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From: Julia Lawall <Julia.Lawall@lip6.fr>
To: Mike Marciniszyn <infinipath@intel.com>
Cc: kernel-janitors@vger.kernel.org, Roland Dreier <roland@kernel.org>,
        Sean Hefty <sean.hefty@intel.com>,
        Hal Rosenstock <hal.rosenstock@gmail.com>, linux-rdma@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: [PATCH 9/10] IB/qib: use safer test on the result of find_first_zero_bit
Date: Wed,  4 Jun 2014 11:07:59 +0200
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From: Julia Lawall <Julia.Lawall@lip6.fr>

Find_first_zero_bit considers BITS_PER_LONG bits at a time, and thus may
return a larger number than the maximum position argument if that position
is not a multiple of BITS_PER_LONG.

The semantic match that finds this problem is as follows:
(http://coccinelle.lip6.fr/)

// <smpl>
@@
expression e1,e2,e3;
statement S1,S2;
@@

e1 = find_first_zero_bit(e2,e3)
...
if (e1 
- ==
+ >=
  e3)
S1 else S2
// </smpl>

Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>

---
 drivers/infiniband/hw/qib/qib_file_ops.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff -u -p a/drivers/infiniband/hw/qib/qib_file_ops.c b/drivers/infiniband/hw/qib/qib_file_ops.c
--- a/drivers/infiniband/hw/qib/qib_file_ops.c
+++ b/drivers/infiniband/hw/qib/qib_file_ops.c
@@ -1187,7 +1187,7 @@ static void assign_ctxt_affinity(struct
 		int cpu;
 		cpu = find_first_zero_bit(qib_cpulist,
 					  qib_cpulist_count);
-		if (cpu == qib_cpulist_count)
+		if (cpu >= qib_cpulist_count)
 			qib_dev_err(dd,
 			"no cpus avail for affinity PID %u\n",
 			current->pid);

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