Re: [PATCH 1/5] initdev:kernel: Asynchronously-discovered device synchronization, v5

David VomLehn
2009-06-05T17:58:27Z

On Tue, May 05, 2009 at 11:47:25AM -0400, Ming Lei wrote:
> On Mon, 4 May 2009 11:07:52 -0400 (EDT)
> Alan Stern <stern@rowland.harvard.edu> wrote:
>
> > On Mon, 4 May 2009, Arjan van de Ven wrote:
...
> > Isn't there still something missing? The wait_for_device_probe()
> > routine would wait until all attached devices had been probed. But
> > why should prepare_namespace() have to wait that long? Wouldn't it be
> > better to wait only until the root device has been registered?
>
> Yes, maybe David should merge the following patch into the patch
> No.5(initdev:kernel: USB and SCSI block init device notification, v3).
>
> Right?
>
> diff --git a/init/do_mounts.c b/init/do_mounts.c
> index dd7ee5f..22fd773 100644
> --- a/init/do_mounts.c
> +++ b/init/do_mounts.c
> @@ -358,6 +358,12 @@ void __init mount_root(void)
> #endif
> }
>
> +static int root_dev_done()
> +{
> + return !!(ROOT_DEV = name_to_dev_t(saved_root_name));
> +}
> +
> +
> /*
> * Prepare the namespace - decide what/where to mount, load ramdisks,
> etc. */
> @@ -398,12 +404,12 @@ void __init prepare_namespace(void)
> goto out;
>
> /* wait for any asynchronous scanning to complete */
> - if ((ROOT_DEV == 0) && root_wait) {
> + 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);
> + do {
> + initdev_wait(BOOTDEV_BLOCK, root_dev_done);
> + } while (!ROOT_DEV);
> async_synchronize_full();
> }

I have something very similar. I'm not completely comfortable with discarding
the rootwait flag, though it should be very rarely used once the initdev
infrastructure is in place.

> Lei Ming

David VomLehn