Fix: gcc-9.1 stack frame size warning

gcc-9.1.0 warns about lttng_session_ioctl taking a too large frame size.

lttng-modules/lttng-abi.c:622:1: warning: the frame size of 2240 bytes
is larger than 2048 bytes [-Wframe-larger-than=]

Combine the variables used in the various case of the switch so they are
not duplicated on the stack by the compiler.

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

diff --git a/lttng-abi.c b/lttng-abi.c
index cc8f1838360faf8e60d7a369fe28924bad0ceb7c..5624b6c4f99839a81f289dd45bc6a5c8e7181b2e 100644 (file)
--- a/lttng-abi.c
+++ b/lttng-abi.c
@@ -514,13 +514,12 @@ static
 long lttng_session_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 {
        struct lttng_session *session = file->private_data;
+       struct lttng_kernel_channel chan_param;
+       struct lttng_kernel_old_channel old_chan_param;
 
        switch (cmd) {
        case LTTNG_KERNEL_OLD_CHANNEL:
        {
-               struct lttng_kernel_channel chan_param;
-               struct lttng_kernel_old_channel old_chan_param;
-
                if (copy_from_user(&old_chan_param,
                                (struct lttng_kernel_old_channel __user *) arg,
                                sizeof(struct lttng_kernel_old_channel)))
@@ -537,8 +536,6 @@ long lttng_session_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
        }
        case LTTNG_KERNEL_CHANNEL:
        {
-               struct lttng_kernel_channel chan_param;
-
                if (copy_from_user(&chan_param,
                                (struct lttng_kernel_channel __user *) arg,
                                sizeof(struct lttng_kernel_channel)))
@@ -558,9 +555,6 @@ long lttng_session_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
                return lttng_session_disable(session);
        case LTTNG_KERNEL_OLD_METADATA:
        {
-               struct lttng_kernel_channel chan_param;
-               struct lttng_kernel_old_channel old_chan_param;
-
                if (copy_from_user(&old_chan_param,
                                (struct lttng_kernel_old_channel __user *) arg,
                                sizeof(struct lttng_kernel_old_channel)))
@@ -577,8 +571,6 @@ long lttng_session_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
        }
        case LTTNG_KERNEL_METADATA:
        {
-               struct lttng_kernel_channel chan_param;
-
                if (copy_from_user(&chan_param,
                                        (struct lttng_kernel_channel __user *) arg,
                                        sizeof(struct lttng_kernel_channel)))