[PATCH] tracing: Do not clean up hiter in mmiotrace read function

From: Steven Rostedt

Date: Tue Jul 21 2026 - 21:32:54 EST


From: Steven Rostedt <rostedt@xxxxxxxxxxx>

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@xxxxxxxxx/
Link: https://lore.kernel.org/all/20260721211143.36dbd559@xxxxxxxxxxxxxxxxxx/

Signed-off-by: Steven Rostedt <rostedt@xxxxxxxxxxx>
---
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