From 40be0c28b33ff0821594a3fa7126354dfe6eccd1 Mon Sep 17 00:00:00 2001 From: Lars Marowsky-Bree Date: Sun, 1 May 2005 08:59:07 -0700 Subject: [PATCH] [PATCH] nbd: Don't create all MAX_NBD devices by default all the time This patches adds the "nbds_max" parameter to the nbd kernel module, which limits the number of nbds allocated. Previously, always all 128 entries were allocated unconditionally, which used to waste resources and needlessly flood the hotplug system with events. (Defaults to 16 now.) Signed-off-by: Lars Marowsky-Bree Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/block/nbd.c | 16 +++++++++++++--- 1 file changed, 13 insertions(+), 3 deletions(-) diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c index efdf04450b..9e268ddedf 100644 --- a/drivers/block/nbd.c +++ b/drivers/block/nbd.c @@ -78,6 +78,7 @@ #define DBG_RX 0x0200 #define DBG_TX 0x0400 static unsigned int debugflags; +static unsigned int nbds_max = 16; #endif /* NDEBUG */ static struct nbd_device nbd_dev[MAX_NBD]; @@ -647,7 +648,13 @@ static int __init nbd_init(void) return -EIO; } - for (i = 0; i < MAX_NBD; i++) { + if (nbds_max > MAX_NBD) { + printk(KERN_CRIT "nbd: cannot allocate more than %u nbds; %u requested.\n", MAX_NBD, + nbds_max); + return -EINVAL; + } + + for (i = 0; i < nbds_max; i++) { struct gendisk *disk = alloc_disk(1); if (!disk) goto out; @@ -673,7 +680,7 @@ static int __init nbd_init(void) dprintk(DBG_INIT, "nbd: debugflags=0x%x\n", debugflags); devfs_mk_dir("nbd"); - for (i = 0; i < MAX_NBD; i++) { + for (i = 0; i < nbds_max; i++) { struct gendisk *disk = nbd_dev[i].disk; nbd_dev[i].file = NULL; nbd_dev[i].magic = LO_MAGIC; @@ -706,8 +713,9 @@ out: static void __exit nbd_cleanup(void) { int i; - for (i = 0; i < MAX_NBD; i++) { + for (i = 0; i < nbds_max; i++) { struct gendisk *disk = nbd_dev[i].disk; + nbd_dev[i].magic = 0; if (disk) { del_gendisk(disk); blk_cleanup_queue(disk->queue); @@ -725,6 +733,8 @@ module_exit(nbd_cleanup); MODULE_DESCRIPTION("Network Block Device"); MODULE_LICENSE("GPL"); +module_param(nbds_max, int, 0444); +MODULE_PARM_DESC(nbds_max, "How many network block devices to initialize."); #ifndef NDEBUG module_param(debugflags, int, 0644); MODULE_PARM_DESC(debugflags, "flags for controlling debug output"); -- 2.39.5