From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from desiato.infradead.org (desiato.infradead.org [90.155.92.199]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 9B0B71C4A0A; Mon, 7 Jul 2025 11:11:20 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=90.155.92.199 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751886682; cv=none; b=fiv4ZD5grJiX8UpD1rM/zNMGuZr+m9kRlI93IoktaBatD2KElh2/dG7vZXC66pHD7OfN5E3TBdU+X3ZQYThxK+H2snZKWaWGe4NYMA9ZSmRwnel89RWlmja4f8bH7+V3kpKAqoc8PPySWoJe4yYzq7nvQMiynxwwPI4RvreHy5Y= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751886682; c=relaxed/simple; bh=Z0DzFa6Ck8MY9mheY3wDTdFe9/hvBRhpNbyrSmBtew8=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=R5ZbY1RMs0XvGrT4iQfWrEkHrM9HQm7ThTurLy/V9eAolRh8OkgfEdqp1hD2g5eeHtDkG+9Ox526BpE6yEk9QMq212R1mpjXoZgQ6hSNFG7oem8JJ6AvHw3pzbW8EKEz3zwKERVGu++Qc6WnZxBRb6CYQlFeFx1pYN0SvncizUg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org; spf=none smtp.mailfrom=infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=qezQPJ3w; arc=none smtp.client-ip=90.155.92.199 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="qezQPJ3w" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=Y28+p4hX9PEUMHUlBkI77beYKGWjbFcITsIbtfbTURs=; b=qezQPJ3wjgMr442XMPlt9n2Ksu W9LQMhSj5LhBqQ8d/2ilKfw/Xh5faImKUfSTZdYh6ljTF4E3OLJydHHiIcupLMTP05tFfBEQA0sbF gT9oR+Zh2Lsy+lTfffMLvfmMsqqNYxllbjKHnDUdez6wLV57ImIeAnx4b3JGg5NzFTB5cd+EEHjWr IoomUVw1wsJXd7cyIvpG1vJkS/D5iUI7eec0+9Y72SE9cAIOPaVWikrOH6Zyy4lMd93gJUhMjMSoq X0hpjXyRXFPvq88lj2eojs0O3NityG+y9vwZDjbcWWLq8S52H1vlmG52cXp6QfWtjxl1HwrQPnkWo 1XK13jmw==; Received: from 77-249-17-252.cable.dynamic.v4.ziggo.nl ([77.249.17.252] helo=noisy.programming.kicks-ass.net) by desiato.infradead.org with esmtpsa (Exim 4.98.2 #2 (Red Hat Linux)) id 1uYjkV-00000008TRB-2rx3; Mon, 07 Jul 2025 11:11:04 +0000 Received: by noisy.programming.kicks-ass.net (Postfix, from userid 1000) id ACA4C300399; Mon, 07 Jul 2025 13:11:02 +0200 (CEST) Date: Mon, 7 Jul 2025 13:11:02 +0200 From: Peter Zijlstra To: Mike Rapoport Cc: Andrew Morton , Andy Lutomirski , Borislav Petkov , Daniel Gomez , Dave Hansen , Ingo Molnar , Luis Chamberlain , Mark Rutland , Masami Hiramatsu , "H. Peter Anvin" , Petr Pavlu , Sami Tolvanen , Steven Rostedt , Thomas Gleixner , linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-modules@vger.kernel.org, linux-trace-kernel@vger.kernel.org, x86@kernel.org Subject: Re: [PATCH 3/8] execmem: rework execmem_cache_free() Message-ID: <20250707111102.GF1613200@noisy.programming.kicks-ass.net> References: <20250704134943.3524829-1-rppt@kernel.org> <20250704134943.3524829-4-rppt@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250704134943.3524829-4-rppt@kernel.org> On Fri, Jul 04, 2025 at 04:49:38PM +0300, Mike Rapoport wrote: > static bool execmem_cache_free(void *ptr) > { > struct maple_tree *busy_areas = &execmem_cache.busy_areas; > unsigned long addr = (unsigned long)ptr; > MA_STATE(mas, busy_areas, addr, addr); > void *area; > + int err; > + > + guard(mutex)(&execmem_cache.mutex); > > area = mas_walk(&mas); > + if (!area) > return false; > > + err = __execmem_cache_free(&mas, ptr, GFP_KERNEL | __GFP_NORETRY); > + if (err) > + goto err_slowpath; > > schedule_work(&execmem_cache_clean_work); > > return true; > + > +err_slowpath: > + mas_store_gfp(&mas, pending_free_set(ptr), GFP_KERNEL); > + execmem_cache.pending_free_cnt++; > + schedule_delayed_work(&execmem_cache_free_work, FREE_DELAY); > + return true; > } This is a bit if an anti-pattern, using guard() and error goto. Since there is only the one site, its best to write it like so: static bool execmem_cache_free(void *ptr) { struct maple_tree *busy_areas = &execmem_cache.busy_areas; unsigned long addr = (unsigned long)ptr; MA_STATE(mas, busy_areas, addr, addr); void *area; int err; guard(mutex)(&execmem_cache.mutex); area = mas_walk(&mas); if (!area) return false; err = __execmem_cache_free(&mas, ptr, GFP_KERNEL | __GFP_NORETRY); if (err) { mas_store_gfp(&mas, pending_free_set(ptr), GFP_KERNEL); execmem_cache.pending_free_cnt++; schedule_delayed_work(&execmem_cache_free_work, FREE_DELAY); return true; } schedule_work(&execmem_cache_clean_work); return true; } And now I have to ask what happens if mas_store_gfp() returns an error?