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powerpc/mm: Clean up memory hotplug failure paths

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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>
This commit is contained in:
David Gibson
2016-02-09 13:32:42 +10:00
committed by Michael Ellerman
parent 27828f98a0
commit 1dace6c665
3 changed files with 44 additions and 19 deletions
Download Patch File Download Diff File Expand all files Collapse all files

38
arch/powerpc/mm/init_64.c
View File

@@ -188,9 +188,9 @@ static int __meminit vmemmap_populated(unsigned long start, int page_size)
*/
#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 @@ static void __meminit vmemmap_create_mapping(unsigned long start,
*/
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 @@ static void vmemmap_remove_mapping(unsigned long start,
}
#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 @@ int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node)
for (; start < end; start += page_size) {
void *p;
int rc;
if (vmemmap_populated(start, page_size))
continue;
@@ -317,7 +325,13 @@ int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node)
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;