Re: [RFC] PCI device list locking

[Chris Wright <chris@wirex.com>]

* Greg KH (greg@kroah.com) wrote:
> 
> Comments?  Places I missed protecting?

Is it safe to ignore pcibios_init?  This happens after smp_init, but are
could there be multiple events (that would effect pcibios_sort)?

> --- a/drivers/pci/proc.c	Tue Jun 17 12:47:27 2003
> +++ b/drivers/pci/proc.c	Tue Jun 17 12:47:27 2003
> @@ -12,6 +12,7 @@
>  #include <linux/proc_fs.h>
>  #include <linux/seq_file.h>
>  #include <linux/smp_lock.h>
> +#include "pci.h"
>  
>  #include <asm/uaccess.h>
>  #include <asm/byteorder.h>
> @@ -311,20 +312,32 @@
>  	struct list_head *p = &pci_devices;
>  	loff_t n = *pos;
>  
> -	/* XXX: surely we need some locking for traversing the list? */
> +	spin_lock(&pci_bus_lock);

should you just grab this lock here (pci_seq_start), and release in
pci_seq_stop, holding for duration of ->seq_start() ->seq_next()
->seq_stop().  IOW, what happens when you grab list element in
->seq_start(), it's removed from list, you reference a bogus ->next
pointer in ->seq_next()?

thanks,
-chris
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