From: Steven Rostedt <rostedt@goodmis.org>
To: LKML <linux-kernel@vger.kernel.org>,
Linux Trace Kernel <linux-trace-kernel@vger.kernel.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Subject: [PATCH] tracing: Do not clean up hiter in mmiotrace read function
Date: Tue, 21 Jul 2026 21:20:10 -0400 [thread overview]
Message-ID: <20260721212010.76e9ed61@gandalf.local.home> (raw)
From: Steven Rostedt <rostedt@goodmis.org>
When the mmiotrace trace was first created, it allocated a descriptor in
its pipe_open() method. Since there was no pipe_close() method when it was
created (in May of 2008, and pipe_close() was added in December of 2009),
it cleaned up the allocated descriptors in the read.
Now that the clean up is in the pipe_close() method that now exists,
remove the clean up from the read as it is no longer needed.
Also simplify the code by inverting the early exit conditional into a
conditional to perform the logic and get rid of the goto.
Link: https://lore.kernel.org/all/20260715143604.14481-1-gaikwad.dcg@gmail.com/
Link: https://lore.kernel.org/all/20260721211143.36dbd559@gandalf.local.home/
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
kernel/trace/trace_mmiotrace.c | 14 +++-----------
1 file changed, 3 insertions(+), 11 deletions(-)
diff --git a/kernel/trace/trace_mmiotrace.c b/kernel/trace/trace_mmiotrace.c
index b88b8d9923ad..ba604c22d2d2 100644
--- a/kernel/trace/trace_mmiotrace.c
+++ b/kernel/trace/trace_mmiotrace.c
@@ -142,21 +142,13 @@ static ssize_t mmio_read(struct trace_iterator *iter, struct file *filp,
if (!overrun_detected)
pr_warn("mmiotrace has lost events\n");
overrun_detected = true;
- goto print_out;
}
- if (!hiter || !hiter->dev)
- return 0;
-
- mmio_print_pcidev(s, hiter->dev);
- hiter->dev = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, hiter->dev);
-
- if (!hiter->dev) {
- destroy_header_iter(hiter);
- iter->private = NULL;
+ if (hiter && hiter->dev) {
+ mmio_print_pcidev(s, hiter->dev);
+ hiter->dev = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, hiter->dev);
}
-print_out:
ret = trace_seq_to_user(s, ubuf, cnt);
return (ret == -EBUSY) ? 0 : ret;
}
--
2.53.0
next reply other threads:[~2026-07-22 1:19 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-07-22 1:20 Steven Rostedt [this message]
2026-07-22 23:24 ` [PATCH] tracing: Do not clean up hiter in mmiotrace read function Masami Hiramatsu
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