From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AH8x225CDmQy1k7rZumwAcR69CXuJMyHz4rniJK9Gy8UmaysGopZf4Fty8++3mY1nIn7rkW/kxj8 ARC-Seal: i=1; a=rsa-sha256; t=1517362005; cv=none; d=google.com; s=arc-20160816; b=IWoPLPZA1fDEp/fm64VPBnYq/KDeJh6fr8KzewluY3DIfhW3yL+2NsZAQ13tiETyqT bwqKxuWyh8bIOcXVq3aQQJZc12hIsY19PiMCA9ev/5ceEjNsAuYl3B7MPbx5RZT7zB6v RCjtBT4a1XJ3830IfS5vh+wUp/YGW0COH6s1fjZBihBITnmrtbH1XFDzDpU8aPm2g9/K V7wNFyKBpM0Ccfj/fsgkNrnrT6txR8AHUEJDuYTDkQSnGLL/edYCYXaC162EnRHt01pY mHv6tzx2EWwD0GqYe3CQ2fte3ywvow7u11G0tKopKqsHb3wFghH7uuSDsvXXvFWEQC7q B9yQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=subject:content-transfer-encoding:content-language:in-reply-to :mime-version:user-agent:date:message-id:from:references:cc:to :arc-authentication-results; bh=DP8m/6iLLuzFcxW1UVQzX0D47PcgaTjbfskiGaeBVYQ=; b=yulk2Q5KrH+aOLvESdfDcdPFfVOLhK5GsdvaWfq3+vR03KxjwRLsjtfnO2CTTjdu8A L/nNHirXdFHh7Gi0UUO69j+UTU9zR9Ybhsubu8gojfSVqU9Fz0stPtTVN3veAWCmckQM 9OcuH7A8HPVC7fPCQt2ivcvmC3B/C7BhMlpFKGSAA+qtdES5FyXekIra3mvlyl13hENR ga7A15qFX34vl8k6tJwSVhYU+ruRp2zKjgvI2ojA7ADinSShQ2HMrLkUH3rXpUhJixFu 0KQZ+VWemyQ+KgyuRqCHkcCt1dg1dv0KGU5nqtiQcUaAHesEf8s0fa5TRnkyKe+wjlBW szbg== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of logang@deltatee.com designates 207.54.116.67 as permitted sender) smtp.mailfrom=logang@deltatee.com Authentication-Results: mx.google.com; spf=pass (google.com: domain of logang@deltatee.com designates 207.54.116.67 as permitted sender) smtp.mailfrom=logang@deltatee.com To: "Srivatsa S. Bhat" , gregkh@linuxfoundation.org Cc: axboe@kernel.dk, jlayton@poochiereds.net, bfields@fieldses.org, linux-kernel@vger.kernel.org References: From: Logan Gunthorpe Message-ID: Date: Tue, 30 Jan 2018 18:26:38 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.5.2 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-SA-Exim-Connect-IP: 172.16.1.162 X-SA-Exim-Rcpt-To: linux-kernel@vger.kernel.org, bfields@fieldses.org, jlayton@poochiereds.net, axboe@kernel.dk, gregkh@linuxfoundation.org, srivatsa@csail.mit.edu X-SA-Exim-Mail-From: logang@deltatee.com Subject: Re: Change in register_blkdev() behavior X-SA-Exim-Version: 4.2.1 (built Tue, 02 Aug 2016 21:08:31 +0000) X-SA-Exim-Scanned: Yes (on ale.deltatee.com) X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: =?utf-8?q?1591067494565207085?= X-GMAIL-MSGID: =?utf-8?q?1591069382771751219?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: On 30/01/18 05:56 PM, Srivatsa S. Bhat wrote: > If the restriction on the major number was intentional, perhaps we > should get the LTP testcase modified for kernel versions >= 4.14. > Otherwise, we should fix register_blkdev to preserve the old behavior. > (I guess the same thing applies to commit 8a932f73e5b "char_dev: order > /proc/devices by major number" as well). The restriction was put in place so the code that prints the devices doesn't have to run through every integer in order to print the devices in order. Given the existing documented fixed numbers in [1] and that future new char devices should be using dynamic allocation, this seemed like a reasonable restriction. It would be pretty trivial to increase the limit but, IMO, setting it to UINT_MAX seems a bit much. Especially given that a lot of the documentation and code still very much has remnants of the 256 limit. (The series that included this patch only just expanded the char dynamic range to above 256). So, I'd suggest the LTP test should change. Logan [1] Documentation/admin-guide/devices.txt