powerpc/mm: Clean up error handling for htab_remove_mapping

Currently, the only error that htab_remove_mapping() can report is -EINVAL,
if removal of bolted HPTEs isn't implemeted for this platform.  We make
a few clean ups to the handling of this:

 * EINVAL isn't really the right code - there's nothing wrong with the
   function's arguments - use ENODEV instead
 * We were also printing a warning message, but that's a decision better
   left up to the callers, so remove it
 * One caller is vmemmap_remove_mapping(), which will just BUG_ON() on
   error, making the warning message redundant, so no change is needed
   there.
 * The other caller is remove_section_mapping().  This is called in the
   memory hot remove path at a point after vmemmap_remove_mapping() so
   if hpte_removebolted isn't implemented, we'd expect to have already
   BUG()ed anyway.  Put a WARN_ON() here, in lieu of a printk() since this
   really shouldn't be happening.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
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 47a0bc12cb65a4978d317211642d322f9def7e67..70490c41e14e28f7441a3426c17f3b9237769dcd 100644 (file)
--- a/arch/powerpc/mm/hash_utils_64.c
+++ b/arch/powerpc/mm/hash_utils_64.c
@@ -273,11 +273,8 @@ int htab_remove_mapping(unsigned long vstart, unsigned long vend,
        shift = mmu_psize_defs[psize].shift;
        step = 1 << shift;
 
-       if (!ppc_md.hpte_removebolted) {
-               printk(KERN_WARNING "Platform doesn't implement "
-                               "hpte_removebolted\n");
-               return -EINVAL;
-       }
+       if (!ppc_md.hpte_removebolted)
+               return -ENODEV;
 
        for (vaddr = vstart; vaddr < vend; vaddr += step)
                ppc_md.hpte_removebolted(vaddr, psize, ssize);
@@ -641,8 +638,10 @@ int create_section_mapping(unsigned long start, unsigned long end)
 
 int remove_section_mapping(unsigned long start, unsigned long end)
 {
-       return htab_remove_mapping(start, end, mmu_linear_psize,
-                       mmu_kernel_ssize);
+       int rc = htab_remove_mapping(start, end, mmu_linear_psize,
+                                    mmu_kernel_ssize);
+       WARN_ON(rc < 0);
+       return rc;
 }
 #endif /* CONFIG_MEMORY_HOTPLUG */