diff options
author | Jérôme Glisse <jglisse@redhat.com> | 2017-09-08 16:12:02 -0700 |
---|---|---|
committer | Linus Torvalds <torvalds@linux-foundation.org> | 2017-09-08 18:26:46 -0700 |
commit | 858b54dabf4363daa3a97b9a722130a8e7cea8c9 (patch) | |
tree | d7603a71e353df51667c57e942c2a2311fed9379 /mm/hmm.c | |
parent | 4ef589dc9b10cdcae75a2b2b0e9b2c5e8a92c378 (diff) | |
download | linux-stable-858b54dabf4363daa3a97b9a722130a8e7cea8c9.tar.gz linux-stable-858b54dabf4363daa3a97b9a722130a8e7cea8c9.tar.bz2 linux-stable-858b54dabf4363daa3a97b9a722130a8e7cea8c9.zip |
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>
Diffstat (limited to 'mm/hmm.c')
-rw-r--r-- | mm/hmm.c | 81 |
1 files changed, 81 insertions, 0 deletions
@@ -19,6 +19,7 @@ */ #include <linux/mm.h> #include <linux/hmm.h> +#include <linux/init.h> #include <linux/rmap.h> #include <linux/swap.h> #include <linux/slab.h> @@ -1096,4 +1097,84 @@ 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) */ |