lightnvm: move rq->error to nvm_rq->error

BugLink: http://bugs.launchpad.net/bugs/1531539

Instead of passing request error into the LightNVM modules, incorporate
it into the nvm_rq.
Signed-off-by: Matias Bjørling <m@bjorling.me>
Signed-off-by: Jens Axboe <axboe@fb.com>
(cherry picked from commit 72d256ec)
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>

drivers/lightnvm/core.c

@@ -291,7 +291,8 @@ EXPORT_SYMBOL(nvm_erase_ppa);
 
 void nvm_end_io(struct nvm_rq *rqd, int error)
 {
-	rqd->end_io(rqd, error);
+	rqd->error = error;
+	rqd->end_io(rqd);
 }
 EXPORT_SYMBOL(nvm_end_io);
 

drivers/lightnvm/gennvm.c

@@ -363,11 +363,11 @@ static void gennvm_mark_blk_bad(struct nvm_dev *dev, struct nvm_rq *rqd)
 		gennvm_blk_set_type(dev, &rqd->ppa_addr, 2);
 }
 
-static void gennvm_end_io(struct nvm_rq *rqd, int error)
+static void gennvm_end_io(struct nvm_rq *rqd)
 {
 	struct nvm_tgt_instance *ins = rqd->ins;
 
-	switch (error) {
+	switch (rqd->error) {
 	case NVM_RSP_SUCCESS:
 	case NVM_RSP_ERR_EMPTYPAGE:
 		break;
@@ -375,7 +375,7 @@ static void gennvm_end_io(struct nvm_rq *rqd, int error)
 		gennvm_mark_blk_bad(rqd->dev, rqd);
 	}
 
-	ins->tt->end_io(rqd, error);
+	ins->tt->end_io(rqd);
 }
 
 static int gennvm_submit_io(struct nvm_dev *dev, struct nvm_rq *rqd)

drivers/lightnvm/rrpc.c

@@ -658,7 +658,7 @@ static void rrpc_end_io_write(struct rrpc *rrpc, struct rrpc_rq *rrqd,
 	}
 }
 
-static void rrpc_end_io(struct nvm_rq *rqd, int error)
+static void rrpc_end_io(struct nvm_rq *rqd)
 {
 	struct rrpc *rrpc = container_of(rqd->ins, struct rrpc, instance);
 	struct rrpc_rq *rrqd = nvm_rq_to_pdu(rqd);

include/linux/lightnvm.h

@@ -149,7 +149,7 @@ struct ppa_addr {
 };
 
 struct nvm_rq;
-typedef void (nvm_end_io_fn)(struct nvm_rq *, int);
+typedef void (nvm_end_io_fn)(struct nvm_rq *);
 
 struct nvm_rq {
 	struct nvm_tgt_instance *ins;
@@ -173,6 +173,8 @@ struct nvm_rq {
 	uint8_t opcode;
 	uint16_t nr_pages;
 	uint16_t flags;
+
+	int error;
 };
 
 static inline struct nvm_rq *nvm_rq_from_pdu(void *pdu)