powerpc/mm: Clean up memory hotplug failure paths
This makes a number of cleanups to handling of mapping failures during
memory hotplug on Power:
For errors creating the linear mapping for the hot-added region:
* This is now reported with EFAULT which is more appropriate than the
previous EINVAL (the failure is unlikely to be related to the
function's parameters)
* An error in this path now prints a warning message, rather than just
silently failing to add the extra memory.
* Previously a failure here could result in the region being partially
mapped. We now clean up any partial mapping before failing.
For errors creating the vmemmap for the hot-added region:
* This is now reported with EFAULT instead of causing a BUG() - this
could happen for external reason (e.g. full hash table) so it's better
to handle this non-fatally
* An error message is also printed, so the failure won't be silent
* As above a failure could cause a partially mapped region, we now
clean this up. [mpe: move htab_remove_mapping() out of #ifdef
CONFIG_MEMORY_HOTPLUG to enable this]
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: Paul Mackerras <paulus@samba.org>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
diff --git a/arch/powerpc/mm/hash_utils_64.c b/arch/powerpc/mm/hash_utils_64.c
index 44f145a..335cd41 100644
--- a/arch/powerpc/mm/hash_utils_64.c
+++ b/arch/powerpc/mm/hash_utils_64.c
@@ -263,7 +263,6 @@
return ret < 0 ? ret : 0;
}
-#ifdef CONFIG_MEMORY_HOTPLUG
int htab_remove_mapping(unsigned long vstart, unsigned long vend,
int psize, int ssize)
{
@@ -290,7 +289,6 @@
return ret;
}
-#endif /* CONFIG_MEMORY_HOTPLUG */
static int __init htab_dt_scan_seg_sizes(unsigned long node,
const char *uname, int depth,
@@ -640,9 +638,16 @@
#ifdef CONFIG_MEMORY_HOTPLUG
int create_section_mapping(unsigned long start, unsigned long end)
{
- return htab_bolt_mapping(start, end, __pa(start),
- pgprot_val(PAGE_KERNEL), mmu_linear_psize,
- mmu_kernel_ssize);
+ int rc = htab_bolt_mapping(start, end, __pa(start),
+ pgprot_val(PAGE_KERNEL), mmu_linear_psize,
+ mmu_kernel_ssize);
+
+ if (rc < 0) {
+ int rc2 = htab_remove_mapping(start, end, mmu_linear_psize,
+ mmu_kernel_ssize);
+ BUG_ON(rc2 && (rc2 != -ENOENT));
+ }
+ return rc;
}
int remove_section_mapping(unsigned long start, unsigned long end)
diff --git a/arch/powerpc/mm/init_64.c b/arch/powerpc/mm/init_64.c
index baa1a23..fbc9448c 100644
--- a/arch/powerpc/mm/init_64.c
+++ b/arch/powerpc/mm/init_64.c
@@ -188,9 +188,9 @@
*/
#ifdef CONFIG_PPC_BOOK3E
-static void __meminit vmemmap_create_mapping(unsigned long start,
- unsigned long page_size,
- unsigned long phys)
+static int __meminit vmemmap_create_mapping(unsigned long start,
+ unsigned long page_size,
+ unsigned long phys)
{
/* Create a PTE encoding without page size */
unsigned long i, flags = _PAGE_PRESENT | _PAGE_ACCESSED |
@@ -208,6 +208,8 @@
*/
for (i = 0; i < page_size; i += PAGE_SIZE)
BUG_ON(map_kernel_page(start + i, phys, flags));
+
+ return 0;
}
#ifdef CONFIG_MEMORY_HOTPLUG
@@ -217,15 +219,20 @@
}
#endif
#else /* CONFIG_PPC_BOOK3E */
-static void __meminit vmemmap_create_mapping(unsigned long start,
- unsigned long page_size,
- unsigned long phys)
+static int __meminit vmemmap_create_mapping(unsigned long start,
+ unsigned long page_size,
+ unsigned long phys)
{
- int mapped = htab_bolt_mapping(start, start + page_size, phys,
- pgprot_val(PAGE_KERNEL),
- mmu_vmemmap_psize,
- mmu_kernel_ssize);
- BUG_ON(mapped < 0);
+ int rc = htab_bolt_mapping(start, start + page_size, phys,
+ pgprot_val(PAGE_KERNEL),
+ mmu_vmemmap_psize, mmu_kernel_ssize);
+ if (rc < 0) {
+ int rc2 = htab_remove_mapping(start, start + page_size,
+ mmu_vmemmap_psize,
+ mmu_kernel_ssize);
+ BUG_ON(rc2 && (rc2 != -ENOENT));
+ }
+ return rc;
}
#ifdef CONFIG_MEMORY_HOTPLUG
@@ -304,6 +311,7 @@
for (; start < end; start += page_size) {
void *p;
+ int rc;
if (vmemmap_populated(start, page_size))
continue;
@@ -317,7 +325,13 @@
pr_debug(" * %016lx..%016lx allocated at %p\n",
start, start + page_size, p);
- vmemmap_create_mapping(start, page_size, __pa(p));
+ rc = vmemmap_create_mapping(start, page_size, __pa(p));
+ if (rc < 0) {
+ pr_warning(
+ "vmemmap_populate: Unable to create vmemmap mapping: %d\n",
+ rc);
+ return -EFAULT;
+ }
}
return 0;
diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c
index d0f0a51..f980da6 100644
--- a/arch/powerpc/mm/mem.c
+++ b/arch/powerpc/mm/mem.c
@@ -119,12 +119,18 @@
struct zone *zone;
unsigned long start_pfn = start >> PAGE_SHIFT;
unsigned long nr_pages = size >> PAGE_SHIFT;
+ int rc;
pgdata = NODE_DATA(nid);
start = (unsigned long)__va(start);
- if (create_section_mapping(start, start + size))
- return -EINVAL;
+ rc = create_section_mapping(start, start + size);
+ if (rc) {
+ pr_warning(
+ "Unable to create mapping for hot added memory 0x%llx..0x%llx: %d\n",
+ start, start + size, rc);
+ return -EFAULT;
+ }
/* this should work for most non-highmem platforms */
zone = pgdata->node_zones +