From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 24C70C432C0 for ; Wed, 20 Nov 2019 19:09:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DE27C206DA for ; Wed, 20 Nov 2019 19:09:24 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="Y2xi4C/j" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727673AbfKTTJX (ORCPT ); Wed, 20 Nov 2019 14:09:23 -0500 Received: from userp2120.oracle.com ([156.151.31.85]:38056 "EHLO userp2120.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726634AbfKTTJW (ORCPT ); Wed, 20 Nov 2019 14:09:22 -0500 Received: from pps.filterd (userp2120.oracle.com [127.0.0.1]) by userp2120.oracle.com (8.16.0.27/8.16.0.27) with SMTP id xAKJ8sRS015101; Wed, 20 Nov 2019 19:08:54 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=from : to : cc : subject : date : message-id : in-reply-to : references; s=corp-2019-08-05; bh=2f29ZPbwmwgY63pJKd6Ice1moDwnDkDoYuGYJbAysmo=; b=Y2xi4C/jDxzdyLpdWGVx5gEh8jmI0nGVCPxaieImefwk00IkjYLZFc8s/lJNThH0vdvt KBk4qWXYyH0TAJcXq/CgYTPSuM9+wcr4NvwX/eDpBUSNxWwalxkDEnw+dyU74En8Zfum ieL3W0Pe6VXH12xHagAr5zaS5ESyr2UaQviuEsb4H6WjFI19JUXmGPjfW6vZBeWWQADX VI9HN2WAjoQ76heaGtPy6/v/fos8Yv/FoZlD3RddN7Bb8fSnVJDJpnRsWbeOAEgAijY3 RY+YwIj4EPNNexRFfHTmI7DrbkUVHmQ4H4jVvg35TWtV+ktom0b/M4Zf00LayuLsmeeO zA== Received: from aserp3030.oracle.com (aserp3030.oracle.com [141.146.126.71]) by userp2120.oracle.com with ESMTP id 2wa9rqqh8y-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 20 Nov 2019 19:08:54 +0000 Received: from pps.filterd (aserp3030.oracle.com [127.0.0.1]) by aserp3030.oracle.com (8.16.0.27/8.16.0.27) with SMTP id xAKJ4AYr167268; Wed, 20 Nov 2019 19:08:51 GMT Received: from userv0122.oracle.com (userv0122.oracle.com [156.151.31.75]) by aserp3030.oracle.com with ESMTP id 2wd47vn2qq-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 20 Nov 2019 19:08:51 +0000 Received: from abhmp0002.oracle.com (abhmp0002.oracle.com [141.146.116.8]) by userv0122.oracle.com (8.14.4/8.14.4) with ESMTP id xAKJ8oOj014401; Wed, 20 Nov 2019 19:08:50 GMT Received: from ca-common-hq.us.oracle.com (/10.211.9.209) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Wed, 20 Nov 2019 11:08:50 -0800 From: Divya Indi To: Steven Rostedt , linux-kernel@vger.kernel.org Cc: Divya Indi , Joe Jin , Srinivas Eeda , Aruna Ramakrishna , Manjunath Patil Subject: [PATCH 1/2] tracing: Adding new functions for kernel access to Ftrace instances Date: Wed, 20 Nov 2019 11:08:38 -0800 Message-Id: <1574276919-11119-2-git-send-email-divya.indi@oracle.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1574276919-11119-1-git-send-email-divya.indi@oracle.com> References: <1574276919-11119-1-git-send-email-divya.indi@oracle.com> X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9447 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1911140001 definitions=main-1911200158 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9447 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1911140001 definitions=main-1911200159 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Adding 2 new functions - 1) struct trace_array *trace_array_get_by_name(const char *name); Return pointer to a trace array with given name. If it does not exist, create and return pointer to the new trace array. 