From: Ira Weiny ira.weiny@intel.com
dax_direct_access() is a special case of accessing pmem via a page offset and without a struct page.
Because the dax driver is well aware of the special protections it has mapped memory with, call dev_access_[en|dis]able() directly instead of the unnecessary overhead of trying to get a page to kmap.
Like kmap though, leverage the existing dax_read[un]lock() functions because they are already required to surround the use of the memory returned from dax_direct_access().
Signed-off-by: Ira Weiny ira.weiny@intel.com --- drivers/dax/super.c | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/drivers/dax/super.c b/drivers/dax/super.c index 021739768093..e8d0a28e6ed2 100644 --- a/drivers/dax/super.c +++ b/drivers/dax/super.c @@ -30,12 +30,14 @@ static DEFINE_SPINLOCK(dax_host_lock);
int dax_read_lock(void) { + dev_access_enable(); return srcu_read_lock(&dax_srcu); } EXPORT_SYMBOL_GPL(dax_read_lock);
void dax_read_unlock(int id) { + dev_access_disable(); srcu_read_unlock(&dax_srcu, id); } EXPORT_SYMBOL_GPL(dax_read_unlock);