aboutsummaryrefslogtreecommitdiffstats
path: root/block/blk.h
diff options
context:
space:
mode:
authorBrian King <brking@linux.vnet.ibm.com>2010-09-10 03:03:21 -0400
committerJens Axboe <jaxboe@fusionio.com>2010-09-10 03:03:21 -0400
commitbe14eb619108fa8b7120eb2c42d66d5f623ae10e (patch)
treecfc8a496c62a429a97c4bc2c5e638c39374f560b /block/blk.h
parentedce6820a9fdda85521211cb334a183e34cc455e (diff)
block: Range check cpu in blk_cpu_to_group
While testing CPU DLPAR, the following problem was discovered. We were DLPAR removing the first CPU, which in this case was logical CPUs 0-3. CPUs 0-2 were already marked offline and we were in the process of offlining CPU 3. After marking the CPU inactive and offline in cpu_disable, but before the cpu was completely idle (cpu_die), we ended up in __make_request on CPU 3. There we looked at the topology map to see which CPU to complete the I/O on and found no CPUs in the cpu_sibling_map. This resulted in the block layer setting the completion cpu to be NR_CPUS, which then caused an oops when we tried to complete the I/O. Fix this by sanity checking the value we return from blk_cpu_to_group to be a valid cpu value. Signed-off-by: Brian King <brking@linux.vnet.ibm.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
Diffstat (limited to 'block/blk.h')
-rw-r--r--block/blk.h8
1 files changed, 6 insertions, 2 deletions
diff --git a/block/blk.h b/block/blk.h
index 6e7dc87141e4..d6b911ac002c 100644
--- a/block/blk.h
+++ b/block/blk.h
@@ -142,14 +142,18 @@ static inline int queue_congestion_off_threshold(struct request_queue *q)
142 142
143static inline int blk_cpu_to_group(int cpu) 143static inline int blk_cpu_to_group(int cpu)
144{ 144{
145 int group = NR_CPUS;
145#ifdef CONFIG_SCHED_MC 146#ifdef CONFIG_SCHED_MC
146 const struct cpumask *mask = cpu_coregroup_mask(cpu); 147 const struct cpumask *mask = cpu_coregroup_mask(cpu);
147 return cpumask_first(mask); 148 group = cpumask_first(mask);
148#elif defined(CONFIG_SCHED_SMT) 149#elif defined(CONFIG_SCHED_SMT)
149 return cpumask_first(topology_thread_cpumask(cpu)); 150 group = cpumask_first(topology_thread_cpumask(cpu));
150#else 151#else
151 return cpu; 152 return cpu;
152#endif 153#endif
154 if (likely(group < NR_CPUS))
155 return group;
156 return cpu;
153} 157}
154 158
155/* 159/*