patch-2.1.88 linux/drivers/acorn/scsi/queue.c

• Lines: 433
• Date: Sat Feb 7 07:15:19 1998
• Orig file: v2.1.87/linux/drivers/acorn/scsi/queue.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.1.87/linux/drivers/acorn/scsi/queue.c linux/drivers/acorn/scsi/queue.c
@@ -0,0 +1,432 @@
+/*
+ * queue.c: queue handling primitives
+ *
+ * (c) 1997 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).
+ */
+
+#define SECTOR_SIZE 512
+
+#include <linux/module.h>
+#include <linux/blk.h>
+#include <linux/kernel.h>
+#include <linux/string.h>
+#include <linux/malloc.h>
+
+#include "../../scsi/scsi.h"
+
+typedef struct queue_entry {
+	struct queue_entry *next;
+	struct queue_entry *prev;
+	unsigned long	   magic;
+	Scsi_Cmnd	   *SCpnt;
+} QE_t;
+
+#define QUEUE_MAGIC_FREE	0xf7e1c9a3
+#define QUEUE_MAGIC_USED	0xf7e1cc33
+
+#include "queue.h"
+
+/*
+ * 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;
+	QE_t *q;
+
+	queue->alloc = queue->free = q = (QE_t *) kmalloc (SECTOR_SIZE, GFP_KERNEL);
+	if (q) {
+		nqueues = SECTOR_SIZE / sizeof (QE_t);
+
+		for (; nqueues; q++, nqueues--) {
+			q->next = q + 1;
+			q->prev = NULL;
+			q->magic = QUEUE_MAGIC_FREE;
+			q->SCpnt = NULL;
+		}
+		q->next = NULL;
+	}
+
+	return q != NULL;
+}
+
+/*
+ * Function: void queue_free (Queue_t *queue)
+ * Purpose : free a queue
+ * Params  : queue - queue to free
+ */
+void queue_free (Queue_t *queue)
+{
+	if (queue->alloc)
+		kfree (queue->alloc);
+}
+     
+
+/*
+ * Function: int queue_add_cmd_ordered (Queue_t *queue, Scsi_Cmnd *SCpnt)
+ * Purpose : Add a new command onto a queue, adding REQUEST_SENSE to head.
+ * Params  : queue - destination queue
+ *	     SCpnt - command to add
+ * Returns : 0 on error, !0 on success
+ */
+int queue_add_cmd_ordered (Queue_t *queue, Scsi_Cmnd *SCpnt)
+{
+	unsigned long flags;
+	QE_t *q;
+
+	save_flags_cli (flags);
+	q = queue->free;
+	if (q)
+		queue->free = q->next;
+
+	if (q) {
+		if (q->magic != QUEUE_MAGIC_FREE) {
+			restore_flags (flags);
+			panic ("scsi queues corrupted - queue entry not free");
+		}
+
+		q->magic = QUEUE_MAGIC_USED;
+		q->SCpnt = SCpnt;
+
+		if (SCpnt->cmnd[0] == REQUEST_SENSE) { /* request_sense gets put on the queue head */
+			if (queue->head) {
+				q->prev = NULL;
+				q->next = queue->head;
+				queue->head->prev = q;
+				queue->head = q;
+			} else {
+			    	q->next = q->prev = NULL;
+			    	queue->head = queue->tail = q;
+			}
+		} else {				/* others get put on the tail */
+			if (queue->tail) {
+				q->next = NULL;
+				q->prev = queue->tail;
+				queue->tail->next = q;
+				queue->tail = q;
+			} else {
+				q->next = q->prev = NULL;
+				queue->head = queue->tail = q;
+			}
+		}    
+	}
+	restore_flags (flags);
+
+	return q != NULL;
+}
+
+/*
+ * Function: int queue_add_cmd_tail (Queue_t *queue, Scsi_Cmnd *SCpnt)
+ * Purpose : Add a new command onto a queue, adding onto tail of list
+ * Params  : queue - destination queue
+ *	     SCpnt - command to add
+ * Returns : 0 on error, !0 on success
+ */
+int queue_add_cmd_tail (Queue_t *queue, Scsi_Cmnd *SCpnt)
+{
+	unsigned long flags;
+	QE_t *q;
+
+	save_flags_cli (flags);
+	q = queue->free;
+	if (q)
+		queue->free = q->next;
+
+	if (q) {
+		if (q->magic != QUEUE_MAGIC_FREE) {
+			restore_flags (flags);
+			panic ("scsi queues corrupted - queue entry not free");
+		}
+
+		q->magic = QUEUE_MAGIC_USED;
+		q->SCpnt = SCpnt;
+
+		if (queue->tail) {
+			q->next = NULL;
+			q->prev = queue->tail;
+			queue->tail->next = q;
+			queue->tail = q;
+		} else {
+			q->next = q->prev = NULL;
+			queue->head = queue->tail = q;
+		}    
+	}
+	restore_flags (flags);
+
+	return q != NULL;
+}
+
+/*
+ * 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 char *exclude)
+{
+	unsigned long flags;
+	Scsi_Cmnd *SCpnt;
+	QE_t *q, *prev;
+
+	save_flags_cli (flags);
+	for (q = queue->head, prev = NULL; q; q = q->next) {
+		if (exclude && !test_bit (q->SCpnt->target * 8 + q->SCpnt->lun, exclude))
+			break;
+		prev = q;
+	}
+
+	if (q) {
+		if (q->magic != QUEUE_MAGIC_USED) {
+			restore_flags (flags);
+			panic ("q_remove_exclude: scsi queues corrupted - queue entry not used");
