Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1040337AbdDVExq (ORCPT ); Sat, 22 Apr 2017 00:53:46 -0400 Received: from mx1.redhat.com ([209.132.183.28]:59942 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932345AbdDVExn (ORCPT ); Sat, 22 Apr 2017 00:53:43 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com 1CB42AC07B Authentication-Results: ext-mx09.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx09.extmail.prod.ext.phx2.redhat.com; spf=pass smtp.mailfrom=jglisse@redhat.com DKIM-Filter: OpenDKIM Filter v2.11.0 mx1.redhat.com 1CB42AC07B 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 , Naoya Horiguchi , David Nellans , =?UTF-8?q?J=C3=A9r=C3=B4me=20Glisse?= , Evgeny Baskakov , Mark Hairgrove , Sherry Cheung , Subhash Gutti Subject: [HMM 14/15] mm/hmm/devmem: dummy HMM device for ZONE_DEVICE memory v3 Date: Fri, 21 Apr 2017 23:30:36 -0400 Message-Id: <20170422033037.3028-15-jglisse@redhat.com> In-Reply-To: <20170422033037.3028-1-jglisse@redhat.com> References: <20170422033037.3028-1-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 [10.5.110.38]); Sat, 22 Apr 2017 04:53:43 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4758 Lines: 172 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 | 88 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 109 insertions(+), 1 deletion(-) diff --git a/include/linux/hmm.h b/include/linux/hmm.h index 50a1115..374e5fd 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; /* @@ -433,6 +433,26 @@ 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_HMM_DEVMEM) */ diff --git a/mm/hmm.c b/mm/hmm.c index 5d882e6..8b6b4c6 100644 --- a/mm/hmm.c +++ b/mm/hmm.c @@ -19,6 +19,7 @@ */ #include #include +#include #include #include #include @@ -1112,4 +1113,91 @@ int hmm_devmem_fault_range(struct hmm_devmem *devmem, return 0; } EXPORT_SYMBOL(hmm_devmem_fault_range); + +/* + * 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; + int ret; + + hmm_device = kzalloc(sizeof(*hmm_device), GFP_KERNEL); + if (!hmm_device) + return ERR_PTR(-ENOMEM); + + ret = alloc_chrdev_region(&hmm_device->device.devt, 0, 1, "hmm_device"); + if (ret < 0) { + kfree(hmm_device); + return NULL; + } + + 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 NULL; + } + 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_HMM_DEVMEM) */ -- 2.9.3