index : linux	frominto-error master
	Contrib clone of linux	matthias

summaryrefslogtreecommitdiffstats

log msg author committer range

path: root/drivers/ata/pata_ns87415.c

Age	Commit message (Expand)	Author
2012-07-25	ata: use module_pci_driver	Axel Lin
2011-07-23	ata: Add and use ata_print_version_once	Joe Perches
2010-05-25	libata-sff: separate out BMDMA init	Tejun Heo
2010-05-19	libata-sff: prd is BMDMA specific	Tejun Heo
2010-03-01	libata: Pass host flags into the pci helper	Alan Cox
2009-12-03	pata_ns87415: Power Management fix	Bartlomiej Zolnierkiewicz
2009-03-24	[libata] convert drivers to use ata.h mode mask defines	Erik Inge Bolsø
2008-10-27	ata: Switch all my stuff to a common address	Alan Cox
2008-05-19	ata: remove FIT() macro	Harvey Harrison
2008-04-17	libata: rename SFF port ops	Tejun Heo
2008-04-17	libata: rename SFF functions	Tejun Heo
2008-04-17	libata: stop overloading port_info->private_data	Tejun Heo
2008-04-17	libata: make ata_pci_init_one() not use ops->irq_handler and pi->sht	Tejun Heo
2008-04-17	libata: implement and use ops inheritance	Tejun Heo
2008-04-17	libata: implement and use SHT initializers	Tejun Heo
2008-04-17	libata: PCI device should be powered up before being accessed	Tejun Heo
2007-10-29	pata_ns87415: define SUPERIO_IDE_MAX_RETRIES	Frank Lichtenheld
2007-10-23	[libata] checkpatch-inspired cleanups	Jeff Garzik
2007-10-12	pata_ns87415: Initial cut at 87415/87560 IDE support	Alan Cox

generated by cgit v1.2.3 (git 2.25.1) at 2024-09-05 18:19:11 +0000

/*
 *  MQ Deadline i/o scheduler - adaptation of the legacy deadline scheduler,
 *  for the blk-mq scheduling framework
 *
 *  Copyright (C) 2016 Jens Axboe <axboe@kernel.dk>
 */
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/blkdev.h>
#include <linux/blk-mq.h>
#include <linux/elevator.h>
#include <linux/bio.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/compiler.h>
#include <linux/rbtree.h>
#include <linux/sbitmap.h>

#include "blk.h"
#include "blk-mq.h"
#include "blk-mq-debugfs.h"
#include "blk-mq-tag.h"
#include "blk-mq-sched.h"

/*
 * See Documentation/block/deadline-iosched.txt
 */
static const int read_expire = HZ / 2;  /* max time before a read is submitted. */
static const int write_expire = 5 * HZ; /* ditto for writes, these limits are SOFT! */
static const int writes_starved = 2;    /* max times reads can starve a write */
static const int fifo_batch = 16;       /* # of sequential requests treated as one
				     by the above parameters. For throughput. */

struct deadline_data {
	/*
	 * run time data
	 */

	/*
	 * requests (deadline_rq s) are present on both sort_list and fifo_list
	 */
	struct rb_root sort_list[2];
	struct list_head fifo_list[2];

	/*
	 * next in sort order. read, write or both are NULL
	 */
	struct request *next_rq[2];
	unsigned int batching;		/* number of sequential requests made */
	unsigned int starved;		/* times reads have starved writes */

	/*
	 * settings that change how the i/o scheduler behaves
	 */
	int fifo_expire[2];
	int fifo_batch;
	int writes_starved;
	int front_merges;

	spinlock_t lock;
	struct list_head dispatch;
};

static inline struct rb_root *
deadline_rb_root(struct deadline_data *dd, struct request *rq)
{
	return &dd->sort_list[rq_data_dir(rq)];
}