+		}
+		if (q->prev != prev)
+			panic ("q_remove_exclude: scsi queues corrupted - q->prev != prev");
+
+		if (!prev) {
+			queue->head = q->next;
+			if (queue->head)
+				queue->head->prev = NULL;
+			else
+				queue->tail = NULL;
+		} else {
+			prev->next = q->next;
+			if (prev->next)
+				prev->next->prev = prev;
+			else
+				queue->tail = prev;
+		}
+
+		SCpnt = q->SCpnt;
+
+		q->next = queue->free;
+		queue->free = q;
+		q->magic = QUEUE_MAGIC_FREE;
+	} else
+		SCpnt = NULL;
+
+	restore_flags (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;
+	QE_t *q;
+
+	save_flags_cli (flags);
+	q = queue->head;
+	if (q) {
+		queue->head = q->next;
+		if (queue->head)
+			queue->head->prev = NULL;
+		else
+			queue->tail = NULL;
+
+		if (q->magic != QUEUE_MAGIC_USED) {
+			restore_flags (flags);
+			panic ("scsi queues corrupted - queue entry not used");
+		}
+
+		SCpnt = q->SCpnt;
+
+		q->next = queue->free;
+		queue->free = q;
+		q->magic = QUEUE_MAGIC_FREE;
+	} else
+		SCpnt = NULL;
+
+	restore_flags (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;
+	Scsi_Cmnd *SCpnt;
+	QE_t *q, *prev;
+
+	save_flags_cli (flags);
+	for (q = queue->head, prev = NULL; q; q = q->next) {
+		if (q->SCpnt->target == target &&
+		    q->SCpnt->lun == lun &&
+		    q->SCpnt->tag == tag)
+			break;
+
+		prev = q;
+	}
+
+	if (q) {
+		if (q->magic != QUEUE_MAGIC_USED) {
+			restore_flags (flags);
+			panic ("q_remove_tgtluntag: scsi queues corrupted - queue entry not used");
+		}
+		if (q->prev != prev)
+			panic ("q_remove_tgtluntag: scsi queues corrupted - q->prev != prev");
+
+		if (!prev) {
+			queue->head = q->next;
+			if (queue->head)
+				queue->head->prev = NULL;
+			else
+				queue->tail = NULL;
+		} else {
+		 	prev->next = q->next;
+			if (prev->next)
+				prev->next->prev = prev;
+			else
+				queue->tail = prev;
+		}
+
+		SCpnt = q->SCpnt;
+
+		q->magic = QUEUE_MAGIC_FREE;
+		q->next = queue->free;
+		queue->free = q;
+	} else
+		SCpnt = NULL;
+
+	restore_flags (flags);
+
+	return SCpnt;
+}
+
+/*
+ * 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)
+{
+	QE_t *q;
+
+	for (q = queue->head; q; q = q->next)
+		if (q->SCpnt->target == target &&
+		    q->SCpnt->lun == lun)
+			break;
+
+	return q != NULL;
+}
+
+/*
+ * Function: int queue_cmdonqueue (queue, SCpnt)
+ * Purpose : check to see if we have a command on the queue
+ * Params  : queue - queue to look in
+ *	     SCpnt - command to find
+ * Returns : 0 if not found, != 0 if found
+ */
+int queue_cmdonqueue (Queue_t *queue, Scsi_Cmnd *SCpnt)
+{
+	QE_t *q;
+
+	for (q = queue->head; q; q = q->next)
+		if (q->SCpnt == SCpnt)
+			break;
+
+	return q != NULL;
+}
+
+/*
+ * Function: int queue_removecmd (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_removecmd (Queue_t *queue, Scsi_Cmnd *SCpnt)
+{
+	unsigned long flags;
+	QE_t *q, *prev;
+
+	save_flags_cli (flags);
+	for (q = queue->head, prev = NULL; q; q = q->next) {
+		if (q->SCpnt == SCpnt)
+			break;
+
+		prev = q;
+	}
+
+	if (q) {
+		if (q->magic != QUEUE_MAGIC_USED) {
+			restore_flags (flags);
+			panic ("q_removecmd: scsi queues corrupted - queue entry not used");
+		}
+		if (q->prev != prev)
+			panic ("q_removecmd: scsi queues corrupted - q->prev != prev");
+
+		if (!prev) {
+			queue->head = q->next;
+			if (queue->head)
+				queue->head->prev = NULL;
+			else
+				queue->tail = NULL;
+		} else {
+			prev->next = q->next;
+			if (prev->next)
+				prev->next->prev = prev;
+			else
+				queue->tail = prev;
+		}
+
+		q->magic = QUEUE_MAGIC_FREE;
+		q->next = queue->free;
+		queue->free = q;
+	}
+
+	restore_flags (flags);
+
+	return q != NULL;
+}
+
+EXPORT_SYMBOL(queue_initialise);
+EXPORT_SYMBOL(queue_free);
+EXPORT_SYMBOL(queue_remove);
+EXPORT_SYMBOL(queue_remove_exclude);
+EXPORT_SYMBOL(queue_add_cmd_ordered);
+EXPORT_SYMBOL(queue_add_cmd_tail);
+EXPORT_SYMBOL(queue_remove_tgtluntag);
+EXPORT_SYMBOL(queue_probetgtlun);
+EXPORT_SYMBOL(queue_cmdonqueue);
+EXPORT_SYMBOL(queue_removecmd);
+
+#ifdef MODULE
+int init_module (void)
+{
+	return 0;
+}
+
+void cleanup_module (void)
+{
+}
+#endif