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-rw-r--r--block/blktrace.c29
1 files changed, 25 insertions, 4 deletions
diff --git a/block/blktrace.c b/block/blktrace.c
index b2cbb4e5d767..8d3a27780260 100644
--- a/block/blktrace.c
+++ b/block/blktrace.c
@@ -75,6 +75,24 @@ static void trace_note_time(struct blk_trace *bt)
local_irq_restore(flags);
}
+void __trace_note_message(struct blk_trace *bt, const char *fmt, ...)
+{
+ int n;
+ va_list args;
+ unsigned long flags;
+ char *buf;
+
+ local_irq_save(flags);
+ buf = per_cpu_ptr(bt->msg_data, smp_processor_id());
+ va_start(args, fmt);
+ n = vscnprintf(buf, BLK_TN_MAX_MSG, fmt, args);
+ va_end(args);
+
+ trace_note(bt, 0, BLK_TN_MESSAGE, buf, n);
+ local_irq_restore(flags);
+}
+EXPORT_SYMBOL_GPL(__trace_note_message);
+
static int act_log_check(struct blk_trace *bt, u32 what, sector_t sector,
pid_t pid)
{
@@ -141,10 +159,7 @@ void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes,
/*
* A word about the locking here - we disable interrupts to reserve
* some space in the relay per-cpu buffer, to prevent an irq
- * from coming in and stepping on our toes. Once reserved, it's
- * enough to get preemption disabled to prevent read of this data
- * before we are through filling it. get_cpu()/put_cpu() does this
- * for us
+ * from coming in and stepping on our toes.
*/
local_irq_save(flags);
@@ -232,6 +247,7 @@ static void blk_trace_cleanup(struct blk_trace *bt)
debugfs_remove(bt->dropped_file);
blk_remove_tree(bt->dir);
free_percpu(bt->sequence);
+ free_percpu(bt->msg_data);
kfree(bt);
}
@@ -346,6 +362,10 @@ int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
if (!bt->sequence)
goto err;
+ bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG);
+ if (!bt->msg_data)
+ goto err;
+
ret = -ENOENT;
dir = blk_create_tree(buts->name);
if (!dir)
@@ -392,6 +412,7 @@ err:
if (bt->dropped_file)
debugfs_remove(bt->dropped_file);
free_percpu(bt->sequence);
+ free_percpu(bt->msg_data);
if (bt->rchan)
relay_close(bt->rchan);
kfree(bt);