lightnvm: enable metadata to be sent to device

Enable metadata buffer to be sent to the device through the metadata
field on the physical rw nvme command. The size of the metadata buffer
must follow dev->oob_size * # of PPAs.

Signed-off-by: Javier González <javier@cnexlabs.com>
Updated description.
Signed-off-by: Matias Bjørling <m@bjorling.me>
Signed-off-by: Jens Axboe <axboe@fb.com>

drivers/nvme/host/lightnvm.c

@@ -467,6 +467,7 @@ static inline void nvme_nvm_rqtocmd(struct request *rq, struct nvm_rq *rqd,
 	c->ph_rw.opcode = rqd->opcode;
 	c->ph_rw.nsid = cpu_to_le32(ns->ns_id);
 	c->ph_rw.spba = cpu_to_le64(rqd->ppa_addr.ppa);
+	c->ph_rw.metadata = cpu_to_le64(rqd->meta_list);
 	c->ph_rw.control = cpu_to_le16(rqd->flags);
 	c->ph_rw.length = cpu_to_le16(rqd->nr_pages - 1);
 

include/linux/lightnvm.h

@@ -230,8 +230,8 @@ struct nvm_rq {
 
 	struct ppa_addr *ppa_list;
 
-	void *metadata;
-	dma_addr_t dma_metadata;
+	void *meta_list;
+	dma_addr_t dma_meta_list;
 
 	struct completion *wait;
 	nvm_end_io_fn *end_io;