From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) (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 E541123A9BD for ; Mon, 12 May 2025 19:03:16 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=90.155.50.34 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1747076598; cv=none; b=LdGkJCU+r1n54Ya24bTBl7lWXI+eaGZHSftalfdG7kOVOpqOrCzJT9DAW5hFgKbCMTquNOqzRlczmAFskp6541Q0sLt28rXO4/aaZnHEYCfxxqGv3B1Mmo37pKKxFAjLLat/a+L2igWgp4wcxCkw1wcmuvvC/PPmr0IOeblztm8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1747076598; c=relaxed/simple; bh=O4H8iAzwOwN+yTMHteguWKtTAD4YhTkV/H8oa2wjqkY=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=b5LEzmBHHEmGOhfH1RAmmezdbjPnmRtHBs9CaEdME/aNP9to8q6OnGej/+lDbRb1kS+9PwhNwSw73dd4bhbmiAZEup4BPXqS+zBGDuduhv/kO/DR7KEp7JMp+wvZI23b7BIo+Tfr/T18IzTkj2QK614djRw05s8Wcfk+v9hv2dY= 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=m8nKzx19; arc=none smtp.client-ip=90.155.50.34 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="m8nKzx19" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; 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=6TU8lovtR+mIfquQ2rCbk6fwLvKUBUsDQ9Gbh5JlI78=; b=m8nKzx198g557xXfy33UFRw+Kr qoyVHoc5J/ZHQWHjy+CmISnWIg9QilqxqRc8j5FTIC44xRVH68NBsZBcQtK0pJzqoGQ8aNBSUKezj 4AoX90aHZB39mu2IfgjZn4nJg61ODpbKGnlMQGDPjujcsDYFgY2ao9ddJgjrhc3+qC7gpe6Ow9ytz 9EpqnIuyHFh+fWWZZLlL6mGmjat0WVnJ7Fth3pWkzPpGj9onP41kYaYjM5iKCJngX659kfFbAtkxU oi6USOiKVK6s1Y9R8W5CYVaxs50SuOTOrGBQA/Cd64UgKVuoz5Ju26v890On9g7o86334/Ia0xUI3 LwARxIjg==; Received: from willy by casper.infradead.org with local (Exim 4.98.2 #2 (Red Hat Linux)) id 1uEYQh-0000000AAGr-304E; Mon, 12 May 2025 19:03:11 +0000 Date: Mon, 12 May 2025 20:03:11 +0100 From: Matthew Wilcox To: Nhat Pham Cc: akpm@linux-foundation.org, hannes@cmpxchg.org, yosryahmed@google.com, yosry.ahmed@linux.dev, chengming.zhou@linux.dev, linux-mm@kvack.org, kernel-team@meta.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH v4] page_io: zswap: do not crash the kernel on decompression failure Message-ID: References: <20250306205011.784787-1-nphamcs@gmail.com> 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: <20250306205011.784787-1-nphamcs@gmail.com> On Thu, Mar 06, 2025 at 12:50:10PM -0800, Nhat Pham wrote: > -static void zswap_decompress(struct zswap_entry *entry, struct folio *folio) > +static bool zswap_decompress(struct zswap_entry *entry, struct folio *folio) Hm, why do it this way? I had it as: -static void zswap_decompress(struct zswap_entry *entry, struct folio *folio) +static int zswap_decompress(struct zswap_entry *entry, struct folio *folio) ... + err = crypto_acomp_decompress(acomp_ctx->req); + err = crypto_wait_req(err, &acomp_ctx->wait); + if (!err && acomp_ctx->req->dlen != PAGE_SIZE) + err = -EIO; which allows us to return something more meaningful than -EIO. Or is doing that a bad idea and we should squash all decompression failures to EIO? (also i really dislike the chained approach: decomp_ret = crypto_wait_req(crypto_acomp_decompress(acomp_ctx->req), &acomp_ctx->wait); that's much harder to understand than the two lines i have above)