mm, hmm: use devm semantics for hmm_devmem_{add, remove}

BugLink: https://bugs.launchpad.net/bugs/1837477
commit 58ef15b765af0d2cbe6799ec564f1dc485010ab8 upstream.

devm semantics arrange for resources to be torn down when
device-driver-probe fails or when device-driver-release completes.
Similar to devm_memremap_pages() there is no need to support an explicit
remove operation when the users properly adhere to devm semantics.

Note that devm_kzalloc() automatically handles allocating node-local
memory.

Link: http://lkml.kernel.org/r/154275559545.76910.9186690723515469051.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jérôme Glisse <jglisse@redhat.com>
Cc: "Jérôme Glisse" <jglisse@redhat.com>
Cc: Logan Gunthorpe <logang@deltatee.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Andrea Righi <andrea.righi@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>

diff --git a/include/linux/hmm.h b/include/linux/hmm.h
index 325017ad9311749820e648949d987f42ef5e0105..805daeee9e94ca027018d9e2b7e36b910af8ffb3 100644 (file)
--- a/include/linux/hmm.h
+++ b/include/linux/hmm.h
@@ -437,8 +437,7 @@ struct hmm_devmem {
  * enough and allocate struct page for it.
  *
  * The device driver can wrap the hmm_devmem struct inside a private device
- * driver struct. The device driver must call hmm_devmem_remove() before the
- * device goes away and before freeing the hmm_devmem struct memory.
+ * driver struct.
  */
 struct hmm_devmem *hmm_devmem_add(const struct hmm_devmem_ops *ops,
                                  struct device *device,
@@ -446,7 +445,6 @@ struct hmm_devmem *hmm_devmem_add(const struct hmm_devmem_ops *ops,
 struct hmm_devmem *hmm_devmem_add_resource(const struct hmm_devmem_ops *ops,
                                           struct device *device,
                                           struct resource *res);
-void hmm_devmem_remove(struct hmm_devmem *devmem);
 
 /*
  * hmm_devmem_page_set_drvdata - set per-page driver data field

diff --git a/mm/hmm.c b/mm/hmm.c
index 333141b24713a6f7d94e9f0de0a15c63e56de5c0..9767a9ad5779d54bb2dc7729a6271a42ed6096dc 100644 (file)
--- a/mm/hmm.c
+++ b/mm/hmm.c
@@ -767,7 +767,6 @@ static void hmm_devmem_ref_exit(void *data)
 
        devmem = container_of(ref, struct hmm_devmem, ref);
        percpu_ref_exit(ref);
-       devm_remove_action(devmem->device, &hmm_devmem_ref_exit, data);
 }
 
 static void hmm_devmem_ref_kill(void *data)
@@ -778,7 +777,6 @@ static void hmm_devmem_ref_kill(void *data)
        devmem = container_of(ref, struct hmm_devmem, ref);
        percpu_ref_kill(ref);
        wait_for_completion(&devmem->completion);
-       devm_remove_action(devmem->device, &hmm_devmem_ref_kill, data);
 }
 
 static int hmm_devmem_fault(struct vm_area_struct *vma,
@@ -819,7 +817,7 @@ static void hmm_devmem_radix_release(struct resource *resource)
        mutex_unlock(&hmm_devmem_lock);
 }
 
-static void hmm_devmem_release(struct device *dev, void *data)
+static void hmm_devmem_release(void *data)
 {
        struct hmm_devmem *devmem = data;
        struct resource *resource = devmem->resource;
@@ -827,11 +825,6 @@ static void hmm_devmem_release(struct device *dev, void *data)
        struct zone *zone;
        struct page *page;
 
-       if (percpu_ref_tryget_live(&devmem->ref)) {
-               dev_WARN(dev, "%s: page mapping is still live!\n", __func__);
-               percpu_ref_put(&devmem->ref);
-       }
-
        /* pages are dead and unused, undo the arch mapping */
        start_pfn = (resource->start & ~(PA_SECTION_SIZE - 1)) >> PAGE_SHIFT;
        npages = ALIGN(resource_size(resource), PA_SECTION_SIZE) >> PAGE_SHIFT;
@@ -962,19 +955,6 @@ error:
        return ret;
 }
 
-static int hmm_devmem_match(struct device *dev, void *data, void *match_data)
-{
-       struct hmm_devmem *devmem = data;
-
-       return devmem->resource == match_data;
-}
-
-static void hmm_devmem_pages_remove(struct hmm_devmem *devmem)
-{
-       devres_release(devmem->device, &hmm_devmem_release,
-                      &hmm_devmem_match, devmem->resource);
-}
-
 /*
  * hmm_devmem_add() - hotplug ZONE_DEVICE memory for device memory
  *
@@ -1002,8 +982,7 @@ struct hmm_devmem *hmm_devmem_add(const struct hmm_devmem_ops *ops,
 
        static_branch_enable(&device_private_key);
 
-       devmem = devres_alloc_node(&hmm_devmem_release, sizeof(*devmem),
-                                  GFP_KERNEL, dev_to_node(device));
+       devmem = devm_kzalloc(device, sizeof(*devmem), GFP_KERNEL);
        if (!devmem)
                return ERR_PTR(-ENOMEM);
 
@@ -1017,11 +996,11 @@ struct hmm_devmem *hmm_devmem_add(const struct hmm_devmem_ops *ops,
        ret = percpu_ref_init(&devmem->ref, &hmm_devmem_ref_release,
                              0, GFP_KERNEL);
        if (ret)
-               goto error_percpu_ref;
+               return ERR_PTR(ret);
 
