From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from shelob.surriel.com (shelob.surriel.com [96.67.55.147]) (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 E4746345CD3; Thu, 18 Jun 2026 17:31:18 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=96.67.55.147 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781803880; cv=none; b=aWZDsV9xnfcOPuPMFR0Efi5DcnJwQp1enKb1ySBNVNbpqlHg7s83LGeHZHZ4DCz+qjesg4HEDKzCSnVzHOtgG1dfutAk88d7Of/i09tianVv634dCAHCtL8g4R1LVlqz1wnQmS5DnWXUX9qLdLgGtvno3CraGBzC5Mr/GChXUGo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781803880; c=relaxed/simple; bh=U/oijo7ClvaXIVAiqpI3ziqQOcJaiLEUx7KQDx1PYTM=; h=Message-ID:Subject:From:To:Cc:Date:In-Reply-To:References: Content-Type:MIME-Version; b=Rr0frTcFh0+yUcL+71QHn1vkLvVWE/sQ2j3y215a2yLJ97OQDp1MioOSCZqAVexUpbduLaotgzpwHSHiME59m7oTX4iJhaZwTm8tvhD1+gLD3fn9DdFULVk7eCuy6H48DuJAWBytIjMZp+euaVOFy2jXGOtsPq9b5dgSGUisw+4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=surriel.com; spf=pass smtp.mailfrom=surriel.com; dkim=pass (2048-bit key) header.d=surriel.com header.i=@surriel.com header.b=a//IhpBP; arc=none smtp.client-ip=96.67.55.147 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=surriel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=surriel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=surriel.com header.i=@surriel.com header.b="a//IhpBP" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=surriel.com ; s=mail; h=MIME-Version:Content-Transfer-Encoding:Content-Type:References: In-Reply-To:Date:Cc:To:From:Subject:Message-ID:Sender:Reply-To:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Id:List-Help:List-Unsubscribe:List-Subscribe: List-Post:List-Owner:List-Archive; bh=U/oijo7ClvaXIVAiqpI3ziqQOcJaiLEUx7KQDx1PYTM=; b=a//IhpBPoymxI394THQOf2TA7e FNxvxldYHIwLFeHXsaBu7LdYSvphVf2MkQBSo/H2XOy3eLF9uxXKhGz/QCUmpQ3N5JGpcAX8Pt5zx z3rK1r1rB7sYcbfFvCo3eFuzD5NRaXgXSeJL636n8IYtQ5QLWfCOSrjxVepO5nHvxkl1TU04sD/Oc xOPEP5hNK0NmWS3hB1TBDPncWOM+Wc7HiiKX+42seB/hd6Ufhj6EIcPgVWs8iZg3QHH32SXTZTl9K x64+ANmws43oD8DmjLmY7raAdqpQ/aQKY5qr/3kLQpZdZ7SjueaAN8290bODHdJW2ymq+0igelHUM MAqGcr6w==; Received: from fangorn.home.surriel.com ([10.0.13.7]) by shelob.surriel.com with esmtpsa (TLS1.2) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.97.1) (envelope-from ) id 1waGZo-000000003gN-1pSm; Thu, 18 Jun 2026 13:30:52 -0400 Message-ID: Subject: Re: [PATCH v3 3/3] iova: defer maple tree erase on GFP_ATOMIC failure From: Rik van Riel To: "Liam R. Howlett" , Jason Gunthorpe Cc: linux-kernel@vger.kernel.org, kernel-team@meta.com, robin.murphy@arm.com, joro@8bytes.org, will@kernel.org, iommu@lists.linux.dev, kyle@mcmartin.ca, Rik van Riel , maple-tree@lists.infradead.org Date: Thu, 18 Jun 2026 13:30:52 -0400 In-Reply-To: References: <61d51d4b5779d80145ceb38e9632a7cc8a79dbec.camel@surriel.com> <20260612164852.GL1066031@ziepe.ca> <20260612180303.GO1066031@ziepe.ca> <20260615115633.GQ1066031@ziepe.ca> <20260617180419.GA231643@ziepe.ca> <20260618152451.GE231643@ziepe.ca> Autocrypt: addr=riel@surriel.com; prefer-encrypt=mutual; keydata=mQENBFIt3aUBCADCK0LicyCYyMa0E1lodCDUBf6G+6C5UXKG1jEYwQu49cc/gUBTTk33A eo2hjn4JinVaPF3zfZprnKMEGGv4dHvEOCPWiNhlz5RtqH3SKJllq2dpeMS9RqbMvDA36rlJIIo47 Z/nl6IA8MDhSqyqdnTY8z7LnQHqq16jAqwo7Ll9qALXz4yG1ZdSCmo80VPetBZZPw7WMjo+1hByv/ lvdFnLfiQ52tayuuC1r9x2qZ/SYWd2M4p/f5CLmvG9UcnkbYFsKWz8bwOBWKg1PQcaYHLx06sHGdY dIDaeVvkIfMFwAprSo5EFU+aes2VB2ZjugOTbkkW2aPSWTRsBhPHhV6dABEBAAG0HlJpayB2YW4gU mllbCA8cmllbEByZWRoYXQuY29tPokBHwQwAQIACQUCW5LcVgIdIAAKCRDOed6ShMTeg05SB/986o gEgdq4byrtaBQKFg5LWfd8e+h+QzLOg/T8mSS3dJzFXe5JBOfvYg7Bj47xXi9I5sM+I9Lu9+1XVb/ r2rGJrU1DwA09TnmyFtK76bgMF0sBEh1ECILYNQTEIemzNFwOWLZZlEhZFRJsZyX+mtEp/WQIygHV WjwuP69VJw+fPQvLOGn4j8W9QXuvhha7u1QJ7mYx4dLGHrZlHdwDsqpvWsW+3rsIqs1BBe5/Itz9o 6y9gLNtQzwmSDioV8KhF85VmYInslhv5tUtMEppfdTLyX4SUKh8ftNIVmH9mXyRCZclSoa6IMd635 Jq1Pj2/Lp64tOzSvN5Y9zaiCc5FucXtB9SaWsgdmFuIFJpZWwgPHJpZWxAc3VycmllbC5jb20+iQE +BBMBAgAoBQJSLd2lAhsjBQkSzAMABgsJCAcDAgYVCAIJCgsEFgIDAQIeAQIXgAAKCRDOed6ShMTe g4PpB/0ZivKYFt0LaB22ssWUrBoeNWCP1NY/lkq2QbPhR3agLB7ZXI97PF2z/5QD9Fuy/FD/jddPx KRTvFCtHcEzTOcFjBmf52uqgt3U40H9GM++0IM0yHusd9EzlaWsbp09vsAV2DwdqS69x9RPbvE/Ne fO5subhocH76okcF/aQiQ+oj2j6LJZGBJBVigOHg+4zyzdDgKM+jp0bvDI51KQ4XfxV593OhvkS3z 3FPx0CE7l62WhWrieHyBblqvkTYgJ6dq4bsYpqxxGJOkQ47WpEUx6onH+rImWmPJbSYGhwBzTo0Mm G1Nb1qGPG+mTrSmJjDRxrwf1zjmYqQreWVSFEt26tBpSaWsgdmFuIFJpZWwgPHJpZWxAZmIuY29tP okBPgQTAQIAKAUCW5LbiAIbIwUJEswDAAYLCQgHAwIGFQgCCQoLBBYCAwECHgECF4AACgkQznneko TE3oOUEQgAsrGxjTC1bGtZyuvyQPcXclap11Ogib6rQywGYu6/Mnkbd6hbyY3wpdyQii/cas2S44N cQj8HkGv91JLVE24/Wt0gITPCH3rLVJJDGQxprHTVDs1t1RAbsbp0XTksZPCNWDGYIBo2aHDwErhI omYQ0Xluo1WBtH/UmHgirHvclsou1Ks9jyTxiPyUKRfae7GNOFiX99+ZlB27P3t8CjtSO831Ij0Ip QrfooZ21YVlUKw0Wy6Ll8EyefyrEYSh8KTm8dQj4O7xxvdg865TLeLpho5PwDRF+/mR3qi8CdGbkE c4pYZQO8UDXUN4S+pe0aTeTqlYw8rRHWF9TnvtpcNzZw== Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.56.2 (3.56.2-2.fc42) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 On Thu, 2026-06-18 at 13:27 -0400, Liam R. Howlett wrote: > On 26/06/18 12:24PM, Jason Gunthorpe wrote: > >=20 > >=20 > > - I like your idea for Rik to try to store NULL to erase, on > > failure > > =C2=A0 store ZERO_ENTRY, and then set a note on the next alloc to clean > > the > > =C2=A0 ZERO_ENTRYs? >=20 > The ZERO_ENTRY can be found by mas_* functions and will cause issues > with the gap searching.=C2=A0 You also have to be careful to handle these > entries in mas_for_each() loops - you don't want to treat them as > valid > entries. >=20 Could it make sense for the maple tree to have something similar to ZERO_ENTRY that is treated like a gap, so the gap search can find it, and get rid of those entries when the gap gets re-used? --=20 All Rights Reversed.