From mboxrd@z Thu Jan 1 00:00:00 1970 From: ira.weiny@intel.com Date: Fri, 9 Oct 2020 12:50:31 -0700 Subject: [Intel-wired-lan] [PATCH RFC PKS/PMEM 56/58] dax: Stray access protection for dax_direct_access() In-Reply-To: <20201009195033.3208459-1-ira.weiny@intel.com> References: <20201009195033.3208459-1-ira.weiny@intel.com> Message-ID: <20201009195033.3208459-57-ira.weiny@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: intel-wired-lan@osuosl.org List-ID: From: Ira Weiny 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. Similar to kmap, we leverage existing functions, dax_read_[un]lock(), because they are already required to surround the use of the memory returned from dax_direct_access(). Signed-off-by: Ira Weiny --- drivers/dax/super.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/dax/super.c b/drivers/dax/super.c index e84070b55463..0ddb3ee73e36 100644 --- a/drivers/dax/super.c +++ b/drivers/dax/super.c @@ -30,6 +30,7 @@ static DEFINE_SPINLOCK(dax_host_lock); int dax_read_lock(void) { + dev_access_enable(false); return srcu_read_lock(&dax_srcu); } EXPORT_SYMBOL_GPL(dax_read_lock); @@ -37,6 +38,7 @@ EXPORT_SYMBOL_GPL(dax_read_lock); void dax_read_unlock(int id) { srcu_read_unlock(&dax_srcu, id); + dev_access_disable(false); } EXPORT_SYMBOL_GPL(dax_read_unlock); -- 2.28.0.rc0.12.gb6a658bd00c9