2) int trace_array_set_clr_event(struct trace_array *tr, const char *system ,const char *event, bool enable); Enable/Disable events to this trace array. Additionally, - To handle reference counters, export trace_array_put() - Due to introduction of the above 2 new functions, we no longer need to export - ftrace_set_clr_event & trace_array_create APIs. Signed-off-by: Divya Indi Reviewed-by: Aruna Ramakrishna --- include/linux/trace.h | 3 +- include/linux/trace_events.h | 3 +- kernel/trace/trace.c | 96 +++++++++++++++++++++++++++++++++++--------- kernel/trace/trace.h | 1 - kernel/trace/trace_events.c | 27 ++++++++++++- 5 files changed, 106 insertions(+), 24 deletions(-) diff --git a/include/linux/trace.h b/include/linux/trace.h index 24fcf07..7fd86d3 100644 --- a/include/linux/trace.h +++ b/include/linux/trace.h @@ -29,7 +29,8 @@ struct trace_export { void trace_printk_init_buffers(void); int trace_array_printk(struct trace_array *tr, unsigned long ip, const char *fmt, ...); -struct trace_array *trace_array_create(const char *name); +void trace_array_put(struct trace_array *tr); +struct trace_array *trace_array_get_by_name(const char *name); int trace_array_destroy(struct trace_array *tr); #endif /* CONFIG_TRACING */ diff --git a/include/linux/trace_events.h b/include/linux/trace_events.h index 8a62731..3898299 100644 --- a/include/linux/trace_events.h +++ b/include/linux/trace_events.h @@ -540,7 +540,8 @@ extern int trace_define_field(struct trace_event_call *call, const char *type, #define is_signed_type(type) (((type)(-1)) < (type)1) int trace_set_clr_event(const char *system, const char *event, int set); - +int trace_array_set_clr_event(struct trace_array *tr, const char *system, + const char *event, bool enable); /* * The double __builtin_constant_p is because gcc will give us an error * if we try to allocate the static variable to fmt if it is not a diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index e0faf81..16332f7 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -297,12 +297,24 @@ static void __trace_array_put(struct trace_array *this_tr) this_tr->ref--; } +/** + * trace_array_put - Decrement the reference counter for this trace array. + * + * NOTE: Use this when we no longer need the trace array returned by + * trace_array_get_by_name(). This ensures the trace array can be later + * destroyed. + * + */ void trace_array_put(struct trace_array *this_tr) { + if (!this_tr) + return; + mutex_lock(&trace_types_lock); __trace_array_put(this_tr); mutex_unlock(&trace_types_lock); } +EXPORT_SYMBOL_GPL(trace_array_put); int call_filter_check_discard(struct trace_event_call *call, void *rec, struct ring_buffer *buffer, @@ -8302,24 +8314,15 @@ static void update_tracer_options(struct trace_array *tr) mutex_unlock(&trace_types_lock); } -struct trace_array *trace_array_create(const char *name) +static struct trace_array *trace_array_create(const char *name) { struct trace_array *tr; int ret; - mutex_lock(&event_mutex); - mutex_lock(&trace_types_lock); - - ret = -EEXIST; - list_for_each_entry(tr, &ftrace_trace_arrays, list) { - if (tr->name && strcmp(tr->name, name) == 0) - goto out_unlock; - } - ret = -ENOMEM; tr = kzalloc(sizeof(*tr), GFP_KERNEL); if (!tr) - goto out_unlock; + return ERR_PTR(ret); tr->name = kstrdup(name, GFP_KERNEL); if (!tr->name) @@ -8364,8 +8367,8 @@ struct trace_array *trace_array_create(const char *name) list_add(&tr->list, &ftrace_trace_arrays); - mutex_unlock(&trace_types_lock); - mutex_unlock(&event_mutex); + tr->ref++; + return tr; @@ -8375,24 +8378,77 @@ struct trace_array *trace_array_create(const char *name) kfree(tr->name); kfree(tr); - out_unlock: - mutex_unlock(&trace_types_lock); - mutex_unlock(&event_mutex); - return ERR_PTR(ret); } -EXPORT_SYMBOL_GPL(trace_array_create); static int instance_mkdir(const char *name) { - return