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author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-17 02:20:36 +0400 |
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committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-17 02:20:36 +0400 |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /drivers/scsi/arm/queue.c | |
download | linux-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.xz |
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Diffstat (limited to 'drivers/scsi/arm/queue.c')
-rw-r--r-- | drivers/scsi/arm/queue.c | 319 |
1 files changed, 319 insertions, 0 deletions
diff --git a/drivers/scsi/arm/queue.c b/drivers/scsi/arm/queue.c new file mode 100644 index 000000000000..e6d159270d29 --- /dev/null +++ b/drivers/scsi/arm/queue.c @@ -0,0 +1,319 @@ +/* + * 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; + 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); + if (queue->alloc) + kfree(queue->alloc); +} + + +/* + * Function: int queue_add_cmd(Queue_t *queue, 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, 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); + if (BAD_MAGIC(q, QUEUE_MAGIC_FREE)) + BUG(); + + 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 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); + if (BAD_MAGIC(q, QUEUE_MAGIC_USED)) + BUG(); + + SET_MAGIC(q, QUEUE_MAGIC_FREE); + list_add(ent, &queue->free); + + return q->SCpnt; +} + +/* + * Function: 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 : Scsi_Cmnd if successful (and a reference), or NULL if no command available + */ +Scsi_Cmnd *queue_remove_exclude(Queue_t *queue, unsigned long *exclude) +{ + unsigned long flags; + struct list_head *l; + 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 + q->SCpnt->device->lun, exclude)) { + SCpnt = __queue_remove(queue, l); + break; + } + } + spin_unlock_irqrestore(&queue->queue_lock, flags); + + return SCpnt; +} + +/* + * Function: Scsi_Cmnd *queue_remove (queue) + * Purpose : removes first SCSI command from a queue + * Params : queue - queue to remove command from + * Returns : Scsi_Cmnd if successful (and a reference), or NULL if no command available + */ +Scsi_Cmnd *queue_remove(Queue_t *queue) +{ + unsigned long flags; + 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: 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 : Scsi_Cmnd if successful, or NULL if no command satisfies requirements + */ +Scsi_Cmnd *queue_remove_tgtluntag (Queue_t *queue, int target, int lun, int tag) +{ + unsigned long flags; + struct list_head *l; + 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, 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, 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"); |