linux-kernel - Re: [PATCH v2 11/28] binder: do unlocked work in binder_alloc_new

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Message-ID: <ZW3goGJBeqTsScI7@google.com>
Date:   Mon, 4 Dec 2023 14:22:24 +0000
From:   Carlos Llamas <cmllamas@...gle.com>
To:     Alice Ryhl <aliceryhl@...gle.com>
Cc:     arve@...roid.com, brauner@...nel.org, gregkh@...uxfoundation.org,
        joel@...lfernandes.org, kernel-team@...roid.com,
        linux-kernel@...r.kernel.org, maco@...roid.com, surenb@...gle.com,
        tkjos@...roid.com
Subject: Re: [PATCH v2 11/28] binder: do unlocked work in
 binder_alloc_new_buf()

On Mon, Dec 04, 2023 at 11:57:04AM +0000, 'Alice Ryhl' via kernel-team wrote:
> > Extract non-critical sections from binder_alloc_new_buf_locked() that
> > don't require holding the alloc->mutex. While we are here, consolidate
> > the checks for size overflow and zero-sized padding into a separate
> > sanitized_size() helper function.
> > 
> > Also add a few touchups to follow the coding guidelines.
> > 
> > Signed-off-by: Carlos Llamas <cmllamas@...gle.com>
> 
> Reviewed-by: Alice Ryhl <aliceryhl@...gle.com>
> 
> > +	if (IS_ERR(buffer)) {
> > +		mutex_unlock(&alloc->mutex);
> > +		goto out;
> > +	}
> > +
> > +	buffer->data_size = data_size;
> > +	buffer->offsets_size = offsets_size;
> > +	buffer->extra_buffers_size = extra_buffers_size;
> >  	mutex_unlock(&alloc->mutex);
> > +
> > +out:
> >  	return buffer;
> >  }
> 
> You could also write this as:
> 
> 	if (!IS_ERR(buffer)) {
> 		buffer->data_size = data_size;
> 		buffer->offsets_size = offsets_size;
> 		buffer->extra_buffers_size = extra_buffers_size;
> 	}
> 
> 	mutex_unlock(&alloc->mutex);
> 	return buffer;

There is a subsequent patch that adds more work after this and makes the
goto statement a better fit (patch 19/28)... at least IMO.

--
Carlos Llamas