mm/hmm/devmem: dummy HMM device for ZONE_DEVICE memory
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. Link: http://lkml.kernel.org/r/20170817000548.32038-13-jglisse@redhat.com Signed-off-by: Jérôme Glisse <jglisse@redhat.com> Signed-off-by: Evgeny Baskakov <ebaskakov@nvidia.com> Signed-off-by: John Hubbard <jhubbard@nvidia.com> Signed-off-by: Mark Hairgrove <mhairgrove@nvidia.com> Signed-off-by: Sherry Cheung <SCheung@nvidia.com> Signed-off-by: Subhash Gutti <sgutti@nvidia.com> Cc: Aneesh Kumar <aneesh.kumar@linux.vnet.ibm.com> Cc: Balbir Singh <bsingharora@gmail.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Dan Williams <dan.j.williams@intel.com> Cc: David Nellans <dnellans@nvidia.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Ross Zwisler <ross.zwisler@linux.intel.com> Cc: Vladimir Davydov <vdavydov.dev@gmail.com> Cc: Bob Liu <liubo95@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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@ -72,11 +72,11 @@
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#if IS_ENABLED(CONFIG_HMM)
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#if IS_ENABLED(CONFIG_HMM)
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#include <linux/device.h>
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#include <linux/migrate.h>
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#include <linux/migrate.h>
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#include <linux/memremap.h>
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#include <linux/memremap.h>
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#include <linux/completion.h>
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#include <linux/completion.h>
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struct hmm;
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struct hmm;
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/*
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/*
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@ -474,6 +474,26 @@ static inline unsigned long hmm_devmem_page_get_drvdata(struct page *page)
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return drvdata[1];
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return drvdata[1];
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}
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}
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/*
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* struct hmm_device - fake device to hang device memory onto
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*
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* @device: device struct
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* @minor: device minor number
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*/
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struct hmm_device {
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struct device device;
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unsigned int minor;
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};
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/*
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* A device driver that wants to handle multiple devices memory through a
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* single fake device can use hmm_device to do so. This is purely a helper and
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* it is not strictly needed, in order to make use of any HMM functionality.
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*/
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struct hmm_device *hmm_device_new(void *drvdata);
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void hmm_device_put(struct hmm_device *hmm_device);
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#endif /* IS_ENABLED(CONFIG_DEVICE_PRIVATE) */
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#endif /* IS_ENABLED(CONFIG_DEVICE_PRIVATE) */
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81
mm/hmm.c
81
mm/hmm.c
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@ -19,6 +19,7 @@
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*/
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*/
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#include <linux/mm.h>
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#include <linux/mm.h>
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#include <linux/hmm.h>
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#include <linux/hmm.h>
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#include <linux/init.h>
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#include <linux/rmap.h>
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#include <linux/rmap.h>
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#include <linux/swap.h>
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#include <linux/swap.h>
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#include <linux/slab.h>
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#include <linux/slab.h>
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@ -1096,4 +1097,84 @@ void hmm_devmem_remove(struct hmm_devmem *devmem)
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devm_release_mem_region(device, start, size);
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devm_release_mem_region(device, start, size);
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}
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}
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EXPORT_SYMBOL(hmm_devmem_remove);
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EXPORT_SYMBOL(hmm_devmem_remove);
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/*
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* A device driver that wants to handle multiple devices memory through a
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* single fake device can use hmm_device to do so. This is purely a helper
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* and it is not needed to make use of any HMM functionality.
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*/
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#define HMM_DEVICE_MAX 256
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static DECLARE_BITMAP(hmm_device_mask, HMM_DEVICE_MAX);
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static DEFINE_SPINLOCK(hmm_device_lock);
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static struct class *hmm_device_class;
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static dev_t hmm_device_devt;
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static void hmm_device_release(struct device *device)
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{
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struct hmm_device *hmm_device;
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hmm_device = container_of(device, struct hmm_device, device);
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spin_lock(&hmm_device_lock);
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clear_bit(hmm_device->minor, hmm_device_mask);
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spin_unlock(&hmm_device_lock);
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kfree(hmm_device);
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}
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struct hmm_device *hmm_device_new(void *drvdata)
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{
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struct hmm_device *hmm_device;
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hmm_device = kzalloc(sizeof(*hmm_device), GFP_KERNEL);
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if (!hmm_device)
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return ERR_PTR(-ENOMEM);
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spin_lock(&hmm_device_lock);
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hmm_device->minor = find_first_zero_bit(hmm_device_mask, HMM_DEVICE_MAX);
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if (hmm_device->minor >= HMM_DEVICE_MAX) {
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spin_unlock(&hmm_device_lock);
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kfree(hmm_device);
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return ERR_PTR(-EBUSY);
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}
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set_bit(hmm_device->minor, hmm_device_mask);
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spin_unlock(&hmm_device_lock);
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dev_set_name(&hmm_device->device, "hmm_device%d", hmm_device->minor);
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hmm_device->device.devt = MKDEV(MAJOR(hmm_device_devt),
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hmm_device->minor);
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hmm_device->device.release = hmm_device_release;
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dev_set_drvdata(&hmm_device->device, drvdata);
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hmm_device->device.class = hmm_device_class;
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device_initialize(&hmm_device->device);
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return hmm_device;
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}
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EXPORT_SYMBOL(hmm_device_new);
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void hmm_device_put(struct hmm_device *hmm_device)
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{
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put_device(&hmm_device->device);
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}
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EXPORT_SYMBOL(hmm_device_put);
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static int __init hmm_init(void)
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{
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int ret;
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ret = alloc_chrdev_region(&hmm_device_devt, 0,
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HMM_DEVICE_MAX,
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"hmm_device");
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if (ret)
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return ret;
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hmm_device_class = class_create(THIS_MODULE, "hmm_device");
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if (IS_ERR(hmm_device_class)) {
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unregister_chrdev_region(hmm_device_devt, HMM_DEVICE_MAX);
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return PTR_ERR(hmm_device_class);
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}
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return 0;
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}
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device_initcall(hmm_init);
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#endif /* IS_ENABLED(CONFIG_DEVICE_PRIVATE) */
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#endif /* IS_ENABLED(CONFIG_DEVICE_PRIVATE) */
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