block: make blktrace use per-cpu buffers for message notes

[linux-2.6-omap-h63xx.git] / block / blktrace.c

diff --git a/block/blktrace.c b/block/blktrace.c
index 568588cd16b22d546771e18fb4e34f9be4811afe..7ae87cc4a163fc0dfcae0f65e6d25e9b185c4b91 100644 (file)
--- a/block/blktrace.c
+++ b/block/blktrace.c
@@ -75,6 +75,23 @@ 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;
+       char *buf;
+
+       preempt_disable();
+       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);
+       preempt_enable();
+}
+EXPORT_SYMBOL_GPL(__trace_note_message);
+
 static int act_log_check(struct blk_trace *bt, u32 what, sector_t sector,
                         pid_t pid)
 {
@@ -232,6 +249,7 @@ 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 +364,10 @@ 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 +414,7 @@ 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);
@@ -476,7 +499,7 @@ int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg)
 
        switch (cmd) {
        case BLKTRACESETUP:
-               strcpy(b, bdevname(bdev, b));
+               bdevname(bdev, b);
                ret = blk_trace_setup(q, b, bdev->bd_dev, arg);
                break;
        case BLKTRACESTART: