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Fri, 16 Dec 2022 09:03:14 +0000 Received: from nalasex01b.na.qualcomm.com (nalasex01b.na.qualcomm.com [10.47.209.197]) by NALASPPMTA02.qualcomm.com (8.17.1.5/8.17.1.5) with ESMTPS id 2BG93DrB001768 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Fri, 16 Dec 2022 09:03:13 GMT Received: from linyyuan-gv.qualcomm.com (10.80.80.8) by nalasex01b.na.qualcomm.com (10.47.209.197) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.986.36; Fri, 16 Dec 2022 01:03:11 -0800 From: Linyu Yuan To: Steven Rostedt , Masami Hiramatsu CC: , , Linyu Yuan Subject: [PATCH v4 2/2] trace: acquire buffer from temparary trace sequence Date: Fri, 16 Dec 2022 17:03:05 +0800 Message-ID: <1671181385-5719-2-git-send-email-quic_linyyuan@quicinc.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1671181385-5719-1-git-send-email-quic_linyyuan@quicinc.com> References: <1671181385-5719-1-git-send-email-quic_linyyuan@quicinc.com> MIME-Version: 1.0 X-Originating-IP: [10.80.80.8] X-ClientProxiedBy: nasanex01b.na.qualcomm.com (10.46.141.250) To nalasex01b.na.qualcomm.com (10.47.209.197) X-QCInternal: smtphost X-Proofpoint-Virus-Version: vendor=nai engine=6200 definitions=5800 signatures=585085 X-Proofpoint-ORIG-GUID: NndQ8hU9bNZO7siWX7Sv_L4x6sWtR09b X-Proofpoint-GUID: NndQ8hU9bNZO7siWX7Sv_L4x6sWtR09b X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.923,Hydra:6.0.545,FMLib:17.11.122.1 definitions=2022-12-16_04,2022-12-15_02,2022-06-22_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 impostorscore=0 clxscore=1015 adultscore=0 mlxscore=0 bulkscore=0 spamscore=0 phishscore=0 mlxlogscore=999 lowpriorityscore=0 suspectscore=0 malwarescore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2212070000 definitions=main-2212160078 X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1752361512964382632?= X-GMAIL-MSGID: =?utf-8?q?1752361512964382632?= there is one dwc3 trace event declare as below, DECLARE_EVENT_CLASS(dwc3_log_event, TP_PROTO(u32 event, struct dwc3 *dwc), TP_ARGS(event, dwc), TP_STRUCT__entry( __field(u32, event) __field(u32, ep0state) __dynamic_array(char, str, DWC3_MSG_MAX) ), TP_fast_assign( __entry->event = event; __entry->ep0state = dwc->ep0state; ), TP_printk("event (%08x): %s", __entry->event, dwc3_decode_event(__get_str(str), DWC3_MSG_MAX, __entry->event, __entry->ep0state)) ); the problem is when trace function called, it will allocate up to DWC3_MSG_MAX bytes from trace event buffer, but never fill the buffer during fast assignment, it only fill the buffer when output function are called, so this means if output function are not called, the buffer will never used. add __get_buf(len) which acquiree buffer from iter->tmp_seq when trace output function called, it allow user write string to acquired buffer. the mentioned dwc3 trace event will changed as below, DECLARE_EVENT_CLASS(dwc3_log_event, TP_PROTO(u32 event, struct dwc3 *dwc), TP_ARGS(event, dwc), TP_STRUCT__entry( __field(u32, event) __field(u32, ep0state) ), TP_fast_assign( __entry->event = event; __entry->ep0state = dwc->ep0state; ), TP_printk("event (%08x): %s", __entry->event, dwc3_decode_event(__get_buf(DWC3_MSG_MAX), DWC3_MSG_MAX, __entry->event, __entry->ep0state)) );. Signed-off-by: Linyu Yuan --- v4: no change v3: fix comment from maintainer in v2 include/linux/trace_seq.h | 6 ++++++ include/trace/stages/stage3_trace_output.h | 8 ++++++++ include/trace/stages/stage7_class_define.h | 1 + kernel/trace/trace_seq.c | 22 ++++++++++++++++++++++ 4 files changed, 37 insertions(+) diff --git a/include/linux/trace_seq.h b/include/linux/trace_seq.h index 5a2c650..4a3bbab 100644 --- a/include/linux/trace_seq.h +++ b/include/linux/trace_seq.h @@ -95,6 +95,7 @@ extern void trace_seq_bitmask(struct trace_seq *s, const unsigned long *maskp, extern int trace_seq_hex_dump(struct trace_seq *s, const char *prefix_str, int prefix_type, int rowsize, int groupsize, const void *buf, size_t len, bool ascii); +char *trace_seq_acquire(struct trace_seq *s, size_t len); #else /* CONFIG_TRACING */ static inline void trace_seq_printf(struct trace_seq *s, const char *fmt, ...) @@ -138,6 +139,11 @@ static inline int trace_seq_path(struct trace_seq *s, const struct path *path) { return 0; } + +static inline char *trace_seq_acquire(struct trace_seq *s, size_t len) +{ + return NULL; +} #endif /* CONFIG_TRACING */ #endif /* _LINUX_TRACE_SEQ_H */ diff --git a/include/trace/stages/stage3_trace_output.h b/include/trace/stages/stage3_trace_output.h index 66374df..f60c453 100644 --- a/include/trace/stages/stage3_trace_output.h +++ b/include/trace/stages/stage3_trace_output.h @@ -139,3 +139,11 @@ u64 ____val = (u64)(value); \ (u32) do_div(____val, NSEC_PER_SEC); \ }) + +/* Macros with flow control statements should be avoided */ +#undef __get_buf +#define __get_buf(len) \ + ({ \ + WARN_ON_ONCE(seq_buf_buffer_left(&p->seq) < (len)); \ + trace_seq_acquire(p, (len)); \ + }) diff --git a/include/trace/stages/stage7_class_define.h b/include/trace/stages/stage7_class_define.h index 8795429..bcb960d 100644 --- a/include/trace/stages/stage7_class_define.h +++ b/include/trace/stages/stage7_class_define.h @@ -23,6 +23,7 @@ #undef __get_rel_sockaddr #undef __print_array #undef __print_hex_dump +#undef __get_buf /* * The below is not executed in the kernel. It is only what is diff --git a/kernel/trace/trace_seq.c b/kernel/trace/trace_seq.c index 9c90b3a..c900b7c 100644 --- a/kernel/trace/trace_seq.c +++ b/kernel/trace/trace_seq.c @@ -403,3 +403,25 @@ int trace_seq_hex_dump(struct trace_seq *s, const char *prefix_str, return 1; } EXPORT_SYMBOL(trace_seq_hex_dump); + +/** + * trace_seq_acquire - acquire seq buffer with size len + * @s: trace sequence descriptor + * @len: size of buffer to be acquired + * + * acquire buffer with size of @len from trace_seq for output usage, + * user can fill string into that buffer. + * + * Returns start address of acquired buffer. + * + * it allow multiple usage in one trace output function call. + */ +char *trace_seq_acquire(struct trace_seq *s, size_t len) +{ + char *ret = trace_seq_buffer_ptr(s); + + seq_buf_commit(&s->seq, len); + + return ret; +} +EXPORT_SYMBOL(trace_seq_acquire);