From: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Date: Thu, 14 Apr 2016 19:29:01 +0000 (-0400)
Subject: Add comment describing ioctl number duplication
X-Git-Tag: v2.9.0-rc1~86
X-Git-Url: https://git.lttng.org./?a=commitdiff_plain;h=fe40f016c667f247b8e81c318cafa173de745fdd;p=lttng-modules.git

Add comment describing ioctl number duplication

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
---

diff --git a/lttng-abi.h b/lttng-abi.h
index e23393ff..9b9a2323 100644
--- a/lttng-abi.h
+++ b/lttng-abi.h
@@ -197,6 +197,11 @@ struct lttng_kernel_filter_bytecode {
 	_IOR(0xF6, 0x58, int32_t)
 #define LTTNG_KERNEL_SESSION_UNTRACK_PID	\
 	_IOR(0xF6, 0x59, int32_t)
+/*
+ * ioctl 0x58 and 0x59 are duplicated here. It works, since _IOR vs _IO
+ * are generating two different ioctl numbers, but this was not done on
+ * purpose. We should generally try to avoid those duplications.
+ */
 #define LTTNG_KERNEL_SESSION_LIST_TRACKER_PIDS	_IO(0xF6, 0x58)
 #define LTTNG_KERNEL_SESSION_METADATA_REGEN	_IO(0xF6, 0x59)