I tried converting umem to see how it fit together, this is what I came
up with. This does use a queue per umem unit, but I think that's the
right split anyways. Maybe at some point we can use the per-major
statically allocated queues...
diff -ur -X /home/axboe/cdrom/exclude /opt/kernel/linux-2.5.20/drivers/block/ll_rw_blk.c linux/drivers/block/ll_rw_blk.c
--- /opt/kernel/linux-2.5.20/drivers/block/ll_rw_blk.c 2002-06-03 10:35:35.000000000 +0200
+++ linux/drivers/block/ll_rw_blk.c 2002-06-04 16:14:40.000000000 +0200
@@ -49,6 +49,9 @@
*/
static kmem_cache_t *request_cachep;
+/*
+ * plug management
+ */
static struct list_head blk_plug_list;
static spinlock_t blk_plug_lock __cacheline_aligned_in_smp = SPIN_LOCK_UNLOCKED;
@@ -795,8 +798,8 @@
* force the transfer to start only after we have put all the requests
* on the list.
*
- * This is called with interrupts off and no requests on the queue.
- * (and with the request spinlock acquired)
+ * This is called with interrupts off and no requests on the queue and
+ * with the queue lock held.
*/
void blk_plug_device(request_queue_t *q)
{
@@ -806,7 +809,7 @@
if (!elv_queue_empty(q))
return;
- if (!test_and_set_bit(QUEUE_FLAG_PLUGGED, &q->queue_flags)) {
+ if (!blk_queue_plugged(q)) {
spin_lock(&blk_plug_lock);
list_add_tail(&q->plug_list, &blk_plug_list);
spin_unlock(&blk_plug_lock);
@@ -814,14 +817,27 @@
}
/*
+ * remove the queue from the plugged list, if present. called with
+ * queue lock held and interrupts disabled.
+ */
+inline int blk_remove_plug(request_queue_t *q)
+{
+ if (blk_queue_plugged(q)) {
+ spin_lock(&blk_plug_lock);
+ list_del_init(&q->plug_list);
+ spin_unlock(&blk_plug_lock);
+ return 1;
+ }
+
+ return 0;
+}
+
+/*
* remove the plug and let it rip..
*/
static inline void __generic_unplug_device(request_queue_t *q)
{
- /*
- * not plugged
- */
- if (!__test_and_clear_bit(QUEUE_FLAG_PLUGGED, &q->queue_flags))
+ if (!blk_remove_plug(q))
return;
if (test_bit(QUEUE_FLAG_STOPPED, &q->queue_flags))
@@ -849,11 +865,10 @@
void generic_unplug_device(void *data)
{
request_queue_t *q = data;
- unsigned long flags;
- spin_lock_irqsave(q->queue_lock, flags);
+ spin_lock_irq(q->queue_lock);
__generic_unplug_device(q);
- spin_unlock_irqrestore(q->queue_lock, flags);
+ spin_unlock_irq(q->queue_lock);
}
/**
@@ -893,6 +908,12 @@
**/
void blk_stop_queue(request_queue_t *q)
{
+ unsigned long flags;
+
+ spin_lock_irqsave(q->queue_lock, flags);
+ blk_remove_plug(q);
+ spin_unlock_irqrestore(q->queue_lock, flags);
+
set_bit(QUEUE_FLAG_STOPPED, &q->queue_flags);
}
@@ -904,45 +925,31 @@
* are currently stopped are ignored. This is equivalent to the older
* tq_disk task queue run.
