From owner-svn-src-head@FreeBSD.ORG Sun Jun 21 06:05:34 2015 Return-Path: Delivered-To: svn-src-head@hub.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id 3843B617; Sun, 21 Jun 2015 06:05:34 +0000 (UTC) (envelope-from cperciva@FreeBSD.org) Received: from svn.freebsd.org (svn.freebsd.org [IPv6:2001:1900:2254:2068::e6a:0]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 25E9DB40; Sun, 21 Jun 2015 06:05:34 +0000 (UTC) (envelope-from cperciva@FreeBSD.org) Received: from svn.freebsd.org ([127.0.1.70]) by svn.freebsd.org (8.14.9/8.14.9) with ESMTP id t5L65YhQ034485; Sun, 21 Jun 2015 06:05:34 GMT (envelope-from cperciva@FreeBSD.org) Received: (from cperciva@localhost) by svn.freebsd.org (8.14.9/8.14.9/Submit) id t5L65Ywc034484; Sun, 21 Jun 2015 06:05:34 GMT (envelope-from cperciva@FreeBSD.org) Message-Id: <201506210605.t5L65Ywc034484@svn.freebsd.org> X-Authentication-Warning: svn.freebsd.org: cperciva set sender to cperciva@FreeBSD.org using -f From: Colin Percival Date: Sun, 21 Jun 2015 06:05:34 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r284664 - head/sys/xen/interface/io X-SVN-Group: head MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-BeenThere: svn-src-head@freebsd.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: SVN commit messages for the src tree for head/-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 21 Jun 2015 06:05:34 -0000 Author: cperciva Date: Sun Jun 21 06:05:33 2015 New Revision: 284664 URL: https://svnweb.freebsd.org/changeset/base/284664 Log: Garbage collect comments which related to the pre-r284296 support for a "segment block" extension in FreeBSD's Xen blkfront/blkback drivers. Since this commit only affects comments, it should have no functional effect. Modified: head/sys/xen/interface/io/blkif.h Modified: head/sys/xen/interface/io/blkif.h ============================================================================== --- head/sys/xen/interface/io/blkif.h Sun Jun 21 05:36:58 2015 (r284663) +++ head/sys/xen/interface/io/blkif.h Sun Jun 21 06:05:33 2015 (r284664) @@ -145,32 +145,6 @@ * The maximum supported size of the request ring buffer in units of * machine pages. The value must be a power of 2. * - * max-requests - * Default Value: BLKIF_MAX_RING_REQUESTS(PAGE_SIZE) - * Maximum Value: BLKIF_MAX_RING_REQUESTS(PAGE_SIZE * max-ring-pages) - * - * The maximum number of concurrent, logical requests supported by - * the backend. - * - * Note: A logical request may span multiple ring entries. - * - * max-request-segments - * Values: - * Default Value: BLKIF_MAX_SEGMENTS_PER_HEADER_BLOCK - * Maximum Value: BLKIF_MAX_SEGMENTS_PER_REQUEST - * - * The maximum value of blkif_request.nr_segments supported by - * the backend. - * - * max-request-size - * Values: - * Default Value: BLKIF_MAX_SEGMENTS_PER_HEADER_BLOCK * PAGE_SIZE - * Maximum Value: BLKIF_MAX_SEGMENTS_PER_REQUEST * PAGE_SIZE - * - * The maximum amount of data, in bytes, that can be referenced by a - * request type that accesses frontend memory (currently BLKIF_OP_READ, - * BLKIF_OP_WRITE, or BLKIF_OP_WRITE_BARRIER). - * *------------------------- Backend Device Properties ------------------------- * * discard-alignment @@ -269,33 +243,6 @@ * The size of the frontend allocated request ring buffer in units of * machine pages. The value must be a power of 2. * - * max-requests - * Values: - * Default Value: BLKIF_MAX_RING_REQUESTS(PAGE_SIZE) - * Maximum Value: BLKIF_MAX_RING_REQUESTS(PAGE_SIZE * max-ring-pages) - * - * The maximum number of concurrent, logical requests that will be - * issued by the frontend. - * - * Note: A logical request may span multiple ring entries. - * - * max-request-segments - * Values: - * Default Value: BLKIF_MAX_SEGMENTS_PER_HEADER_BLOCK - * Maximum Value: MIN(255, backend/max-request-segments) - * - * The maximum value the frontend will set in the - * blkif_request.nr_segments field. - * - * max-request-size - * Values: - * Default Value: BLKIF_MAX_SEGMENTS_PER_HEADER_BLOCK * PAGE_SIZE - * Maximum Value: max-request-segments * PAGE_SIZE - * - * The maximum amount of data, in bytes, that can be referenced by - * a request type that accesses frontend memory (currently BLKIF_OP_READ, - * BLKIF_OP_WRITE, or BLKIF_OP_WRITE_BARRIER). - * *------------------------- Virtual Device Properties ------------------------- * * device-type @@ -457,7 +404,9 @@ #define BLKIF_OP_DISCARD 5 /* - * Maximum scatter/gather segments per request (header + segment blocks). + * Maximum scatter/gather segments per request. + * This is carefully chosen so that sizeof(blkif_ring_t) <= PAGE_SIZE. + * NB. This could be 12 if the ring indexes weren't stored in the same page. */ #define BLKIF_MAX_SEGMENTS_PER_REQUEST 11 @@ -478,21 +427,6 @@ typedef struct blkif_request_segment blk /* * Starting ring element for any I/O request. - * - * One or more segment blocks can be inserted into the request ring - * just after a blkif_request_t, allowing requests to operate on - * up to BLKIF_MAX_SEGMENTS_PER_REQUEST. - * - * BLKIF_SEGS_TO_BLOCKS() can be used on blkif_requst.nr_segments - * to determine the number of contiguous ring entries associated - * with this request. - * - * Note: Due to the way Xen request rings operate, the producer and - * consumer indices of the ring must be incremented by the - * BLKIF_SEGS_TO_BLOCKS() value of the associated request. - * (e.g. a response to a 3 ring entry request must also consume - * 3 entries in the ring, even though only the first ring entry - * in the response has any data.) */ struct blkif_request { uint8_t operation; /* BLKIF_OP_??? */