From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-wr1-f41.google.com (mail-wr1-f41.google.com [209.85.221.41]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 490A43F888F for ; Wed, 10 Jun 2026 13:55:36 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.221.41 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781099737; cv=none; b=gO4pkhrOyQbuq2NRatY200EijkHUwdNJF2KI7uo0a9rQFOFCn7hjWYAJ7fyd+KJEMIc5B0ZkAkDdS1Wj5l41nlILLYwvrJfgK2qxlc4Td5ylQraeXXkcs59TCjzq3DCWTbaTzesloiKRAdNlHMUEHbNctVGl4/XzbqZN+J8YWmo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781099737; c=relaxed/simple; bh=nt244tUHpxINImQJOka9hSreeGR91MwZI5IU3d4SKrI=; h=Mime-Version:Content-Type:Date:Message-Id:Cc:Subject:From:To: References:In-Reply-To; b=fpsf0UgZBs7JTd1TiaX7MWQBh75EbYaMAiwe+E4K4/AyPI61JOtCgLQuIHkWoarC57D4CfPhEs5rzh9ZNqispIiFlPN54Wa5890AP/W5GhgkPlhnZ6brLJ6UfOyviA/3N2a5i6DibiZuzsgDCsaNaQTtaPnFUG/psPOLobvGG0U= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=BOnR3NXn; arc=none smtp.client-ip=209.85.221.41 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="BOnR3NXn" Received: by mail-wr1-f41.google.com with SMTP id ffacd0b85a97d-45ef56d9b67so5308204f8f.2 for ; Wed, 10 Jun 2026 06:55:36 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1781099735; x=1781704535; darn=vger.kernel.org; h=in-reply-to:references:to:from:subject:cc:message-id:date :content-transfer-encoding:mime-version:from:to:cc:subject:date :message-id:reply-to; bh=zrfD1plP1bimcA7C6IrsDX2w89PrVAfDKwGHaQaTOpA=; b=BOnR3NXnRVlBYnrqoRI/u4Kfp4NwJRhTug1nif8Kmm5r1FmvFCmbzKck1a2zmdsf2H X1aRCIfLtK3cYtbtXWKvtqlR+a1vuyLqPIs1174aCV4Z2AvI6rSEZFebZKsB1sWoRJ3v AHcL5PsnK6jDzy9gBfbN/XU1S6VEoeGWTSp6vytNkPFNiQ6/DaYF07JKdZv/cDtoQgRY TbT/ywT5emwxOId8+i/h08utyOuH3FEbyJ4C1PZzMn4Yl/m61UZHYfMflK3WBtwOPcan RkfJXGP2d3rRSy/h1JuvLxIRq9kWYcW3/ufiVG/t8KWx0KJVng+HyvTWteTRNn9ToCje 8mYA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1781099735; x=1781704535; h=in-reply-to:references:to:from:subject:cc:message-id:date :content-transfer-encoding:mime-version:x-gm-gg:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=zrfD1plP1bimcA7C6IrsDX2w89PrVAfDKwGHaQaTOpA=; b=IOcLoeTH1kiJvXjXncX7ew/+93WOy9WQlkh3A1HcEZLcMcpNn9ks+TsCpYqP4uW9vx FFJ2sSbuMSju8tCp3os66etNHAGeaBtOl8wqG1TYf0+IEeIob989Kcn/d3lTF6aT8uRl Zfw3MH7i/8lAoquNtUSvJNZYCd0wbr6TG+q09vVWQUmC5qc6gZTHB9QfUAjwPYra2t9V wEUdYEQBPbISl1JHr4cD1WpFmcWeZwwh3svSvW/XN7eY2ixKIUdX72T+SszSPlLPylmD bMlvzmk3ijUQx8WJFZzo5r01+8jZPaLp/pFUpdI3SERalhwaKWt2h0RG6hBrAp57C1m0 Vppw== X-Gm-Message-State: AOJu0YzSOIx1EIeWcm3M6hWQs/jdm2Fvou+k4kI7oew/d79GRefr90lZ 8JNQ7/o4/93xUgnJqoXMtdLioM7vXLHoGcVPJbo61dMcEUbdu3sp6iTa X-Gm-Gg: Acq92OG1xbO09sdUsb1hPdRC5mlUL5MgjjU7IMOP18zCd7sZFBUQAlrxYvPOu30kHa9 W4h5kijLl4z5biPE4ZUY1IvwPsiw0e9OjTsNFVboe+vucM3D44A14ulkqEVcaLhxF1mKXLXSn7a CskpbU679ChIcJeWMfDVA/v5t78Bm6tseAwSBgfOsSyaQNJ/zQrken1dybqbExigpjx+4CzkxB9 5NU/B99mPPfi8M3vxmzVID6GPgwgJc+kx1EWsszVUYIyd0OsDMyEOSH0l9CkYS7gg670+saPSc7 