PTR_ERR_OR_ZERO(trace_array_create(name)); + struct trace_array *tr; + int ret; + + mutex_lock(&event_mutex); + mutex_lock(&trace_types_lock); + + ret = -EEXIST; + list_for_each_entry(tr, &ftrace_trace_arrays, list) { + if (tr->name && strcmp(tr->name, name) == 0) + goto out_unlock; + } + + tr = trace_array_create(name); + + ret = PTR_ERR_OR_ZERO(tr); + +out_unlock: + mutex_unlock(&trace_types_lock); + mutex_unlock(&event_mutex); + return ret; +} + +/** + * trace_array_get_by_name - Create/Lookup a trace array, given its name. + * @name: The name of the trace array to be looked up/created. + * + * Returns pointer to trace array with given name. + * NULL, if it cannot be created. + * + * NOTE: This function increments the reference counter associated with the + * trace array returned. This makes sure it cannot be freed while in use. + * Use trace_array_put() once the trace array is no longer needed. + * + */ +struct trace_array *trace_array_get_by_name(const char *name) +{ + struct trace_array *tr; + + mutex_lock(&event_mutex); + mutex_lock(&trace_types_lock); + + list_for_each_entry(tr, &ftrace_trace_arrays, list) { + if (tr->name && strcmp(tr->name, name) == 0) + goto out_unlock; + } + + tr = trace_array_create(name); + + if (IS_ERR(tr)) + tr = NULL; +out_unlock: + if (tr) + tr->ref++; + + mutex_unlock(&trace_types_lock); + mutex_unlock(&event_mutex); + return tr; } +EXPORT_SYMBOL_GPL(trace_array_get_by_name); static int __remove_instance(struct trace_array *tr) { int i; - if (tr->ref || (tr->current_trace && tr->current_trace->ref)) + /* Reference counter for a newly created trace array = 1. */ + if (tr->ref > 1 || (tr->current_trace && tr->current_trace->ref)) return -EBUSY; list_del(&tr->list); diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index 66ff63e..643faaa 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -338,7 +338,6 @@ enum { extern struct mutex trace_types_lock; extern int trace_array_get(struct trace_array *tr); -extern void trace_array_put(struct trace_array *tr); extern int tracing_set_time_stamp_abs(struct trace_array *tr, bool abs); extern int tracing_set_clock(struct trace_array *tr, const char *clockstr); diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c index 2621995..c58ef22 100644 --- a/kernel/trace/trace_events.c +++ b/kernel/trace/trace_events.c @@ -834,7 +834,6 @@ static int ftrace_set_clr_event(struct trace_array *tr, char *buf, int set) return ret; } -EXPORT_SYMBOL_GPL(ftrace_set_clr_event); /** * trace_set_clr_event - enable or disable an event @@ -859,6 +858,32 @@ int trace_set_clr_event(const char *system, const char *event, int set) } EXPORT_SYMBOL_GPL(trace_set_clr_event); +/** + * trace_array_set_clr_event - enable or disable an event for a trace array. + * @tr: concerned trace array. + * @system: system name to match (NULL for any system) + * @event: event name to match (NULL for all events, within system) + * @enable: true to enable, false to disable + * + * This is a way for other parts of the kernel to enable or disable + * event recording. + * + * Returns 0 on success, -EINVAL if the parameters do not match any + * registered events. + */ +int trace_array_set_clr_event(struct trace_array *tr, const char *system, + const char *event, bool enable) +{ + int set; + + if (!tr) + return -ENOENT; + + set = (enable == true) ? 1 : 0; + return __ftrace_set_clr_event(tr, NULL, system, event, set); +} +EXPORT_SYMBOL_GPL(trace_array_set_clr_event); + /* 128 should be much more than enough */ #define EVENT_BUF_SIZE 127 -- 1.8.3.1