1 files changed, 55 insertions, 57 deletions

diff --git a/sound/core/seq/seq_fifo.c b/sound/core/seq/seq_fifo.c
index 0d75afa786bc..91cce1890111 100644
--- a/sound/core/seq/seq_fifo.c
+++ b/sound/core/seq/seq_fifo.c
@@ -1,26 +1,13 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 /*
  *   ALSA sequencer FIFO
  *   Copyright (c) 1998 by Frank van de Pol <fvdpol@coil.demon.nl>
- *
- *
- *   This program is free software; you can redistribute it and/or modify
- *   it under the terms of the GNU General Public License as published by
- *   the Free Software Foundation; either version 2 of the License, or
- *   (at your option) any later version.
- *
- *   This program is distributed in the hope that it will be useful,
- *   but WITHOUT ANY WARRANTY; without even the implied warranty of
- *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- *   GNU General Public License for more details.
- *
- *   You should have received a copy of the GNU General Public License
- *   along with this program; if not, write to the Free Software
- *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
- *
  */
 
 #include <sound/core.h>
 #include <linux/slab.h>
+#include <linux/sched/signal.h>
+
 #include "seq_fifo.h"
 #include "seq_lock.h"
 
@@ -33,10 +20,8 @@ struct snd_seq_fifo *snd_seq_fifo_new(int poolsize)
 	struct snd_seq_fifo *f;
 
 	f = kzalloc(sizeof(*f), GFP_KERNEL);
-	if (f == NULL) {
-		snd_printd("malloc failed for snd_seq_fifo_new() \n");
+	if (!f)
 		return NULL;
-	}
 
 	f->pool = snd_seq_pool_new(poolsize);
 	if (f->pool == NULL) {
@@ -72,6 +57,9 @@ void snd_seq_fifo_delete(struct snd_seq_fifo **fifo)
 		return;
 	*fifo = NULL;
 
+	if (f->pool)
+		snd_seq_pool_mark_closing(f->pool);
+
 	snd_seq_fifo_clear(f);
 
 	/* wake up clients if any */
@@ -95,18 +83,16 @@ static struct snd_seq_event_cell *fifo_cell_out(struct snd_seq_fifo *f);
 void snd_seq_fifo_clear(struct snd_seq_fifo *f)
 {
 	struct snd_seq_event_cell *cell;
-	unsigned long flags;
 
 	/* clear overflow flag */
 	atomic_set(&f->overflow, 0);
 
 	snd_use_lock_sync(&f->use_lock);
-	spin_lock_irqsave(&f->lock, flags);
+	guard(spinlock_irq)(&f->lock);
 	/* drain the fifo */
 	while ((cell = fifo_cell_out(f)) != NULL) {
 		snd_seq_cell_free(cell);
 	}
-	spin_unlock_irqrestore(&f->lock, flags);
 }
 
 
@@ -115,37 +101,34 @@ int snd_seq_fifo_event_in(struct snd_seq_fifo *f,
 			  struct snd_seq_event *event)
 {
 	struct snd_seq_event_cell *cell;
-	unsigned long flags;
 	int err;
 
 	if (snd_BUG_ON(!f))
 		return -EINVAL;
 
-	snd_use_lock_use(&f->use_lock);
-	err = snd_seq_event_dup(f->pool, event, &cell, 1, NULL); /* always non-blocking */
+	guard(snd_seq_fifo)(f);
+	err = snd_seq_event_dup(f->pool, event, &cell, 1, NULL, NULL); /* always non-blocking */
 	if (err < 0) {
-		if (err == -ENOMEM)
+		if ((err == -ENOMEM) || (err == -EAGAIN))
 			atomic_inc(&f->overflow);
-		snd_use_lock_free(&f->use_lock);
 		return err;
 	}
 		
 	/* append new cells to fifo */
-	spin_lock_irqsave(&f->lock, flags);
-	if (f->tail != NULL)
-		f->tail->next = cell;
-	f->tail = cell;
-	if (f->head == NULL)
-		f->head = cell;
-	f->cells++;
-	spin_unlock_irqrestore(&f->lock, flags);
+	scoped_guard(spinlock_irqsave, &f->lock) {
+		if (f->tail != NULL)
+			f->tail->next = cell;
+		f->tail = cell;
+		if (f->head == NULL)
+			f->head = cell;
+		cell->next = NULL;
+		f->cells++;
+	}
 
 	/* wakeup client */
 	if (waitqueue_active(&f->input_sleep))
 		wake_up(&f->input_sleep);
 
