[PATCH v7 05/12] nvdimm: virtio_pmem: use GFP_NOIO for flush requests

[Li Chen]

virtio_pmem_flush() can run from pmem_submit_bio() while filesystem IO
is waiting on the flush completion. The request object allocation can
sleep, but it should not enter filesystem or block IO reclaim from this
flush path.

Use GFP_NOIO for the request allocation. The virtqueue descriptor
allocation still uses GFP_ATOMIC because it runs under pmem_lock.

Signed-off-by: Li Chen <me@linux.beauty>
---
Changes in v7:
- Keep GFP_NOIO for the virtio-pmem request allocation after removing the
  child flush bio path.
Changes in v6:
- New patch; keep GFP_NOIO only for the virtio-pmem request allocation.

 drivers/nvdimm/nd_virtio.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/nvdimm/nd_virtio.c b/drivers/nvdimm/nd_virtio.c
index 8e16b7780be1a..a35044afddf34 100644
--- a/drivers/nvdimm/nd_virtio.c
+++ b/drivers/nvdimm/nd_virtio.c
@@ -61,7 +61,7 @@ static int virtio_pmem_flush(struct nd_region *nd_region)
 		return -EIO;
 	}
 
-	req_data = kmalloc_obj(*req_data);
+	req_data = kmalloc_obj(*req_data, GFP_NOIO);
 	if (!req_data)
 		return -ENOMEM;
 
-- 
2.52.0