Messages in this thread | | | Date | Thu, 9 Nov 2017 08:50:16 +0100 | From | Michal Hocko <> | Subject | Re: [PATCH] mm, vmstat: Make sure mutex is a global static |
| |
On Wed 08-11-17 07:21:20, Kees Cook wrote: > On Tue, Nov 7, 2017 at 11:43 PM, Vlastimil Babka <vbabka@suse.cz> wrote: > > On 11/07/2017 10:38 PM, Kees Cook wrote: [...] > >> +static DEFINE_MUTEX(vm_numa_stat_lock); > >> + > >> int sysctl_vm_numa_stat_handler(struct ctl_table *table, int write, > >> void __user *buffer, size_t *length, loff_t *ppos) > >> { > >> int ret, oldval; > >> - DEFINE_MUTEX(vm_numa_stat_lock); > > > > Yeah it was Michal who suggested scoping the mutex here instead of > > global scope, but I think he didn't mean to remove the 'static' > > qualifier, and we both missed that in the review :( > > So the scope under sysctl_vm_numa_stat_handler() should be okay, just > > with the 'static' added. > > That part is a matter of taste, I guess. :) But yes, static is important.
The primary reason I prefer function scope lock is that it is less tempting to reuse the lock for something else that way. But this is hardly something to insist on. So I am ok with the file scope as well. -- Michal Hocko SUSE Labs
| |