From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 D2A7B28640B; Thu, 21 Aug 2025 15:47:47 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755791267; cv=none; b=ey8NQvHCCrHf9WWtE7bjMBW6GfkFR9thpNr0V5xUOa/DsZMKnHYUEDbapvp9xKsRZkCn2zOUTORfGI76fMV80lhXccNUiuwKi1+2zD+2inEpBYVqXmw+JtuUI6Y/86/fzQY+J0MWnsTrgS3rTXX5iE3PZw66bw185+xVxriJwCw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755791267; c=relaxed/simple; bh=S7ZDNRuDN0Px39uvl3kGUiH5rUHiJ947Q7oG72mYLyM=; h=Date:From:To:Cc:Subject:Message-ID:MIME-Version:Content-Type: Content-Disposition:In-Reply-To; b=Ja7gc1ugwyi/kiRJN4iC2sZNtN3xuJsSVZA3UDL0ZE0IqQ113ktxCoBXNgZQf7XNmbJnPhdDqqwnwnp/IbMlPQOcnCwp/QhZmdQwRVrUvE3GI96S5Z2ZieUkQ/nzNQV4/gs6QXldJb/kArrYbsT//9YdnMYqiMHvb7rJd26vRgY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=MscgbS+g; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="MscgbS+g" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 36F9BC4CEEB; Thu, 21 Aug 2025 15:47:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1755791267; bh=S7ZDNRuDN0Px39uvl3kGUiH5rUHiJ947Q7oG72mYLyM=; h=Date:From:To:Cc:Subject:In-Reply-To:From; b=MscgbS+g6vgu3O2fCBH+GFkHaj9RV9bFHVSOAGzlNcDlqfTQ9uvBM5sGec4QHB54J 8HN6pK57H05Sl8Hmev554PCSXDI/k8+iSZMW//AWJ7FMdxEGMNtk0s1JCn1x/j5wwk QneKi5VO60b2EecDGGPzhpH4JHgmj0Sv2Bpnrtw3613TEp4ZUBnBt+X7x6TTOx8Avn 2upbV4W2QwtyLrWCCdm8Qdu7A5aYN8fY9pWOxJkhj3Wt4k6FysvSoSIrPChRcVPNTc 2TT38sYfMWjptjkkcirFlW8kis46lKdL9v1qJuk4M9Exm5HkVZ9Xx+UusnjLU14FbF 9Ltd67nqsNiDQ== Date: Thu, 21 Aug 2025 10:47:45 -0500 From: Bjorn Helgaas To: Ilpo =?utf-8?B?SsOkcnZpbmVu?= Cc: linux-pci@vger.kernel.org, Bjorn Helgaas , Krzysztof =?utf-8?Q?Wilczy=C5=84ski?= , Tudor Ambarus , Rio , D Scott Phillips , LKML , Christian =?utf-8?B?S8O2bmln?= , stable@vger.kernel.org Subject: Re: [PATCH v2 1/3] PCI: Relaxed tail alignment should never increase min_align Message-ID: <20250821154745.GA677624@bhelgaas> Precedence: bulk X-Mailing-List: linux-pci@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: On Thu, Aug 21, 2025 at 06:24:12PM +0300, Ilpo Järvinen wrote: > On Thu, 21 Aug 2025, Ilpo Järvinen wrote: > > On Thu, 21 Aug 2025, Bjorn Helgaas wrote: > > > On Mon, Jun 30, 2025 at 05:26:39PM +0300, Ilpo Järvinen wrote: > > > > When using relaxed tail alignment for the bridge window, > > > > pbus_size_mem() also tries to minimize min_align, which can under > > > > certain scenarios end up increasing min_align from that found by > > > > calculate_mem_align(). > > > > > > > > Ensure min_align is not increased by the relaxed tail alignment. > > > > > > > > Eventually, it would be better to add calculate_relaxed_head_align() > > > > similar to calculate_mem_align() which finds out what alignment can be > > > > used for the head without introducing any gaps into the bridge window > > > > to give flexibility on head address too. But that looks relatively > > > > complex algorithm so it requires much more testing than fixing the > > > > immediate problem causing a regression. > > > > > > > > Fixes: 67f9085596ee ("PCI: Allow relaxed bridge window tail sizing for optional resources") > > > > Reported-by: Rio > > > > > > Was there a regression report URL we could include here? > > > > There's the Lore thread only: > > > > https://lore.kernel.org/all/o2bL8MtD_40-lf8GlslTw-AZpUPzm8nmfCnJKvS8RQ3NOzOW1uq1dVCEfRpUjJ2i7G2WjfQhk2IWZ7oGp-7G-jXN4qOdtnyOcjRR0PZWK5I=@r26.me/ The email thread is fine and contains good information about how the reporter tripped over it. > > (It's so far back that if there was something else, I've forgotten them > > by now but looking at the exchanges in the thread, it doesn't look like > > bugzilla entry or so made out of it.) > > Making it "official" tag in case that's easier for you to handle > automatically... > > Link: https://lore.kernel.org/all/o2bL8MtD_40-lf8GlslTw-AZpUPzm8nmfCnJKvS8RQ3NOzOW1uq1dVCEfRpUjJ2i7G2WjfQhk2IWZ7oGp-7G-jXN4qOdtnyOcjRR0PZWK5I=@r26.me/ Thanks for all of these, I added them to the commit logs. Bjorn