-	snd_use_lock_free(&f->use_lock);
-
 	return 0; /* success */
 
 }
@@ -155,7 +138,8 @@ static struct snd_seq_event_cell *fifo_cell_out(struct snd_seq_fifo *f)
 {
 	struct snd_seq_event_cell *cell;
 
-	if ((cell = f->head) != NULL) {
+	cell = f->head;
+	if (cell) {
 		f->head = cell->next;
 
 		/* reset tail if this was the last element */
@@ -175,7 +159,7 @@ int snd_seq_fifo_cell_out(struct snd_seq_fifo *f,
 {
 	struct snd_seq_event_cell *cell;
 	unsigned long flags;
-	wait_queue_t wait;
+	wait_queue_entry_t wait;
 
 	if (snd_BUG_ON(!f))
 		return -EINVAL;
@@ -191,9 +175,9 @@ int snd_seq_fifo_cell_out(struct snd_seq_fifo *f,
 		}
 		set_current_state(TASK_INTERRUPTIBLE);
 		add_wait_queue(&f->input_sleep, &wait);
-		spin_unlock_irq(&f->lock);
+		spin_unlock_irqrestore(&f->lock, flags);
 		schedule();
-		spin_lock_irq(&f->lock);
+		spin_lock_irqsave(&f->lock, flags);
 		remove_wait_queue(&f->input_sleep, &wait);
 		if (signal_pending(current)) {
 			spin_unlock_irqrestore(&f->lock, flags);
@@ -210,14 +194,13 @@ int snd_seq_fifo_cell_out(struct snd_seq_fifo *f,
 void snd_seq_fifo_cell_putback(struct snd_seq_fifo *f,
 			       struct snd_seq_event_cell *cell)
 {
-	unsigned long flags;
-
 	if (cell) {
-		spin_lock_irqsave(&f->lock, flags);
+		guard(spinlock_irqsave)(&f->lock);
 		cell->next = f->head;
 		f->head = cell;
+		if (!f->tail)
+			f->tail = cell;
 		f->cells++;
-		spin_unlock_irqrestore(&f->lock, flags);
 	}
 }
 
@@ -227,13 +210,13 @@ int snd_seq_fifo_poll_wait(struct snd_seq_fifo *f, struct file *file,
 			   poll_table *wait)
 {
 	poll_wait(file, &f->input_sleep, wait);
+	guard(spinlock_irq)(&f->lock);
 	return (f->cells > 0);
 }
 
 /* change the size of pool; all old events are removed */
 int snd_seq_fifo_resize(struct snd_seq_fifo *f, int poolsize)
 {
-	unsigned long flags;
 	struct snd_seq_pool *newpool, *oldpool;
 	struct snd_seq_event_cell *cell, *next, *oldhead;
 
@@ -249,17 +232,21 @@ int snd_seq_fifo_resize(struct snd_seq_fifo *f, int poolsize)
 		return -ENOMEM;
 	}
 
-	spin_lock_irqsave(&f->lock, flags);
-	/* remember old pool */
-	oldpool = f->pool;
-	oldhead = f->head;
-	/* exchange pools */
-	f->pool = newpool;
-	f->head = NULL;
-	f->tail = NULL;
-	f->cells = 0;
-	/* NOTE: overflow flag is not cleared */
-	spin_unlock_irqrestore(&f->lock, flags);
+	scoped_guard(spinlock_irq, &f->lock) {
+		/* remember old pool */
+		oldpool = f->pool;
+		oldhead = f->head;
+		/* exchange pools */
+		f->pool = newpool;
+		f->head = NULL;
+		f->tail = NULL;
+		f->cells = 0;
+		/* NOTE: overflow flag is not cleared */
+	}
+
+	/* close the old pool and wait until all users are gone */
+	snd_seq_pool_mark_closing(oldpool);
+	snd_use_lock_sync(&f->use_lock);
 
 	/* release cells in old pool */
 	for (cell = oldhead; cell; cell = next) {
@@ -270,3 +257,14 @@ int snd_seq_fifo_resize(struct snd_seq_fifo *f, int poolsize)
 
 	return 0;
 }
+
+/* get the number of unused cells safely */
+int snd_seq_fifo_unused_cells(struct snd_seq_fifo *f)
+{
+	if (!f)
+		return 0;
+
+	guard(snd_seq_fifo)(f);
+	guard(spinlock_irqsave)(&f->lock);
+	return snd_seq_unused_cells(f->pool);
+}