From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail.zeus03.de (zeus03.de [194.117.254.33]) (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 276D2429CFB for ; Thu, 17 Sep 2026 08:23:18 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=194.117.254.33 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789633409; cv=none; b=I0+RlNrUSLOX+9rjnrnTBC0niKXaIEcnfAB5igSBD1PDC09T2f0beoIANvz/qCDNKcK1fU4nJXfVCoyOCYMmCpBZIJ64y/wGfaNFSBAVXb1iForUZVEasEqpuesKTKJ6RHnpEVpokzbuY6Dquor5S3d8lIFejTuSiS2JVVGc0Q4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789633409; c=relaxed/simple; bh=ozlPasX8P+4BiqJfuQBxSkRBNiQCjbUcr+uITbfRvTY=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=UFfPSEJAXuGJ+tn8tHi/dd+vFfBt/SDwQuql7NE1X3GPzrXGSTAY+HH5gtiGP13nIp4KrM4CBhmr4R+59f8byQJK1QfgwV743Gzs1T00PnlIqybG78EPkIhTr4qHMd+jKurQJ9R46589TxhHMk8c4JmOEbat2d9Y5B5LfVyz3kA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=sang-engineering.com; spf=pass smtp.mailfrom=sang-engineering.com; dkim=pass (2048-bit key) header.d=sang-engineering.com header.i=@sang-engineering.com header.b=BuXV+9U5; arc=none smtp.client-ip=194.117.254.33 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=sang-engineering.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=sang-engineering.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=sang-engineering.com header.i=@sang-engineering.com header.b="BuXV+9U5" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= sang-engineering.com; h=date:from:to:cc:subject:message-id :references:mime-version:content-type:in-reply-to; s=k1; bh=ozlP asX8P+4BiqJfuQBxSkRBNiQCjbUcr+uITbfRvTY=; b=BuXV+9U5IJAKFZYD15Vp iQucFX+GKXVvy/ydgP7/7YTPfIlDW9m9N344Cbr0tjdQKxGd9OEVpIBlgNnehmGP BDTvA4ZaiPu4Xb7pT6spKXRFG+gJGk6duuzB9/6YhmsxLE/ZqMi0CKAh5Vyw85Iw Zpcul+FG7YdprmMn3MHh1oCLlws/e7yPcUbIlRXBWINSR/XGy/4KoBHnELmO9zdQ 1qPGd2SEAKu+usGuvHDJZZXIWDcLXfWs5K0w95/+E8DIa3KHTLWicAlzBxL4kWPf qd90xqvzYKxZmtdXiO/pww/Josvwyg2aIg/+4VsOAtNfAL0VZUmClMYxQA/qpQOO Wg== Received: (qmail 1915165 invoked from network); 17 Sep 2026 10:23:08 +0200 Received: by mail.zeus03.de with ESMTPSA (TLS_AES_256_GCM_SHA384 encrypted, authenticated); 17 Sep 2026 10:23:08 +0200 X-UD-Smtp-Session: l3s3148p1@cWVmfqlbAMAujnsL Date: Thu, 17 Sep 2026 10:23:07 +0200 From: Wolfram Sang To: Laurent Pinchart Cc: linux-renesas-soc@vger.kernel.org, Koichiro Den , Vinod Koul , Frank Li , Geert Uytterhoeven , Magnus Damm , dmaengine@vger.kernel.org Subject: Re: [PATCH 2/3] dmaengine: rcar-dmac: Add missing dma_descriptor_unmap() Message-ID: References: <20260917071208.36888-1-wsa+renesas@sang-engineering.com> <20260917071208.36888-3-wsa+renesas@sang-engineering.com> <20260917073825.GB4019@killaraus.ideasonboard.com> Precedence: bulk X-Mailing-List: dmaengine@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="vOsYjcL/nMUoWmob" Content-Disposition: inline In-Reply-To: <20260917073825.GB4019@killaraus.ideasonboard.com> --vOsYjcL/nMUoWmob Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Thu, Sep 17, 2026 at 10:38:25AM +0300, Laurent Pinchart wrote: > On Thu, Sep 17, 2026 at 09:12:07AM +0200, Wolfram Sang wrote: > > From: Koichiro Den > >=20 > > Call dma_descriptor_unmap() right after dma_cookie_complete() in the > > threaded IRQ completion path. Without this, streaming DMA mappings > > attached to the descriptor are never released and may eventually exhaust > > DMA mapping resources (e.g. IOVA with an IOMMU or bounce-buffer slots > > with SWIOTLB), leading to dma_map_* failures. >=20 > That looks like a horrible API. It pushes a requirement onto drivers to > clean up something done by clients, and is completely undocumented. > Can't those calls be moved somewhere in the DMA engine core ? In general, I agree. No bandwidth for an API cleanup here, though. 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