From patchwork Wed Sep 2 00:03:28 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Lee Duncan X-Patchwork-Id: 7107601 Return-Path: X-Original-To: patchwork-linux-scsi@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork1.web.kernel.org (Postfix) with ESMTP id 3C0FF9F1CD for ; Wed, 2 Sep 2015 00:03:40 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 4BC51205B8 for ; Wed, 2 Sep 2015 00:03:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2B8EB20523 for ; Wed, 2 Sep 2015 00:03:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751564AbbIBADh (ORCPT ); Tue, 1 Sep 2015 20:03:37 -0400 Received: from mx2.suse.de ([195.135.220.15]:37116 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751169AbbIBADh (ORCPT ); Tue, 1 Sep 2015 20:03:37 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (charybdis-ext.suse.de [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id 94D12AD3E; Wed, 2 Sep 2015 00:03:35 +0000 (UTC) Received: by worklaptop.gonzoleeman.net (Postfix, from userid 1000) id B532A40C60; Tue, 1 Sep 2015 17:03:31 -0700 (PDT) From: Lee Duncan To: Cc: , , , Lee Duncan Subject: [PATCHv3] Update scsi host to use ida for host number Date: Tue, 1 Sep 2015 17:03:28 -0700 Message-Id: <1441152208-20634-1-git-send-email-lduncan@suse.com> X-Mailer: git-send-email 2.1.4 Sender: linux-scsi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org X-Spam-Status: No, score=-6.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, T_RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Each Scsi_host instance gets a host number starting at 0, but this is implemented with an atomic integer, and rollover doesn't seem to have been considered. Another side-effect of this design is that scsi host numbers used by iscsi are never reused, thereby making rollover more likely. This patch converts Scsi_host instances to use ida to manage their instance numbers. This also means that host instance numbers will be reused, when available. Changes from v2: * Use host_put_index() throughout * Put host index code together Changes from v1: * Added inline host_put_index() and its use Signed-off-by: Lee Duncan Reviewed-by: Hannes Reinecke Reviewed-by: Johannes Thumshirn --- drivers/scsi/hosts.c | 47 ++++++++++++++++++++++++++++++++++++++--------- 1 file changed, 38 insertions(+), 9 deletions(-) diff --git a/drivers/scsi/hosts.c b/drivers/scsi/hosts.c index 8bb173e01084..a47944867e65 100644 --- a/drivers/scsi/hosts.c +++ b/drivers/scsi/hosts.c @@ -33,7 +33,7 @@ #include #include #include - +#include #include #include #include @@ -42,8 +42,6 @@ #include "scsi_logging.h" -static atomic_t scsi_host_next_hn = ATOMIC_INIT(0); /* host_no for next new host */ - static void scsi_host_cls_release(struct device *dev) { @@ -304,6 +302,31 @@ int scsi_add_host_with_dma(struct Scsi_Host *shost, struct device *dev, } EXPORT_SYMBOL(scsi_add_host_with_dma); +static DEFINE_SPINLOCK(host_index_lock); +static DEFINE_IDA(host_index_ida); + +static int host_get_index(int *index) +{ + int error = -ENOMEM; + + do { + if (!ida_pre_get(&host_index_ida, GFP_KERNEL)) + break; + spin_lock(&host_index_lock); + error = ida_get_new(&host_index_ida, index); + spin_unlock(&host_index_lock); + } while (error == -EAGAIN); + + return error; +} + +static inline void host_put_index(int index) +{ + spin_lock(&host_index_lock); + ida_remove(&host_index_ida, index); + spin_unlock(&host_index_lock); +} + static void scsi_host_dev_release(struct device *dev) { struct Scsi_Host *shost = dev_to_shost(dev); @@ -337,6 +360,8 @@ static void scsi_host_dev_release(struct device *dev) kfree(shost->shost_data); + host_put_index(shost->host_no); + if (parent) put_device(parent); kfree(shost); @@ -370,6 +395,8 @@ struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize) { struct Scsi_Host *shost; gfp_t gfp_mask = GFP_KERNEL; + int index; + int error; if (sht->unchecked_isa_dma && privsize) gfp_mask |= __GFP_DMA; @@ -388,11 +415,11 @@ struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize) init_waitqueue_head(&shost->host_wait); mutex_init(&shost->scan_mutex); - /* - * subtract one because we increment first then return, but we need to - * know what the next host number was before increment - */ - shost->host_no = atomic_inc_return(&scsi_host_next_hn) - 1; + error = host_get_index(&index); + if (error < 0) + goto fail_kfree; + shost->host_no = index; + shost->dma_channel = 0xff; /* These three are default values which can be overridden */ @@ -477,7 +504,7 @@ struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize) shost_printk(KERN_WARNING, shost, "error handler thread failed to spawn, error = %ld\n", PTR_ERR(shost->ehandler)); - goto fail_kfree; + goto fail_free_index; } shost->tmf_work_q = alloc_workqueue("scsi_tmf_%d", @@ -493,6 +520,8 @@ struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize) fail_kthread: kthread_stop(shost->ehandler); + fail_free_index: + host_put_index(index); fail_kfree: kfree(shost); return NULL;