From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-wm1-f46.google.com (mail-wm1-f46.google.com [209.85.128.46]) (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 AD12E33121E for ; Wed, 13 May 2026 13:29:13 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.46 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778678955; cv=none; b=PPN+e+R8QsdmZqJ2ky1GmCSEGZe/cnpLiM3tEEJ1iHVbJTshD+ijx0ZLO7zhSidlPCDddqU00/6+oamKkPzEka0zLSJ+4EoV67lAKzOdQUhHmnySoFT9Z/ZdYgKAOFL5+gPmc2Fp1brnr1RKdbqNQwmoNiEB3mofSlvGJ0LLFZ8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778678955; c=relaxed/simple; bh=qvrzIgPI09xnL+lPNRKw47FDVzkn2xkt2K7Rwhlyrpg=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=Jg+/1CRqoJQpJpQoa02ewDQBzc/pPa28JAQmCgOoACSPo7rQm4dCB2rGnfoJWhK/GDbAsAK/KUt7nFBOMuCM0RtkiR/UQrN8FIco61dw1LjdT/70kPy3prVdNNpXrKh3WzxHl9Xo5C0gSNenCY43QvTnxUyun5DxP+/uV5UtLjI= 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=a107B9Ew; arc=none smtp.client-ip=209.85.128.46 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="a107B9Ew" Received: by mail-wm1-f46.google.com with SMTP id 5b1f17b1804b1-488b3f8fa2bso73856885e9.1 for ; Wed, 13 May 2026 06:29:13 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1778678952; x=1779283752; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:subject:cc:to:from:date:from:to:cc:subject:date :message-id:reply-to; bh=+cq+23+E96HQoAhwgeeSJr3+OJ8IJX5BGImZhad/wV8=; b=a107B9Ew/L+JG9kf+Z1nV/fx/+/Yb5mbJ9IZSmqcqG5NRhHtSigWVxLyt5e4tVheRP fVjtYzbSvKxWG/9swUAl2JC7bOL4zt7vyjCnIC8OuK2OMjbgJBd7ZXSOd9A2k/U6ZdZx IjexhbZVncU3yj8qsWTZZXbphJKEGru0GTV9TW0VSNxNUEF9TejQU1LxeC23owu6b8iT ERboyV8DTmKJyNrtYYu2ZtgNGMFqTuCpA+7JxZMpzt9wq45ITtvGgvRTJ8s7Z9NXHaiv Dc2JWteKzwRsB8GUKRASoBUvNyZQ288ROHW0dQRuuliK8uDWf25EzvdXbuywp4OcMKw3 hDpw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1778678952; x=1779283752; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:subject:cc:to:from:date:x-gm-gg:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to; bh=+cq+23+E96HQoAhwgeeSJr3+OJ8IJX5BGImZhad/wV8=; b=UlsTUHGsN7sK3qtw+i6H1D+kYjxQS4Dj3Rs97jTmKQdQmPJmjifKLukFnLyiUg1ihO fDuTwHraxTV9gZVh4BlyMQZimRQWg7Bm7C4TWNnHtf3ocw+7YKoOcabJN01oABo7Imlf 78dry192e3e8th5e7pK9lpT5FzlwO/Lw/yO+b+k1PIRswGK3rkP2hFL/PAho6D73ZJFx PojxmJLHYpy29ayDfhiFEPW230a0e0TBQIzmfm2OnZRafD/addGERaSLeohrt4T5z7m6 XTCgSj7nmcjZ5iCr7aF41qFI4XkDRr+AWo/yBurCRJ/d5N9+nF1ppGmpKm2yGRWonkjw AorQ== X-Forwarded-Encrypted: i=1; AFNElJ9MFH8wOaWftihJXtHUgGnUP6b6QpWleirthZjVPOC9Hk/FEuCrDvCbToOnLRKQkY8BnelOY9VTJLMs5+Cw@vger.kernel.org X-Gm-Message-State: AOJu0Yx0RxObuvdnw6KCFnrS1GAqGgBwZOdKHqGQeuptomOrpRxOyj9v LG3asE0gqCFr9su9mEpq2J5LYHs61VFnH3ynxx6wDpp36ffTEXgcG98J X-Gm-Gg: Acq92OG8+Q3ZtB4M4C5jxRD0m+5EVnQoqq43TXemNO90Mcg4d8MopulePmXirGdoMix YBT+2AOSuTaPhutP5ilFbyMJcR4PK8KCQPXDKoNx4xG0oG8Bqoge1lCasZmr3OFx0LEILx+ObLB 3qzSTrl3guo3lNHzO+5bNArr8sIrW75VC3P+2Eb5xzRlhvxx+igSDXOTncQpDtN7g/l6z0wIsHz Bmh1nRhG0DfP6PMqu5Nyw5L/IKdVAHJWOlYe9M5OyGpQQlUadnHX5lpYTmhBsmkGPFGI6clnGFq Ohi0eCwZsCCigdbrKNo2HaiZL2MjDUwSrZw0PkGDq8/O2yWfJPnc4GMpK/aZxojiZ7MQ2R8wDwC