atari floppy: Stop sharing request queue across multiple gendisks

o Use one request queue per gendisk instead of sharing the queue.

o Don't have hardware. No compile testing or run time testing done. Completely
  untested.

Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

1 files changed, 39 insertions, 11 deletions

diff --git a/drivers/block/ataflop.c b/drivers/block/ataflop.c
index aceb96476524..0f4eec442e5d 100644
--- a/drivers/block/ataflop.c
+++ b/drivers/block/ataflop.c
@@ -79,8 +79,8 @@
 
 #undef DEBUG
 
-static struct request_queue *floppy_queue;
 static struct request *fd_request;
+static int fdc_queue;
 
 /* Disk types: DD, HD, ED */
 static struct atari_disk_type {
@@ -1391,6 +1391,29 @@ static void setup_req_params( int drive )
                         ReqTrack, ReqSector, (unsigned long)ReqData ));
 }
 
+/*
+ * Round-robin between our available drives, doing one request from each
+ */
+static struct request *set_next_request(void)
+{
+        struct request_queue *q;
+        int old_pos = fdc_queue;
+        struct request *rq;
+
+        do {
+                q = unit[fdc_queue].disk->queue;
+                if (++fdc_queue == FD_MAX_UNITS)
+                        fdc_queue = 0;
+                if (q) {
+                        rq = blk_fetch_request(q);
+                        if (rq)
+                                break;
+                }
+        } while (fdc_queue != old_pos);
+
+        return rq;
+}
+
 
 static void redo_fd_request(void)
 {
@@ -1405,7 +1428,7 @@ static void redo_fd_request(void)
 
 repeat:
         if (!fd_request) {
-                fd_request = blk_fetch_request(floppy_queue);
+                fd_request = set_next_request();
                 if (!fd_request)
                         goto the_end;
         }
@@ -1932,10 +1955,6 @@ static int __init atari_floppy_init (void)
         PhysTrackBuffer = virt_to_phys(TrackBuffer);
         BufferDrive = BufferSide = BufferTrack = -1;
 
-        floppy_queue = blk_init_queue(do_fd_request, &ataflop_lock);
-        if (!floppy_queue)
-                goto Enomem;
-
         for (i = 0; i < FD_MAX_UNITS; i++) {
                 unit[i].track = -1;
                 unit[i].flags = 0;
@@ -1944,7 +1963,10 @@ static int __init atari_floppy_init (void)
                 sprintf(unit[i].disk->disk_name, "fd%d", i);
                 unit[i].disk->fops = &floppy_fops;
                 unit[i].disk->private_data = &unit[i];
-                unit[i].disk->queue = floppy_queue;
+                unit[i].disk->queue = blk_init_queue(do_fd_request,
+                                        &ataflop_lock);
+                if (!unit[i].disk->queue)
+                        goto Enomem;
                 set_capacity(unit[i].disk, MAX_DISK_SIZE * 2);
                 add_disk(unit[i].disk);
         }
@@ -1959,10 +1981,14 @@ static int __init atari_floppy_init (void)
 
         return 0;
 Enomem:
-        while (i--)
+        while (i--) {
+                struct request_queue *q = unit[i].disk->queue;
+
                 put_disk(unit[i].disk);
-        if (floppy_queue)
-                blk_cleanup_queue(floppy_queue);
+                if (q)
+                        blk_cleanup_queue(q);
+        }
+
         unregister_blkdev(FLOPPY_MAJOR, "fd");
         return -ENOMEM;
 }
@@ -2011,12 +2037,14 @@ static void __exit atari_floppy_exit(void)
         int i;
         blk_unregister_region(MKDEV(FLOPPY_MAJOR, 0), 256);
         for (i = 0; i < FD_MAX_UNITS; i++) {
+                struct request_queue *q = unit[i].disk->queue;
+
                 del_gendisk(unit[i].disk);
                 put_disk(unit[i].disk);
+                blk_cleanup_queue(q);
         }
         unregister_blkdev(FLOPPY_MAJOR, "fd");
 
-        blk_cleanup_queue(floppy_queue);
         del_timer_sync(&fd_timer);
         atari_stram_free( DMABuffer );
 }