This patch changes device_shutdown() to use a newly introduce safe reverse list traversal. We experienced loops on system reboot if we had removed and re-inserted our device from the device list. We noticed this problem on PPC405. Our PCI IDE device comes and goes a lot. Our hypothesis was that there was a loop caused by the driver->shutdown freeing memory. It is possible that we do something wrong as well, but being unable to reboot is kind of nasty. Signed-off-by: Michael Richardson <[email protected]> --- drivers/base/power/shutdown.c | 4 ++-- include/linux/list.h | 13 +++++++++++++ 2 files changed, 15 insertions(+), 2 deletions(-) applies-to: 96a0b5842e24d6736c698cdbd820a3ad9d8d9f10 49291875d63ec697510fc4cc9a1766b7400ee2d3 diff --git a/drivers/base/power/shutdown.c b/drivers/base/power/shutdown.c index f50a08b..3a417c8 100644 --- a/drivers/base/power/shutdown.c +++ b/drivers/base/power/shutdown.c @@ -35,10 +35,10 @@ extern int sysdev_shutdown(void); */ void device_shutdown(void) { - struct device * dev; + struct device * dev, *devn; down_write(&devices_subsys.rwsem); - list_for_each_entry_reverse(dev, &devices_subsys.kset.list, + list_for_each_entry_safe_reverse(dev, devn, &devices_subsys.kset.list, kobj.entry) { if (dev->driver && dev->driver->shutdown) { dev_dbg(dev, "shutdown\n"); diff --git a/include/linux/list.h b/include/linux/list.h index 8e33882..b31ec32 100644 --- a/include/linux/list.h +++ b/include/linux/list.h @@ -436,6 +436,19 @@ static inline void list_splice_init(stru pos = n, n = list_entry(n->member.next, typeof(*n), member)) /** + * list_for_each_entry_safe_reverse - iterate backwards over list of given type safe against removal of list entry + * @pos: the type * to use as a loop counter. + * @n: another type * to use as temporary storage + * @head: the head for your list. + * @member: the name of the list_struct within the struct. + */ +#define list_for_each_entry_safe_reverse(pos, n, head, member) \ + for (pos = list_entry((head)->prev, typeof(*pos), member), \ + n = list_entry(pos->member.next, typeof(*pos), member); \ + &pos->member != (head); \ + pos = n, n = list_entry(n->member.prev, typeof(*n), member)) + +/** * list_for_each_rcu - iterate over an rcu-protected list * @pos: the &struct list_head to use as a loop counter. * @head: the head for your list. --- 0.99.9.GIT
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