On Sun, 11 Oct 2009 15:45:16 +0200 (CEST)
John Kacur <jkacur@xxxxxxxxxx> wrote:
[linux-scsi cc'd]
> Locking in ch_open is covered by the spin_lock, it serializes the calls
> to idr_find and scsi_device_get. The BKL appears redundant to me here.
I'm not so sure. In fact there are some quite umm interesting questions
about this code, and some of them are shared with other modules too.
Consider the following sequence
CPU1 CPU2
register_chrdev
ok
open device
takes lock
scsi_register_driver
error
unregister_chrdev
error
unload
??????
We don't allocate any idr entries in open so the paths don't seem to leak
and the module itself looks correct. Looking at the bigger picture
however I am not sure what the module loader is trying to do in
kernel/module.c with the code at
if (ret < 0) {
/* Init routine failed: abort. Try to protect us from
buggy refcounters. */
mod->state = MODULE_STATE_GOING;
synchronize_sched();
module_put(mod);
blocking_notifier_call_chain(&module_notify_list,
but it doesn't seem to be sufficient for what may go on ?
Rusty ?
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