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Message-Id: <1453948866-22808-4-git-send-email-david@gibson.dropbear.id.au>
Date: Thu, 28 Jan 2016 13:41:05 +1100
From: David Gibson <david@...son.dropbear.id.au>
To: mpe@...erman.id.au, benh@...nel.crashing.org
Cc: paulus@...ba.org, linuxppc-dev@...ts.ozlabs.org,
linux-kernel@...r.kernel.org,
David Gibson <david@...son.dropbear.id.au>
Subject: [PATCH 3/4] arch/powerpc: 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.
Signed-off-by: David Gibson <david@...son.dropbear.id.au>
---
arch/powerpc/mm/hash_utils_64.c | 13 ++++++++++---
arch/powerpc/mm/init_64.c | 38 ++++++++++++++++++++++++++------------
arch/powerpc/mm/mem.c | 10 ++++++++--
3 files changed, 44 insertions(+), 17 deletions(-)
diff --git a/arch/powerpc/mm/hash_utils_64.c b/arch/powerpc/mm/hash_utils_64.c
index 0737eae..e88a86e 100644
--- a/arch/powerpc/mm/hash_utils_64.c
+++ b/arch/powerpc/mm/hash_utils_64.c
@@ -635,9 +635,16 @@ static unsigned long __init htab_get_table_size(void)
#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..0cc944b 100644
--- a/arch/powerpc/mm/init_64.c
+++ b/arch/powerpc/mm/init_64.c
@@ -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",
+ rc);
+ return -EFAULT;
+ }
}
return 0;
diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c
index 22d94c3..1593f89 100644
--- a/arch/powerpc/mm/mem.c
+++ b/arch/powerpc/mm/mem.c
@@ -119,12 +119,18 @@ int arch_add_memory(int nid, u64 start, u64 size, bool for_device)
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 crate mapping for hot added memory 0x%llx..0x%llx: %d",
+ start, start + size, rc);
+ return -EFAULT;
+ }
/* this should work for most non-highmem platforms */
zone = pgdata->node_zones +
--
2.5.0
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