**/
+#define blk_plug_entry(entry) list_entry((entry), request_queue_t, plug_list)
void blk_run_queues(void)
{
- struct list_head *n, *tmp, local_plug_list;
- unsigned long flags;
+ struct list_head local_plug_list;
INIT_LIST_HEAD(&local_plug_list);
+ spin_lock_irq(&blk_plug_lock);
+
/*
* this will happen fairly often
*/
- spin_lock_irqsave(&blk_plug_lock, flags);
if (list_empty(&blk_plug_list)) {
- spin_unlock_irqrestore(&blk_plug_lock, flags);
+ spin_unlock_irq(&blk_plug_lock);
return;
}
list_splice(&blk_plug_list, &local_plug_list);
INIT_LIST_HEAD(&blk_plug_list);
- spin_unlock_irqrestore(&blk_plug_lock, flags);
+ spin_unlock_irq(&blk_plug_lock);
+
+ while (!list_empty(&local_plug_list)) {
+ request_queue_t *q = blk_plug_entry(local_plug_list.next);
- /*
- * local_plug_list is now a private copy we can traverse lockless
- */
- list_for_each_safe(n, tmp, &local_plug_list) {
- request_queue_t *q = list_entry(n, request_queue_t, plug_list);
-
- if (!test_bit(QUEUE_FLAG_STOPPED, &q->queue_flags)) {
- list_del(&q->plug_list);
- generic_unplug_device(q);
- }
- }
-
- /*
- * add any remaining queue back to plug list
- */
- if (!list_empty(&local_plug_list)) {
- spin_lock_irqsave(&blk_plug_lock, flags);
- list_splice(&local_plug_list, &blk_plug_list);
- spin_unlock_irqrestore(&blk_plug_lock, flags);
+ q->unplug_fn(q);
}
}
@@ -1085,6 +1092,7 @@
q->front_merge_fn = ll_front_merge_fn;
q->merge_requests_fn = ll_merge_requests_fn;
q->prep_rq_fn = NULL;
+ q->unplug_fn = generic_unplug_device;
q->queue_flags = (1 << QUEUE_FLAG_CLUSTER);
q->queue_lock = lock;
@@ -1352,7 +1360,7 @@
static int __make_request(request_queue_t *q, struct bio *bio)
{
struct request *req, *freereq = NULL;
- int el_ret, rw, nr_sectors, cur_nr_sectors, barrier;
+ int el_ret, rw, nr_sectors, cur_nr_sectors;
struct list_head *insert_here;
sector_t sector;
@@ -1368,16 +1376,12 @@
*/
blk_queue_bounce(q, &bio);
- spin_lock_prefetch(q->queue_lock);
-
- barrier = test_bit(BIO_RW_BARRIER, &bio->bi_rw);
-
spin_lock_irq(q->queue_lock);
again:
req = NULL;
insert_here = q->queue_head.prev;
- if (blk_queue_empty(q) || barrier) {
+ if (blk_queue_empty(q) || bio_barrier(bio)) {
blk_plug_device(q);
goto get_rq;
}
@@ -1477,7 +1481,7 @@
/*
* REQ_BARRIER implies no merging, but lets make it explicit
*/
- if (barrier)
+ if (bio_barrier(bio))
req->flags |= (REQ_BARRIER | REQ_NOMERGE);
req->errors = 0;
@@ -1489,9 +1493,7 @@
req->buffer = bio_data(bio); /* see ->buffer comment above */
req->waiting = NULL;
req->bio = req->biotail = bio;
- if (bio->bi_bdev)
- req->rq_dev = to_kdev_t(bio->bi_bdev->bd_dev);
- else req->rq_dev = NODEV;
+ req->rq_dev = to_kdev_t(bio->bi_bdev->bd_dev);
add_request(q, req, insert_here);
out:
if (freereq)
@@ -2002,6 +2004,8 @@
EXPORT_SYMBOL(generic_make_request);
EXPORT_SYMBOL(blkdev_release_request);
EXPORT_SYMBOL(generic_unplug_device);
+EXPORT_SYMBOL(blk_plug_device);
+EXPORT_SYMBOL(blk_remove_plug);
EXPORT_SYMBOL(blk_attempt_remerge);
EXPORT_SYMBOL(blk_max_low_pfn);
EXPORT_SYMBOL(blk_max_pfn);
diff -ur -X /home/axboe/cdrom/exclude /opt/kernel/linux-2.5.20/drivers/block/umem.c linux/drivers/block/umem.c
--- /opt/kernel/linux-2.5.20/drivers/block/umem.c 2002-05-29 20:42:54.000000000 +0200
+++ linux/drivers/block/umem.c 2002-06-04 16:13:48.000000000 +0200
@@ -128,6 +128,8 @@
*/
struct bio *bio, *currentbio, **biotail;
+ request_queue_t queue;
+
struct mm_page {
dma_addr_t page_dma;
struct mm_dma_desc *desc;
@@ -141,8 +143,6 @@
struct tasklet_struct tasklet;
unsigned int dma_status;
- struct tq_struct plug_tq;
-
struct {
int good;
int warned;
@@ -383,7 +383,10 @@
static void mm_unplug_device(void *data)
{
- struct cardinfo *card = data;
+ request_queue_t *q = data;
+ struct cardinfo *card = q->queuedata;
+
+ blk_remove_plug(q);
