NBD: remove limit on max number of nbd devices

Remove the arbitrary 128 device limit for NBD.  nbds_max can now be set to
any number.  In certain scenarios where devices are used sparsely we have
run into the 128 device limit.

Signed-off-by: Paul Clements <paul.clements@steeleye.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2 files changed, 4 insertions, 7 deletions

diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
index ae3106045ee5..018753c59b8e 100644
--- a/drivers/block/nbd.c
+++ b/drivers/block/nbd.c
@@ -54,7 +54,7 @@ static unsigned int debugflags;
 #endif /* NDEBUG */
 
 static unsigned int nbds_max = 16;
-static struct nbd_device nbd_dev[MAX_NBD];
+static struct nbd_device *nbd_dev;
 
 /*
  * Use just one lock (or at most 1 per NIC). Two arguments for this:
@@ -649,11 +649,9 @@ static int __init nbd_init(void)
 
         BUILD_BUG_ON(sizeof(struct nbd_request) != 28);
 
-        if (nbds_max > MAX_NBD) {
-                printk(KERN_CRIT "nbd: cannot allocate more than %u nbds; %u requested.\n", MAX_NBD,
-                                nbds_max);
-                return -EINVAL;
-        }
+        nbd_dev = kcalloc(nbds_max, sizeof(*nbd_dev), GFP_KERNEL);
+        if (!nbd_dev)
+                return -ENOMEM;
 
         for (i = 0; i < nbds_max; i++) {
                 struct gendisk *disk = alloc_disk(1);
diff --git a/include/linux/nbd.h b/include/linux/nbd.h
index cc2b47240a8f..986572081e19 100644
--- a/include/linux/nbd.h
+++ b/include/linux/nbd.h
@@ -35,7 +35,6 @@ enum {
 };
 
 #define nbd_cmd(req) ((req)->cmd[0])
-#define MAX_NBD 128
 
 /* userspace doesn't need the nbd_device structure */
 #ifdef __KERNEL__