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