From cc1ed7542c8c26af0f501da8006b9fce03e9aaca Mon Sep 17 00:00:00 2001 From: Pierre Ossman Date: Sun, 15 Jul 2007 23:40:35 -0700 Subject: init: wait for asynchronously scanned block devices Some buses (e.g. USB and MMC) do their scanning of devices in the background, causing a race between them and prepare_namespace(). In order to be able to use these buses without an initrd, we now wait for the device specified in root= to actually show up. If the device never shows up than we will hang in an infinite loop. In order to not mess with setups that reboot on panic, the feature must be turned on via the command line option "rootwait". [bunk@stusta.de: root_wait can become static] Signed-off-by: Pierre Ossman Cc: Al Viro Cc: Christoph Hellwig Signed-off-by: Adrian Bunk Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- init/do_mounts.c | 24 ++++++++++++++++++++++-- 1 file changed, 22 insertions(+), 2 deletions(-) (limited to 'init') diff --git a/init/do_mounts.c b/init/do_mounts.c index 46fe407fb03..4efa1e5385e 100644 --- a/init/do_mounts.c +++ b/init/do_mounts.c @@ -25,6 +25,7 @@ int __initdata rd_doload; /* 1 = load RAM disk, 0 = don't load */ int root_mountflags = MS_RDONLY | MS_SILENT; char * __initdata root_device_name; static char __initdata saved_root_name[64]; +static int __initdata root_wait; dev_t ROOT_DEV; @@ -216,6 +217,16 @@ static int __init root_dev_setup(char *line) __setup("root=", root_dev_setup); +static int __init rootwait_setup(char *str) +{ + if (*str) + return 0; + root_wait = 1; + return 1; +} + +__setup("rootwait", rootwait_setup); + static char * __initdata root_mount_data; static int __init root_data_setup(char *str) { @@ -438,11 +449,20 @@ void __init prepare_namespace(void) root_device_name += 5; } - is_floppy = MAJOR(ROOT_DEV) == FLOPPY_MAJOR; - if (initrd_load()) goto out; + /* wait for any asynchronous scanning to complete */ + if ((ROOT_DEV == 0) && root_wait) { + printk(KERN_INFO "Waiting for root device %s...\n", + saved_root_name); + while (driver_probe_done() != 0 || + (ROOT_DEV = name_to_dev_t(saved_root_name)) == 0) + msleep(100); + } + + is_floppy = MAJOR(ROOT_DEV) == FLOPPY_MAJOR; + if (is_floppy && rd_doload && rd_load_disk(0)) ROOT_DEV = Root_RAM0; -- cgit v1.2.3