[PATCH 7/8] block: drbd: avoid to use BIO_MAX_SIZE

Ming Lei
2016-03-22T06:13:07Z

drbd is the only user of BIO_MAX_SIZE, so use BIO_MAX_PAGES
instead.

Signed-off-by: Ming Lei <ming.lei@canonical.com>
---
drivers/block/drbd/drbd_int.h | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/block/drbd/drbd_int.h b/drivers/block/drbd/drbd_int.h
index c227fd4..10bfff1 100644
--- a/drivers/block/drbd/drbd_int.h
+++ b/drivers/block/drbd/drbd_int.h
@@ -1327,14 +1327,14 @@ struct bm_extent {
#endif
#endif

-/* BIO_MAX_SIZE is 256 * PAGE_CACHE_SIZE,
+/* Estimate max bio size as 256 * PAGE_CACHE_SIZE,
* so for typical PAGE_CACHE_SIZE of 4k, that is (1<<20) Byte.
* Since we may live in a mixed-platform cluster,
* we limit us to a platform agnostic constant here for now.
* A followup commit may allow even bigger BIO sizes,
* once we thought that through. */
#define DRBD_MAX_BIO_SIZE (1U << 20)
-#if DRBD_MAX_BIO_SIZE > BIO_MAX_SIZE
+#if DRBD_MAX_BIO_SIZE > (BIO_MAX_PAGES << PAGE_CACHE_SHIFT)
#error Architecture not supported: DRBD_MAX_BIO_SIZE > BIO_MAX_SIZE
#endif
#define DRBD_MAX_BIO_SIZE_SAFE (1U << 12) /* Works always = 4k */
--
1.9.1