spin_lock_bh(&card->lock);
activate(card);
@@ -577,7 +580,7 @@
card->biotail = &bio->bi_next;
spin_unlock_bh(&card->lock);
- queue_task(&card->plug_tq, &tq_disk);
+ blk_plug_device(q);
return 0;
}
@@ -1064,11 +1067,12 @@
card->bio = NULL;
card->biotail = &card->bio;
+ blk_queue_make_request(&card->queue, mm_make_request);
+ card->queue.queuedata = card;
+ card->queue.unplug_fn = mm_unplug_device;
+
tasklet_init(&card->tasklet, process_page, (unsigned long)card);
- card->plug_tq.sync = 0;
- card->plug_tq.routine = &mm_unplug_device;
- card->plug_tq.data = card;
card->check_batteries = 0;
mem_present = readb(card->csr_remap + MEMCTRLSTATUS_MEMORY);
@@ -1277,9 +1281,6 @@
add_gendisk(&mm_gendisk);
- blk_queue_make_request(BLK_DEFAULT_QUEUE(MAJOR_NR),
- mm_make_request);
-
blk_size[MAJOR_NR] = mm_gendisk.sizes;
for (i = 0; i < num_cards; i++) {
register_disk(&mm_gendisk, mk_kdev(MAJOR_NR, i<<MM_SHIFT), MM_SHIFT,
diff -ur -X /home/axboe/cdrom/exclude /opt/kernel/linux-2.5.20/include/linux/bio.h linux/include/linux/bio.h
--- /opt/kernel/linux-2.5.20/include/linux/bio.h 2002-05-29 20:42:57.000000000 +0200
+++ linux/include/linux/bio.h 2002-06-04 16:14:59.000000000 +0200
@@ -123,7 +123,7 @@
#define bio_offset(bio) bio_iovec((bio))->bv_offset
#define bio_sectors(bio) ((bio)->bi_size >> 9)
#define bio_data(bio) (page_address(bio_page((bio))) + bio_offset((bio)))
-#define bio_barrier(bio) ((bio)->bi_rw & (1 << BIO_BARRIER))
+#define bio_barrier(bio) ((bio)->bi_rw & (1 << BIO_RW_BARRIER))
/*
* will die
diff -ur -X /home/axboe/cdrom/exclude /opt/kernel/linux-2.5.20/include/linux/blkdev.h linux/include/linux/blkdev.h
--- /opt/kernel/linux-2.5.20/include/linux/blkdev.h 2002-06-03 10:35:40.000000000 +0200
+++ linux/include/linux/blkdev.h 2002-06-04 16:15:22.000000000 +0200
@@ -116,7 +116,7 @@
typedef request_queue_t * (queue_proc) (kdev_t dev);
typedef int (make_request_fn) (request_queue_t *q, struct bio *bio);
typedef int (prep_rq_fn) (request_queue_t *, struct request *);
-typedef void (unplug_device_fn) (void *q);
+typedef void (unplug_fn) (void *q);
enum blk_queue_state {
Queue_down,
@@ -160,6 +160,7 @@
merge_requests_fn *merge_requests_fn;
make_request_fn *make_request_fn;
prep_rq_fn *prep_rq_fn;
+ unplug_fn *unplug_fn;
struct backing_dev_info backing_dev_info;
@@ -209,13 +210,11 @@
#define RQ_SCSI_DONE 0xfffe
#define RQ_SCSI_DISCONNECTING 0xffe0
-#define QUEUE_FLAG_PLUGGED 0 /* queue is plugged */
-#define QUEUE_FLAG_CLUSTER 1 /* cluster several segments into 1 */
-#define QUEUE_FLAG_QUEUED 2 /* uses generic tag queueing */
-#define QUEUE_FLAG_STOPPED 3 /* queue is stopped */
+#define QUEUE_FLAG_CLUSTER 0 /* cluster several segments into 1 */
+#define QUEUE_FLAG_QUEUED 1 /* uses generic tag queueing */
+#define QUEUE_FLAG_STOPPED 2 /* queue is stopped */
-#define blk_queue_plugged(q) test_bit(QUEUE_FLAG_PLUGGED, &(q)->queue_flags)
-#define blk_mark_plugged(q) set_bit(QUEUE_FLAG_PLUGGED, &(q)->queue_flags)
+#define blk_queue_plugged(q) !list_empty(&(q)->plug_list)
#define blk_queue_tagged(q) test_bit(QUEUE_FLAG_QUEUED, &(q)->queue_flags)
#define blk_queue_empty(q) elv_queue_empty(q)
#define list_entry_rq(ptr) list_entry((ptr), struct request, queuelist)
@@ -295,6 +294,7 @@
extern struct request *blk_get_request(request_queue_t *, int, int);
extern void blk_put_request(struct request *);
extern void blk_plug_device(request_queue_t *);
+extern int blk_remove_plug(request_queue_t *);
extern void blk_recount_segments(request_queue_t *, struct bio *);
extern inline int blk_phys_contig_segment(request_queue_t *q, struct bio *, struct bio *);
extern inline int blk_hw_contig_segment(request_queue_t *q, struct bio *, struct bio *);
-- Jens Axboe- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/