On 10/9/20 12:50 PM, ira.weiny@xxxxxxxxx wrote:
From: Ira Weiny <ira.weiny@xxxxxxxxx>
The pmem driver uses a cached virtual address to access its memory
directly. Because the nvdimm driver is well aware of the special
protections it has mapped memory with, we call dev_access_[en|dis]able()
around the direct pmem->virt_addr (pmem_addr) usage instead of the
unnecessary overhead of trying to get a page to kmap.
Signed-off-by: Ira Weiny <ira.weiny@xxxxxxxxx>
---
drivers/nvdimm/pmem.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c
index fab29b514372..e4dc1ae990fc 100644
--- a/drivers/nvdimm/pmem.c
+++ b/drivers/nvdimm/pmem.c
@@ -148,7 +148,9 @@ static blk_status_t pmem_do_read(struct pmem_device *pmem,
if (unlikely(is_bad_pmem(&pmem->bb, sector, len)))
return BLK_STS_IOERR;
+ dev_access_enable(false);
rc = read_pmem(page, page_off, pmem_addr, len);
+ dev_access_disable(false);
Hi Ira!
The APIs should be tweaked to use a symbol (GLOBAL, PER_THREAD), instead of
true/false. Try reading the above and you'll see that it sounds like it's
doing the opposite of what it is ("enable_this(false)" sounds like a clumsy
API design to *disable*, right?). And there is no hint about the scope.
And it *could* be so much more readable like this:
dev_access_enable(DEV_ACCESS_THIS_THREAD);
thanks,
--
John Hubbard
NVIDIA
