[PATCH] drm: reorder struct drm_ioctl_desc to save space on 64 bitbuilds

From: Richard Kennedy
Date: Wed Mar 18 2009 - 13:27:03 EST


drm: reorder struct drm_ioctl_desc to save space on 64 bit builds

shrinks drm_ioctl_desc from 24 bytes to 16 bytes by reordering members
to remove padding.

updates DRM_IOCTL_DEF macro to initialise structure members by name to
handle the structure reorder.

The applied patch reduces data used in drm.ko from 10440 to 9032

Signed-off-by: Richard Kennedy <richard@xxxxxxxxxxxxxxx>
---

This patch is against v2.6.29-rc8, it compiles but hasn't had any other
testing as I don't have any of this hardware.

size reports
drm.ko
text data bss
106297 10440 144 116881 1c891
106297 9032 144 115473 1c311 +patch

I also built these 2 drivers
sis.ko
text data bss
3817 2116 0 5933 172d
3817 1932 0 5749 1675 +patch

radeon.ko
text data bss
94744 9880 16400 121024
94744 9656 16400 120800 +patch

regards
Richard


diff --git a/include/drm/drmP.h b/include/drm/drmP.h
index e5f4ae9..62c2ef3 100644
--- a/include/drm/drmP.h
+++ b/include/drm/drmP.h
@@ -281,16 +281,16 @@ typedef int drm_ioctl_compat_t(struct file *filp, unsigned int cmd,

struct drm_ioctl_desc {
unsigned int cmd;
- drm_ioctl_t *func;
int flags;
+ drm_ioctl_t *func;
};

/**
* Creates a driver or general drm_ioctl_desc array entry for the given
* ioctl, for use by drm_ioctl().
*/
-#define DRM_IOCTL_DEF(ioctl, func, flags) \
- [DRM_IOCTL_NR(ioctl)] = {ioctl, func, flags}
+#define DRM_IOCTL_DEF(ioctl, _func, _flags) \
+ [DRM_IOCTL_NR(ioctl)] = {.cmd = ioctl, .func = _func, .flags = _flags}

struct drm_magic_entry {
struct list_head head;


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