Messages in this thread Patches in this message | | | Date | Tue, 3 May 2005 13:13:53 +0200 | From | David Welton <> | Subject | Re: rootdelay |
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> Ok, I updated to 2.6.11.8, and indeed it does have problems that > weren't there before - although in my case it can't mount the root > partition because it's not quite ready yet. In part, it seems to be > caused by the fact that the USB start up sequence introduces a new > thread that delays the scsi_host_scan by 5 seconds, which is long > enough to cause problems. I added some code to wait for not only the > disk name to be online, but the partition, but even that doesn't seem > to be quite enough.
> Is there anyplace generic that could be hooked that will report when a > device is actually online and ready to run? Perhaps I was just lucky > in the past with add_disk :-/
I "fixed" the problem by not letting storage_probe in storage/usb.c finish until the scan_thread is done. That doesn't seem elegant - perhaps there is a better place to put the wait_for_completion(&us->scsi_scan_done) call so that the scanning thread can go off and do its thing, but will still be waited on where it counts?
I am including a copy of the patch inline, as well as attaching it. I suspect that gmail will mangle the inline version some...
Thankyou, Dave
diff -uprN -X dontdiff linux-2.6.11.8/drivers/block/genhd.c linux-wakeup/drivers/block/genhd.c --- linux-2.6.11.8/drivers/block/genhd.c 2005-04-30 03:27:21.000000000 +0200 +++ linux-wakeup/drivers/block/genhd.c 2005-05-02 19:22:13.000000000 +0200 @@ -14,9 +14,14 @@ #include <linux/slab.h> #include <linux/kmod.h> #include <linux/kobj_map.h> +#include <linux/wait.h> +#include <linux/sched.h> #define MAX_PROBE_HASH 255 /* random */ +DECLARE_WAIT_QUEUE_HEAD(disk_wait_h); +EXPORT_SYMBOL(disk_wait_h); + static struct subsystem block_subsys; static DECLARE_MUTEX(block_subsys_sem); @@ -58,6 +63,49 @@ int get_blkdev_list(char *p) } #endif +/* + * Returns an array of all the block device names and partitions. + */ + +char **get_blkdevs(void) +{ + int i = 0; + int n = 0; + int len = 0; + struct list_head *p; + char **names = NULL; + struct gendisk *sgp; + char buf[BDEVNAME_SIZE]; + + down_read(&block_subsys.rwsem); + + list_for_each(p, &block_subsys.kset.list) { + len ++; + } + + names = kmalloc(sizeof(char *) * len + 1, GFP_KERNEL); + + list_for_each(p, &block_subsys.kset.list) { + sgp = list_entry(p, struct gendisk, kobj.entry); + names[i] = kmalloc(strlen(disk_name(sgp, 0, buf)), GFP_KERNEL); + strcpy(names[i], disk_name(sgp, 0, buf)); + + for (n = 0; n < sgp->minors - 1; n++) { + struct hd_struct *hd = sgp->part[n]; + if (hd && hd->nr_sects) { + names[i] = kmalloc(strlen(disk_name(sgp, n+1, buf)), GFP_KERNEL); + strcpy(names[i], disk_name(sgp, n+1, buf)); + i ++; + } + } + } + names[i] = NULL; + up_read(&block_subsys.rwsem); + return names; +} + +EXPORT_SYMBOL(get_blkdevs); + int register_blkdev(unsigned int major, const char *name) { struct blk_major_name **n, *p; @@ -192,6 +240,11 @@ void add_disk(struct gendisk *disk) disk->minors, NULL, exact_match, exact_lock, disk); register_disk(disk); blk_register_queue(disk); + + /* Wake up queue in init/main.c. */ + printk("Waking up queue on %s\n", + disk->disk_name); + wake_up_interruptible(&disk_wait_h); } EXPORT_SYMBOL(add_disk); diff -uprN -X dontdiff linux-2.6.11.8/drivers/usb/storage/usb.c linux-wakeup/drivers/usb/storage/usb.c --- linux-2.6.11.8/drivers/usb/storage/usb.c 2005-04-30 03:25:25.000000000 +0200 +++ linux-wakeup/drivers/usb/storage/usb.c 2005-05-03 12:15:29.000000000 +0200 @@ -1009,6 +1009,7 @@ static int storage_probe(struct usb_inte /* Start up the thread for delayed SCSI-device scanning */ result = kernel_thread(usb_stor_scan_thread, us, CLONE_VM); + if (result < 0) { printk(KERN_WARNING USB_STORAGE "Unable to start the device-scanning thread\n"); @@ -1016,6 +1017,8 @@ static int storage_probe(struct usb_inte goto BadDevice; } + wait_for_completion(&us->scsi_scan_done); + return 0; /* We come here if there are any problems */ diff -uprN -X dontdiff linux-2.6.11.8/include/linux/genhd.h