s4k95poqgcOz6ean4HlQYrYSJ13GXztaDDjvbOk89yv5hIhKWdgGGWT27e8dozshYfXmiz3386u aJDrn5iQ+TtibEIT4gxs6WrDj1vTso8moIBfEJ9rax3T7h9+B5WYWPuaKY3K3fjln41rFuOZcOj 400fsQLwT3aLFXcm2jGAcYjukhFT3osLZYi3pg1D7bjTp+yra+gyDgA/3X9DMxWJUty14= X-Received: by 2002:adf:e014:0:20b0:45e:f29d:d438 with SMTP id ffacd0b85a97d-46030618a38mr27777125f8f.28.1781099734405; Wed, 10 Jun 2026 06:55:34 -0700 (PDT) Received: from localhost ([195.100.225.50]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-4601f2dcde3sm73903398f8f.1.2026.06.10.06.55.32 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 10 Jun 2026 06:55:33 -0700 (PDT) Precedence: bulk X-Mailing-List: linux-block@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=UTF-8 Date: Wed, 10 Jun 2026 15:55:32 +0200 Message-Id: Cc: , , , Subject: Re: [PATCH v2 23/83] block: rnull: add discard support From: "Malte Wechter" To: "Andreas Hindborg" , "Liam R. Howlett" , "Alice Ryhl" , "Anna-Maria Behnsen" , "Benno Lossin" , =?utf-8?q?Bj=C3=B6rn_Roy_Baron?= , "Boqun Feng" , "Danilo Krummrich" , "FUJITA Tomonori" , "Frederic Weisbecker" , "Gary Guo" , "Jens Axboe" , "John Stultz" , "Lorenzo Stoakes" , "Lyude Paul" , "Miguel Ojeda" , "Stephen Boyd" , "Thomas Gleixner" , "Trevor Gross" X-Mailer: aerc 0.21.0 References: <20260609-rnull-v6-19-rc5-send-v2-0-82c7404542e2@kernel.org> <20260609-rnull-v6-19-rc5-send-v2-23-82c7404542e2@kernel.org> In-Reply-To: <20260609-rnull-v6-19-rc5-send-v2-23-82c7404542e2@kernel.org> On Tue Jun 9, 2026 at 9:08 PM CEST, Andreas Hindborg wrote: > Add support for discard operations to the rnull block driver: > - Add discard module parameter and configfs attribute. > - Set max_hw_discard_sectors when discard is enabled. > - Add sector occupancy tracking. > - Add discard handling that frees sectors and removes empty pages. > - Discard operations require memory backing to function. > > The discard feature uses a bitmap to track which sectors in each page are > occupied, allowing cleanup of pages when they are empty. > > Signed-off-by: Andreas Hindborg > --- > drivers/block/rnull/configfs.rs | 15 +++++ > drivers/block/rnull/rnull.rs | 120 ++++++++++++++++++++++++++++++++++= +----- > 2 files changed, 121 insertions(+), 14 deletions(-) > > diff --git a/drivers/block/rnull/configfs.rs b/drivers/block/rnull/config= fs.rs > index 2f3fa81ea121..e47399cd45a4 100644 > --- a/drivers/block/rnull/configfs.rs > +++ b/drivers/block/rnull/configfs.rs ... > } > }) > ); > + > +configfs_attribute!(DeviceConfig, 10, > + show: |this, page| show_field(this.data.lock().discard, page), > + store: |this, page| store_with_power_check(this, page, |data, page| = { > + if !data.memory_backed { > + return Err(EINVAL); > + } > + data.discard =3D kstrtobool_bytes(page)?; > + Ok(()) > + }) > +); Should it be ok to set 'discard' to 0 if 'emory_backed' is not set? In the C null_blk driver, 'discard' defaults to 0 if 'memory_backed' is not= set, it is also ignored (and defaulted to 0) if 'zoned' is enabled. Best regards, Malte