Commit 1dace6c6 authored by David Gibson's avatar David Gibson Committed by Michael Ellerman
Browse files

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: default avatarDavid Gibson <david@gibson.dropbear.id.au>
Reviewed-by: default avatarPaul Mackerras <paulus@samba.org>
Reviewed-by: default avatarAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
parent 27828f98

arch/powerpc/mm/hash_utils_64.c

+10 −5
Original line number Diff line number Diff line
@@ -263,7 +263,6 @@ int htab_bolt_mapping(unsigned long vstart, unsigned long vend, 
	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 @@ int htab_remove_mapping(unsigned long vstart, unsigned long vend, 


	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 @@ 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),

	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)

arch/powerpc/mm/init_64.c

+26 −12
Original line number Diff line number Diff line
@@ -188,7 +188,7 @@ static int __meminit vmemmap_populated(unsigned long start, int page_size) 
 */



#ifdef CONFIG_PPC_BOOK3E

static void __meminit vmemmap_create_mapping(unsigned long start,

static int __meminit vmemmap_create_mapping(unsigned long start,

					    unsigned long page_size,

					    unsigned long phys)

{
@@ -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,

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,

	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(mapped < 0);

		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;

arch/powerpc/mm/mem.c

+8 −2
Original line number Diff line number Diff line
@@ -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 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 +

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