freebsd-dev/sys/cam/cam_queue.c

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/*
* CAM request queue management functions.
*
* Copyright (c) 1997 Justin T. Gibbs.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions, and the following disclaimer,
* without modification, immediately at the beginning of the file.
* 2. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR
* ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $Id$
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/types.h>
#include <sys/malloc.h>
#include <cam/cam.h>
#include <cam/cam_ccb.h>
#include <cam/cam_queue.h>
#include <cam/cam_debug.h>
static __inline int
queue_cmp(cam_pinfo **queue_array, int i, int j);
static __inline void
swap(cam_pinfo **queue_array, int i, int j);
static void heap_up(cam_pinfo **queue_array, int new_index);
static void heap_down(cam_pinfo **queue_array, int index,
int last_index);
struct camq *
camq_alloc(int size)
{
struct camq *camq;
camq = (struct camq *)malloc(sizeof(*camq), M_DEVBUF, M_NOWAIT);
if (camq != NULL) {
if (camq_init(camq, size) != 0) {
free(camq, M_DEVBUF);
camq = NULL;
}
}
return (camq);
}
int
camq_init(struct camq *camq, int size)
{
bzero(camq, sizeof(*camq));
camq->array_size = size;
if (camq->array_size != 0) {
camq->queue_array = (cam_pinfo**)malloc(size*sizeof(cam_pinfo*),
M_DEVBUF, M_NOWAIT);
if (camq->queue_array == NULL) {
printf("camq_init: - cannot malloc array!\n");
return (1);
}
}
return (0);
}
/*
* Free a camq structure. This should only be called if a controller
* driver failes somehow during its attach routine or is unloaded and has
* obtained a camq structure. The XPT should ensure that the queue
* is empty before calling this routine.
*/
void
camq_free(struct camq *queue)
{
if (queue != NULL) {
camq_fini(queue);
free(queue, M_DEVBUF);
}
}
void
camq_fini(struct camq *queue)
{
if (queue->queue_array != NULL) {
free(queue->queue_array, M_DEVBUF);
}
}
u_int32_t
camq_resize(struct camq *queue, int new_size)
{
cam_pinfo **new_array;
#ifdef DIAGNOSTIC
if (new_size < queue->entries)
panic("camq_resize: New queue size can't accomodate "
"queued entries.");
#endif
new_array = (cam_pinfo **)malloc(new_size * sizeof(cam_pinfo *),
M_DEVBUF, M_NOWAIT);
if (new_array == NULL) {
/* Couldn't satisfy request */
return (CAM_RESRC_UNAVAIL);
}
if (queue->queue_array != NULL) {
bcopy(queue->queue_array, new_array,
queue->entries * sizeof(cam_pinfo *));
free(queue->queue_array, M_DEVBUF);
}
queue->queue_array = new_array;
queue->array_size = new_size;
return (CAM_REQ_CMP);
}
/*
* camq_regen: Given an array of cam_pinfo* elements with the
* Heap(0, num_elements) property, perform the second half of
* a heap sort, and assign new generation numbers to all entries.
* It is assumed that the starting generation number plus the
* number of entries in the queue is smaller than the wrap point
* of the generation number.
*/
void
camq_regen(struct camq *queue)
{
int index;
for (index = 0; index < queue->entries; index++) {
heap_down(queue->queue_array, index, queue->entries);
queue->queue_array[index]->generation = queue->generation++;
}
/* A sorted array is still a heap, so we are done */
}
/*
* camq_insert: Given an array of cam_pinfo* elememnts with
* the Heap(0, num_elements) property and array_size - num_elements >= 1,
* output Heap(0, num_elements+1) including new_entry in the array.
