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 3FF882F4301 for ; Wed, 11 Jun 2025 23:09:34 +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=1749683375; cv=none; b=IPmO/3xHJtRYDzsXYrXTac8aHfR1aob2ovZ7sQSxA9qo6D5NKTjNUaKPN3KY9M4L8jOtmAwv9JUAoAUk7HZT6XOzC/pD+fuL1bV9WLbY8fQZP/0EYelBDev/yD1OUXZutp6mPbySmyYc3lrRyu5k4SjoF9YJKYaWuwjYfhoJzsc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1749683375; c=relaxed/simple; bh=+mZf/PE/zwc6zUQWsJI9PGkMPBHoNjyTaMs700Efda0=; h=Message-ID:Date:MIME-Version:Subject:To:References:From: In-Reply-To:Content-Type; b=uS6W/n19HigqlCOer4LuHDyowCN3qz7Nar6OGHSX4Mkfbxo7PEwBppH+NXj6sMJU849joxKpcZ2wMQDlzntBvtGekiiHN8mVMAlXIZOdqsXPcdSN9q+KYIFCMwqeteNdMfBsA0a1l8kR9TpbVozcve4LXD0vG8UoIw/VSy5oDgA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=f8Oe6qoa; 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="f8Oe6qoa" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6B62AC4CEEF; Wed, 11 Jun 2025 23:09:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1749683374; bh=+mZf/PE/zwc6zUQWsJI9PGkMPBHoNjyTaMs700Efda0=; h=Date:Subject:To:References:From:In-Reply-To:From; b=f8Oe6qoaV1CecP4uhQoWHWnEX0FCqzvaEDrosl5/KNBlEL7SHJ94mTR7G3g6QIw8w D8suY2j/Y5+e889cUpyjzE5hfA70YYY01xLC1q+X9YJHPSoaa5HoXMvX4+1dXvCX6c XtMcGj6LwqjECiBu8r+qWQQ5p1Q4TGC/Xf5xKYe/8A6GLwyiAMH6ahgQrjVyvRZooq 5elSPQn9XifK0uYUWXihsi4fQjhyqseqf5nNFZXi6DlKxGNDavfAENM/UtCycHcU3J TQCquQw/hBxlviiXjB+OUCMHXbt35WKwp0NpCKrFSWy4KhwBUWRfSM8JOM3Phf2aI1 4hW/kIWyuDVhQ== Message-ID: Date: Thu, 12 Jun 2025 08:09:33 +0900 Precedence: bulk X-Mailing-List: linux-scsi@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2] scsi: sd: Set a default optimal IO size if one is not defined To: Bart Van Assche , "Martin K . Petersen" , linux-scsi@vger.kernel.org References: <20250611122921.3960656-1-dlemoal@kernel.org> Content-Language: en-US From: Damien Le Moal Organization: Western Digital Research In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 6/12/25 00:35, Bart Van Assche wrote: > On 6/11/25 5:29 AM, Damien Le Moal wrote: >> +static void sd_set_io_opt(struct scsi_disk *sdkp, unsigned int dev_max, >> + struct queue_limits *lim) >> +{ >> + struct scsi_device *sdp = sdkp->device; >> + struct Scsi_Host *shost = sdp->host; >> + >> + lim->io_opt = shost->opt_sectors << SECTOR_SHIFT; >> + if (sd_validate_opt_xfer_size(sdkp, dev_max)) >> + lim->io_opt = min_not_zero(lim->io_opt, >> + logical_to_bytes(sdp, sdkp->opt_xfer_blocks)); >> + if (!lim->io_opt) { >> + lim->io_opt = ALIGN_DOWN(lim->max_sectors << SECTOR_SHIFT, >> + sdkp->physical_block_size - 1); >> + sd_first_printk(KERN_INFO, sdkp, >> + "Using default optimal transfer size of %u bytes\n", >> + lim->io_opt); >> + } >> +} > > shost->opt_sectors and lim->max_sectors both have type unsigned int so > when shifting these left there is a risk of overflow. As an example, > from the scsi_debug driver: > > .max_sectors = -1U, The code already was like that for opt_sectors and no-one complained. > Shouldn't integer overflows be prevented instead of letting these > happen? Sure, can do that. -- Damien Le Moal Western Digital Research