[PATCH 06/22] mm: factor out a devm_request_free_mem_region helper

Christoph Hellwig
2019-06-13T15:45:30Z

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>
---
include/linux/ioport.h | 2 ++
kernel/resource.c | 39 +++++++++++++++++++++++++++++++++++++++
mm/hmm.c | 33 ++++-----------------------------
3 files changed, 45 insertions(+), 29 deletions(-)

diff --git a/include/linux/ioport.h b/include/linux/ioport.h
index da0ebaec25f0..76a33ae3bf6c 100644
--- a/include/linux/ioport.h
+++ b/include/linux/ioport.h
@@ -286,6 +286,8 @@ 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 158f04ec1d4f..99c58134ed1c 100644
--- 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 too
+ * @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 hotpluged 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 e1dc98407e7b..13a16faf0a77 100644
--- a/mm/hmm.c
+++ b/mm/hmm.c
@@ -26,8 +26,6 @@
#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;

@@ -1372,7 +1370,6 @@ 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;

@@ -1398,32 +1395,10 @@ 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);
--
2.20.1