From 02c62304e6af60f1963695c6bc1bbffe619aa585 Mon Sep 17 00:00:00 2001 From: "Alan D. Brunelle" Date: Wed, 11 Jun 2008 09:12:52 +0200 Subject: Added in user-injected messages into blk traces This allows a user to annotate the blk trace stream: writing a suitable message to {/sys/kernel/debug}/block//msg will have it propagated into the trace stream. Signed-off-by: Alan D. Brunelle Signed-off-by: Jens Axboe --- block/blktrace.c | 45 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 45 insertions(+) (limited to 'block') diff --git a/block/blktrace.c b/block/blktrace.c index 8d3a27780260..eb9651ccb241 100644 --- a/block/blktrace.c +++ b/block/blktrace.c @@ -244,6 +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); @@ -291,6 +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. @@ -380,6 +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) @@ -409,6 +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); -- cgit v1.2.3