[PATCH 4/4] memremap: provide a not device managed memremap_pages
From: Christoph Hellwig
Date: Fri Aug 16 2019 - 02:55:14 EST
The kvmppc ultravisor code wants a device private memory pool that is
system wide and not attached to a device. Instead of faking up one
provide a low-level memremap_pages for it. Note that this function is
not exported, and doesn't have a cleanup routine associated with it to
discourage use from more driver like users.
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
---
include/linux/memremap.h | 2 +
mm/memremap.c | 84 +++++++++++++++++++++++++---------------
2 files changed, 54 insertions(+), 32 deletions(-)
diff --git a/include/linux/memremap.h b/include/linux/memremap.h
index 8f0013e18e14..fb2a0bd826b9 100644
--- a/include/linux/memremap.h
+++ b/include/linux/memremap.h
@@ -123,6 +123,8 @@ static inline struct vmem_altmap *pgmap_altmap(struct dev_pagemap *pgmap)
}
#ifdef CONFIG_ZONE_DEVICE
+void *memremap_pages(struct dev_pagemap *pgmap, int nid);
+void memunmap_pages(struct dev_pagemap *pgmap);
void *devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap);
void devm_memunmap_pages(struct device *dev, struct dev_pagemap *pgmap);
struct dev_pagemap *get_dev_pagemap(unsigned long pfn,
diff --git a/mm/memremap.c b/mm/memremap.c
index 4e11da4ecab9..9e163fe367ae 100644
--- a/mm/memremap.c
+++ b/mm/memremap.c
@@ -102,9 +102,8 @@ static void dev_pagemap_cleanup(struct dev_pagemap *pgmap)
pgmap->ref = NULL;
}
-static void devm_memremap_pages_release(void *data)
+void memunmap_pages(struct dev_pagemap *pgmap)
{
- struct dev_pagemap *pgmap = data;
struct resource *res = &pgmap->res;
unsigned long pfn;
int nid;
@@ -134,6 +133,12 @@ static void devm_memremap_pages_release(void *data)
WARN_ONCE(pgmap->altmap.alloc, "failed to free all reserved pages\n");
devmap_managed_enable_put();
}
+EXPORT_SYMBOL_GPL(memunmap_pages);
+
+static void devm_memremap_pages_release(void *data)
+{
+ memunmap_pages(data);
+}
static void dev_pagemap_percpu_release(struct percpu_ref *ref)
{
@@ -143,27 +148,12 @@ static void dev_pagemap_percpu_release(struct percpu_ref *ref)
complete(&pgmap->done);
}
-/**
- * devm_memremap_pages - remap and provide memmap backing for the given resource
- * @dev: hosting device for @res
- * @pgmap: pointer to a struct dev_pagemap
- *
- * Notes:
- * 1/ At a minimum the res and type members of @pgmap must be initialized
- * by the caller before passing it to this function
- *
- * 2/ The altmap field may optionally be initialized, in which case
- * PGMAP_ALTMAP_VALID must be set in pgmap->flags.
- *
- * 3/ The ref field may optionally be provided, in which pgmap->ref must be
- * 'live' on entry and will be killed and reaped at
- * devm_memremap_pages_release() time, or if this routine fails.
- *
- * 4/ res is expected to be a host memory range that could feasibly be
- * treated as a "System RAM" range, i.e. not a device mmio range, but
- * this is not enforced.
+/*
+ * Not device managed version of dev_memremap_pages, undone by
+ * memunmap_pages(). Please use dev_memremap_pages if you have a struct
+ * device available.
*/
-void *devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap)
+void *memremap_pages(struct dev_pagemap *pgmap, int nid)
{
struct resource *res = &pgmap->res;
struct dev_pagemap *conflict_pgmap;
@@ -174,7 +164,7 @@ void *devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap)
.altmap = pgmap_altmap(pgmap),
};
pgprot_t pgprot = PAGE_KERNEL;
- int error, nid, is_ram;
+ int error, is_ram;
bool need_devmap_managed = true;
switch (pgmap->type) {
@@ -229,7 +219,7 @@ void *devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap)
conflict_pgmap = get_dev_pagemap(PHYS_PFN(res->start), NULL);
if (conflict_pgmap) {
- dev_WARN(dev, "Conflicting mapping in same section\n");
+ WARN(1, "Conflicting mapping in same section\n");
put_dev_pagemap(conflict_pgmap);
error = -ENOMEM;
goto err_array;
@@ -237,7 +227,7 @@ void *devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap)
conflict_pgmap = get_dev_pagemap(PHYS_PFN(res->end), NULL);
if (conflict_pgmap) {
- dev_WARN(dev, "Conflicting mapping in same section\n");
+ WARN(1, "Conflicting mapping in same section\n");
put_dev_pagemap(conflict_pgmap);
error = -ENOMEM;
goto err_array;
@@ -258,7 +248,6 @@ void *devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap)
if (error)
goto err_array;
- nid = dev_to_node(dev);
if (nid < 0)
nid = numa_mem_id();
@@ -314,12 +303,6 @@ void *devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap)
PHYS_PFN(res->start),
PHYS_PFN(resource_size(res)), pgmap);
percpu_ref_get_many(pgmap->ref, pfn_end(pgmap) - pfn_first(pgmap));
-
- error = devm_add_action_or_reset(dev, devm_memremap_pages_release,
- pgmap);
- if (error)
- return ERR_PTR(error);
-
return __va(res->start);
err_add_memory:
@@ -334,6 +317,43 @@ void *devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap)
devmap_managed_enable_put();
return ERR_PTR(error);
}
+EXPORT_SYMBOL_GPL(memremap_pages);
+
+/**
+ * devm_memremap_pages - remap and provide memmap backing for the given resource
+ * @dev: hosting device for @res
+ * @pgmap: pointer to a struct dev_pagemap
+ *
+ * Notes:
+ * 1/ At a minimum the res and type members of @pgmap must be initialized
+ * by the caller before passing it to this function
+ *
+ * 2/ The altmap field may optionally be initialized, in which case
+ * PGMAP_ALTMAP_VALID must be set in pgmap->flags.
+ *
+ * 3/ The ref field may optionally be provided, in which pgmap->ref must be
+ * 'live' on entry and will be killed and reaped at
+ * devm_memremap_pages_release() time, or if this routine fails.
+ *
+ * 4/ res is expected to be a host memory range that could feasibly be
+ * treated as a "System RAM" range, i.e. not a device mmio range, but
+ * this is not enforced.
+ */
+void *devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap)
+{
+ int error;
+ void *ret;
+
+ ret = memremap_pages(pgmap, dev_to_node(dev));
+ if (IS_ERR(ret))
+ return ret;
+
+ error = devm_add_action_or_reset(dev, devm_memremap_pages_release,
+ pgmap);
+ if (error)
+ return ERR_PTR(error);
+ return ret;
+}
EXPORT_SYMBOL_GPL(devm_memremap_pages);
void devm_memunmap_pages(struct device *dev, struct dev_pagemap *pgmap)
--
2.20.1