On 07/01/2025 01:24, Matthew Sakai wrote:
Hi John,
Hi Matt,
I'm all for getting rid of warnings where we can, but I'm not convinced
this is the right approach here.
First, we use snprintf here because we really do want to limit the
string to 15 bytes.
Out of curiosity, why is that?
BTW, as I understand, for CONFIG_DM_VDO=m, the module name is "dm_vdo".
So why different MODULE_NAME if MODULE is not defined ("dm-vdo")?
Making this constant larger doesn't maintain that.
This change also increases the size of struct vdo (in vdo.h) by about 50
bytes. While that's not a lot, it does seem unnecessary.
In practice, we know that the our module name is only about 6 bytes, and
the instance number will never be more than 3, so snprintf will never
actually truncate anything here. Would checking for a non-zero return
value suppress the error?
I'm also confused because I don't understand the difference between this
line and the similar use of snprintf at drivers/md/dm-vdo/funnel-
workqueue.c:430, which I presume does not trigger a warning?
For that snprintf usage, the compiler just doesn't know the possible
length of @name, as it is a pointer. That is why it is a good reason to
use snprintf.
Anyway, I'd be happy with a version that suppresses the warning without
changing the size of any structures.
Matt Sakai
Thanks,
John