*/
void
camq_insert(struct camq *queue, cam_pinfo *new_entry)
{
#ifdef DIAGNOSTIC
if (queue->entries >= queue->array_size)
panic("camq_insert: Attempt to insert into a full queue");
#endif
queue->queue_array[queue->entries] = new_entry;
new_entry->index = queue->entries;
if (queue->entries != 0)
heap_up(queue->queue_array, queue->entries);
queue->entries++;
}
/*
* camq_remove: Given an array of cam_pinfo* elevements with the
* Heap(0, num_elements) property and an index such that 0 <= index <=
* num_elements, remove that entry and restore the Heap(0, num_elements-1)
* property.
*/
cam_pinfo *
camq_remove(struct camq *queue, int index)
{
cam_pinfo *removed_entry;
if ((queue->entries - index) <= 0)
return (NULL);
removed_entry = queue->queue_array[index];
queue->entries--;
if (queue->entries != index) {
queue->queue_array[index] = queue->queue_array[queue->entries];
queue->queue_array[index]->index = index;
heap_down(queue->queue_array, index, queue->entries);
}
removed_entry->index = CAM_UNQUEUED_INDEX;
return (removed_entry);
}
/*
* camq_change_priority: Given an array of cam_pinfo* elements with the
* Heap(0, num_entries) property, an index such that 0 <= index <= num_elements,
* and an new priority for the element at index, change the priority of
* element index and restore the Heap(0, num_elements) property.
*/
void
camq_change_priority(struct camq *queue, int index, u_int32_t new_priority)
{
if (new_priority > queue->queue_array[index]->priority) {
queue->queue_array[index]->priority = new_priority;
heap_down(queue->queue_array, index, queue->entries);
} else {
/* new_priority <= old_priority */
queue->queue_array[index]->priority = new_priority;
heap_up(queue->queue_array, index);
}
}
struct cam_devq *
cam_devq_alloc(int devices, int openings)
{
struct cam_devq *devq;
devq = (struct cam_devq *)malloc(sizeof(*devq), M_DEVBUF, M_NOWAIT);
if (devq == NULL) {
printf("cam_devq_alloc: - cannot malloc!\n");
return (NULL);
}
if (cam_devq_init(devq, devices, openings) != 0) {
free(devq, M_DEVBUF);
return (NULL);
}
return (devq);
}
int
cam_devq_init(struct cam_devq *devq, int devices, int openings)
{
bzero(devq, sizeof(*devq));
if (camq_init(&devq->alloc_queue, devices) != 0) {
return (1);
}
if (camq_init(&devq->send_queue, devices) != 0) {
camq_fini(&devq->alloc_queue);
return (1);
}
devq->alloc_openings = openings;
devq->alloc_active = 0;
devq->send_openings = openings;
devq->send_active = 0;
return (0);
}
void
cam_devq_free(struct cam_devq *devq)
{
camq_free(&devq->alloc_queue);
camq_free(&devq->send_queue);
free(devq, M_DEVBUF);
}
u_int32_t
cam_devq_resize(struct cam_devq *camq, int devices)
{
u_int32_t retval;
retval = camq_resize(&camq->alloc_queue, devices);
if (retval == CAM_REQ_CMP)
retval = camq_resize(&camq->send_queue, devices);
return (retval);
}
struct cam_ccbq *
cam_ccbq_alloc(int openings)
{
struct cam_ccbq *ccbq;
ccbq = (struct cam_ccbq *)malloc(sizeof(*ccbq), M_DEVBUF, M_NOWAIT);
if (ccbq == NULL) {
printf("cam_ccbq_alloc: - cannot malloc!\n");
return (NULL);
}
if (cam_ccbq_init(ccbq, openings) != 0) {
free(ccbq, M_DEVBUF);
return (NULL);
}
return (ccbq);
}
void
cam_ccbq_free(struct cam_ccbq *ccbq)
{
if (ccbq) {
camq_fini(&ccbq->queue);
free(ccbq, M_DEVBUF);
}
}
u_int32_t
cam_ccbq_resize(struct cam_ccbq *ccbq, int new_size)
{
int delta;
int space_left;
delta = new_size - (ccbq->dev_active + ccbq->dev_openings);
space_left = new_size
- ccbq->queue.entries
- ccbq->held
- ccbq->dev_active;
/*
* Only attempt to change the underlying queue size if we are
* shrinking it and there is space for all outstanding entries
* in the new array or we have been requested to grow the array.
* We don't fail in the case where we can't reduce the array size,
* but clients that care that the queue be "garbage collected"
* should detect this condition and call us again with the
* same size once the outstanding entries have been processed.
*/
if (space_left < 0
|| camq_resize(&ccbq->queue, new_size) == CAM_REQ_CMP) {
ccbq->devq_openings += delta;
ccbq->dev_openings += delta;
return (CAM_REQ_CMP);
} else {
return (CAM_RESRC_UNAVAIL);
}
}
int
cam_ccbq_init(struct cam_ccbq *ccbq, int openings)
{
bzero(ccbq, sizeof(*ccbq));
if (camq_init(&ccbq->queue, openings) != 0) {
return (1);
}
ccbq->devq_openings = openings;
ccbq->dev_openings = openings;
TAILQ_INIT(&ccbq->active_ccbs);
return (0);
}
void
cam_ccbq_regen(struct cam_ccbq *ccbq)
{
struct ccb_hdr *ccbh;
/* First get all of the guys down at a device */
ccbh = ccbq->active_ccbs.tqh_first;
while (ccbh != NULL) {
ccbh->pinfo.generation = ccbq->queue.generation++;
ccbh = ccbh->xpt_links.tqe.tqe_next;
}
/* Now get everyone in our CAM queue */
camq_regen(&ccbq->queue);
}
/*
* Heap routines for manipulating CAM queues.
*/
/*
* queue_cmp: Given an array of cam_pinfo* elements and indexes i
* and j, return less than 0, 0, or greater than 0 if i is less than,
* equal too, or greater than j respectively.
*/
static __inline int
queue_cmp(cam_pinfo **queue_array, int i, int j)
{
if (queue_array[i]->priority == queue_array[j]->priority)
return ( queue_array[i]->generation
- queue_array[j]->generation );
else
return ( queue_array[i]->priority
- queue_array[j]->priority );
}
/*
* swap: Given an array of cam_pinfo* elements and indexes i and j,
* exchange elements i and j.
*/
static __inline void
swap(cam_pinfo **queue_array, int i, int j)
{
cam_pinfo *temp_qentry;
temp_qentry = queue_array[j];
queue_array[j] = queue_array[i];
queue_array[i] = temp_qentry;
queue_array[j]->index = j;
queue_array[i]->index = i;
}
/*
* heap_up: Given an array of cam_pinfo* elements with the
* Heap(0, new_index-1) property and a new element in location
* new_index, output Heap(0, new_index).
*/
static void
heap_up(cam_pinfo **queue_array, int new_index)
{
int child;
int parent;
child = new_index;
while (child != 0) {
parent = child >> 1;
if (queue_cmp(queue_array, parent, child) <= 0)
break;
swap(queue_array, parent, child);
child = parent;
}
}
/*
* heap_down: Given an array of cam_pinfo* elements with the
* Heap(1, num_entries - 1) property with index 0 containing an unsorted
* entry, output Heap(0, num_entries - 1).
*/
static void
heap_down(cam_pinfo **queue_array, int index, int num_entries)
{
int child;
int parent;
parent = index;
child = parent == 0 ? 1 : parent << 1;
for (; child < num_entries; child = parent << 1) {
if (child + 1 < num_entries) {
/* child+1 is the right child of parent */
if (queue_cmp(queue_array, child + 1, child) < 0)
child++;
}
/* child is now the least child of parent */
if (queue_cmp(queue_array, parent, child) <= 0)
break;
swap(queue_array, child, parent);
parent = child;
}
}