[PATCH 32/32] block: remove __REQ op defs and reduce bi_op/bi_rw sizes

From: mchristi
Date: Wed Nov 04 2015 - 17:09:50 EST


From: Mike Christie <mchristi@xxxxxxxxxx>

This patches removes the __REQ/REQ definitions for operations
now defined by REQ_OPs.

There is now no need for bi_rw to be a long, so this makes it a
int. I also moved the priority to its own field, but I guess I could
have just kept this in the bi_rw since there is only 16 bio related
REQ_XYZ flags.

bi_op is also no longer a bitmap, so it only needs to be a u8/char,
so that is changed too.

This is more of a RFC patch, because I still need to update the rest
of the block layer code that was treating bi_rw as a long and I can
also shrink the request->cmd_flags.

I was not sure if or how much or where people wanted to stick things.
There also appears to be room in the bi_flags field. If bi_flags is
only using 13 bits and there are only 16 REQ_XYZs bits related bios,
I could put them all in one variable if we wanted to go wild with trying
to shrink the bio while I am at it..

Signed-off-by: Mike Christie <mchristi@xxxxxxxxxx>
---
include/linux/bio.h | 13 ++-----------
include/linux/blk_types.h | 23 ++++++-----------------
include/trace/events/f2fs.h | 1 -
3 files changed, 8 insertions(+), 29 deletions(-)

diff --git a/include/linux/bio.h b/include/linux/bio.h
index 7cbad7a..34a20cf 100644
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -44,18 +44,9 @@
#define BIO_MAX_SIZE (BIO_MAX_PAGES << PAGE_CACHE_SHIFT)
#define BIO_MAX_SECTORS (BIO_MAX_SIZE >> 9)

-/*
- * upper 16 bits of bi_rw define the io priority of this bio
- */
-#define BIO_PRIO_SHIFT (8 * sizeof(unsigned long) - IOPRIO_BITS)
-#define bio_prio(bio) ((bio)->bi_rw >> BIO_PRIO_SHIFT)
+#define bio_prio(bio) (bio)->bi_ioprio
#define bio_prio_valid(bio) ioprio_valid(bio_prio(bio))
-
-#define bio_set_prio(bio, prio) do { \
- WARN_ON(prio >= (1 << IOPRIO_BITS)); \
- (bio)->bi_rw &= ((1UL << BIO_PRIO_SHIFT) - 1); \
- (bio)->bi_rw |= ((unsigned long) (prio) << BIO_PRIO_SHIFT); \
-} while (0)
+#define bio_set_prio(bio, prio) ((bio)->bi_ioprio = prio)

/*
* various member access, note that bio_data should of course not be used
diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index 581d353..c32ae3c 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -48,14 +48,9 @@ struct bio {
struct block_device *bi_bdev;
unsigned int bi_flags; /* status, command, etc */
int bi_error;
- unsigned long bi_rw; /* bottom bits rq_flags_bits
- * top bits priority
- */
- /*
- * this will be a u8 in the next patches and bi_rw can be shrunk to
- * a u32. For compat in these transistional patches op is a int here.
- */
- int bi_op; /* REQ_OP */
+ unsigned int bi_rw; /* rq_flags_bits */
+ unsigned short bi_ioprio;
+ u8 bi_op; /* REQ_OP */


struct bvec_iter bi_iter;
@@ -151,7 +146,6 @@ struct bio {
*/
enum rq_flag_bits {
/* common flags */
- __REQ_WRITE, /* not set, read. set, write */
__REQ_FAILFAST_DEV, /* no driver retries of device errors */
__REQ_FAILFAST_TRANSPORT, /* no driver retries of transport errors */
__REQ_FAILFAST_DRIVER, /* no driver retries of driver errors */
@@ -159,9 +153,7 @@ enum rq_flag_bits {
__REQ_SYNC, /* request is sync (sync write or read) */
__REQ_META, /* metadata io request */
__REQ_PRIO, /* boost priority in cfq */
- __REQ_DISCARD, /* request to discard sectors */
- __REQ_SECURE, /* secure discard (used with __REQ_DISCARD) */
- __REQ_WRITE_SAME, /* write same block many times */
+ __REQ_SECURE, /* secure discard (used with REQ_OP_DISCARD) */

__REQ_NOIDLE, /* don't anticipate more IO after this one */
__REQ_INTEGRITY, /* I/O includes block integrity payload */
@@ -198,15 +190,12 @@ enum rq_flag_bits {
__REQ_NR_BITS, /* stops here */
};

-#define REQ_WRITE (1ULL << __REQ_WRITE)
#define REQ_FAILFAST_DEV (1ULL << __REQ_FAILFAST_DEV)
#define REQ_FAILFAST_TRANSPORT (1ULL << __REQ_FAILFAST_TRANSPORT)
#define REQ_FAILFAST_DRIVER (1ULL << __REQ_FAILFAST_DRIVER)
#define REQ_SYNC (1ULL << __REQ_SYNC)
#define REQ_META (1ULL << __REQ_META)
#define REQ_PRIO (1ULL << __REQ_PRIO)
-#define REQ_DISCARD (1ULL << __REQ_DISCARD)
-#define REQ_WRITE_SAME (1ULL << __REQ_WRITE_SAME)
#define REQ_NOIDLE (1ULL << __REQ_NOIDLE)
#define REQ_INTEGRITY (1ULL << __REQ_INTEGRITY)

@@ -250,8 +239,8 @@ enum rq_flag_bits {
enum req_op {
REQ_OP_READ,
REQ_OP_WRITE,
- REQ_OP_DISCARD,
- REQ_OP_WRITE_SAME,
+ REQ_OP_DISCARD, /* request to discard sectors */
+ REQ_OP_WRITE_SAME, /* write same block many times */
};

#endif /* __LINUX_BLK_TYPES_H */
diff --git a/include/trace/events/f2fs.h b/include/trace/events/f2fs.h
index 0c7301b..2446a2f 100644
--- a/include/trace/events/f2fs.h
+++ b/include/trace/events/f2fs.h
@@ -31,7 +31,6 @@ TRACE_DEFINE_ENUM(BG_GC);
TRACE_DEFINE_ENUM(LFS);
TRACE_DEFINE_ENUM(SSR);
TRACE_DEFINE_ENUM(__REQ_RAHEAD);
-TRACE_DEFINE_ENUM(__REQ_WRITE);
TRACE_DEFINE_ENUM(__REQ_SYNC);
TRACE_DEFINE_ENUM(__REQ_NOIDLE);
TRACE_DEFINE_ENUM(__REQ_FLUSH);
--
1.8.3.1

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