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)