Re: [PATCH] ext4: extents: Remove unnecessary ‘NULL’ values from path

[Theodore Ts'o]

On Tue, Apr 02, 2024 at 10:41:40AM +0800, Li zeming wrote:
> path is assigned first, so it does not need to initialize the
> assignment.

That's technically true, but the compiler is perfectly capable of
optimizing it out.  So it's harmless, and removing it does make the
code a bit more fragile, since it needs to be set so that the cleanup
code doesn't accidentally dereference an uninitialized pointer:

out:
	up_read(&ei->i_data_sem);
	ext4_free_ext_path(path);
	return ret;


So if later on, we add code which does a "goto out" on an error,
before path gets initialized, that would be bad.  So removing the
"unnecessary" set has no upside, and it has a potential disadvantage.


	      	      	 	     - Ted