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Date: Mon, 1 Apr 2024 23:55:02 -0400
From: "Theodore Ts'o" <tytso@mit.edu>
To: Li zeming <zeming@nfschina.com>
Cc: adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH] ext4: extents: =?utf-8?Q?Remov?=
 =?utf-8?B?ZSB1bm5lY2Vzc2FyeSDigJhOVUxM4oCZ?= values from path
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In-Reply-To: <20240402024140.28456-1-zeming@nfschina.com>

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