linux-wakeup/include/linux/genhd.h --- linux-2.6.11.8/include/linux/genhd.h 2005-04-30 03:24:13.000000000 +0200 +++ linux-wakeup/include/linux/genhd.h 2005-05-02 12:04:50.000000000 +0200 @@ -16,6 +16,10 @@ #include <linux/smp.h> #include <linux/string.h> #include <linux/fs.h> +#include <linux/wait.h> + +/* Wait queue to wait on disks coming online. */ +extern wait_queue_head_t disk_wait_h; enum { /* These three have identical behaviour; use the second one if DOS FDISK gets @@ -232,6 +236,7 @@ extern struct gendisk *get_gendisk(dev_t extern void set_device_ro(struct block_device *bdev, int flag); extern void set_disk_ro(struct gendisk *disk, int flag); +extern char **get_blkdevs(void); /* drivers/char/random.c */ extern void add_disk_randomness(struct gendisk *disk); diff -uprN -X dontdiff linux-2.6.11.8/init/do_mounts.c linux-wakeup/init/do_mounts.c --- linux-2.6.11.8/init/do_mounts.c 2005-04-30 03:26:32.000000000 +0200 +++ linux-wakeup/init/do_mounts.c 2005-05-02 19:22:51.000000000 +0200 @@ -12,6 +12,8 @@ #include <linux/nfs_fs_sb.h> #include <linux/nfs_mount.h> +#include <linux/genhd.h> + #include "do_mounts.h" extern int get_filesystem_list(char * buf); @@ -360,8 +362,35 @@ void __init change_floppy(char *fmt, ... } #endif +/* + * match_root_name - Returns 1 if the root_device_name appears amongst + * the list of block devices, 0 otherwise. + */ + +static int __init match_root_name(void) { + char **names = NULL; + int i = 0; + int match = 0; + + names = get_blkdevs(); + while (names[i] != NULL) { + if (match == 0 && strncmp(names[i], + root_device_name, + strlen(root_device_name)) == 0) { + match = 1; + printk("Block device %s matches %s root_device_name, continuing\n", + names[i], root_device_name); + } + kfree(names[i]); + i ++; + } + kfree(names); + return match; +} + void __init mount_root(void) { + #ifdef CONFIG_ROOT_NFS if (MAJOR(ROOT_DEV) == UNNAMED_MAJOR) { if (mount_nfs_root()) @@ -383,6 +412,14 @@ void __init mount_root(void) change_floppy("root floppy"); } #endif + + /* Here, we wait for the root device to show up, or if it's + * already there, we just go on. */ + while (!match_root_name()) { + printk("Waiting for root device to wake us up\n"); + interruptible_sleep_on(&disk_wait_h); + } + create_dev("/dev/root", ROOT_DEV, root_device_name); mount_block_root("/dev/root", root_mountflags); } diff -uprN -X dontdiff linux-2.6.11.8/init/main.c linux-wakeup/init/main.c --- linux-2.6.11.8/init/main.c 2005-04-30 03:24:18.000000000 +0200 +++ linux-wakeup/init/main.c 2005-05-02 12:04:50.000000000 +0200 @@ -47,6 +47,11 @@ #include <linux/mempolicy.h> #include <linux/key.h> +#include <linux/genhd.h> +#include <linux/wait.h> +#include <linux/sched.h> + + #include <asm/io.h> #include <asm/bugs.h> #include <asm/setup.h>diff -uprN -X dontdiff linux-2.6.11.8/drivers/block/genhd.c linux-wakeup/drivers/block/genhd.c --- linux-2.6.11.8/drivers/block/genhd.c 2005-04-30 03:27:21.000000000 +0200 +++ linux-wakeup/drivers/block/genhd.c 2005-05-02 19:22:13.000000000 +0200 @@ -14,9 +14,14 @@ #include <linux/slab.h> #include <linux/kmod.h> #include <linux/kobj_map.h> +#include <linux/wait.h> +#include <linux/sched.h> #define MAX_PROBE_HASH 255 /* random */ +DECLARE_WAIT_QUEUE_HEAD(disk_wait_h); +EXPORT_SYMBOL(disk_wait_h); + static struct subsystem block_subsys; static DECLARE_MUTEX(block_subsys_sem); @@ -58,6 +63,49 @@ int get_blkdev_list(char *p) } #endif +/* + * Returns an array of all the block device names and partitions. + */ + +char **get_blkdevs(void) +{ + int i = 0; + int n = 0; + int len = 0; + struct list_head *p; + char **names = NULL; + struct gendisk *sgp; + char buf[BDEVNAME_SIZE]; + + down_read(&block_subsys.rwsem); + + list_for_each(p, &block_subsys.kset.list) { + len ++; + } + + names = kmalloc(sizeof(char *) * len + 1, GFP_KERNEL); + + list_for_each(p, &block_subsys.kset.list) { + sgp = list_entry(p, struct gendisk, kobj.entry); + names[i] = kmalloc(strlen(disk_name(sgp, 0, buf)), GFP_KERNEL); + strcpy(names[i], disk_name(sgp, 0, buf)); + + for (n = 0; n < sgp->minors - 1; n++) { + struct hd_struct *hd = sgp->part[n]; + if (hd && hd->nr_sects) { + names[i] = kmalloc(strlen(disk_name(sgp, n+1, buf)), GFP_KERNEL); + strcpy(names[i], disk_name(sgp, n+1, buf)); + i ++; + } + } + } + names[i] = NULL; + up_read(&block_subsys.rwsem); + return names; +} + +EXPORT_SYMBOL(get_blkdevs); + int register_blkdev(unsigned int major, const char *name) { struct blk_major_name **n, *p; @@ -192,6 +240,11 @@ void add_disk(struct gendisk *disk) disk->minors, NULL, exact_match, exact_lock, disk); register_disk(disk); blk_register_queue(disk); + + /* Wake up queue in init/main.c. */ + printk("Waking up queue on %s\n", + disk->disk_name); + wake_up_interruptible(&disk_wait_h); } EXPORT_SYMBOL(add_disk); diff -uprN -X dontdiff linux-2.6.11.8/drivers/usb/storage/usb.c linux-wakeup/drivers/usb/storage/usb.c --- linux-2.6.11.8/drivers/usb/storage/usb.c 2005-04-30 03:25:25.000000000 +0200 +++ linux-wakeup/drivers/usb/storage/usb.c 2005-05-03 12:15:29.000000000 +0200 @@ -1009,6 +1009,7 @@ static int storage_probe(struct usb_inte /* Start up the thread for delayed SCSI-device scanning */ result = kernel_thread(usb_stor_scan_thread, us, CLONE_VM); + if (result < 0) { printk(KERN_WARNING USB_STORAGE "Unable to start the device-scanning thread\n"); @@ -1016,6 +1017,8 @@ static int storage_probe(struct usb_inte goto BadDevice; } + wait_for_completion(&us->scsi_scan_done); + return 0; /* We come here if there are any problems */ diff -uprN -X dontdiff linux-2.6.11.8/include/linux/genhd.h linux-wakeup/include/linux/genhd.h --- linux-2.6.11.8/include/linux/genhd.h 2005-04-30 03:24:13.000000000 +0200 +++ linux-wakeup/include/linux/genhd.h 2005-05-02 12:04:50.000000000 +0200 @@ -16,6 +16,10 @@ #include <linux/smp.h> #include <linux/string.h> #include <linux/fs.h> +#include <linux/wait.h> + +/* Wait queue to wait on disks coming online. */ +extern wait_queue_head_t disk_wait_h; enum { /* These three have identical behaviour; use the second one if DOS FDISK gets @@ -232,6 +236,7 @@ extern struct gendisk *get_gendisk(dev_t extern void set_device_ro(struct block_device *bdev, int flag); extern void set_disk_ro(struct gendisk *disk, int flag); +extern char **get_blkdevs(void); /* drivers/char/random.c */ extern void add_disk_randomness(struct gendisk *disk); diff -uprN -X dontdiff linux-2.6.11.8/init/do_mounts.c linux-wakeup/init/do_mounts.c --- linux-2.6.11.8/init/do_mounts.c 2005-04-30 03:26:32.000000000 +0200 +++ linux-wakeup/init/do_mounts.c 2005-05-02 19:22:51.000000000 +0200 @@ -12,6 +12,8 @@ #include <linux/nfs_fs_sb.h> #include <linux/nfs_mount.h> +#include <linux/genhd.h> + #include "do_mounts.h" extern int get_filesystem_list(char * buf); @@ -360,8 +362,35 @@ void __init change_floppy(char *fmt, ... } #endif +/* + * match_root_name - Returns 1 if the root_device_name appears amongst + * the list of block devices, 0 otherwise. + */ + +static int __init match_root_name(void) { + char **names = NULL; + int i = 0; + int match = 0; + + names = get_blkdevs(); + while (names[i] != NULL) { + if (match == 0 && strncmp(names[i], + root_device_name, + strlen(root_device_name)) == 0) { + match = 1; + printk("Block device %s matches %s root_device_name, continuing\n", + names[i], root_device_name); + } + kfree(names[i]); + i ++; + } + kfree(names); + return match; +} + void __init mount_root(void) { + #ifdef CONFIG_ROOT_NFS if (MAJOR(ROOT_DEV) == UNNAMED_MAJOR) { if (mount_nfs_root()) @@ -383,6 +412,14 @@ void __init mount_root(void) change_floppy("root floppy"); } #endif + + /* Here, we wait for the root device to show up, or if it's + * already there, we just go on. */ + while (!match_root_name()) { + printk("Waiting for root device to wake us up\n"); + interruptible_sleep_on(&disk_wait_h); + } + create_dev("/dev/root", ROOT_DEV, root_device_name); mount_block_root("/dev/root", root_mountflags); } diff -uprN -X dontdiff linux-2.6.11.8/init/main.c linux-wakeup/init/main.c --- linux-2.6.11.8/init/main.c 2005-04-30 03:24:18.000000000 +0200 +++ linux-wakeup/init/main.c 2005-05-02 12:04:50.000000000 +0200 @@ -47,6 +47,11 @@ #include <linux/mempolicy.h> #include <linux/key.h> +#include <linux/genhd.h> +#include <linux/wait.h> +#include <linux/sched.h> + + #include <asm/io.h> #include <asm/bugs.h> #include <asm/setup.h> | |