1 files changed, 188 insertions, 46 deletions

diff --git a/io_uring/sqpoll.c b/io_uring/sqpoll.c
index 559652380672..74c1a130cd87 100644
--- a/io_uring/sqpoll.c
+++ b/io_uring/sqpoll.c
@@ -10,14 +10,20 @@
 #include <linux/slab.h>
 #include <linux/audit.h>
 #include <linux/security.h>
+#include <linux/cpuset.h>
+#include <linux/sched/cputime.h>
 #include <linux/io_uring.h>
 
 #include <uapi/linux/io_uring.h>
 
 #include "io_uring.h"
+#include "tctx.h"
+#include "napi.h"
+#include "cancel.h"
 #include "sqpoll.h"
 
 #define IORING_SQPOLL_CAP_ENTRIES_VALUE 8
+#define IORING_TW_CAP_ENTRIES_VALUE	32
 
 enum {
 	IO_SQ_THREAD_SHOULD_STOP = 0,
@@ -27,7 +33,7 @@ enum {
 void io_sq_thread_unpark(struct io_sq_data *sqd)
 	__releases(&sqd->lock)
 {
-	WARN_ON_ONCE(sqd->thread == current);
+	WARN_ON_ONCE(sqpoll_task_locked(sqd) == current);
 
 	/*
 	 * Do the dance but not conditional clear_bit() because it'd race with
@@ -37,29 +43,38 @@ void io_sq_thread_unpark(struct io_sq_data *sqd)
 	if (atomic_dec_return(&sqd->park_pending))
 		set_bit(IO_SQ_THREAD_SHOULD_PARK, &sqd->state);
 	mutex_unlock(&sqd->lock);
+	wake_up(&sqd->wait);
 }
 
 void io_sq_thread_park(struct io_sq_data *sqd)
 	__acquires(&sqd->lock)
 {
-	WARN_ON_ONCE(sqd->thread == current);
+	struct task_struct *tsk;
 
 	atomic_inc(&sqd->park_pending);
 	set_bit(IO_SQ_THREAD_SHOULD_PARK, &sqd->state);
 	mutex_lock(&sqd->lock);
-	if (sqd->thread)
-		wake_up_process(sqd->thread);
+
+	tsk = sqpoll_task_locked(sqd);
+	if (tsk) {
+		WARN_ON_ONCE(tsk == current);
+		wake_up_process(tsk);
+	}
 }
 
 void io_sq_thread_stop(struct io_sq_data *sqd)
 {
-	WARN_ON_ONCE(sqd->thread == current);
+	struct task_struct *tsk;
+
 	WARN_ON_ONCE(test_bit(IO_SQ_THREAD_SHOULD_STOP, &sqd->state));
 
 	set_bit(IO_SQ_THREAD_SHOULD_STOP, &sqd->state);
 	mutex_lock(&sqd->lock);
-	if (sqd->thread)
-		wake_up_process(sqd->thread);
+	tsk = sqpoll_task_locked(sqd);
+	if (tsk) {
+		WARN_ON_ONCE(tsk == current);
+		wake_up_process(tsk);
+	}
 	mutex_unlock(&sqd->lock);
 	wait_for_completion(&sqd->exited);
 }
@@ -103,29 +118,21 @@ static struct io_sq_data *io_attach_sq_data(struct io_uring_params *p)
 {
 	struct io_ring_ctx *ctx_attach;
 	struct io_sq_data *sqd;
-	struct fd f;
+	CLASS(fd, f)(p->wq_fd);
 
-	f = fdget(p->wq_fd);
-	if (!f.file)
+	if (fd_empty(f))
 		return ERR_PTR(-ENXIO);
-	if (!io_is_uring_fops(f.file)) {
-		fdput(f);
+	if (!io_is_uring_fops(fd_file(f)))
 		return ERR_PTR(-EINVAL);
-	}
 
-	ctx_attach = f.file->private_data;
+	ctx_attach = fd_file(f)->private_data;
 	sqd = ctx_attach->sq_data;
-	if (!sqd) {
-		fdput(f);
+	if (!sqd)
 		return ERR_PTR(-EINVAL);
-	}
-	if (sqd->task_tgid != current->tgid) {
-		fdput(f);
+	if (sqd->task_tgid != current->tgid)
 		return ERR_PTR(-EPERM);
-	}
 
 	refcount_inc(&sqd->refs);
-	fdput(f);
 	return sqd;
 }
 
@@ -164,7 +171,38 @@ static inline bool io_sqd_events_pending(struct io_sq_data *sqd)
 	return READ_ONCE(sqd->state);
 }
 
