Re: [PATCH] video: fbdev: via_aux_vt1636: remove VLA usage
From: Eric Engestrom <hidden>
Date: 2018-03-09 10:11:54
Also in:
dri-devel, lkml
On Wednesday, 2018-03-07 13:47:03 -0600, Gustavo A. R. Silva wrote:
quoted hunk ↗ jump to hunk
In preparation to enabling -Wvla, remove VLA and replace it with a fixed-length array instead. Also, remove variable 'len'. Notice that no new IDs have been added in seven years. Signed-off-by: Gustavo A. R. Silva <redacted> --- drivers/video/fbdev/via/via_aux_vt1636.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)diff --git a/drivers/video/fbdev/via/via_aux_vt1636.c b/drivers/video/fbdev/via/via_aux_vt1636.c index 9e015c1..d6273a4 100644 --- a/drivers/video/fbdev/via/via_aux_vt1636.c +++ b/drivers/video/fbdev/via/via_aux_vt1636.c@@ -35,10 +35,10 @@ void via_aux_vt1636_probe(struct via_aux_bus *bus) .addr = 0x40, .name = name}; /* check vendor id and device id */ - const u8 id[] = {0x06, 0x11, 0x45, 0x33}, len = ARRAY_SIZE(id); - u8 tmp[len]; + const u8 id[4] = {0x06, 0x11, 0x45, 0x33}; + u8 tmp[4]; - if (!via_aux_read(&drv, 0x00, tmp, len) || memcmp(id, tmp, len)) + if (!via_aux_read(&drv, 0x00, tmp, 4) || memcmp(id, tmp, 4))
I would recommend keeping ARRAY_SIZE(); even if nothing's been added in a while, it's still clearer in the code if we can see where these `4` come from. Something like this instead? ----8<----
@@ -35,10 +35,10 @@ void via_aux_vt1636_probe(struct via_aux_bus *bus) .addr = 0x40, .name = name}; /* check vendor id and device id */ - const u8 id[] = {0x06, 0x11, 0x45, 0x33}, len = ARRAY_SIZE(id); - u8 tmp[len]; + const u8 id[] = {0x06, 0x11, 0x45, 0x33}; + u8 tmp[ARRAY_SIZE(id)]; - if (!via_aux_read(&drv, 0x00, tmp, len) || memcmp(id, tmp, len)) + if (!via_aux_read(&drv, 0x00, tmp, ARRAY_SIZE(id)) || memcmp(id, tmp, ARRAY_SIZE(id))) return; printk(KERN_INFO "viafb: Found %s\n", name); ---->8----
Note that sizeof is evaluated a compile time, so `u8 tmp[ARRAY_SIZE(id)]` is *not* a VLA. All that's needed was to remove `len` :)
return; printk(KERN_INFO "viafb: Found %s\n", name); -- 2.7.4 _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel