Messages in this thread Patch in this message | | | From | tom.leiming@gmail ... | Subject | [PATCH] driver core: remove polling for driver_probe_done(v2) | Date | Fri, 30 Jan 2009 10:31:42 +0800 |
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From: Ming Lei <tom.leiming@gmail.com>
This patch renames driver_probe_done to driver_wait_probe_done, and make it wait on condition of probing done to remove polling for it in fs initialization. Also add driver_wait_probe_done_and_dev_appear(name) to allow callers to wait until all probing is done AND until the device @name exists.
Removing polling in fs initialization may lead to a faster boot.
Signed-off-by: Ming Lei <tom.leiming@gmail.com> --- drivers/base/dd.c | 26 +++++++++++++++++++------- include/linux/device.h | 3 ++- init/do_mounts.c | 9 ++++----- init/do_mounts_md.c | 5 +++-- 4 files changed, 28 insertions(+), 15 deletions(-)
diff --git a/drivers/base/dd.c b/drivers/base/dd.c index 9b721d3..ab8c30f 100644 --- a/drivers/base/dd.c +++ b/drivers/base/dd.c @@ -21,6 +21,7 @@ #include <linux/module.h> #include <linux/kthread.h> #include <linux/wait.h> +#include <linux/mount.h> #include "base.h" #include "power/power.h" @@ -153,21 +154,32 @@ done: } /** - * driver_probe_done - * Determine if the probe sequence is finished or not. + * driver_probe_wait_done + * wait until the probe sequence is finished. * - * Should somehow figure out how to use a semaphore, not an atomic variable... */ -int driver_probe_done(void) +void driver_wait_probe_done(void) { pr_debug("%s: probe_count = %d\n", __func__, atomic_read(&probe_count)); - if (atomic_read(&probe_count)) - return -EBUSY; - return 0; + + wait_event(probe_waitqueue, atomic_read(&probe_count) == 0); } /** + * driver_wait_probe_done_and_dev_appear + * wait until the probe sequence is finished _and_ the dev @name appears. + * + */ +void driver_wait_probe_done_and_dev_appear(char *name) +{ + pr_debug("%s: probe_count = %d\n", __func__, + atomic_read(&probe_count)); + + wait_event(probe_waitqueue, (atomic_read(&probe_count) == 0) && + name_to_dev_t(name)); +} +/** * driver_probe_device - attempt to bind device & driver together * @drv: driver to bind a device to * @dev: device to try to bind to the driver diff --git a/include/linux/device.h b/include/linux/device.h index 45e5b19..7e2e138 100644 --- a/include/linux/device.h +++ b/include/linux/device.h @@ -146,7 +146,8 @@ extern struct device_driver *get_driver(struct device_driver *drv); extern void put_driver(struct device_driver *drv); extern struct device_driver *driver_find(const char *name, struct bus_type *bus); -extern int driver_probe_done(void); +extern void driver_wait_probe_done(void); +extern void driver_wait_probe_done_and_dev_appear(char *name); /* sysfs interface for exporting driver attributes */ diff --git a/init/do_mounts.c b/init/do_mounts.c index 708105e..1bf34fc 100644 --- a/init/do_mounts.c +++ b/init/do_mounts.c @@ -371,8 +371,8 @@ void __init prepare_namespace(void) } /* wait for the known devices to complete their probing */ - while (driver_probe_done() != 0) - msleep(100); + driver_wait_probe_done(); + async_synchronize_full(); md_run_setup(); @@ -396,9 +396,8 @@ void __init prepare_namespace(void) 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); + driver_wait_probe_done_and_dev_appear(saved_root_name); + ROOT_DEV = name_to_dev_t(saved_root_name); } is_floppy = MAJOR(ROOT_DEV) == FLOPPY_MAJOR; diff --git a/init/do_mounts_md.c b/init/do_mounts_md.c index ff95e31..bcea03b 100644 --- a/init/do_mounts_md.c +++ b/init/do_mounts_md.c @@ -281,8 +281,9 @@ static void __init autodetect_raid(void) */ printk(KERN_INFO "md: Waiting for all devices to be available before autodetect\n"); printk(KERN_INFO "md: If you don't use raid, use raid=noautodetect\n"); - while (driver_probe_done() < 0) - msleep(100); + + driver_wait_probe_done(); + fd = sys_open("/dev/md0", 0, 0); if (fd >= 0) { sys_ioctl(fd, RAID_AUTORUN, raid_autopart); -- 1.6.0
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