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Diffstat (limited to 'block/blktrace.c')
-rw-r--r--block/blktrace.c55
1 files changed, 49 insertions, 6 deletions
diff --git a/block/blktrace.c b/block/blktrace.c
index 7ae87cc4a163..eb9651ccb241 100644
--- a/block/blktrace.c
+++ b/block/blktrace.c
@@ -79,16 +79,17 @@ void __trace_note_message(struct blk_trace *bt, const char *fmt, ...)
{
int n;
va_list args;
+ unsigned long flags;
char *buf;
- preempt_disable();
+ 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);
- preempt_enable();
+ local_irq_restore(flags);
}
EXPORT_SYMBOL_GPL(__trace_note_message);
@@ -158,10 +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);
@@ -246,6 +244,7 @@ err:
static void blk_trace_cleanup(struct blk_trace *bt)
{
relay_close(bt->rchan);
+ debugfs_remove(bt->msg_file);
debugfs_remove(bt->dropped_file);
blk_remove_tree(bt->dir);
free_percpu(bt->sequence);
@@ -293,6 +292,44 @@ static const struct file_operations blk_dropped_fops = {
.read = blk_dropped_read,
};
+static int blk_msg_open(struct inode *inode, struct file *filp)
+{
+ filp->private_data = inode->i_private;
+
+ return 0;
+}
+
+static ssize_t blk_msg_write(struct file *filp, const char __user *buffer,
+ size_t count, loff_t *ppos)
+{
+ char *msg;
+ struct blk_trace *bt;
+
+ if (count > BLK_TN_MAX_MSG)
+ return -EINVAL;
+
+ msg = kmalloc(count, GFP_KERNEL);
+ if (msg == NULL)
+ return -ENOMEM;
+
+ if (copy_from_user(msg, buffer, count)) {
+ kfree(msg);
+ return -EFAULT;
+ }
+
+ bt = filp->private_data;
+ __trace_note_message(bt, "%s", msg);
+ kfree(msg);
+
+ return count;
+}
+
+static const struct file_operations blk_msg_fops = {
+ .owner = THIS_MODULE,
+ .open = blk_msg_open,
+ .write = blk_msg_write,
+};
+
/*
* Keep track of how many times we encountered a full subbuffer, to aid
* the user space app in telling how many lost events there were.
@@ -382,6 +419,10 @@ int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
if (!bt->dropped_file)
goto err;
+ bt->msg_file = debugfs_create_file("msg", 0222, dir, bt, &blk_msg_fops);
+ if (!bt->msg_file)
+ goto err;
+
bt->rchan = relay_open("trace", dir, buts->buf_size,
buts->buf_nr, &blk_relay_callbacks, bt);
if (!bt->rchan)
@@ -411,6 +452,8 @@ err:
if (dir)
blk_remove_tree(dir);
if (bt) {
+ if (bt->msg_file)
+ debugfs_remove(bt->msg_file);
if (bt->dropped_file)
debugfs_remove(bt->dropped_file);
free_percpu(bt->sequence);