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/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;