--- /dev/null
+/*
+ * linux/drivers/acorn/scsi/queue.c: queue handling primitives
+ *
+ * Copyright (C) 1997-2000 Russell King
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * 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.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(sizeof(QE_t) * nqueues, GFP_KERNEL);
+ 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 &&
+ 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");
Code Review / kvmfornfv.git / blobdiff