	}	spin_unlock(&ctx->napi_lock);} static inline void io_napi_remove_stale(struct io_ring_ctx *ctx, bool is_stale){	if (is_stale)		__io_napi_remove_stale(ctx);} static inline bool io_napi_busy_loop_timeout(unsigned long start_time,					     unsigned long bp_usec){	if (bp_usec) {		unsigned long end_time = start_time + bp_usec;		unsigned long now = busy_loop_current_time(); 		return time_after(now, end_time);	} 	return true;} static bool io_napi_busy_loop_should_end(void *data,					 unsigned long start_time){	struct io_wait_queue *iowq = data; 	if (signal_pending(current))		return true;	if (io_should_wake(iowq) || io_has_work(iowq->ctx))		return true;	if (io_napi_busy_loop_timeout(start_time, iowq->napi_busy_poll_to))		return true; 	return false;} static bool __io_napi_do_busy_loop(struct io_ring_ctx *ctx,				   void *loop_end_arg){	struct io_napi_entry *e;	bool (*loop_end)(void *, unsigned long) = NULL;	bool is_stale = false; 	if (loop_end_arg)		loop_end = io_napi_busy_loop_should_end; 	list_for_each_entry_rcu(e, &ctx->napi_list, list) {		napi_busy_loop_rcu(e->napi_id, loop_end, loop_end_arg,				   ctx->napi_prefer_busy_poll, BUSY_POLL_BUDGET); 		if (time_after(jiffies, e->timeout))			is_stale = true;	} 	return is_stale;} static void io_napi_blocking_busy_loop(struct io_ring_ctx *ctx,				       struct io_wait_queue *iowq){	unsigned long start_time = busy_loop_current_time();	void *loop_end_arg = NULL;	bool is_stale = false; 	/* Singular lists use a different napi loop end check function and are	 * only executed once.	 */	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(); 	io_napi_remove_stale(ctx, is_stale);} /* * io_napi_init() - Init napi settings * @ctx: pointer to io-uring context structure * * Init napi settings in the io-uring context. */void io_napi_init(struct io_ring_ctx *ctx){	INIT_LIST_HEAD(&ctx->napi_list);	spin_lock_init(&ctx->napi_lock);	ctx->napi_prefer_busy_poll = false;	ctx->napi_busy_poll_to = READ_ONCE(sysctl_net_busy_poll);} /* * io_napi_free() - Deallocate napi * @ctx: pointer to io-uring context structure * * Free the napi list and the hash table in the io-uring context. */void io_napi_free(struct io_ring_ctx *ctx){	struct io_napi_entry *e;	LIST_HEAD(napi_list);	unsigned int i; 	spin_lock(&ctx->napi_lock);	hash_for_each(ctx->napi_ht, i, e, node) {		hash_del_rcu(&e->node);		kfree_rcu(e, rcu);	}	spin_unlock(&ctx->napi_lock);} /* * io_napi_register() - Register napi with io-uring * @ctx: pointer to io-uring context structure * @arg: pointer to io_uring_napi structure * * Register napi in the io-uring context. */int io_register_napi(struct io_ring_ctx *ctx, void __user *arg){	const struct io_uring_napi curr = {		.busy_poll_to 	  = ctx->napi_busy_poll_to,		.prefer_busy_poll = ctx->napi_prefer_busy_poll	};	struct io_uring_napi napi; 	if (copy_from_user(&napi, arg, sizeof(napi)))		return -EFAULT;	if (napi.pad[0] || napi.pad[1] || napi.pad[2] || napi.resv)		return -EINVAL; 	if (copy_to_user(arg, &curr, sizeof(curr)))		return -EFAULT; 	WRITE_ONCE(ctx->napi_busy_poll_to, napi.busy_poll_to);	WRITE_ONCE(ctx->napi_prefer_busy_poll, !!napi.prefer_busy_poll);	WRITE_ONCE(ctx->napi_enabled, true);	return 0;} /* * io_napi_unregister() - Unregister napi with io-uring * @ctx: pointer to io-uring context structure * @arg: pointer to io_uring_napi structure * * Unregister napi. If arg has been specified copy the busy poll timeout and * prefer busy poll setting to the passed in structure. */int io_unregister_napi(struct io_ring_ctx *ctx, void __user *arg){	const struct io_uring_napi curr = {		.busy_poll_to 	  = ctx->napi_busy_poll_to,		.prefer_busy_poll = ctx->napi_prefer_busy_poll	}; 	if (arg && copy_to_user(arg, &curr, sizeof(curr)))		return -EFAULT; 	WRITE_ONCE(ctx->napi_busy_poll_to, 0);	WRITE_ONCE(ctx->napi_prefer_busy_poll, false);	WRITE_ONCE(ctx->napi_enabled, false);	return 0;} /* * __io_napi_adjust_timeout() - Add napi id to the busy poll list * @ctx: pointer to io-uring context structure * @iowq: pointer to io wait queue * @ts: pointer to timespec or NULL * * Adjust the busy loop timeout according to timespec and busy poll timeout. */void __io_napi_adjust_timeout(struct io_ring_ctx *ctx, struct io_wait_queue *iowq,			      struct timespec64 *ts){	unsigned int poll_to = READ_ONCE(ctx->napi_busy_poll_to); 	if (ts) {		struct timespec64 poll_to_ts = ns_to_timespec64(1000 * (s64)poll_to); 		if (timespec64_compare(ts, &poll_to_ts) > 0) {			*ts = timespec64_sub(*ts, poll_to_ts);		} else {			u64 to = timespec64_to_ns(ts); 			do_div(to, 1000);			ts->tv_sec = 0;			ts->tv_nsec = 0;		}	} 	iowq->napi_busy_poll_to = poll_to;} /* * __io_napi_busy_loop() - execute busy poll loop * @ctx: pointer to io-uring context structure * @iowq: pointer to io wait queue * * Execute the busy poll loop and merge the spliced off list. */void __io_napi_busy_loop(struct io_ring_ctx *ctx, struct io_wait_queue *iowq){	iowq->napi_prefer_busy_poll = READ_ONCE(ctx->napi_prefer_busy_poll); 	if (!(ctx->flags & IORING_SETUP_SQPOLL) && ctx->napi_enabled)		io_napi_blocking_busy_loop(ctx, iowq);} /* * io_napi_sqpoll_busy_poll() - busy poll loop for sqpoll * @ctx: pointer to io-uring context structure * * Splice of the napi list and execute the napi busy poll loop. */int io_napi_sqpoll_busy_poll(struct io_ring_ctx *ctx){	LIST_HEAD(napi_list);	bool is_stale = false; 	if (!READ_ONCE(ctx->napi_busy_poll_to))		return 0;	if (list_empty_careful(&ctx->napi_list))		return 0; 	rcu_read_lock();	is_stale = __io_napi_do_busy_loop(ctx, NULL);	rcu_read_unlock(); 	io_napi_remove_stale(ctx, is_stale);	return 1;} #endif