block: disable preemption before using sched_clock()

Commit 9195291e5f05e01d67f9a09c756b8aca8f009089 added calls to sched_clock() from preemptible code. sched_clock() is both the wrong interface AND cannot be called without preempt disabled. Apply a temporary fix to get rid of the warnings, a real patch is in the works. Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

block: disable preemption before using sched_clock()
Commit 9195291e5f05e01d67f9a09c756b8aca8f009089 added calls to sched_clock() from preemptible code. sched_clock() is both the wrong interface AND cannot be called without preempt disabled. Apply a temporary fix to get rid of the warnings, a real patch is in the works. Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
Jens Axboe
1 parent 713b686494
Showing 1 changed file with 9 additions and 0 deletions Side-by-side Diff
include/linux/blkdev.h
@@ -1211,14 +1211,23 @@
 int kblockd_schedule_work(struct request_queue *q, struct work_struct *work);
  
 #ifdef CONFIG_BLK_CGROUP
+/*
+ * This should not be using sched_clock(). A real patch is in progress
+ * to fix this up, until that is in place we need to disable preemption
+ * around sched_clock() in this function and set_io_start_time_ns().
+ */
 static inline void set_start_time_ns(struct request *req)
 {
+	preempt_disable();
 	req->start_time_ns = sched_clock();
+	preempt_enable();
 }
  
 static inline void set_io_start_time_ns(struct request *req)
 {
+	preempt_disable();
 	req->io_start_time_ns = sched_clock();
+	preempt_enable();
 }
  
 static inline uint64_t rq_start_time_ns(struct request *req)
...	...	@@ -1211,14 +1211,23 @@
1211	1211	int kblockd_schedule_work(struct request_queue q, struct work_struct work);
1212	1212
1213	1213	#ifdef CONFIG_BLK_CGROUP
	1214	+/*
	1215	+ * This should not be using sched_clock(). A real patch is in progress
	1216	+ * to fix this up, until that is in place we need to disable preemption
	1217	+ * around sched_clock() in this function and set_io_start_time_ns().
	1218	+ */
1214	1219	static inline void set_start_time_ns(struct request *req)
1215	1220	{
	1221	+ preempt_disable();
1216	1222	req->start_time_ns = sched_clock();
	1223	+ preempt_enable();
1217	1224	}
1218	1225
1219	1226	static inline void set_io_start_time_ns(struct request *req)
1220	1227	{
	1228	+ preempt_disable();
1221	1229	req->io_start_time_ns = sched_clock();
	1230	+ preempt_enable();
1222	1231	}
1223	1232
1224	1233	static inline uint64_t rq_start_time_ns(struct request *req)