-static int __io_sq_thread(struct io_ring_ctx *ctx, bool cap_entries)
+struct io_sq_time {
+	bool started;
+	u64 usec;
+};
+
+u64 io_sq_cpu_usec(struct task_struct *tsk)
+{
+	u64 utime, stime;
+
+	task_cputime_adjusted(tsk, &utime, &stime);
+	do_div(stime, 1000);
+	return stime;
+}
+
+static void io_sq_update_worktime(struct io_sq_data *sqd, struct io_sq_time *ist)
+{
+	if (!ist->started)
+		return;
+	ist->started = false;
+	sqd->work_time += io_sq_cpu_usec(current) - ist->usec;
+}
+
+static void io_sq_start_worktime(struct io_sq_time *ist)
+{
+	if (ist->started)
+		return;
+	ist->started = true;
+	ist->usec = io_sq_cpu_usec(current);
+}
+
+static int __io_sq_thread(struct io_ring_ctx *ctx, struct io_sq_data *sqd,
+			  bool cap_entries, struct io_sq_time *ist)
 {
 	unsigned int to_submit;
 	int ret = 0;
@@ -174,9 +212,11 @@ static int __io_sq_thread(struct io_ring_ctx *ctx, bool cap_entries)
 	if (cap_entries && to_submit > IORING_SQPOLL_CAP_ENTRIES_VALUE)
 		to_submit = IORING_SQPOLL_CAP_ENTRIES_VALUE;
 
-	if (!wq_list_empty(&ctx->iopoll_list) || to_submit) {
+	if (to_submit || !wq_list_empty(&ctx->iopoll_list)) {
 		const struct cred *creds = NULL;
 
+		io_sq_start_worktime(ist);
+
 		if (ctx->sq_creds != current_cred())
 			creds = override_creds(ctx->sq_creds);
 
@@ -212,32 +252,87 @@ static bool io_sqd_handle_event(struct io_sq_data *sqd)
 		mutex_unlock(&sqd->lock);
 		if (signal_pending(current))
 			did_sig = get_signal(&ksig);
-		cond_resched();
+		wait_event(sqd->wait, !atomic_read(&sqd->park_pending));
 		mutex_lock(&sqd->lock);
+		sqd->sq_cpu = raw_smp_processor_id();
 	}
 	return did_sig || test_bit(IO_SQ_THREAD_SHOULD_STOP, &sqd->state);
 }
 
+/*
+ * Run task_work, processing the retry_list first. The retry_list holds
+ * entries that we passed on in the previous run, if we had more task_work
+ * than we were asked to process. Newly queued task_work isn't run until the
+ * retry list has been fully processed.
+ */
+static unsigned int io_sq_tw(struct llist_node **retry_list, int max_entries)
+{
+	struct io_uring_task *tctx = current->io_uring;
+	unsigned int count = 0;
+
+	if (*retry_list) {
+		*retry_list = io_handle_tw_list(*retry_list, &count, max_entries);
+		if (count >= max_entries)
+			goto out;
+		max_entries -= count;
+	}
+	*retry_list = tctx_task_work_run(tctx, max_entries, &count);
+out:
+	if (task_work_pending(current))
+		task_work_run();
+	return count;
+}
+
+static bool io_sq_tw_pending(struct llist_node *retry_list)
+{
+	struct io_uring_task *tctx = current->io_uring;
+
+	return retry_list || !llist_empty(&tctx->task_list);
+}
+
 static int io_sq_thread(void *data)
 {
+	struct llist_node *retry_list = NULL;
 	struct io_sq_data *sqd = data;
 	struct io_ring_ctx *ctx;
 	unsigned long timeout = 0;
-	char buf[TASK_COMM_LEN];
+	char buf[TASK_COMM_LEN] = {};
 	DEFINE_WAIT(wait);
 
