linux-next: build warning after merge of the rcu tree

From: Stephen Rothwell
Date: Sun Sep 05 2010 - 22:14:29 EST


Hi Paul,

After merging the rcu tree, today's linux-next build
(powerpc ppc64_defconfig) produced this warning:

drivers/md/raid1.c: In function 'read_balance':
drivers/md/raid1.c:445: warning: operation on 'new_disk' may be undefined

I am picking on the rcu tree because the line above has not changed since
2005. The line is:

for (rdev = rcu_dereference(conf->mirrors[new_disk].rdev);
r1_bio->bios[new_disk] == IO_BLOCKED ||
!rdev || !test_bit(In_sync, &rdev->flags)
|| test_bit(WriteMostly, &rdev->flags);
rdev = rcu_dereference(conf->mirrors[++new_disk].rdev)) {

Where new_disk is being updated in the parameter to the last
rcu_dereference.

--
Cheers,
Stephen Rothwell sfr@xxxxxxxxxxxxxxxx
http://www.canb.auug.org.au/~sfr/

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