From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753376Ab1GYVoC (ORCPT ); Mon, 25 Jul 2011 17:44:02 -0400 Received: from mail-pz0-f42.google.com ([209.85.210.42]:63998 "EHLO mail-pz0-f42.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753346Ab1GYVn6 (ORCPT ); Mon, 25 Jul 2011 17:43:58 -0400 From: Jim Cromie To: jbaron@redhat.com Cc: bvanassche@acm.org, joe@perches.com, gregkh@suse.de, linux-kernel@vger.kernel.org, gnb@fmeh.org, Jim Cromie Subject: [PATCH 25/25] dynamic_debug: add $DBGFS/dynamic_debug/pending Date: Mon, 25 Jul 2011 15:42:50 -0600 Message-Id: <1311630170-26057-26-git-send-email-jim.cromie@gmail.com> X-Mailer: git-send-email 1.7.4.1 In-Reply-To: <1311630170-26057-1-git-send-email-jim.cromie@gmail.com> References: <1311630170-26057-1-git-send-email-jim.cromie@gmail.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org add pending file so user can see queries that are pending. This needs work - it currently loops through all pending queries, but doesnt terminate - it starts over at the beginning. Signed-off-by: Jim Cromie --- lib/dynamic_debug.c | 169 ++++++++++++++++++++++++++++++++++++++++++++++++++- 1 files changed, 168 insertions(+), 1 deletions(-) diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c index 6dbefb7..0f0bc61 100644 --- a/lib/dynamic_debug.c +++ b/lib/dynamic_debug.c @@ -65,6 +65,10 @@ struct ddebug_iter { unsigned int idx; }; +struct pending_iter { + struct pending_query *elem; +}; + static DEFINE_MUTEX(ddebug_lock); static LIST_HEAD(ddebug_tables); static int verbose = 0; @@ -948,6 +952,162 @@ static const struct file_operations ddebug_proc_fops = { .write = ddebug_proc_write }; +/* + * Set the iterator to point to the first pending_query object + * and return a pointer to that first object. Returns + * NULL if there are no pending_querys at all. + */ +static struct pending_query *pending_iter_first(struct pending_iter *iter) +{ + if (list_empty(&pending_queries)) + return NULL; + iter->elem = list_entry(pending_queries.next, + struct pending_query, link); + return iter->elem; +} + +/* + * Advance the iterator to point to the next pending_query + * object from the one the iterator currently points at, + * and returns a pointer to the new pending_query. Returns + * NULL if the iterator has seen all the pending_querys. + */ +static struct pending_query *pending_iter_next(struct pending_iter *iter) +{ + if (iter->elem == NULL) + return NULL; + if (list_is_last(&iter->elem->link, &pending_queries)) { + iter->elem = NULL; + return NULL; + } + iter->elem = list_entry(iter->elem->link.next, + struct pending_query, link); + return iter->elem; +} + +/* + * Seq_ops start method. Called at the start of every + * read() call from userspace. Takes the pending_lock and + * seeks the seq_file's iterator to the given position. + */ +static void *pending_proc_start(struct seq_file *m, loff_t *pos) +{ + struct pending_iter *iter = m->private; + struct pending_query *pq; + int n = *pos; + + pr_debug("called m=%p *pos=%lld\n", m, (unsigned long long)*pos); + + mutex_lock(&ddebug_lock); + + if (!n) + return SEQ_START_TOKEN; + if (n < 0) + return NULL; + pq = pending_iter_first(iter); + /*while (pq != NULL && --n > 0) + pq = pending_iter_next(iter); + */ + return pq; +} + +/* + * Seq_ops next method. Called several times within a read() + * call from userspace, with pending_lock held. Walks to the + * next pending_query object with a special case for the header line. + */ +static void *pending_proc_next(struct seq_file *m, void *p, loff_t *pos) +{ + struct pending_iter *iter = m->private; + struct pending_query *pq; + + pr_debug("called m=%p p=%p *pos=%lld\n", + m, p, (unsigned long long)*pos); + + if (p == SEQ_START_TOKEN) + pq = pending_iter_first(iter); + else + pq = pending_iter_next(iter); + ++*pos; + return pq; +} + +/* + * Seq_ops show method. Called several times within a read() + * call from userspace, with pending_lock held. Formats the + * current pending_query as a single human-readable line, with a + * special case for the header line. + */ +static int pending_proc_show(struct seq_file *m, void *p) +{ + struct pending_iter *iter = m->private; + struct pending_query *pq = p; + char *qstr; + + pr_debug("called m=%p p=%p\n", m, p); + + if (p == SEQ_START_TOKEN) { + seq_puts(m, "# file module func line flags\n"); + return 0; + } + + seq_printf(m, "%s\n", qstr = show_pending_query(iter->elem)); + kfree(qstr); + return 0; +} + +/* + * Seq_ops stop method. Called at the end of each read() + * call from userspace. Drops pending_lock. + */ +static void pending_proc_stop(struct seq_file *m, void *p) +{ + pr_debug("called m=%p p=%p\n", m, p); + mutex_unlock(&ddebug_lock); +} + +static const struct seq_operations pending_proc_seqops = { + .start = pending_proc_start, + .next = pending_proc_next, + .show = pending_proc_show, + .stop = pending_proc_stop +}; + +/* + * File_ops->open method for /dynamic_debug/control. Does the seq_file + * setup dance, and also creates an iterator to walk the pending_querys. + * Note that we create a seq_file always, even for O_WRONLY files + * where it's not needed, as doing so simplifies the ->release method. + */ +static int pending_proc_open(struct inode *inode, struct file *file) +{ + struct pending_iter *iter; + int err; + + if (verbose) + pr_info("called\n"); + + iter = kzalloc(sizeof(*iter), GFP_KERNEL); + if (iter == NULL) + return -ENOMEM; + + err = seq_open(file, &pending_proc_seqops); + if (err) { + kfree(iter); + return err; + } + ((struct seq_file *) file->private_data)->private = iter; + return 0; +} + +static const struct file_operations pending_proc_fops = { + .owner = THIS_MODULE, + .open = pending_proc_open, + .read = seq_read, + .llseek = seq_lseek, + .release = seq_release_private, +}; + /* apply matching queries in pending-queries list. Called with lock held */ static void apply_pending_queries(struct ddebug_table *dt) { @@ -1051,7 +1211,7 @@ static __initdata int ddebug_init_success; static int __init dynamic_debug_init_debugfs(void) { - struct dentry *dir, *file; + struct dentry *dir, *file, *file2; if (!ddebug_init_success) return -ENODEV; @@ -1065,6 +1225,13 @@ static int __init dynamic_debug_init_debugfs(void) debugfs_remove(dir); return -ENOMEM; } + file2 = debugfs_create_file("pending", 0444, dir, NULL, + &pending_proc_fops); + if (!file2) { + debugfs_remove(file); + debugfs_remove(dir); + return -ENOMEM; + } return 0; } -- 1.7.4.1