+	/* offload context creation failed, just exit */
+	if (!current->io_uring) {
+		mutex_lock(&sqd->lock);
+		rcu_assign_pointer(sqd->thread, NULL);
+		put_task_struct(current);
+		mutex_unlock(&sqd->lock);
+		goto err_out;
+	}
+
 	snprintf(buf, sizeof(buf), "iou-sqp-%d", sqd->task_pid);
 	set_task_comm(current, buf);
 
-	if (sqd->sq_cpu != -1)
+	/* reset to our pid after we've set task_comm, for fdinfo */
+	sqd->task_pid = current->pid;
+
+	if (sqd->sq_cpu != -1) {
 		set_cpus_allowed_ptr(current, cpumask_of(sqd->sq_cpu));
-	else
+	} else {
 		set_cpus_allowed_ptr(current, cpu_online_mask);
-	current->flags |= PF_NO_SETAFFINITY;
+		sqd->sq_cpu = raw_smp_processor_id();
+	}
+
+	/*
+	 * Force audit context to get setup, in case we do prep side async
+	 * operations that would trigger an audit call before any issue side
+	 * audit has been done.
+	 */
+	audit_uring_entry(IORING_OP_NOP);
+	audit_uring_exit(true, 0);
 
 	mutex_lock(&sqd->lock);
 	while (1) {
 		bool cap_entries, sqt_spin = false;
+		struct io_sq_time ist = { };
 
 		if (io_sqd_events_pending(sqd) || signal_pending(current)) {
 			if (io_sqd_handle_event(sqd))
@@ -247,23 +342,37 @@ static int io_sq_thread(void *data)
 
 		cap_entries = !list_is_singular(&sqd->ctx_list);
 		list_for_each_entry(ctx, &sqd->ctx_list, sqd_list) {
-			int ret = __io_sq_thread(ctx, cap_entries);
+			int ret = __io_sq_thread(ctx, sqd, cap_entries, &ist);
 
 			if (!sqt_spin && (ret > 0 || !wq_list_empty(&ctx->iopoll_list)))
 				sqt_spin = true;
 		}
-		if (io_run_task_work())
+		if (io_sq_tw(&retry_list, IORING_TW_CAP_ENTRIES_VALUE))
 			sqt_spin = true;
 
+		list_for_each_entry(ctx, &sqd->ctx_list, sqd_list) {
+			if (io_napi(ctx)) {
+				io_sq_start_worktime(&ist);
+				io_napi_sqpoll_busy_poll(ctx);
+			}
+		}
+
+		io_sq_update_worktime(sqd, &ist);
+
 		if (sqt_spin || !time_after(jiffies, timeout)) {
-			cond_resched();
 			if (sqt_spin)
 				timeout = jiffies + sqd->sq_thread_idle;
+			if (unlikely(need_resched())) {
+				mutex_unlock(&sqd->lock);
+				cond_resched();
+				mutex_lock(&sqd->lock);
+				sqd->sq_cpu = raw_smp_processor_id();
+			}
 			continue;
 		}
 
 		prepare_to_wait(&sqd->wait, &wait, TASK_INTERRUPTIBLE);
-		if (!io_sqd_events_pending(sqd) && !task_work_pending(current)) {
+		if (!io_sqd_events_pending(sqd) && !io_sq_tw_pending(retry_list)) {
 			bool needs_sched = true;
 
 			list_for_each_entry(ctx, &sqd->ctx_list, sqd_list) {
@@ -291,6 +400,7 @@ static int io_sq_thread(void *data)
 				mutex_unlock(&sqd->lock);
 				schedule();
 				mutex_lock(&sqd->lock);
+				sqd->sq_cpu = raw_smp_processor_id();
 			}
 			list_for_each_entry(ctx, &sqd->ctx_list, sqd_list)
 				atomic_andnot(IORING_SQ_NEED_WAKEUP,
@@ -301,18 +411,22 @@ static int io_sq_thread(void *data)
 		timeout = jiffies + sqd->sq_thread_idle;
 	}
 
+	if (retry_list)
+		io_sq_tw(&retry_list, UINT_MAX);
+
 	io_uring_cancel_generic(true, sqd);
-	sqd->thread = NULL;
+	rcu_assign_pointer(sqd->thread, NULL);
+	put_task_struct(current);
 	list_for_each_entry(ctx, &sqd->ctx_list, sqd_list)
 		atomic_or(IORING_SQ_NEED_WAKEUP, &ctx->rings->sq_flags);
 	io_run_task_work();
 	mutex_unlock(&sqd->lock);
-
+err_out:
 	complete(&sqd->exited);
 	do_exit(0);
 }
 
