Take the RCU critical sections into the callers of to_vmem_altmap so that
we can read the page map inside the critical section. Also rename the
remaining helper to __lookup_dev_pagemap to fit into the current naming
scheme.
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
---
arch/powerpc/mm/init_64.c | 5 ++-
arch/x86/mm/init_64.c | 5 ++-
include/linux/memremap.h | 15 ++++----
kernel/memremap.c | 90 +++++++++++++++++++++++++----------------------
4 files changed, 61 insertions(+), 54 deletions(-)
diff --git a/arch/powerpc/mm/init_64.c b/arch/powerpc/mm/init_64.c
index 872eed5a0867..7a78e432813f 100644
--- a/arch/powerpc/mm/init_64.c
+++ b/arch/powerpc/mm/init_64.c
@@ -201,11 +201,14 @@ int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node)
continue;
/* pgmap lookups only work at section boundaries */
- pgmap = to_vmem_altmap(SECTION_ALIGN_DOWN(start));
+ rcu_read_lock();
+ pgmap = __lookup_dev_pagemap((struct page *)
+ SECTION_ALIGN_DOWN(start));
if (pgmap)
p = dev_pagemap_alloc_block_buf(pgmap, page_size);
else
p = vmemmap_alloc_block_buf(page_size, node);
+ rcu_read_unlock();
if (!p)
return -ENOMEM;
diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
index bc01dc3b07a5..d07b173d277c 100644
--- a/arch/x86/mm/init_64.c
+++ b/arch/x86/mm/init_64.c
@@ -1409,9 +1409,11 @@ static int __meminit vmemmap_populate_hugepages(unsigned long start,
int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node)
{
- struct dev_pagemap *pgmap = to_vmem_altmap(start);
+ struct dev_pagemap *pgmap;
int err;
+ rcu_read_lock();
+ pgmap = __lookup_dev_pagemap((struct page *)start);
if (boot_cpu_has(X86_FEATURE_PSE))
err = vmemmap_populate_hugepages(start, end, node, pgmap);
else if (pgmap) {
@@ -1420,6 +1422,7 @@ int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node)
err = -ENOMEM;
} else
err = vmemmap_populate_basepages(start, end, node);
+ rcu_read_unlock();
if (!err)
sync_global_pgds(start, end - 1);
return err;
diff --git a/include/linux/memremap.h b/include/linux/memremap.h
index 7bea9a1b75f7..a7faf9174977 100644
--- a/include/linux/memremap.h
+++ b/include/linux/memremap.h
@@ -10,15 +10,6 @@
struct resource;
struct device;
-#ifdef CONFIG_ZONE_DEVICE
-struct dev_pagemap *to_vmem_altmap(unsigned long memmap_start);
-#else
-static inline struct dev_pagemap *to_vmem_altmap(unsigned long memmap_start)
-{
- return NULL;
-}
-#endif
-
/*
* Specialize ZONE_DEVICE memory into multiple types each having differents
* usage.
@@ -124,6 +115,7 @@ struct dev_pagemap {
#ifdef CONFIG_ZONE_DEVICE
void *devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap);
+struct dev_pagemap *__lookup_dev_pagemap(struct page *start_page);
struct dev_pagemap *get_dev_pagemap(unsigned long pfn,
struct dev_pagemap *pgmap);
static inline bool is_zone_device_page(const struct page *page);
@@ -144,6 +136,11 @@ static inline void *devm_memremap_pages(struct device *dev,
return ERR_PTR(-ENXIO);
}
+static inline struct dev_pagemap *__lookup_dev_pagemap(struct page *start_page)
+{
+ return NULL;
+}
+
static inline struct dev_pagemap *get_dev_pagemap(unsigned long pfn,
struct dev_pagemap *pgmap)
{
diff --git a/kernel/memremap.c b/kernel/memremap.c
index 01529eeb06ad..b3e8b5028bec 100644
--- a/kernel/memremap.c
+++ b/kernel/memremap.c
@@ -241,6 +241,16 @@ int device_private_entry_fault(struct vm_area_struct *vma,
EXPORT_SYMBOL(device_private_entry_fault);
