From nobody Wed Feb 11 00:59:30 2026 Received: from esa3.hgst.iphmx.com (esa3.hgst.iphmx.com [216.71.153.141]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2A05432038D; Mon, 20 Oct 2025 13:41:44 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=216.71.153.141 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760967705; cv=none; b=s2rAEPjg6m/DNn5dlT7WYmHEJza15OlWdbihgrAmMJvwghTLPf88WMkcOTdkq3LutzbweJH7YfvGGvEmgWrNLVVkMOmqtXOh2TzoMN4snGPrLTqyIiBvWySQWAS41YZl6finforCNQ3frF4SsZvxFdBEYp5gIAnozuOUr2p5nzY= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760967705; c=relaxed/simple; bh=aSKlpte3/6fimeQh+rQvxtI4gXBHXMXDuYzzfy+EVC0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=sgGoFlfaljaAuRje+li0/9B6Nm+1fAbcTD5I70kDGWFtL5t8EFJSi40r4nV3Hm9h8dwZskb1bzJhx9XAfAMnMcGyy47oAL06f01BSJmFPH62BLPRBLhFDxsgEg1rpUBIqknzNUnwpLDbATFOfO+uB+aVI9xFIlB5xrjzUDQ2XHY= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=wdc.com; spf=pass smtp.mailfrom=wdc.com; dkim=pass (2048-bit key) header.d=wdc.com header.i=@wdc.com header.b=VtzIwNzj; arc=none smtp.client-ip=216.71.153.141 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=wdc.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=wdc.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=wdc.com header.i=@wdc.com header.b="VtzIwNzj" DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=wdc.com; i=@wdc.com; q=dns/txt; s=dkim.wdc.com; t=1760967705; x=1792503705; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=aSKlpte3/6fimeQh+rQvxtI4gXBHXMXDuYzzfy+EVC0=; b=VtzIwNzjmPRj3EX9hsTTtEMPuJTV+TdjigVVl6xWIBDGFVdYfZ2NVNlq x7zN9/5A7u+w6tSVuTgCzf2wpdN6jLDxVy4u+8f9Xn4kvSK/JnqT4E2Fo FC5r687BvYlyqHRL3CMROssSFvF2iDl/sNcH0LdNsYZlqPG3HYcifU+eF XtK171HuuurAICfS4W4Ql/S1jmUJzVuCk7oY+4qxvxyINAigDegkWkcCD Pr6zhr/E2C9umrWq4HachsA0o5VnBLNYh6PTyHmU3e156WCbgYUbjdNX+ rJCGG6rDyiklFmoUPgSlZOinWhLsMjhWCB+WD1bO5212vLSgZj5h+xFbb A==; X-CSE-ConnectionGUID: xtfTvtFsTAW5SrlAXC8n4g== X-CSE-MsgGUID: 5OxWNyBFT1ennm+TKHjM/g== X-IronPort-AV: E=Sophos;i="6.19,242,1754928000"; d="scan'208";a="134518624" Received: from uls-op-cesaip02.wdc.com (HELO uls-op-cesaep03.wdc.com) ([199.255.45.15]) by ob1.hgst.iphmx.com with ESMTP; 20 Oct 2025 21:41:44 +0800 IronPort-SDR: 68f63c17_hURQxFZGUBSMTKCndty7ipHDtgf0bBK3Yr9IibrXnZRSMX5 LI0Ku4lmEfeUtWSz3buBUydZz3BwSB+goPmv5Hg== Received: from uls-op-cesaip02.wdc.com ([10.248.3.37]) by uls-op-cesaep03.wdc.com with ESMTP/TLS/ECDHE-RSA-AES128-GCM-SHA256; 20 Oct 2025 06:41:44 -0700 WDCIronportException: Internal Received: from 1pgdl13.ad.shared (HELO neo.fritz.box) ([10.224.28.46]) by uls-op-cesaip02.wdc.com with ESMTP; 20 Oct 2025 06:41:40 -0700 From: Johannes Thumshirn To: axboe@kernel.dk Cc: chaitanyak@nvidia.com, dlemoal@kernel.org, hare@suse.de, hch@lst.de, john.g.garry@oracle.com, linux-block@vger.kernel.org, linux-btrace@vger.kernel.org, linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, martin.petersen@oracle.com, mathieu.desnoyers@efficios.com, mhiramat@kernel.org, naohiro.aota@wdc.com, rostedt@goodmis.org, shinichiro.kawasaki@wdc.com, Johannes Thumshirn Subject: [PATCH v4 03/16] blktrace: split out relaying a blktrace event Date: Mon, 20 Oct 2025 15:41:10 +0200 Message-ID: <20251020134123.119058-4-johannes.thumshirn@wdc.com> X-Mailer: git-send-email 2.51.0 In-Reply-To: <20251020134123.119058-1-johannes.thumshirn@wdc.com> References: <20251020134123.119058-1-johannes.thumshirn@wdc.