floppy: switch to one queue per drive instead of sharing a queue
Pretty straight forward conversion. Note that we do round-robin
between the drives that have available requests, before we simply
used the drive that the IO scheduler told us to. Since the IO
scheduler doesn't care about multiple devices per queue, the resulting
sort would not have made sense.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/drivers/block/floppy.c b/drivers/block/floppy.c
index 862b40c9..a82f986 100644
--- a/drivers/block/floppy.c
+++ b/drivers/block/floppy.c
@@ -249,8 +249,8 @@
#include <linux/completion.h>
static struct request *current_req;
-static struct request_queue *floppy_queue;
static void do_fd_request(struct request_queue * q);
+static int set_next_request(void);
#ifndef fd_get_dma_residue
#define fd_get_dma_residue() get_dma_residue(FLOPPY_DMA)
@@ -412,6 +412,7 @@
static struct block_device *opened_bdev[N_DRIVE];
static DEFINE_MUTEX(open_lock);
static struct floppy_raw_cmd *raw_cmd, default_raw_cmd;
+static int fdc_queue;
/*
* This struct defines the different floppy types.
@@ -931,8 +932,8 @@
del_timer(&fd_timeout);
cont = NULL;
clear_bit(0, &fdc_busy);
- if (current_req || blk_peek_request(floppy_queue))
- do_fd_request(floppy_queue);
+ if (current_req || set_next_request())
+ do_fd_request(current_req->q);
spin_unlock_irqrestore(&floppy_lock, flags);
wake_up(&fdc_wait);
}
@@ -2316,8 +2317,8 @@
* logical buffer */
static void request_done(int uptodate)
{
- struct request_queue *q = floppy_queue;
struct request *req = current_req;
+ struct request_queue *q;
unsigned long flags;
int block;
@@ -2329,6 +2330,8 @@
return;
}
+ q = req->q;
+
if (uptodate) {
/* maintain values for invalidation on geometry
* change */
@@ -2897,6 +2900,32 @@
return 2;
}
+/*
+ * Round-robin between our available drives, doing one request from each
+ */
+static int set_next_request(void)
+{
+ struct request_queue *q;
+ int old_pos = fdc_queue;
+
+ spin_lock_irq(&floppy_lock);
+
+ old_pos = fdc_queue;
+ do {
+ q = disks[fdc_queue]->queue;
+ if (++fdc_queue == N_DRIVE)
+ fdc_queue = 0;
+ if (q) {
+ current_req = blk_fetch_request(q);
+ if (current_req)
+ break;
+ }
+ } while (fdc_queue != old_pos);
+
+ spin_unlock_irq(&floppy_lock);
+ return current_req != NULL;
+}
+
static void redo_fd_request(void)
{
#define REPEAT {request_done(0); continue; }
@@ -2909,17 +2938,17 @@
for (;;) {
if (!current_req) {
- struct request *req;
+ int pending;
- spin_lock_irq(floppy_queue->queue_lock);
- req = blk_fetch_request(floppy_queue);
- spin_unlock_irq(floppy_queue->queue_lock);
- if (!req) {
+ spin_lock_irq(&floppy_lock);
+ pending = set_next_request();
+ spin_unlock_irq(&floppy_lock);
+
+ if (!pending) {
do_floppy = NULL;
unlock_fdc();
return;
}
- current_req = req;
}
drive = (long)current_req->rq_disk->private_data;
set_fdc(drive);
@@ -4200,6 +4229,13 @@
goto out_put_disk;
}
+ disks[dr]->queue = blk_init_queue(do_fd_request, &floppy_lock);
+ if (!disks[dr]->queue) {
+ err = -ENOMEM;
+ goto out_put_disk;
+ }
+
+ blk_queue_max_sectors(disks[dr]->queue, 64);
disks[dr]->major = FLOPPY_MAJOR;
disks[dr]->first_minor = TOMINOR(dr);
disks[dr]->fops = &floppy_fops;
@@ -4218,13 +4254,6 @@
if (err)
goto out_unreg_blkdev;
- floppy_queue = blk_init_queue(do_fd_request, &floppy_lock);
- if (!floppy_queue) {
- err = -ENOMEM;
- goto out_unreg_driver;
- }
- blk_queue_max_sectors(floppy_queue, 64);
-
blk_register_region(MKDEV(FLOPPY_MAJOR, 0), 256, THIS_MODULE,
floppy_find, NULL, NULL);
@@ -4351,7 +4380,6 @@
/* to be cleaned up... */
disks[drive]->private_data = (void *)(long)drive;
- disks[drive]->queue = floppy_queue;
disks[drive]->flags |= GENHD_FL_REMOVABLE;
disks[drive]->driverfs_dev = &floppy_device[drive].dev;
add_disk(disks[drive]);
@@ -4367,8 +4395,6 @@
floppy_release_irq_and_dma();
out_unreg_region:
blk_unregister_region(MKDEV(FLOPPY_MAJOR, 0), 256);
- blk_cleanup_queue(floppy_queue);
-out_unreg_driver:
platform_driver_unregister(&floppy_driver);
out_unreg_blkdev:
unregister_blkdev(FLOPPY_MAJOR, "fd");
@@ -4376,6 +4402,8 @@
while (dr--) {
del_timer(&motor_off_timer[dr]);
put_disk(disks[dr]);
+ if (disks[dr]->queue)
+ blk_cleanup_queue(disks[dr]->queue);
}
return err;
}
@@ -4602,11 +4630,11 @@
platform_device_unregister(&floppy_device[drive]);
}
put_disk(disks[drive]);
+ blk_cleanup_queue(disks[drive]->queue);
}
del_timer_sync(&fd_timeout);
del_timer_sync(&fd_timer);
- blk_cleanup_queue(floppy_queue);
if (usage_count)
floppy_release_irq_and_dma();
