From: Glauber Costa <glommer@parallels.com>
Date: Wed, 25 Apr 2012 23:01:48 +0000 (-0700)
Subject: fs/buffer.c: remove BUG() in possible but rare condition
X-Git-Tag: v3.4-rc5~28^2~9
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=61065a30af8df4b8989c2ac7a1f4b4034e4df2d5;p=pandora-kernel.git

fs/buffer.c: remove BUG() in possible but rare condition

While stressing the kernel with with failing allocations today, I hit the
following chain of events:

alloc_page_buffers():

	bh = alloc_buffer_head(GFP_NOFS);
	if (!bh)
		goto no_grow; <= path taken

grow_dev_page():
        bh = alloc_page_buffers(page, size, 0);
        if (!bh)
                goto failed;  <= taken, consequence of the above

and then the failed path BUG()s the kernel.

The failure is inserted a litte bit artificially, but even then, I see no
reason why it should be deemed impossible in a real box.

Even though this is not a condition that we expect to see around every
time, failed allocations are expected to be handled, and BUG() sounds just
too much.  As a matter of fact, grow_dev_page() can return NULL just fine
in other circumstances, so I propose we just remove it, then.

Signed-off-by: Glauber Costa <glommer@parallels.com>
Cc: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---

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