From patchwork Thu Oct 29 14:58:25 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christoph Hellwig X-Patchwork-Id: 1390201 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org (client-ip=23.128.96.18; helo=vger.kernel.org; envelope-from=linux-ide-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: ozlabs.org; dkim=pass (2048-bit key; secure) header.d=infradead.org header.i=@infradead.org header.a=rsa-sha256 header.s=casper.20170209 header.b=ASnCR9qI; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by ozlabs.org (Postfix) with ESMTP id 4CMTJz15yjz9sSC for ; Fri, 30 Oct 2020 02:05:39 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728008AbgJ2PFd (ORCPT ); Thu, 29 Oct 2020 11:05:33 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42546 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727048AbgJ2PFc (ORCPT ); Thu, 29 Oct 2020 11:05:32 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AE056C0613D2; Thu, 29 Oct 2020 08:05:32 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=Content-Transfer-Encoding:MIME-Version: References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From:Sender:Reply-To: Content-Type:Content-ID:Content-Description; bh=1xf9vIrBcurBVDY7G2ISkg6IFgku9NAy9qOlTzU7bWc=; b=ASnCR9qIaY/6KL3KbEYVs6xQkM 2SaAzJcPo639CQk11qq+g/3pDHxdXVpAGpEEB+w+flTOh+9jN1fCcE+Ld99LG/O07j5siXEK/hmqr 25WsdUcQm36FO+wyAkvNLRKUSkdlsL/3aizVHPwdX/nREv3fYPYdHId4yjFGZ0huM9RAdN8Zny8os Cf546oWodcUWSlrvDVrF/cbauRcmmOlJTauVTctzWFQlQlLWvaY69qGI3xfUiXbqPDZWl4cOBuGgw wodZycr5yfA6b5ZNf2s6SkTZsS8Fj2e0SptHSlKKD7qv7nsd+lC+hILCcDfJGR19bT8KDe7iVxeko /Q3wCMAw==; Received: from 089144193201.atnat0002.highway.a1.net ([89.144.193.201] helo=localhost) by casper.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1kY9UO-0005jJ-K6; Thu, 29 Oct 2020 15:05:22 +0000 From: Christoph Hellwig To: Jens Axboe Cc: Greg Kroah-Hartman , "Rafael J. Wysocki" , Denis Efremov , "David S. Miller" , Song Liu , Al Viro , Finn Thain , Michael Schmitz , linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, linux-ide@vger.kernel.org, linux-raid@vger.kernel.org, linux-scsi@vger.kernel.org, linux-m68k@lists.linux-m68k.org Subject: [PATCH 02/18] block: open code kobj_map into in block/genhd.c Date: Thu, 29 Oct 2020 15:58:25 +0100 Message-Id: <20201029145841.144173-3-hch@lst.de> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20201029145841.144173-1-hch@lst.de> References: <20201029145841.144173-1-hch@lst.de> MIME-Version: 1.0 X-SRS-Rewrite: SMTP reverse-path rewritten from by casper.infradead.org. See http://www.infradead.org/rpr.html Precedence: bulk List-ID: X-Mailing-List: linux-ide@vger.kernel.org Copy and paste the kobj_map functionality in the block code in preparation for completely rewriting it. Signed-off-by: Christoph Hellwig Reviewed-by: Greg Kroah-Hartman --- block/genhd.c | 130 +++++++++++++++++++++++++++++++++++++++++++++----- 1 file changed, 117 insertions(+), 13 deletions(-) diff --git a/block/genhd.c b/block/genhd.c index 3ed591970ea640..0e22ca64aca09e 100644 --- a/block/genhd.c +++ b/block/genhd.c @@ -17,7 +17,6 @@ #include #include #include -#include #include #include #include @@ -29,6 +28,16 @@ static DEFINE_MUTEX(block_class_lock); static struct kobject *block_depr; +struct bdev_map { + struct bdev_map *next; + dev_t dev; + unsigned long range; + struct module *owner; + struct kobject *(*probe)(dev_t, int *, void *); + int (*lock)(dev_t, void *); + void *data; +} *bdev_map[255]; + /* for extended dynamic devt allocation, currently only one major is used */ #define NR_EXT_DEVT (1 << MINORBITS) @@ -517,8 +526,6 @@ void unregister_blkdev(unsigned int major, const char *name) EXPORT_SYMBOL(unregister_blkdev); -static struct kobj_map *bdev_map; - /** * blk_mangle_minor - scatter minor numbers apart * @minor: minor number to mangle @@ -645,16 +652,60 @@ void blk_register_region(dev_t