/*
 * get the request after `rq' in sector-sorted order
 */
static inline struct request *
deadline_latter_request(struct request *rq)
{
	struct rb_node *node = rb_next(&rq->rb_node);

	if (node)
		return rb_entry_rq(node);

	return NULL;
}

static void
deadline_add_rq_rb(struct deadline_data *dd, struct request *rq)
{
	struct rb_root *root = deadline_rb_root(dd, rq);

	elv_rb_add(root, rq);
}

static inline void
deadline_del_rq_rb(struct deadline_data *dd, struct request *rq)
{
	const int data_dir = rq_data_dir(rq);

	if (dd->next_rq[data_dir] == rq)
		dd->next_rq[data_dir] = deadline_latter_request(rq);

	elv_rb_del(deadline_rb_root(dd, rq), rq);
}

/*
 * remove rq from rbtree and fifo.
 */
static void deadline_remove_request(struct request_queue *q, struct request *rq)
{
	struct deadline_data *dd = q->elevator->elevator_data;

	list_del_init(&rq->queuelist);

	/*
	 * We might not be on the rbtree, if we are doing an insert merge
	 */
	if (!RB_EMPTY_NODE(&rq->rb_node))
		deadline_del_rq_rb(dd, rq);

	elv_rqhash_del(q, rq);
	if (q->last_merge == rq)
		q->last_merge = NULL;
}

static void dd_request_merged(struct request_queue *q, struct request *req,
			      enum elv_merge type)
{
	struct deadline_data *dd = q->elevator->elevator_data;

	/*
	 * if the merge was a front merge, we need to reposition request
	 */
	if (type == ELEVATOR_FRONT_MERGE) {
		elv_rb_del(deadline_rb_root(dd, req), req);
		deadline_add_rq_rb(dd, req);
	}
}

static void dd_merged_requests(struct request_queue *q, struct request *req,
			       struct request *next)
{
	/*
	 * if next expires before rq, assign its expire time to rq
	 * and move into next position (next will be deleted) in fifo
	 */
	if (!list_empty(&req->queuelist) && !list_empty(&next->queuelist)) {
		if (time_before((unsigned long)next->fifo_time,
				(unsigned long)req->fifo_time)) {
			list_move(&req->queuelist, &next->queuelist);
			req->fifo_time = next->fifo_time;
		}
	}

	/*
	 * kill knowledge of next, this one is a goner
	 */
	deadline_remove_request(q, next);
}

/*
 * move an entry to dispatch queue
 */
static void
deadline_move_request(struct deadline_data *dd, struct request *rq)
{
	const int data_dir = rq_data_dir(rq);

	dd->next_rq[READ] = NULL;
	dd->next_rq[WRITE] = NULL;
	dd->next_rq[data_dir] = deadline_latter_request(rq);

	/*
	 * take it off the sort and fifo list
	 */
	deadline_remove_request(rq->q, rq);
}

/*
 * deadline_check_fifo returns 0 if there are no expired requests on the fifo,
 * 1 otherwise. Requires !list_empty(&dd->fifo_list[data_dir])
 */
static inline int deadline_check_fifo(struct deadline_data *dd, int ddir)
{
	struct request *rq = rq_entry_fifo(dd->fifo_list[ddir].next);

	/*
	 * rq is expired!
	 */
	if (time_after_eq(jiffies, (unsigned long)rq->fifo_time))
		return 1;

	return 0;
}

/*
 * deadline_dispatch_requests selects the best request according to
 * read/write expire, fifo_batch, etc
 */
static struct request *__dd_dispatch_request(struct blk_mq_hw_ctx *hctx)
{
	struct deadline_data *dd = hctx->queue->elevator->elevator_data;
	struct request *rq;
	bool reads, writes;
	int data_dir;

	if (!list_empty(&dd->dispatch)) {
		rq = list_first_entry(&dd->dispatch, struct request, queuelist);
		list_del_init(&rq->queuelist);
		goto done;
	}

	reads = !list_empty(&dd->fifo_list[READ]);
	writes = !list_empty(&dd->fifo_list[WRITE]);

	/*
	 * batches are currently reads XOR writes
	 */
	if (dd->next_rq[WRITE])
		rq = dd->next_rq[WRITE];
	else
		rq = dd->next_rq[READ];

	if (rq && dd->batching < dd->fifo_batch)
		/* we have a next request are still entitled to batch */
		goto dispatch_request;

	/*
	 * at this point we are not running a batch. select the appropriate
	 * data direction (read / write)
	 */

	if (reads) {
		BUG_ON(RB_EMPTY_ROOT(&dd->sort_list[READ]));

		if (writes && (dd->starved++ >= dd->writes_starved))
			goto dispatch_writes;

		data_dir = READ;

		goto dispatch_find_request;
	}

	/*
	 * there are either no reads or writes have been starved
	 */