[md:for-next 29/29] ERROR: "__tracepoint_block_unplug" [drivers/md/raid456.ko] undefined!

[md:for-next 29/29] ERROR: "__tracepoint_block_unplug" [drivers/md/raid456.ko] undefined!

[Fengguang Wu]

Hi NeilBrown,

FYI, kernel build failed on

tree:   git://neil.brown.name/md for-next/14817e9
head:   14817e9a6dab027db44783d28429d14f601547a2
commit: 14817e9a6dab027db44783d28429d14f601547a2 [29/29] md/raid5: add blktrace calls
config: sparc64-defconfig

ERROR: "__tracepoint_block_unplug" [drivers/md/raid456.ko] undefined!

The root cause is, the block trace points are only available when
block/blk-core.c is compiled in.

---
0-DAY kernel build testing backend         Open Source Technology Centre
Fengguang Wu <wfg@linux.intel.com>                     Intel Corporation

Re: [md:for-next 29/29] ERROR: "__tracepoint_block_unplug" [drivers/md/raid456.ko] undefined!

[NeilBrown]

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On Mon, 24 Sep 2012 16:15:13 +0800 Fengguang Wu <fengguang.wu@intel.com>
wrote:

> Hi NeilBrown,
> 
> FYI, kernel build failed on
> 
> tree:   git://neil.brown.name/md for-next/14817e9
> head:   14817e9a6dab027db44783d28429d14f601547a2
> commit: 14817e9a6dab027db44783d28429d14f601547a2 [29/29] md/raid5: add blktrace calls
> config: sparc64-defconfig
> 
> ERROR: "__tracepoint_block_unplug" [drivers/md/raid456.ko] undefined!
> 
> The root cause is, the block trace points are only available when
> block/blk-core.c is compiled in.

Hi,
 thanks for this.
blk-core must be compiled in, else raid456 wouldn't get compiled
CONFIG_MD_RAID456 eventually depends on CONFIG_BLOCK.

The problem is simply that tracepoint_block_unplug hasn't been exported.
This fixes it:

diff --git a/block/blk-core.c b/block/blk-core.c
index 4b4dbdf..ef55ae0 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -40,6 +40,7 @@
 EXPORT_TRACEPOINT_SYMBOL_GPL(block_bio_remap);
 EXPORT_TRACEPOINT_SYMBOL_GPL(block_rq_remap);
 EXPORT_TRACEPOINT_SYMBOL_GPL(block_bio_complete);
+EXPORT_TRACEPOINT_SYMBOL_GPL(block_unplug);
 
 DEFINE_IDA(blk_queue_ida);
 

I'll see if Jens will take it.

Thanks,
NeilBrown

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