parport/pcd: stop sharing request queue across multiple gendisks

Compile-tested only.

Cc: Tim Waugh <tim@cyberelk.net>
Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

diff --git a/drivers/block/paride/pcd.c b/drivers/block/paride/pcd.c
index 939641d6e2625e80babab415331c1ac187d88251..b1267ef34d5a7d918a5be1ff6d50194f96f78f33 100644 (file)
--- a/drivers/block/paride/pcd.c
+++ b/drivers/block/paride/pcd.c
@@ -300,6 +300,11 @@ static void pcd_init_units(void)
                struct gendisk *disk = alloc_disk(1);
                if (!disk)
                        continue;
+               disk->queue = blk_init_queue(do_pcd_request, &pcd_lock);
+               if (!disk->queue) {
+                       put_disk(disk);
+                       continue;
+               }
                cd->disk = disk;
                cd->pi = &cd->pia;
                cd->present = 0;
@@ -735,18 +740,36 @@ static int pcd_detect(void)
 }
 
 /* I/O request processing */
-static struct request_queue *pcd_queue;
+static int pcd_queue;
+
+static int set_next_request(void)
+{
+       struct pcd_unit *cd;
+       struct request_queue *q;
+       int old_pos = pcd_queue;
+
+       do {
+               cd = &pcd[pcd_queue];
+               q = cd->present ? cd->disk->queue : NULL;
+               if (++pcd_queue == PCD_UNITS)
+                       pcd_queue = 0;
+               if (q) {
+                       pcd_req = blk_fetch_request(q);
+                       if (pcd_req)
+                               break;
+               }
+       } while (pcd_queue != old_pos);
+
+       return pcd_req != NULL;
+}
 
-static void do_pcd_request(struct request_queue * q)
+static void pcd_request(void)
 {
        if (pcd_busy)
                return;
        while (1) {
-               if (!pcd_req) {
-                       pcd_req = blk_fetch_request(q);
-                       if (!pcd_req)
-                               return;
-               }
+               if (!pcd_req && !set_next_request())
+                       return;
 
                if (rq_data_dir(pcd_req) == READ) {
                        struct pcd_unit *cd = pcd_req->rq_disk->private_data;
@@ -766,6 +789,11 @@ static void do_pcd_request(struct request_queue * q)
        }
 }
 
+static void do_pcd_request(struct request_queue *q)
+{
+       pcd_request();
+}
+
 static inline void next_request(int err)
 {
        unsigned long saved_flags;
@@ -774,7 +802,7 @@ static inline void next_request(int err)
        if (!__blk_end_request_cur(pcd_req, err))
                pcd_req = NULL;
        pcd_busy = 0;
-       do_pcd_request(pcd_queue);
+       pcd_request();
        spin_unlock_irqrestore(&pcd_lock, saved_flags);
 }
 
@@ -849,7 +877,7 @@ static void do_pcd_read_drq(void)
 
        do_pcd_read();
        spin_lock_irqsave(&pcd_lock, saved_flags);
-       do_pcd_request(pcd_queue);
+       pcd_request();
        spin_unlock_irqrestore(&pcd_lock, saved_flags);
 }
 
@@ -957,19 +985,10 @@ static int __init pcd_init(void)
                return -EBUSY;
        }
 
-       pcd_queue = blk_init_queue(do_pcd_request, &pcd_lock);
-       if (!pcd_queue) {
-               unregister_blkdev(major, name);
-               for (unit = 0, cd = pcd; unit < PCD_UNITS; unit++, cd++)
-                       put_disk(cd->disk);
-               return -ENOMEM;
-       }
-
        for (unit = 0, cd = pcd; unit < PCD_UNITS; unit++, cd++) {
                if (cd->present) {
                        register_cdrom(&cd->info);
                        cd->disk->private_data = cd;
-                       cd->disk->queue = pcd_queue;
                        add_disk(cd->disk);
                }
        }
@@ -988,9 +1007,9 @@ static void __exit pcd_exit(void)
                        pi_release(cd->pi);
                        unregister_cdrom(&cd->info);
                }
+               blk_cleanup_queue(cd->disk->queue);
                put_disk(cd->disk);
        }
-       blk_cleanup_queue(pcd_queue);
        unregister_blkdev(major, name);
        pi_unregister_driver(par_drv);
 }