// SPDX-License-Identifier: GPL-2.0-only/* *  linux/drivers/acorn/scsi/queue.c: queue handling primitives * *  Copyright (C) 1997-2000 Russell King * *  Changelog: *   15-Sep-1997 RMK	Created. *   11-Oct-1997 RMK	Corrected problem with queue_remove_exclude *			not updating internal linked list properly *			(was causing commands to go missing). *   30-Aug-2000 RMK	Use Linux list handling and spinlocks */#include <linux/module.h>#include <linux/blkdev.h>#include <linux/kernel.h>#include <linux/string.h>#include <linux/slab.h>#include <linux/spinlock.h>#include <linux/list.h>#include <linux/init.h> #include <scsi/scsi.h>#include <scsi/scsi_cmnd.h>#include <scsi/scsi_device.h>#include <scsi/scsi_eh.h>#include <scsi/scsi_tcq.h> #define DEBUG typedef struct queue_entry {	struct list_head   list;	struct scsi_cmnd   *SCpnt;#ifdef DEBUG	unsigned long	   magic;#endif} QE_t; #ifdef DEBUG#define QUEUE_MAGIC_FREE	0xf7e1c9a3#define QUEUE_MAGIC_USED	0xf7e1cc33 #define SET_MAGIC(q,m)	((q)->magic = (m))#define BAD_MAGIC(q,m)	((q)->magic != (m))#else#define SET_MAGIC(q,m)	do { } while (0)#define BAD_MAGIC(q,m)	(0)#endif #include "queue.h" #define NR_QE	32 /* * Function: void queue_initialise (Queue_t *queue) * Purpose : initialise a queue * Params  : queue - queue to initialise */int queue_initialise (Queue_t *queue){	unsigned int nqueues = NR_QE;	QE_t *q; 	spin_lock_init(&queue->queue_lock);	INIT_LIST_HEAD(&queue->head);	INIT_LIST_HEAD(&queue->free); 	/*	 * If life was easier, then SCpnt would have a	 * host-available list head, and we wouldn't	 * need to keep free lists or allocate this	 * memory.	 */	queue->alloc = q = kmalloc_objs(QE_t, nqueues);	if (q) {		for (; nqueues; q++, nqueues--) {			SET_MAGIC(q, QUEUE_MAGIC_FREE);			q->SCpnt = NULL;			list_add(&q->list, &queue->free);		}	} 	return queue->alloc != NULL;} /* * Function: void queue_free (Queue_t *queue) * Purpose : free a queue * Params  : queue - queue to free */void queue_free (Queue_t *queue){	if (!list_empty(&queue->head))		printk(KERN_WARNING "freeing non-empty queue %p\n", queue);	kfree(queue->alloc);}      /* * Function: int __queue_add(Queue_t *queue, struct scsi_cmnd *SCpnt, int head) * Purpose : Add a new command onto a queue, adding REQUEST_SENSE to head. * Params  : queue - destination queue *	     SCpnt - command to add *	     head  - add command to head of queue * Returns : 0 on error, !0 on success */int __queue_add(Queue_t *queue, struct scsi_cmnd *SCpnt, int head){	unsigned long flags;	struct list_head *l;	QE_t *q;	int ret = 0; 	spin_lock_irqsave(&queue->queue_lock, flags);	if (list_empty(&queue->free))		goto empty; 	l = queue->free.next;	list_del(l); 	q = list_entry(l, QE_t, list);	BUG_ON(BAD_MAGIC(q, QUEUE_MAGIC_FREE)); 	SET_MAGIC(q, QUEUE_MAGIC_USED);	q->SCpnt = SCpnt; 	if (head)		list_add(l, &queue->head);	else		list_add_tail(l, &queue->head); 	ret = 1;empty:	spin_unlock_irqrestore(&queue->queue_lock, flags);	return ret;} static struct scsi_cmnd *__queue_remove(Queue_t *queue, struct list_head *ent){	QE_t *q; 	/*	 * Move the entry from the "used" list onto the "free" list	 */	list_del(ent);	q = list_entry(ent, QE_t, list);	BUG_ON(BAD_MAGIC(q, QUEUE_MAGIC_USED)); 	SET_MAGIC(q, QUEUE_MAGIC_FREE);	list_add(ent, &queue->free); 	return q->SCpnt;} /* * Function: struct scsi_cmnd *queue_remove_exclude (queue, exclude) * Purpose : remove a SCSI command from a queue * Params  : queue   - queue to remove command from *	     exclude - bit array of target&lun which is busy * Returns : struct scsi_cmnd if successful (and a reference), or NULL if no command available */struct scsi_cmnd *queue_remove_exclude(Queue_t *queue, unsigned long *exclude){	unsigned long flags;	struct list_head *l;	struct scsi_cmnd *SCpnt = NULL; 	spin_lock_irqsave(&queue->queue_lock, flags);	list_for_each(l, &queue->head) {		QE_t *q = list_entry(l, QE_t, list);		if (!test_bit(q->SCpnt->device->id * 8 +			      (u8)(q->SCpnt->device->lun & 0x7), exclude)) {			SCpnt = __queue_remove(queue, l);			break;		}	}	spin_unlock_irqrestore(&queue->queue_lock, flags); 	return SCpnt;} /* * Function: struct scsi_cmnd *queue_remove (queue) * Purpose : removes first SCSI command from a queue * Params  : queue   - queue to remove command from * Returns : struct scsi_cmnd if successful (and a reference), or NULL if no command available */struct scsi_cmnd *queue_remove(Queue_t *queue){	unsigned long flags;	struct scsi_cmnd *SCpnt = NULL; 	spin_lock_irqsave(&queue->queue_lock, flags);	if (!list_empty(&queue->head))		SCpnt = __queue_remove(queue, queue->head.next);	spin_unlock_irqrestore(&queue->queue_lock, flags); 	return SCpnt;} /* * Function: struct scsi_cmnd *queue_remove_tgtluntag (queue, target, lun, tag) * Purpose : remove a SCSI command from the queue for a specified target/lun/tag * Params  : queue  - queue to remove command from *	     target - target that we want *	     lun    - lun on device *	     tag    - tag on device * Returns : struct scsi_cmnd if successful, or NULL if no command satisfies requirements */struct scsi_cmnd *queue_remove_tgtluntag(Queue_t *queue, int target, int lun,					 int tag){	unsigned long flags;	struct list_head *l;	struct scsi_cmnd *SCpnt = NULL; 	spin_lock_irqsave(&queue->queue_lock, flags);	list_for_each(l, &queue->head) {		QE_t *q = list_entry(l, QE_t, list);		if (q->SCpnt->device->id == target && q->SCpnt->device->lun == lun &&		    scsi_cmd_to_rq(q->SCpnt)->tag == tag) {			SCpnt = __queue_remove(queue, l);			break;		}	}	spin_unlock_irqrestore(&queue->queue_lock, flags); 	return SCpnt;} /* * Function: queue_remove_all_target(queue, target) * Purpose : remove all SCSI commands from the queue for a specified target * Params  : queue  - queue to remove command from *           target - target device id * Returns : nothing */void queue_remove_all_target(Queue_t *queue, int target){	unsigned long flags;	struct list_head *l; 	spin_lock_irqsave(&queue->queue_lock, flags);	list_for_each(l, &queue->head) {		QE_t *q = list_entry(l, QE_t, list);		if (q->SCpnt->device->id == target)			__queue_remove(queue, l);	}	spin_unlock_irqrestore(&queue->queue_lock, flags);} /* * Function: int queue_probetgtlun (queue, target, lun) * Purpose : check to see if we have a command in the queue for the specified *	     target/lun. * Params  : queue  - queue to look in *	     target - target we want to probe *	     lun    - lun on target * Returns : 0 if not found, != 0 if found */int queue_probetgtlun (Queue_t *queue, int target, int lun){	unsigned long flags;	struct list_head *l;	int found = 0; 	spin_lock_irqsave(&queue->queue_lock, flags);	list_for_each(l, &queue->head) {		QE_t *q = list_entry(l, QE_t, list);		if (q->SCpnt->device->id == target && q->SCpnt->device->lun == lun) {			found = 1;			break;		}	}	spin_unlock_irqrestore(&queue->queue_lock, flags); 	return found;} /* * Function: int queue_remove_cmd(Queue_t *queue, struct scsi_cmnd *SCpnt) * Purpose : remove a specific command from the queues * Params  : queue - queue to look in *	     SCpnt - command to find * Returns : 0 if not found */int queue_remove_cmd(Queue_t *queue, struct scsi_cmnd *SCpnt){	unsigned long flags;	struct list_head *l;	int found = 0; 	spin_lock_irqsave(&queue->queue_lock, flags);	list_for_each(l, &queue->head) {		QE_t *q = list_entry(l, QE_t, list);		if (q->SCpnt == SCpnt) {			__queue_remove(queue, l);			found = 1;			break;		}	}	spin_unlock_irqrestore(&queue->queue_lock, flags); 	return found;} EXPORT_SYMBOL(queue_initialise);EXPORT_SYMBOL(queue_free);EXPORT_SYMBOL(__queue_add);EXPORT_SYMBOL(queue_remove);EXPORT_SYMBOL(queue_remove_exclude);EXPORT_SYMBOL(queue_remove_tgtluntag);EXPORT_SYMBOL(queue_remove_cmd);EXPORT_SYMBOL(queue_remove_all_target);EXPORT_SYMBOL(queue_probetgtlun); MODULE_AUTHOR("Russell King");MODULE_DESCRIPTION("SCSI command queueing");MODULE_LICENSE("GPL");