14 Jul
2020
14 Jul
'20
7:10 p.m.
On Tue, Jul 14, 2020 at 10:40:57AM +0200, Peter Zijlstra wrote:
On Tue, Jul 14, 2020 at 12:02:16AM -0700, ira.weiny@intel.com wrote:
+static pgprot_t dev_protection_enable_get(struct dev_pagemap *pgmap, pgprot_t prot) +{
- if (pgmap->flags & PGMAP_PROT_ENABLED && dev_page_pkey != PKEY_INVALID) {
pgprotval_t val = pgprot_val(prot);mutex_lock(&dev_prot_enable_lock);dev_protection_enable++;/* Only enable the static branch 1 time */if (dev_protection_enable == 1)static_branch_enable(&dev_protection_static_key);mutex_unlock(&dev_prot_enable_lock);prot = __pgprot(val | _PAGE_PKEY(dev_page_pkey));- }
- return prot;
+}
+static void dev_protection_enable_put(struct dev_pagemap *pgmap) +{
- if (pgmap->flags & PGMAP_PROT_ENABLED && dev_page_pkey != PKEY_INVALID) {
mutex_lock(&dev_prot_enable_lock);dev_protection_enable--;if (dev_protection_enable == 0)static_branch_disable(&dev_protection_static_key);mutex_unlock(&dev_prot_enable_lock);- }
+}
That's an anti-pattern vs static_keys, I'm thinking you actually want static_key_slow_{inc,dec}() instead of {enable,disable}().
Thanks. I'll go read the doc for those as I'm not familiar with them.
Ira