block: better op and flags encoding

Now that we don't need the common flags to overflow outside the range
of a 32-bit type we can encode them the same way for both the bio and
request fields.  This in addition allows us to place the operation
first (and make some room for more ops while we're at it) and to
stop having to shift around the operation values.

In addition this allows passing around only one value in the block layer
instead of two (and eventuall also in the file systems, but we can do
that later) and thus clean up a lot of code.

Last but not least this allows decreasing the size of the cmd_flags
field in struct request to 32-bits.  Various functions passing this
value could also be updated, but I'd like to avoid the churn for now.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
(cherry picked from commit ef295ecf090d3e86e5b742fc6ab34f1122a43773)

Conflicts:
	block/blk-mq.c
	include/linux/blk_types.h
	include/linux/blkdev.h

1 files changed, 7 insertions, 7 deletions

diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c
index 4e17d55ba127..77bf690cbacb 100644
--- a/kernel/trace/blktrace.c
+++ b/kernel/trace/blktrace.c
@@ -1789,14 +1789,14 @@ void blk_dump_cmd(char *buf, struct request *rq)
 	}
 }
 
-void blk_fill_rwbs(char *rwbs, int op, u32 rw, int bytes)
+void blk_fill_rwbs(char *rwbs, unsigned int op, int bytes)
 {
 	int i = 0;
 
-	if (rw & REQ_PREFLUSH)
+	if (op & REQ_PREFLUSH)
 		rwbs[i++] = 'F';
 
-	switch (op) {
+	switch (op & REQ_OP_MASK) {
 	case REQ_OP_WRITE:
 	case REQ_OP_WRITE_SAME:
 		rwbs[i++] = 'W';
@@ -1818,13 +1818,13 @@ void blk_fill_rwbs(char *rwbs, int op, u32 rw, int bytes)
 		rwbs[i++] = 'N';
 	}
 
-	if (rw & REQ_FUA)
+	if (op & REQ_FUA)
 		rwbs[i++] = 'F';
-	if (rw & REQ_RAHEAD)
+	if (op & REQ_RAHEAD)
 		rwbs[i++] = 'A';
-	if (rw & REQ_SYNC)
+	if (op & REQ_SYNC)
 		rwbs[i++] = 'S';
-	if (rw & REQ_META)
+	if (op & REQ_META)
 		rwbs[i++] = 'M';
 
 	rwbs[i] = '\0';