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

From	Ming Lei <ming.lei@canonical.com>
Newsgroups	linux.kernel
Subject	[PATCH 7/8] block: drbd: avoid to use BIO_MAX_SIZE
Date	2016-03-22 07:20 +0100
Message-ID	<rfnPA-qn-15@gated-at.bofh.it> (permalink)
References	<rfnPz-qn-7@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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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

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[PATCH 7/8] block: drbd: avoid to use BIO_MAX_SIZE Ming Lei <ming.lei@canonical.com> - 2016-03-22 07:20 +0100
  Re: [PATCH 7/8] block: drbd: avoid to use BIO_MAX_SIZE Christoph Hellwig <hch@infradead.org> - 2016-03-29 09:40 +0200
    Re: [PATCH 7/8] block: drbd: avoid to use BIO_MAX_SIZE Lars Ellenberg <lars.ellenberg@linbit.com> - 2016-03-29 10:20 +0200

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