Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752664AbdHQAHz (ORCPT ); Wed, 16 Aug 2017 20:07:55 -0400 Received: from mx1.redhat.com ([209.132.183.28]:41664 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752250AbdHQAGP (ORCPT ); Wed, 16 Aug 2017 20:06:15 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com DC4F2C000674 Authentication-Results: ext-mx07.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx07.extmail.prod.ext.phx2.redhat.com; spf=fail smtp.mailfrom=jglisse@redhat.com From: =?UTF-8?q?J=C3=A9r=C3=B4me=20Glisse?= To: akpm@linux-foundation.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org Cc: John Hubbard , Dan Williams , David Nellans , Balbir Singh , =?UTF-8?q?J=C3=A9r=C3=B4me=20Glisse?= , Evgeny Baskakov , Mark Hairgrove , Sherry Cheung , Subhash Gutti Subject: [HMM-v25 12/19] mm/hmm/devmem: dummy HMM device for ZONE_DEVICE memory v3 Date: Wed, 16 Aug 2017 20:05:41 -0400 Message-Id: <20170817000548.32038-13-jglisse@redhat.com> In-Reply-To: <20170817000548.32038-1-jglisse@redhat.com> References: <20170817000548.32038-1-jglisse@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.31]); Thu, 17 Aug 2017 00:06:15 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4679 Lines: 165 This introduce a dummy HMM device class so device driver can use it to create hmm_device for the sole purpose of registering device memory. It is useful to device driver that want to manage multiple physical device memory under same struct device umbrella. Changed since v2: - use device_initcall() and drop everything that is module specific Changed since v1: - Improve commit message - Add drvdata parameter to set on struct device Signed-off-by: Jérôme Glisse Signed-off-by: Evgeny Baskakov Signed-off-by: John Hubbard Signed-off-by: Mark Hairgrove Signed-off-by: Sherry Cheung Signed-off-by: Subhash Gutti --- include/linux/hmm.h | 22 ++++++++++++++- mm/hmm.c | 81 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 102 insertions(+), 1 deletion(-) diff --git a/include/linux/hmm.h b/include/linux/hmm.h index 0a8e5e3688e8..aeba696a4385 100644 --- a/include/linux/hmm.h +++ b/include/linux/hmm.h @@ -72,11 +72,11 @@ #if IS_ENABLED(CONFIG_HMM) +#include #include #include #include - struct hmm; /* @@ -474,6 +474,26 @@ static inline unsigned long hmm_devmem_page_get_drvdata(struct page *page) return drvdata[1]; } + + +/* + * struct hmm_device - fake device to hang device memory onto + * + * @device: device struct + * @minor: device minor number + */ +struct hmm_device { + struct device device; + unsigned int minor; +}; + +/* + * A device driver that wants to handle multiple devices memory through a + * single fake device can use hmm_device to do so. This is purely a helper and + * it is not strictly needed, in order to make use of any HMM functionality. + */ +struct hmm_device *hmm_device_new(void *drvdata); +void hmm_device_put(struct hmm_device *hmm_device); #endif /* IS_ENABLED(CONFIG_DEVICE_PRIVATE) */ diff --git a/mm/hmm.c b/mm/hmm.c index afc9ab22228c..8c5ce5f76b2e 100644 --- a/mm/hmm.c +++ b/mm/hmm.c @@ -19,6 +19,7 @@ */ #include #include +#include #include #include #include @@ -1111,4 +1112,84 @@ void hmm_devmem_remove(struct hmm_devmem *devmem) devm_release_mem_region(device, start, size); } EXPORT_SYMBOL(hmm_devmem_remove); + +/* + * A device driver that wants to handle multiple devices memory through a + * single fake device can use hmm_device to do so. This is purely a helper + * and it is not needed to make use of any HMM functionality. + */ +#define HMM_DEVICE_MAX 256 + +static DECLARE_BITMAP(hmm_device_mask, HMM_DEVICE_MAX); +static DEFINE_SPINLOCK(hmm_device_lock); +static struct class *hmm_device_class; +static dev_t hmm_device_devt; + +static void hmm_device_release(struct device *device) +{ + struct hmm_device *hmm_device; + + hmm_device = container_of(device, struct hmm_device, device); + spin_lock(&hmm_device_lock); + clear_bit(hmm_device->minor, hmm_device_mask); + spin_unlock(&hmm_device_lock); + + kfree(hmm_device); +} + +struct hmm_device *hmm_device_new(void *drvdata) +{ + struct hmm_device *hmm_device; + + hmm_device = kzalloc(sizeof(*hmm_device), GFP_KERNEL); + if (!hmm_device) + return ERR_PTR(-ENOMEM); + + spin_lock(&hmm_device_lock); + hmm_device->minor = find_first_zero_bit(hmm_device_mask, HMM_DEVICE_MAX); + if (hmm_device->minor >= HMM_DEVICE_MAX) { + spin_unlock(&hmm_device_lock); + kfree(hmm_device); + return ERR_PTR(-EBUSY); + } + set_bit(hmm_device->minor, hmm_device_mask); + spin_unlock(&hmm_device_lock); + + dev_set_name(&hmm_device->device, "hmm_device%d", hmm_device->minor); + hmm_device->device.devt = MKDEV(MAJOR(hmm_device_devt), + hmm_device->minor); + hmm_device->device.release = hmm_device_release; + dev_set_drvdata(&hmm_device->device, drvdata); + hmm_device->device.class = hmm_device_class; + device_initialize(&hmm_device->device); + + return hmm_device; +} +EXPORT_SYMBOL(hmm_device_new); + +void hmm_device_put(struct hmm_device *hmm_device) +{ + put_device(&hmm_device->device); +} +EXPORT_SYMBOL(hmm_device_put); + +static int __init hmm_init(void) +{ + int ret; + + ret = alloc_chrdev_region(&hmm_device_devt, 0, + HMM_DEVICE_MAX, + "hmm_device"); + if (ret) + return ret; + + hmm_device_class = class_create(THIS_MODULE, "hmm_device"); + if (IS_ERR(hmm_device_class)) { + unregister_chrdev_region(hmm_device_devt, HMM_DEVICE_MAX); + return PTR_ERR(hmm_device_class); + } + return 0; +} + +device_initcall(hmm_init); #endif /* IS_ENABLED(CONFIG_DEVICE_PRIVATE) */ -- 2.13.4