block: replace end_request() with [__]blk_end_request_cur()

end_request() has been kept around for backward compatibility;
however, it's about time for it to go away.

* There aren't too many users left.

* Its use of @updtodate is pretty confusing.

* In some cases, newer code ends up using mixture of end_request() and
  [__]blk_end_request[_all](), which is way too confusing.

So, add [__]blk_end_request_cur() and replace end_request() with it.
Most conversions are straightforward.  Noteworthy ones are...

* paride/pcd: next_request() updated to take 0/-errno instead of 1/0.

* paride/pf: pf_end_request() and next_request() updated to take
  0/-errno instead of 1/0.

* xd: xd_readwrite() updated to return 0/-errno instead of 1/0.

* mtd/mtd_blkdevs: blktrans_discard_request() updated to return
  0/-errno instead of 1/0.  Unnecessary local variable res
  initialization removed from mtd_blktrans_thread().

[ Impact: cleanup ]

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Joerg Dorchain <joerg@dorchain.net>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
Acked-by: Laurent Vivier <Laurent@lvivier.info>
Cc: Tim Waugh <tim@cyberelk.net>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Jeremy Fitzhardinge <jeremy@xensource.com>
Cc: Markus Lidel <Markus.Lidel@shadowconnect.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Pete Zaitcev <zaitcev@redhat.com>
Cc: unsik Kim <donari75@gmail.com>
diff --git a/drivers/block/amiflop.c b/drivers/block/amiflop.c
index 8df436f..b99a2a6 100644
--- a/drivers/block/amiflop.c
+++ b/drivers/block/amiflop.c
@@ -1359,7 +1359,7 @@
 #endif
 		block = CURRENT->sector + cnt;
 		if ((int)block > floppy->blocks) {
-			end_request(CURRENT, 0);
+			__blk_end_request_cur(CURRENT, -EIO);
 			goto repeat;
 		}
 
@@ -1373,11 +1373,11 @@
 
 		if ((rq_data_dir(CURRENT) != READ) && (rq_data_dir(CURRENT) != WRITE)) {
 			printk(KERN_WARNING "do_fd_request: unknown command\n");
-			end_request(CURRENT, 0);
+			__blk_end_request_cur(CURRENT, -EIO);
 			goto repeat;
 		}
 		if (get_track(drive, track) == -1) {
-			end_request(CURRENT, 0);
+			__blk_end_request_cur(CURRENT, -EIO);
 			goto repeat;
 		}
 
@@ -1391,7 +1391,7 @@
 
 			/* keep the drive spinning while writes are scheduled */
 			if (!fd_motor_on(drive)) {
-				end_request(CURRENT, 0);
+				__blk_end_request_cur(CURRENT, -EIO);
 				goto repeat;
 			}
 			/*
@@ -1410,7 +1410,7 @@
 	CURRENT->nr_sectors -= CURRENT->current_nr_sectors;
 	CURRENT->sector += CURRENT->current_nr_sectors;
 
-	end_request(CURRENT, 1);
+	__blk_end_request_cur(CURRENT, 0);
 	goto repeat;
 }