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// SPDX-License-Identifier: GPL-2.0-or-later/* *  ALSA sequencer Memory Manager *  Copyright (c) 1998 by Frank van de Pol <fvdpol@coil.demon.nl> *                        Jaroslav Kysela <perex@perex.cz> *                2000 by Takashi Iwai <tiwai@suse.de> */ #include <linux/init.h>#include <linux/export.h>#include <linux/slab.h>#include <linux/sched/signal.h>#include <linux/mm.h>#include <sound/core.h> #include <sound/seq_kernel.h>#include "seq_memory.h"#include "seq_queue.h"#include "seq_info.h"#include "seq_lock.h" static inline int snd_seq_pool_available(struct snd_seq_pool *pool){	return pool->total_elements - atomic_read(&pool->counter);} static inline int snd_seq_output_ok(struct snd_seq_pool *pool){	return snd_seq_pool_available(pool) >= pool->room;} /* * Variable length event: * The event like sysex uses variable length type. * The external data may be stored in three different formats. * 1) kernel space *    This is the normal case. *      ext.data.len = length *      ext.data.ptr = buffer pointer * 2) user space *    When an event is generated via read(), the external data is *    kept in user space until expanded. *      ext.data.len = length | SNDRV_SEQ_EXT_USRPTR *      ext.data.ptr = userspace pointer * 3) chained cells *    When the variable length event is enqueued (in prioq or fifo), *    the external data is decomposed to several cells. *      ext.data.len = length | SNDRV_SEQ_EXT_CHAINED *      ext.data.ptr = the additiona cell head *         -> cell.next -> cell.next -> .. */ /* * exported: * call dump function to expand external data. */ static int get_var_len(const struct snd_seq_event *event){	if ((event->flags & SNDRV_SEQ_EVENT_LENGTH_MASK) != SNDRV_SEQ_EVENT_LENGTH_VARIABLE)		return -EINVAL; 	return event->data.ext.len & ~SNDRV_SEQ_EXT_MASK;} static int dump_var_event(const struct snd_seq_event *event,			  snd_seq_dump_func_t func, void *private_data,			  int offset, int maxlen){	int len, err;	struct snd_seq_event_cell *cell; 	len = get_var_len(event);	if (len <= 0)		return len;	if (len <= offset)		return 0;	if (maxlen && len > offset + maxlen)		len = offset + maxlen; 	if (event->data.ext.len & SNDRV_SEQ_EXT_USRPTR) {		char buf[32];		char __user *curptr = (char __force __user *)event->data.ext.ptr;		curptr += offset;		len -= offset;		while (len > 0) {			int size = sizeof(buf);			if (len < size)				size = len;			if (copy_from_user(buf, curptr, size))				return -EFAULT;			err = func(private_data, buf, size);			if (err < 0)				return err;			curptr += size;			len -= size;		}		return 0;	}	if (!(event->data.ext.len & SNDRV_SEQ_EXT_CHAINED))		return func(private_data, event->data.ext.ptr + offset,			    len - offset); 	cell = (struct snd_seq_event_cell *)event->data.ext.ptr;	for (; len > 0 && cell; cell = cell->next) {		int size = sizeof(struct snd_seq_event);		char *curptr = (char *)&cell->event; 		if (offset >= size) {			offset -= size;			len -= size;			continue;		}		if (len < size)			size = len;		err = func(private_data, curptr + offset, size - offset);		if (err < 0)			return err;		offset = 0;		len -= size;	}	return 0;} int snd_seq_dump_var_event(const struct snd_seq_event *event,			   snd_seq_dump_func_t func, void *private_data){	return dump_var_event(event, func, private_data, 0, 0);}EXPORT_SYMBOL(snd_seq_dump_var_event);  /* * exported: * expand the variable length event to linear buffer space. */ static int seq_copy_in_kernel(void *ptr, void *src, int size){	char **bufptr = ptr; 	memcpy(*bufptr, src, size);	*bufptr += size;	return 0;} static int seq_copy_in_user(void *ptr, void *src, int size){	char __user **bufptr = ptr; 	if (copy_to_user(*bufptr, src, size))		return -EFAULT;	*bufptr += size;	return 0;} static int expand_var_event(const