#endif /* CONFIG_DEVICE_PRIVATE */
+struct dev_pagemap *__lookup_dev_pagemap(struct page *start_page)
+{
+ struct dev_pagemap *pgmap;
+
+ pgmap = radix_tree_lookup(&pgmap_radix, page_to_pfn(start_page));
+ if (!pgmap || !pgmap->base_pfn)
+ return NULL;
+ return pgmap;
+}
+
static unsigned long __dev_pagemap_offset(struct dev_pagemap *pgmap)
{
/* number of pfns from base where pfn_to_page() is valid */
@@ -249,7 +259,16 @@ static unsigned long __dev_pagemap_offset(struct dev_pagemap *pgmap)
unsigned long dev_pagemap_offset(struct page *page)
{
- return __dev_pagemap_offset(to_vmem_altmap((uintptr_t)page));
+ struct dev_pagemap *pgmap;
+ unsigned long ret = 0;
+
+ rcu_read_lock();
+ pgmap = __lookup_dev_pagemap(page);
+ if (pgmap)
+ ret = __dev_pagemap_offset(pgmap);
+ rcu_read_unlock();
+
+ return ret;
}
static void pgmap_radix_release(struct resource *res)
@@ -430,66 +449,51 @@ EXPORT_SYMBOL(devm_memremap_pages);
int dev_pagemap_add_pages(unsigned long phys_start_pfn, unsigned nr_pages)
{
struct dev_pagemap *pgmap;
+ int ret = 0;
- pgmap = to_vmem_altmap((unsigned long) pfn_to_page(phys_start_pfn));
- if (!pgmap)
- return 0;
+ rcu_read_lock();
+ pgmap = __lookup_dev_pagemap(pfn_to_page(phys_start_pfn));
+ if (pgmap) {
+ if (pgmap->base_pfn != phys_start_pfn ||
+ __dev_pagemap_offset(pgmap) > nr_pages) {
+ pr_warn_once("memory add fail, invalid map\n");
+ ret = -EINVAL;
+ }
- if (pgmap->base_pfn != phys_start_pfn ||
- __dev_pagemap_offset(pgmap) > nr_pages) {
- pr_warn_once("memory add fail, invalid map\n");
- return -EINVAL;
+ pgmap->alloc = 0;
}
-
- pgmap->alloc = 0;
- return 0;
+ rcu_read_unlock();
+ return ret;
}
unsigned long dev_pagemap_start_pfn(unsigned long start_pfn)
{
- struct dev_pagemap *pgmap = to_vmem_altmap(__pfn_to_phys(start_pfn));
+ struct page *page = (struct page *)__pfn_to_phys(start_pfn);
+ struct dev_pagemap *pgmap;
+ unsigned long ret = 0;
+ rcu_read_lock();
+ pgmap = __lookup_dev_pagemap(page);
if (pgmap && start_pfn == pgmap->base_pfn)
- return pgmap->reserve;
- return 0;
+ ret = pgmap->reserve;
+ rcu_read_unlock();
+ return ret;
}
bool dev_pagemap_free_pages(struct page *page, unsigned nr_pages)
{
- struct dev_pagemap *pgmap = to_vmem_altmap((uintptr_t)page);
-
- if (!pgmap)
- return false;
- pgmap->alloc -= nr_pages;
- return true;
-}
-
-struct dev_pagemap *to_vmem_altmap(unsigned long memmap_start)
-{
- /*
- * 'memmap_start' is the virtual address for the first "struct
- * page" in this range of the vmemmap array. In the case of
- * CONFIG_SPARSEMEM_VMEMMAP a page_to_pfn conversion is simple
- * pointer arithmetic, so we can perform this to_vmem_altmap()
- * conversion without concern for the initialization state of
- * the struct page fields.
- */
- struct page *page = (struct page *) memmap_start;
struct dev_pagemap *pgmap;
+ bool ret = false;
- /*
- * Unconditionally retrieve a dev_pagemap associated with the
- * given physical address, this is only for use in the
- * arch_{add|remove}_memory() for setting up and tearing down
- * the memmap.
- */
rcu_read_lock();
- pgmap = radix_tree_lookup(&pgmap_radix, page_to_pfn(page));
+ pgmap = __lookup_dev_pagemap(page);
+ if (pgmap) {
+ pgmap->alloc -= nr_pages;
+ ret = true;
+ }
rcu_read_unlock();
- if (!pgmap || !pgmap->base_pfn)
- return NULL;
- return pgmap;
+ return ret;
}
/**
--
2.14.2
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