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Split out the code relaying a blktrace event to user-space using relayfs. This enables adding a second version supporting a new version of the protocol. Reviewed-by: Christoph Hellwig Reviewed-by: Damien Le Moal Signed-off-by: Johannes Thumshirn --- kernel/trace/blktrace.c | 60 ++++++++++++++++++++++------------------- 1 file changed, 32 insertions(+), 28 deletions(-) diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c index 25a0a1b09747..51745832c713 100644 --- a/kernel/trace/blktrace.c +++ b/kernel/trace/blktrace.c @@ -91,6 +91,26 @@ static void record_blktrace_event(struct blk_io_trace *t= , pid_t pid, int cpu, memcpy((void *)t + sizeof(*t) + cgid_len, pdu_data, pdu_len); } =20 +static void relay_blktrace_event(struct blk_trace *bt, unsigned long seque= nce, + pid_t pid, int cpu, sector_t sector, int bytes, + u32 what, int error, u64 cgid, + ssize_t cgid_len, void *pdu_data, int pdu_len) +{ + struct blk_io_trace *t; + size_t trace_len =3D sizeof(*t) + pdu_len + cgid_len; + + t =3D relay_reserve(bt->rchan, trace_len); + if (!t) + return; + + t->magic =3D BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION; + t->sequence =3D sequence; + t->time =3D ktime_to_ns(ktime_get()); + + record_blktrace_event(t, pid, cpu, sector, bytes, what, bt->dev, error, + cgid, cgid_len, pdu_data, pdu_len); +} + /* * Send out a notify message. */ @@ -126,16 +146,9 @@ static void trace_note(struct blk_trace *bt, pid_t pid= , int action, if (!bt->rchan) return; =20 - t =3D relay_reserve(bt->rchan, trace_len); - if (t) { - t->magic =3D BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION; - t->time =3D ktime_to_ns(ktime_get()); - - record_blktrace_event(t, pid, cpu, 0, 0, - action | (cgid ? __BLK_TN_CGROUP : 0), - bt->dev, 0, cgid, cgid_len, (void *)data, - len); - } + relay_blktrace_event(bt, 0, pid, cpu, 0, 0, + action | (cgid ? __BLK_TN_CGROUP : 0), 0, cgid, + cgid_len, (void *)data, len); } =20 /* @@ -246,7 +259,6 @@ static void __blk_add_trace(struct blk_trace *bt, secto= r_t sector, int bytes, struct task_struct *tsk =3D current; struct ring_buffer_event *event =3D NULL; struct trace_buffer *buffer =3D NULL; - struct blk_io_trace *t; unsigned long flags =3D 0; unsigned long *sequence; unsigned int trace_ctx =3D 0; @@ -278,20 +290,21 @@ static void __blk_add_trace(struct blk_trace *bt, sec= tor_t sector, int bytes, return; cpu =3D raw_smp_processor_id(); =20 - trace_len =3D sizeof(*t) + pdu_len + cgid_len; if (blk_tracer) { tracing_record_cmdline(current); =20 buffer =3D blk_tr->array_buffer.buffer; trace_ctx =3D tracing_gen_ctx_flags(0); + trace_len =3D sizeof(struct blk_io_trace) + pdu_len + cgid_len; event =3D trace_buffer_lock_reserve(buffer, TRACE_BLK, trace_len, trace_ctx); if (!event) return; - t =3D ring_buffer_event_data(event); =20 - record_blktrace_event(t, pid, cpu, sector, bytes, what, bt->dev, - error, cgid, cgid_len, pdu_data, pdu_len); + record_blktrace_event(ring_buffer_event_data(event), + pid, cpu, sector, bytes, what, bt->dev, + error, cgid, cgid_len, pdu_data, + pdu_len); =20 trace_buffer_unlock_commit(blk_tr, buffer, event, trace_ctx); return; @@ -306,19 +319,10 @@ static void __blk_add_trace(struct blk_trace *bt, sec= tor_t sector, int bytes, * from coming in and stepping on our toes. */ local_irq_save(flags); - t =3D relay_reserve(bt->rchan, trace_len); - if (t) { - sequence =3D per_cpu_ptr(bt->sequence, cpu); - - t->magic =3D BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION; - t->sequence =3D ++(*sequence); - t->time =3D ktime_to_ns(ktime_get()); - - record_blktrace_event(t, pid, cpu, sector, bytes, what, - bt->dev, error, cgid, cgid_len, - pdu_data, pdu_len); - } - + sequence =3D per_cpu_ptr(bt->sequence, cpu); + (*sequence)++; + relay_blktrace_event(bt, *sequence, pid, cpu, sector, bytes, what, + error, cgid, cgid_len, pdu_data, pdu_len); local_irq_restore(flags); } =20 --=20 2.51.0