devt, unsigned long range, struct module *module, struct kobject *(*probe)(dev_t, int *, void *), int (*lock)(dev_t, void *), void *data) { - kobj_map(bdev_map, devt, range, module, probe, lock, data); -} + unsigned n = MAJOR(devt + range - 1) - MAJOR(devt) + 1; + unsigned index = MAJOR(devt); + unsigned i; + struct bdev_map *p; + + n = min(n, 255u); + p = kmalloc_array(n, sizeof(struct bdev_map), GFP_KERNEL); + if (p == NULL) + return; + for (i = 0; i < n; i++, p++) { + p->owner = module; + p->probe = probe; + p->lock = lock; + p->dev = devt; + p->range = range; + p->data = data; + } + + mutex_lock(&block_class_lock); + for (i = 0, p -= n; i < n; i++, p++, index++) { + struct bdev_map **s = &bdev_map[index % 255]; + while (*s && (*s)->range < range) + s = &(*s)->next; + p->next = *s; + *s = p; + } + mutex_unlock(&block_class_lock); +} EXPORT_SYMBOL(blk_register_region); void blk_unregister_region(dev_t devt, unsigned long range) { - kobj_unmap(bdev_map, devt, range); -} + unsigned n = MAJOR(devt + range - 1) - MAJOR(devt) + 1; + unsigned index = MAJOR(devt); + unsigned i; + struct bdev_map *found = NULL; + mutex_lock(&block_class_lock); + for (i = 0; i < min(n, 255u); i++, index++) { + struct bdev_map **s; + for (s = &bdev_map[index % 255]; *s; s = &(*s)->next) { + struct bdev_map *p = *s; + if (p->dev == devt && p->range == range) { + *s = p->next; + if (!found) + found = p; + break; + } + } + } + mutex_unlock(&block_class_lock); + kfree(found); +} EXPORT_SYMBOL(blk_unregister_region); static struct kobject *exact_match(dev_t devt, int *partno, void *data) @@ -976,6 +1027,47 @@ static ssize_t disk_badblocks_store(struct device *dev, return badblocks_store(disk->bb, page, len, 0); } +static struct gendisk *lookup_gendisk(dev_t dev, int *partno) +{ + struct kobject *kobj; + struct bdev_map *p; + unsigned long best = ~0UL; + +retry: + mutex_lock(&block_class_lock); + for (p = bdev_map[MAJOR(dev) % 255]; p; p = p->next) { + struct kobject *(*probe)(dev_t, int *, void *); + struct module *owner; + void *data; + + if (p->dev > dev || p->dev + p->range - 1 < dev) + continue; + if (p->range - 1 >= best) + break; + if (!try_module_get(p->owner)) + continue; + owner = p->owner; + data = p->data; + probe = p->probe; + best = p->range - 1; + *partno = dev - p->dev; + if (p->lock && p->lock(dev, data) < 0) { + module_put(owner); + continue; + } + mutex_unlock(&block_class_lock); + kobj = probe(dev, partno, data); + /* Currently ->owner protects _only_ ->probe() itself. */ + module_put(owner); + if (kobj) + return dev_to_disk(kobj_to_dev(kobj)); + goto retry; + } + mutex_unlock(&block_class_lock); + return NULL; +} + + /** * get_gendisk - get partitioning information for a given device * @devt: device to get partitioning information for @@ -993,11 +1085,7 @@ struct gendisk *get_gendisk(dev_t devt, int *partno) might_sleep(); if (MAJOR(devt) != BLOCK_EXT_MAJOR) { - struct kobject *kobj; - - kobj = kobj_lookup(bdev_map, devt, partno); - if (kobj) - disk = dev_to_disk(kobj_to_dev(kobj)); + disk = lookup_gendisk(devt, partno); } else { struct hd_struct *part; @@ -1210,6 +1298,22 @@ static struct kobject *base_probe(dev_t devt, int *partno, void *data) return NULL; } +static void bdev_map_init(void) +{ + struct bdev_map *base; + int i; + + base = kzalloc(sizeof(*base), GFP_KERNEL); + if (!base) + panic("cannot allocate bdev_map"); + + base->dev = 1; + base->range = ~0 ; + base->probe = base_probe; + for (i = 0; i < 255; i++) + bdev_map[i] = base; +} + static int __init genhd_device_init(void) { int error; @@ -1218,7 +1322,7 @@ static int __init genhd_device_init(void) error = class_register(&block_class); if (unlikely(error)) return error; - bdev_map = kobj_map_init(base_probe, &block_class_lock); + bdev_map_init(); blk_dev_init(); register_blkdev(BLOCK_EXT_MAJOR, "blkext");