-       ret = devm_add_action(device, hmm_devmem_ref_exit, &devmem->ref);
+       ret = devm_add_action_or_reset(device, hmm_devmem_ref_exit, &devmem->ref);
        if (ret)
-               goto error_devm_add_action;
+               return ERR_PTR(ret);
 
        size = ALIGN(size, PA_SECTION_SIZE);
        addr = min((unsigned long)iomem_resource.end,
@@ -1041,16 +1020,12 @@ struct hmm_devmem *hmm_devmem_add(const struct hmm_devmem_ops *ops,
 
                devmem->resource = devm_request_mem_region(device, addr, size,
                                                           dev_name(device));
-               if (!devmem->resource) {
-                       ret = -ENOMEM;
-                       goto error_no_resource;
-               }
+               if (!devmem->resource)
+                       return ERR_PTR(-ENOMEM);
                break;
        }
-       if (!devmem->resource) {
-               ret = -ERANGE;
-               goto error_no_resource;
-       }
+       if (!devmem->resource)
+               return ERR_PTR(-ERANGE);
 
        devmem->resource->desc = IORES_DESC_DEVICE_PRIVATE_MEMORY;
        devmem->pfn_first = devmem->resource->start >> PAGE_SHIFT;
@@ -1059,28 +1034,13 @@ struct hmm_devmem *hmm_devmem_add(const struct hmm_devmem_ops *ops,
 
        ret = hmm_devmem_pages_create(devmem);
        if (ret)
-               goto error_pages;
-
-       devres_add(device, devmem);
+               return ERR_PTR(ret);
 
-       ret = devm_add_action(device, hmm_devmem_ref_kill, &devmem->ref);
-       if (ret) {
-               hmm_devmem_remove(devmem);
+       ret = devm_add_action_or_reset(device, hmm_devmem_release, devmem);
+       if (ret)
                return ERR_PTR(ret);
-       }
 
        return devmem;
-
-error_pages:
-       devm_release_mem_region(device, devmem->resource->start,
-                               resource_size(devmem->resource));
-error_no_resource:
-error_devm_add_action:
-       hmm_devmem_ref_kill(&devmem->ref);
-       hmm_devmem_ref_exit(&devmem->ref);
-error_percpu_ref:
-       devres_free(devmem);
-       return ERR_PTR(ret);
 }
 EXPORT_SYMBOL(hmm_devmem_add);
 
@@ -1096,8 +1056,7 @@ struct hmm_devmem *hmm_devmem_add_resource(const struct hmm_devmem_ops *ops,
 
        static_branch_enable(&device_private_key);
 
-       devmem = devres_alloc_node(&hmm_devmem_release, sizeof(*devmem),
-                                  GFP_KERNEL, dev_to_node(device));
+       devmem = devm_kzalloc(device, sizeof(*devmem), GFP_KERNEL);
        if (!devmem)
                return ERR_PTR(-ENOMEM);
 
@@ -1111,12 +1070,12 @@ struct hmm_devmem *hmm_devmem_add_resource(const struct hmm_devmem_ops *ops,
        ret = percpu_ref_init(&devmem->ref, &hmm_devmem_ref_release,
                              0, GFP_KERNEL);
        if (ret)
-               goto error_percpu_ref;
+               return ERR_PTR(ret);
 
-       ret = devm_add_action(device, hmm_devmem_ref_exit, &devmem->ref);
+       ret = devm_add_action_or_reset(device, hmm_devmem_ref_exit,
+                       &devmem->ref);
        if (ret)
-               goto error_devm_add_action;
-
+               return ERR_PTR(ret);
 
        devmem->pfn_first = devmem->resource->start >> PAGE_SHIFT;
        devmem->pfn_last = devmem->pfn_first +
@@ -1124,59 +1083,21 @@ struct hmm_devmem *hmm_devmem_add_resource(const struct hmm_devmem_ops *ops,
 
        ret = hmm_devmem_pages_create(devmem);
        if (ret)
-               goto error_devm_add_action;
+               return ERR_PTR(ret);
 
-       devres_add(device, devmem);
+       ret = devm_add_action_or_reset(device, hmm_devmem_release, devmem);
+       if (ret)
+               return ERR_PTR(ret);
 
-       ret = devm_add_action(device, hmm_devmem_ref_kill, &devmem->ref);
-       if (ret) {
-               hmm_devmem_remove(devmem);
+       ret = devm_add_action_or_reset(device, hmm_devmem_ref_kill,
+                       &devmem->ref);
+       if (ret)
                return ERR_PTR(ret);
-       }
 
        return devmem;
-
-error_devm_add_action:
-       hmm_devmem_ref_kill(&devmem->ref);
-       hmm_devmem_ref_exit(&devmem->ref);
-error_percpu_ref:
-       devres_free(devmem);
-       return ERR_PTR(ret);
 }
 EXPORT_SYMBOL(hmm_devmem_add_resource);
 
-/*
- * hmm_devmem_remove() - remove device memory (kill and free ZONE_DEVICE)
- *
- * @devmem: hmm_devmem struct use to track and manage the ZONE_DEVICE memory
- *
- * This will hot-unplug memory that was hotplugged by hmm_devmem_add on behalf
- * of the device driver. It will free struct page and remove the resource that
- * reserved the physical address range for this device memory.
- */
-void hmm_devmem_remove(struct hmm_devmem *devmem)
-{
-       resource_size_t start, size;
-       struct device *device;
-       bool cdm = false;
-
-       if (!devmem)
-               return;
-
-       device = devmem->device;
-       start = devmem->resource->start;
-       size = resource_size(devmem->resource);
-
-       cdm = devmem->resource->desc == IORES_DESC_DEVICE_PUBLIC_MEMORY;
-       hmm_devmem_ref_kill(&devmem->ref);
-       hmm_devmem_ref_exit(&devmem->ref);
-       hmm_devmem_pages_remove(devmem);
-
-       if (!cdm)
-               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