Messages in this thread | | | From | Arnd Bergmann <> | Subject | Re: [GIT, RFC] Killing the Big Kernel Lock | Date | Mon, 29 Mar 2010 23:18:09 +0200 |
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On Monday 29 March 2010 19:59:39 Frederic Weisbecker wrote: > On Mon, Mar 29, 2010 at 12:04:24PM +0100, Arnd Bergmann wrote: > > On Monday 29 March 2010, Frederic Weisbecker wrote: > > > On Mon, Mar 29, 2010 at 01:18:48AM +0200, Frederic Weisbecker wrote: > > > > @@ -1943,7 +1949,7 @@ static ssize_t proc_fdinfo_read(struct file *file, char __user *buf, > > > > } > > > > > > > > static const struct file_operations proc_fdinfo_file_operations = { > > > > - .open = nonseekable_open, > > > > + .llseek = generic_file_llseek, > > > > .read = proc_fdinfo_read, > > > > }; > > > > > > > > > > > > Replacing default_llseek() by generic_file_llseek() as you > > > > did for most of the other parts is fine. > > > > > > > > But the above changes the semantics as it makes it seekable. > > > > Why not just keeping it as is? It just ends up in no_llseek(). > > > > The default is default_llseek, which uses the BKL and cannot be > > used if procfs is builtin and the BKL is a module. > > Yeah, but you removed the nonseekable_open and made generic_file_llseek > in llseek on this one. > This makes it seekable while it wasn't, changing its ABI. > It wasn't taking the bkl before that as it was calling > no_llseek().
Ah, I see what you mean. That change was certainly not intentional an should be reverted. Thanks for pointing this out.
> > The BKL in procfs is only for proc files that have registered > > their own .ioctl instead of .unlocked_ioctl method. Converting > > every file_operations instance to provide an unlocked_ioctl > > (as one of the other patches does) makes sure that this path > > is never taken. BTW, there are less than a handful of procfs files > > that provide an ioctl operation, and those probably should never > > have been merged. > > > There are three of them. I'm going to make them .unlocked_ioctl > and push the bkl inside, and warn on further uses of .ioctl, > without applying the bkl there anymore. > > That plus your bkl removal in proc seek, should totally remove the > bkl from procfs.
Ok
Arnd
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