[PATCH v2 07/11] md: add a helper md_config_align_limits()

This helper will be used by personalities that want to align bio to
io_opt to get best IO bandwidth.

Also add the new flag to UNSUPPORTED_MDDEV_FLAGS for now, following
patches will enable this for personalities.

Signed-off-by: Yu Kuai <[email protected]>
---
 drivers/md/md.h    | 11 +++++++++++
 drivers/md/raid0.c |  3 ++-
 drivers/md/raid1.c |  3 ++-
 drivers/md/raid5.c |  3 ++-
 4 files changed, 17 insertions(+), 3 deletions(-)

diff --git a/drivers/md/md.h b/drivers/md/md.h
index e7aba83b708b..ddf989f2a139 100644
--- a/drivers/md/md.h
+++ b/drivers/md/md.h
@@ -1091,6 +1091,17 @@ static inline bool rdev_blocked(struct md_rdev *rdev)
 	return false;
 }
 
+static inline void md_config_align_limits(struct mddev *mddev,
+					  struct queue_limits *lim)
+{
+	if ((lim->max_hw_sectors << 9) < lim->io_opt)
+		lim->max_hw_sectors = lim->io_opt >> 9;
+	else
+		lim->max_hw_sectors = rounddown(lim->max_hw_sectors,
+						lim->io_opt >> 9);
+	set_bit(MD_BIO_ALIGN, &mddev->flags);
+}
+
 #define mddev_add_trace_msg(mddev, fmt, args...)			\
 do {									\
 	if (!mddev_is_dm(mddev))					\
diff --git a/drivers/md/raid0.c b/drivers/md/raid0.c
index d83b2b1c0049..f3814a69cd13 100644
--- a/drivers/md/raid0.c
+++ b/drivers/md/raid0.c
@@ -29,7 +29,8 @@ module_param(default_layout, int, 0644);
 	 (1L << MD_HAS_PPL) |		\
 	 (1L << MD_HAS_MULTIPLE_PPLS) |	\
 	 (1L << MD_FAILLAST_DEV) |	\
-	 (1L << MD_SERIALIZE_POLICY))
+	 (1L << MD_SERIALIZE_POLICY) |	\
+	 (1L << MD_BIO_ALIGN))
 
 /*
  * inform the user of the raid configuration
diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index f4c7004888af..1a957dba2640 100644
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -42,7 +42,8 @@
 	((1L << MD_HAS_JOURNAL) |	\
 	 (1L << MD_JOURNAL_CLEAN) |	\
 	 (1L << MD_HAS_PPL) |		\
-	 (1L << MD_HAS_MULTIPLE_PPLS))
+	 (1L << MD_HAS_MULTIPLE_PPLS) |	\
+	 (1L << MD_BIO_ALIGN))
 
 static void allow_barrier(struct r1conf *conf, sector_t sector_nr);
 static void lower_barrier(struct r1conf *conf, sector_t sector_nr);
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index db0afb0b70e8..005a2404de27 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -59,7 +59,8 @@
 #define UNSUPPORTED_MDDEV_FLAGS		\
 	((1L << MD_FAILFAST_SUPPORTED) |	\
 	 (1L << MD_FAILLAST_DEV) |		\
-	 (1L << MD_SERIALIZE_POLICY))
+	 (1L << MD_SERIALIZE_POLICY) |		\
+	 (1L << MD_BIO_ALIGN))
 
 
 #define cpu_to_group(cpu) cpu_to_node(cpu)
-- 
2.51.0