Received-SPF: pass (google.com: domain of linux-ext4-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Date:   Thu, 13 Apr 2023 23:04:43 -0700
From:   Christoph Hellwig <hch@infradead.org>
To:     "Ritesh Harjani (IBM)" <ritesh.list@gmail.com>
Cc:     linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org,
        Jan Kara <jack@suse.cz>, Christoph Hellwig <hch@infradead.org>,
        "Darrick J . Wong" <djwong@kernel.org>,
        Ojaswin Mujoo <ojaswin@linux.ibm.com>,
        Disha Goel <disgoel@linux.ibm.com>
Subject: Re: [RFCv3 10/10] iomap: Add trace points for DIO path
Message-ID: <ZDjs+/T/mf1nHUHI@infradead.org>
References: <cover.1681365596.git.ritesh.list@gmail.com>
 <93ab8386c4620395c5e674a7930506895fc758ef.1681365596.git.ritesh.list@gmail.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <93ab8386c4620395c5e674a7930506895fc758ef.1681365596.git.ritesh.list@gmail.com>
Precedence: bulk

> +	trace_iomap_dio_rw_begin(iocb, iter, dio_flags, done_before, ret);
>  	dio = __iomap_dio_rw(iocb, iter, ops, dops, dio_flags, private,
>  			     done_before);
>  	if (IS_ERR_OR_NULL(dio)) {
> @@ -689,6 +691,7 @@ iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
>  	}
>  	ret = iomap_dio_complete(dio);
>  out:
> +	trace_iomap_dio_rw_end(iocb, iter, dio_flags, done_before, ret);

The trace_iomap_dio_rw_end tracepoint heere seems a bit weird,
and we'll miss it for file systems using  __iomap_dio_rw directly.

I'd instead add a trace_iomap_dio_rw_queued for the case where
__iomap_dio_rw returns ERR_PTR(-EIOCBQUEUED), as otherwise we're
nicely covered by the complete trace points.

> +		  __print_flags(__entry->dio_flags, "|", TRACE_IOMAP_DIO_STRINGS),

Please avoid the overly lone line here.