On Wed, 29 Jan 2014 10:29:56 -0800 Sebastian Capella sebastian.capella@linaro.org wrote:
Hi Andrew,
By the way, I do see a call (sysfs_streq) in use for this purpose other places. Sorry, I didn't find it while looking at the original problem. I'm not sure if this is preferable, but it appears to have been added specifically for the strings coming through sysfs.
Yes, I wrote it ;)
I didn't think sysfs_streq() is well suited to this problem. And the issue of possibly-null-terminated-strings coming in from userspace is a common one, so it is desirable that we build up the suite of utilities to handle this.
There are probably quite a lot of open-coded \n trimming loops which can be cleaned up using such tools.
grep -r "if .* == '\\n'" .
My preference is copying the string and cleaning it up before passing it to internal functions, even though we incur an allocation.
Yes. Here on the kernel/userspace boundary we are typically running in GFP_KERNEL context and the code is not performance critical - it is a good fit.