struct snd_seq_event *event,			    int offset, int size, char *buf, bool in_kernel){	if (event->data.ext.len & SNDRV_SEQ_EXT_USRPTR) {		if (! in_kernel)			return -EINVAL;		if (copy_from_user(buf,				   (char __force __user *)event->data.ext.ptr + offset,				   size))			return -EFAULT;		return 0;	}	return dump_var_event(event,			     in_kernel ? seq_copy_in_kernel : seq_copy_in_user,			     &buf, offset, size);} int snd_seq_expand_var_event(const struct snd_seq_event *event, int count, char *buf,			     int in_kernel, int size_aligned){	int len, newlen, err; 	len = get_var_len(event);	if (len < 0)		return len;	newlen = len;	if (size_aligned > 0)		newlen = roundup(len, size_aligned);	if (count < newlen)		return -EAGAIN;	err = expand_var_event(event, 0, len, buf, in_kernel);	if (err < 0)		return err;	if (len != newlen) {		if (in_kernel)			memset(buf + len, 0, newlen - len);		else if (clear_user((__force void __user *)buf + len,				    newlen - len))			return -EFAULT;	}	return newlen;}EXPORT_SYMBOL(snd_seq_expand_var_event); int snd_seq_expand_var_event_at(const struct snd_seq_event *event, int count,				char *buf, int offset){	int len, err; 	len = get_var_len(event);	if (len < 0)		return len;	if (len <= offset)		return 0;	len -= offset;	if (len > count)		len = count;	err = expand_var_event(event, offset, len, buf, true);	if (err < 0)		return err;	return len;}EXPORT_SYMBOL_GPL(snd_seq_expand_var_event_at); /* * release this cell, free extended data if available */ static inline void free_cell(struct snd_seq_pool *pool,			     struct snd_seq_event_cell *cell){	cell->next = pool->free;	pool->free = cell;	atomic_dec(&pool->counter);} void snd_seq_cell_free(struct snd_seq_event_cell * cell){	struct snd_seq_pool *pool; 	if (snd_BUG_ON(!cell))		return;	pool = cell->pool;	if (snd_BUG_ON(!pool))		return; 	guard(spinlock_irqsave)(&pool->lock);	free_cell(pool, cell);	if (snd_seq_ev_is_variable(&cell->event)) {		if (cell->event.data.ext.len & SNDRV_SEQ_EXT_CHAINED) {			struct snd_seq_event_cell *curp, *nextptr;			curp = cell->event.data.ext.ptr;			for (; curp; curp = nextptr) {				nextptr = curp->next;				curp->next = pool->free;				free_cell(pool, curp);			}		}	}	if (waitqueue_active(&pool->output_sleep)) {		/* has enough space now? */		if (snd_seq_output_ok(pool))			wake_up(&pool->output_sleep);	}}  /* * allocate an event cell. */static int snd_seq_cell_alloc(struct snd_seq_pool *pool,			      struct snd_seq_event_cell **cellp,			      int nonblock, struct file *file,			      struct mutex *mutexp){	struct snd_seq_event_cell *cell;	unsigned long flags;	int err = -EAGAIN;	wait_queue_entry_t wait; 	if (pool == NULL)		return -EINVAL; 	*cellp = NULL; 	init_waitqueue_entry(&wait, current);	spin_lock_irqsave(&pool->lock, flags);	if (pool->ptr == NULL) {	/* not initialized */		pr_debug("ALSA: seq: pool is not initialized\n");		err = -EINVAL;		goto __error;	}	while (pool->free == NULL && ! nonblock && ! pool->closing) { 		set_current_state(TASK_INTERRUPTIBLE);		add_wait_queue(&pool->output_sleep, &wait);		spin_unlock_irqrestore(&pool->lock, flags);		if (mutexp)			mutex_unlock(mutexp);		schedule();		if (mutexp)			mutex_lock(mutexp);		spin_lock_irqsave(&pool->lock, flags);		remove_wait_queue(&pool->output_sleep, &wait);		/* interrupted? */		if (signal_pending(current)) {			err = -ERESTARTSYS;			goto __error;		}	}	if (pool->closing) { /* closing.. */		err = -ENOMEM;		goto __error;	} 	cell = pool->free;	if (cell) {		int used;		pool->free = cell->next;		atomic_inc(&pool->counter);		used = atomic_read(&pool->counter);		if (pool->max_used < used)			pool->max_used = used;		pool->event_alloc_success++;		/* clear cell pointers */		cell->next = NULL;		err = 0;	} else		pool->event_alloc_failures++;	*cellp = cell; __error:	spin_unlock_irqrestore(&pool->lock, flags);	return err;}  /* * duplicate the event to a cell. * if the event has external data, the data is decomposed to additional * cells. */int snd_seq_event_dup(struct snd_seq_pool *pool, struct snd_seq_event *event,		      struct snd_seq_event_cell **cellp, int nonblock,		      struct file *file, struct mutex *mutexp){	int ncells, err;	unsigned int extlen;	struct snd_seq_event_cell *cell;	int size; 	*cellp = NULL; 	ncells = 0;	extlen = 0;	if (snd_seq_ev_is_variable(event)) {		extlen = event->data.ext.len & ~SNDRV_SEQ_EXT_MASK;		ncells = DIV_ROUND_UP(extlen, sizeof(struct snd_seq_event));	}	if (ncells >= pool->total_elements)		return -ENOMEM; 	err = snd_seq_cell_alloc(pool, &cell, nonblock, file, mutexp);	if (err < 0)		return err; 	/* copy the event */	size = snd_seq_event_packet_size(event);	memcpy(&cell->ump, event, size);#if IS_ENABLED(CONFIG_SND_SEQ_UMP)	if (size < sizeof(cell->ump))		cell->ump.raw.extra = 0;#endif 	/* decompose */	if (snd_seq_ev_is_variable(event)) {		int len = extlen;		int is_chained = event->data.ext.len & SNDRV_SEQ_EXT_CHAINED;		int is_usrptr = event->data.ext.len & SNDRV_SEQ_EXT_USRPTR;		struct snd_seq_event_cell *src, *tmp, *tail;		char *buf; 		cell->event.data.ext.len = extlen | SNDRV_SEQ_EXT_CHAINED;		cell->event.data.ext.ptr = NULL; 		src = (struct snd_seq_event_cell *)event->data.ext.ptr;		buf = (char *)event->data.ext.ptr;		tail = NULL; 		while (ncells-- > 0) {			size = sizeof(struct snd_seq_event);			if (len < size)				size = len;			err = snd_seq_cell_alloc(pool, &tmp, nonblock, file,						 mutexp);			if (err < 0)				goto __error;			if (cell->event.data.ext.ptr == NULL)				cell->event.data.ext.ptr = tmp;			if (tail)				tail->next = tmp;			tail = tmp;			/* copy chunk */			if (is_chained && src) {				tmp->event = src->event;				src = src->next;			} else if (is_usrptr) {				if (copy_from_user(&tmp->event, (char __force __user *)buf, size)) {					err = -EFAULT;					goto __error;				}			} else {				memcpy(&tmp->event, buf, size);			}			buf += size;			len -= size;		}	} 	*cellp = cell;	return 0; __error:	snd_seq_cell_free(cell);	return err;}   /* poll wait */int snd_seq_pool_poll_wait(struct snd_seq_pool *pool, struct file *file,			   poll_table *wait){	poll_wait(file, &pool->output_sleep, wait);	guard(spinlock_irq)(&pool->lock);	return snd_seq_output_ok(pool);}  /* allocate room specified number of events */int snd_seq_pool_init(struct snd_seq_pool *pool){	int cell;	struct snd_seq_event_cell *cellptr; 	if (snd_BUG_ON(!pool))		return -EINVAL; 	cellptr = kvmalloc_objs(struct snd_seq_event_cell, pool->size);	if (!cellptr)		return -ENOMEM; 	/* add new cells to the free cell list */	guard(spinlock_irq)(&pool->lock);	if (pool->ptr) {		kvfree(cellptr);		return 0;	} 	pool->ptr = cellptr;	pool->free = NULL; 	for (cell = 0; cell < pool->size; cell++) {		cellptr = pool->ptr + cell;		cellptr->pool = pool;		cellptr->next = pool->free;		pool->free = cellptr;	}	pool->room = (pool->size + 1) / 2; 	/* init statistics */	pool->max_used = 0;	pool->total_elements = pool->size;	return 0;} /* refuse the further insertion to the pool */void snd_seq_pool_mark_closing(struct snd_seq_pool *pool){	if (snd_BUG_ON(!pool))		return;	guard(spinlock_irqsave)(&pool->lock);	pool->closing = 1;} /* remove events */int snd_seq_pool_done(struct snd_seq_pool *pool){	struct snd_seq_event_cell *ptr; 	if (snd_BUG_ON(!pool))		return -EINVAL; 	/* wait for closing all threads */	if (waitqueue_active(&pool->output_sleep))		wake_up(&pool->output_sleep); 	while (atomic_read(&pool->counter) > 0)		schedule_timeout_uninterruptible(1);		/* release all resources */	scoped_guard(spinlock_irq, &pool->lock) {		ptr = pool->ptr;		pool->ptr = NULL;		pool->free = NULL;

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