mm: factor out a devm_request_free_mem_region helper

Keep the physical address allocation that hmm_add_device does with the
rest of the resource code, and allow future reuse of it without the hmm
wrapper.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jason Gunthorpe <jgg@mellanox.com>
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

diff --git a/include/linux/ioport.h b/include/linux/ioport.h
index dd961882bc749e1419b73071131726a97f171e0a..a02b290ca08a29676c9c1e5ca7e0c2feb062ffce 100644 (file)
--- a/include/linux/ioport.h
+++ b/include/linux/ioport.h
@@ -285,6 +285,8 @@ static inline bool resource_overlaps(struct resource *r1, struct resource *r2)
        return (r1->start <= r2->end && r1->end >= r2->start);
 }
 
+struct resource *devm_request_free_mem_region(struct device *dev,
+               struct resource *base, unsigned long size);
 
 #endif /* __ASSEMBLY__ */
 #endif /* _LINUX_IOPORT_H */

diff --git a/kernel/resource.c b/kernel/resource.c
index 158f04ec1d4fad91702c7c38a972f3f1775fb727..d22423e85cf801ba358581f08390041c0929a2cf 100644 (file)
--- a/kernel/resource.c
+++ b/kernel/resource.c
@@ -1628,6 +1628,45 @@ void resource_list_free(struct list_head *head)
 }
 EXPORT_SYMBOL(resource_list_free);
 
+#ifdef CONFIG_DEVICE_PRIVATE
+/**
+ * devm_request_free_mem_region - find free region for device private memory
+ *
+ * @dev: device struct to bind the resource to
+ * @size: size in bytes of the device memory to add
+ * @base: resource tree to look in
+ *
+ * This function tries to find an empty range of physical address big enough to
+ * contain the new resource, so that it can later be hotplugged as ZONE_DEVICE
+ * memory, which in turn allocates struct pages.
+ */
+struct resource *devm_request_free_mem_region(struct device *dev,
+               struct resource *base, unsigned long size)
+{
+       resource_size_t end, addr;
+       struct resource *res;
+
+       size = ALIGN(size, 1UL << PA_SECTION_SHIFT);
+       end = min_t(unsigned long, base->end, (1UL << MAX_PHYSMEM_BITS) - 1);
+       addr = end - size + 1UL;
+
+       for (; addr > size && addr >= base->start; addr -= size) {
+               if (region_intersects(addr, size, 0, IORES_DESC_NONE) !=
+                               REGION_DISJOINT)
+                       continue;
+
+               res = devm_request_mem_region(dev, addr, size, dev_name(dev));
+               if (!res)
+                       return ERR_PTR(-ENOMEM);
+               res->desc = IORES_DESC_DEVICE_PRIVATE_MEMORY;
+               return res;
+       }
+
+       return ERR_PTR(-ERANGE);
+}
+EXPORT_SYMBOL_GPL(devm_request_free_mem_region);
+#endif /* CONFIG_DEVICE_PRIVATE */
+
 static int __init strict_iomem(char *str)
 {
        if (strstr(str, "relaxed"))

diff --git a/mm/hmm.c b/mm/hmm.c
index e7dd2ab8f9ab0319b190f6159bc04c1faa2de9b8..48574f8485bb9351a66da145db218e1c526d09d0 100644 (file)
--- a/mm/hmm.c
+++ b/mm/hmm.c
@@ -25,8 +25,6 @@
 #include <linux/mmu_notifier.h>
 #include <linux/memory_hotplug.h>
 
-#define PA_SECTION_SIZE (1UL << PA_SECTION_SHIFT)
-
 #if IS_ENABLED(CONFIG_HMM_MIRROR)
 static const struct mmu_notifier_ops hmm_mmu_notifier_ops;
 
@@ -1408,7 +1406,6 @@ struct hmm_devmem *hmm_devmem_add(const struct hmm_devmem_ops *ops,
                                  unsigned long size)
 {
        struct hmm_devmem *devmem;
-       resource_size_t addr;
        void *result;
        int ret;
 
@@ -1430,32 +1427,10 @@ struct hmm_devmem *hmm_devmem_add(const struct hmm_devmem_ops *ops,
        if (ret)
                return ERR_PTR(ret);
 
-       size = ALIGN(size, PA_SECTION_SIZE);
-       addr = min((unsigned long)iomem_resource.end,
-                  (1UL << MAX_PHYSMEM_BITS) - 1);
-       addr = addr - size + 1UL;
-
-       /*
-        * FIXME add a new helper to quickly walk resource tree and find free
-        * range
-        *
-        * FIXME what about ioport_resource resource ?
-        */
-       for (; addr > size && addr >= iomem_resource.start; addr -= size) {
-               ret = region_intersects(addr, size, 0, IORES_DESC_NONE);
-               if (ret != REGION_DISJOINT)
-                       continue;
-
-               devmem->resource = devm_request_mem_region(device, addr, size,
-                                                          dev_name(device));
-               if (!devmem->resource)
-                       return ERR_PTR(-ENOMEM);
-               break;
-       }
-       if (!devmem->resource)
-               return ERR_PTR(-ERANGE);
-
-       devmem->resource->desc = IORES_DESC_DEVICE_PRIVATE_MEMORY;
+       devmem->resource = devm_request_free_mem_region(device, &iomem_resource,
+                       size);
+       if (IS_ERR(devmem->resource))
+               return ERR_CAST(devmem->resource);
        devmem->pfn_first = devmem->resource->start >> PAGE_SHIFT;
        devmem->pfn_last = devmem->pfn_first +
                           (resource_size(devmem->resource) >> PAGE_SHIFT);