hd: stop sharing request queue across multiple gendisks

Compile-tested only.

Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

diff --git a/drivers/block/hd.c b/drivers/block/hd.c
index 6043648..79d63b2 100644 (file)
--- a/drivers/block/hd.c
+++ b/drivers/block/hd.c
@@ -95,7 +95,7 @@
 #define ICRC_ERR               0x80    /* new meaning:  CRC error during transfer */
 
 static DEFINE_SPINLOCK(hd_lock);
-static struct request_queue *hd_queue;
+static unsigned int hd_queue;
 static struct request *hd_req;
 
 #define TIMEOUT_VALUE  (6*HZ)
@@ -537,7 +537,7 @@ static void hd_times_out(unsigned long dummy)
        if (!hd_req)
                return;
 
-       spin_lock_irq(hd_queue->queue_lock);
+       spin_lock_irq(&hd_lock);
        reset = 1;
        name = hd_req->rq_disk->disk_name;
        printk("%s: timeout\n", name);
@@ -548,7 +548,7 @@ static void hd_times_out(unsigned long dummy)
                hd_end_request_cur(-EIO);
        }
        hd_request();
-       spin_unlock_irq(hd_queue->queue_lock);
+       spin_unlock_irq(&hd_lock);
 }
 
 static int do_special_op(struct hd_i_struct *disk, struct request *req)
@@ -566,6 +566,25 @@ static int do_special_op(struct hd_i_struct *disk, struct request *req)
        return 1;
 }
 
+static int set_next_request(void)
+{
+       struct request_queue *q;
+       int old_pos = hd_queue;
+
+       do {
+               q = hd_gendisk[hd_queue]->queue;
+               if (++hd_queue == NR_HD)
+                       hd_queue = 0;
+               if (q) {
+                       hd_req = blk_fetch_request(q);
+                       if (hd_req)
+                               break;
+               }
+       } while (hd_queue != old_pos);
+
+       return hd_req != NULL;
+}
+
 /*
  * The driver enables interrupts as much as possible.  In order to do this,
  * (a) the device-interrupt is disabled before entering hd_request(),
@@ -587,12 +606,9 @@ static void hd_request(void)
 repeat:
        del_timer(&device_timer);
 
-       if (!hd_req) {
-               hd_req = blk_fetch_request(hd_queue);
-               if (!hd_req) {
-                       do_hd = NULL;
-                       return;
-               }
+       if (!hd_req && !set_next_request()) {
+               do_hd = NULL;
+               return;
        }
        req = hd_req;
 
@@ -676,7 +692,7 @@ static irqreturn_t hd_interrupt(int irq, void *dev_id)
 {
        void (*handler)(void) = do_hd;
 
-       spin_lock(hd_queue->queue_lock);
+       spin_lock(&hd_lock);
 
        do_hd = NULL;
        del_timer(&device_timer);
@@ -684,7 +700,7 @@ static irqreturn_t hd_interrupt(int irq, void *dev_id)
                handler = unexpected_hd_interrupt;
        handler();
 
-       spin_unlock(hd_queue->queue_lock);
+       spin_unlock(&hd_lock);
 
        return IRQ_HANDLED;
 }
@@ -700,16 +716,8 @@ static int __init hd_init(void)
        if (register_blkdev(HD_MAJOR, "hd"))
                return -1;
 
-       hd_queue = blk_init_queue(do_hd_request, &hd_lock);
-       if (!hd_queue) {
-               unregister_blkdev(HD_MAJOR, "hd");
-               return -ENOMEM;
-       }
-
-       blk_queue_max_hw_sectors(hd_queue, 255);
        init_timer(&device_timer);
        device_timer.function = hd_times_out;
-       blk_queue_logical_block_size(hd_queue, 512);
 
        if (!NR_HD) {
                /*
@@ -742,7 +750,11 @@ static int __init hd_init(void)
                sprintf(disk->disk_name, "hd%c", 'a'+drive);
                disk->private_data = p;
                set_capacity(disk, p->head * p->sect * p->cyl);
-               disk->queue = hd_queue;
+               disk->queue = blk_init_queue(do_hd_request, &hd_lock);
+               if (!disk->queue)
+                       goto Enomem;
+               blk_queue_max_hw_sectors(disk->queue, 255);
+               blk_queue_logical_block_size(disk->queue, 512);
                p->unit = drive;
                hd_gendisk[drive] = disk;
                printk("%s: %luMB, CHS=%d/%d/%d\n",
@@ -781,11 +793,15 @@ out1:
 out:
        del_timer(&device_timer);
        unregister_blkdev(HD_MAJOR, "hd");
-       blk_cleanup_queue(hd_queue);
        return -1;
 Enomem:
-       while (drive--)
-               put_disk(hd_gendisk[drive]);
+       for (drive = 0; drive < NR_HD; drive++) {
+               if (hd_gendisk[drive]) {
+                       if (hd_gendisk[drive]->queue)
+                               blk_cleanup_queue(hd_gendisk[drive]->queue);
+                       put_disk(hd_gendisk[drive]);
+               }
+       }
        goto out;
 }