oB5hzQvd8nNt1fF08312IihjklRfVpCynufcEYP37FkZNdTB5R/dMOLYo10/PoEYnHWY161cDqD vl7E7y7q9p7WVYc8gWEuymLwHqC2bBUXvAX7KZfCr77sg5ptaVjwhImMR/PXh2 X-Received: by 2002:a5d:591c:0:b0:446:708e:1e8d with SMTP id ffacd0b85a97d-45ac4504a13mr9930360f8f.30.1778678951817; Wed, 13 May 2026 06:29:11 -0700 (PDT) Received: from pumpkin (82-69-66-36.dsl.in-addr.zen.co.uk. [82.69.66.36]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-4549120ec0asm40068578f8f.17.2026.05.13.06.29.11 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 13 May 2026 06:29:11 -0700 (PDT) Date: Wed, 13 May 2026 14:29:09 +0100 From: David Laight To: Pavel Begunkov Cc: Jens Axboe , Keith Busch , Christoph Hellwig , Sagi Grimberg , Alexander Viro , Christian Brauner , Andrew Morton , Sumit Semwal , Christian =?UTF-8?B?S8O2bmln?= , linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, linux-nvme@lists.infradead.org, linux-fsdevel@vger.kernel.org, io-uring@vger.kernel.org, linux-media@vger.kernel.org, dri-devel@lists.freedesktop.org, linaro-mm-sig@lists.linaro.org, Nitesh Shetty , Kanchan Joshi , Anuj Gupta , Tushar Gohad , William Power , Phil Cayton , Jason Gunthorpe Subject: Re: [PATCH v3 02/10] iov_iter: add iterator type for dmabuf maps Message-ID: <20260513142909.03ae6c2b@pumpkin> In-Reply-To: <20260513110557.705bdeed@pumpkin> References: <20a233d2f35274817aa643cc0fe113707eb47e72.1777475843.git.asml.silence@gmail.com> <20260513110557.705bdeed@pumpkin> X-Mailer: Claws Mail 4.1.1 (GTK 3.24.38; arm-unknown-linux-gnueabihf) Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Wed, 13 May 2026 11:05:57 +0100 David Laight wrote: ... > > @@ -575,7 +575,8 @@ void iov_iter_advance(struct iov_iter *i, size_t size) > > { > > if (unlikely(i->count < size)) > > size = i->count; > > - if (likely(iter_is_ubuf(i)) || unlikely(iov_iter_is_xarray(i))) { > > + if (likely(iter_is_ubuf(i)) || unlikely(iov_iter_is_xarray(i)) || > > + unlikely(iov_iter_is_dmabuf_map(i))) { > > > Doesn't the extra check add more code to all the non-ubuf cases? > This could be fixed by either making iter_type a bitmask (with one bit set) > or writing an iter_is_one_of(i, ITER_xxx, ITER_yyy) define that uses > '(1 << i->iter_type) & ((1 << ITER_xxx) | ...)' This seems to DTRT: #define _ITER_IS_ONE_OF(iter, t1, t2, t3, t4, t5, t6, t7, t8, ...) \ ((1u << (iter)->iter_type) & ((1u << ITER_##t1) | (1u << ITER_##t2) | \ (1u << ITER_##t3) | (1u << ITER_##t4) | (1u << ITER_##t5) | \ (1u << ITER_##t6) | (1u << ITER_##t7) | (1u << ITER_##t8))) #define ITER_IS_ONE_OF(iter, t, ...) \ _ITER_IS_ONE_OF(iter, t, ## __VA_ARGS__, t, t, t, t, t, t, t) int foo(void *); int f(struct iov_iter *i) { return ITER_IS_ONE_OF(i, UBUF, KVEC) ? foo(i) : 0; } See https://godbolt.org/z/sMz93zah1 Pasting ITER_ on the front ensures the values are constants of the right type. OTOH it makes it harder to search for uses of each type. You could paste _ITER_ on the front, elsewhere define _ITER_ITER_UVEC to be ITER_UVEC (etc), and require the caller use the full name. -- David