-int io_sqpoll_wait_sq(struct io_ring_ctx *ctx)
+void io_sqpoll_wait_sq(struct io_ring_ctx *ctx)
 {
 	DEFINE_WAIT(wait);
 
@@ -327,7 +441,6 @@ int io_sqpoll_wait_sq(struct io_ring_ctx *ctx)
 	} while (!signal_pending(current));
 
 	finish_wait(&ctx->sqo_sq_wait, &wait);
-	return 0;
 }
 
 __cold int io_sq_offload_create(struct io_ring_ctx *ctx,
@@ -338,16 +451,11 @@ __cold int io_sq_offload_create(struct io_ring_ctx *ctx,
 	/* Retain compatibility with failing for an invalid attach attempt */
 	if ((ctx->flags & (IORING_SETUP_ATTACH_WQ | IORING_SETUP_SQPOLL)) ==
 				IORING_SETUP_ATTACH_WQ) {
-		struct fd f;
-
-		f = fdget(p->wq_fd);
-		if (!f.file)
+		CLASS(fd, f)(p->wq_fd);
+		if (fd_empty(f))
 			return -ENXIO;
-		if (!io_is_uring_fops(f.file)) {
-			fdput(f);
+		if (!io_is_uring_fops(fd_file(f)))
 			return -EINVAL;
-		}
-		fdput(f);
 	}
 	if (ctx->flags & IORING_SETUP_SQPOLL) {
 		struct task_struct *tsk;
@@ -383,11 +491,22 @@ __cold int io_sq_offload_create(struct io_ring_ctx *ctx,
 			return 0;
 
 		if (p->flags & IORING_SETUP_SQ_AFF) {
+			cpumask_var_t allowed_mask;
 			int cpu = p->sq_thread_cpu;
 
 			ret = -EINVAL;
 			if (cpu >= nr_cpu_ids || !cpu_online(cpu))
 				goto err_sqpoll;
+			ret = -ENOMEM;
+			if (!alloc_cpumask_var(&allowed_mask, GFP_KERNEL))
+				goto err_sqpoll;
+			ret = -EINVAL;
+			cpuset_cpus_allowed(current, allowed_mask);
+			if (!cpumask_test_cpu(cpu, allowed_mask)) {
+				free_cpumask_var(allowed_mask);
+				goto err_sqpoll;
+			}
+			free_cpumask_var(allowed_mask);
 			sqd->sq_cpu = cpu;
 		} else {
 			sqd->sq_cpu = -1;
@@ -401,7 +520,11 @@ __cold int io_sq_offload_create(struct io_ring_ctx *ctx,
 			goto err_sqpoll;
 		}
 
-		sqd->thread = tsk;
+		mutex_lock(&sqd->lock);
+		rcu_assign_pointer(sqd->thread, tsk);
+		mutex_unlock(&sqd->lock);
+
+		get_task_struct(tsk);
 		ret = io_uring_alloc_task_context(tsk, ctx);
 		wake_up_new_task(tsk);
 		if (ret)
@@ -411,7 +534,6 @@ __cold int io_sq_offload_create(struct io_ring_ctx *ctx,
 		ret = -EINVAL;
 		goto err;
 	}
-
 	return 0;
 err_sqpoll:
 	complete(&ctx->sq_data->exited);
@@ -419,3 +541,23 @@ err:
 	io_sq_thread_finish(ctx);
 	return ret;
 }
+
+__cold int io_sqpoll_wq_cpu_affinity(struct io_ring_ctx *ctx,
+				     cpumask_var_t mask)
+{
+	struct io_sq_data *sqd = ctx->sq_data;
+	int ret = -EINVAL;
+
+	if (sqd) {
+		struct task_struct *tsk;
+
+		io_sq_thread_park(sqd);
+		/* Don't set affinity for a dying thread */
+		tsk = sqpoll_task_locked(sqd);
+		if (tsk)
+			ret = io_wq_cpu_affinity(tsk->io_uring, mask);
+		io_sq_thread_unpark(sqd);
+	}
+
+	return ret;
+}