Memory hotplug / ACPI: Simplify memory removal
Now that the memory offlining should be taken care of by the
companion device offlining code in acpi_scan_hot_remove(), the
ACPI memory hotplug driver doesn't need to offline it in
remove_memory() any more. Moreover, since the return value of
remove_memory() is not used, it's better to make it be a void
function and trigger a BUG() if the memory scheduled for removal is
not offline.
Change the code in accordance with the above observations.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Toshi Kani <toshi.kani@hp.com>
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index a39841d..7026fbc 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -1670,24 +1670,6 @@
}
#ifdef CONFIG_MEMORY_HOTREMOVE
-/**
- * offline_memory_block_cb - callback function for offlining memory block
- * @mem: the memory block to be offlined
- * @arg: buffer to hold error msg
- *
- * Always return 0, and put the error msg in arg if any.
- */
-static int offline_memory_block_cb(struct memory_block *mem, void *arg)
-{
- int *ret = arg;
- int error = device_offline(&mem->dev);
-
- if (error != 0 && *ret == 0)
- *ret = error;
-
- return 0;
-}
-
static int is_memblock_offlined_cb(struct memory_block *mem, void *arg)
{
int ret = !is_memblock_offlined(mem);
@@ -1813,54 +1795,22 @@
}
EXPORT_SYMBOL(try_offline_node);
-int __ref remove_memory(int nid, u64 start, u64 size)
+void __ref remove_memory(int nid, u64 start, u64 size)
{
- unsigned long start_pfn, end_pfn;
- int ret = 0;
- int retry = 1;
-
- start_pfn = PFN_DOWN(start);
- end_pfn = PFN_UP(start + size - 1);
-
- /*
- * When CONFIG_MEMCG is on, one memory block may be used by other
- * blocks to store page cgroup when onlining pages. But we don't know
- * in what order pages are onlined. So we iterate twice to offline
- * memory:
- * 1st iterate: offline every non primary memory block.
- * 2nd iterate: offline primary (i.e. first added) memory block.
- */
-repeat:
- walk_memory_range(start_pfn, end_pfn, &ret,
- offline_memory_block_cb);
- if (ret) {
- if (!retry)
- return ret;
-
- retry = 0;
- ret = 0;
- goto repeat;
- }
+ int ret;
lock_memory_hotplug();
/*
- * we have offlined all memory blocks like this:
- * 1. lock memory hotplug
- * 2. offline a memory block
- * 3. unlock memory hotplug
- *
- * repeat step1-3 to offline the memory block. All memory blocks
- * must be offlined before removing memory. But we don't hold the
- * lock in the whole operation. So we should check whether all
- * memory blocks are offlined.
+ * All memory blocks must be offlined before removing memory. Check
+ * whether all memory blocks in question are offline and trigger a BUG()
+ * if this is not the case.
*/
-
- ret = walk_memory_range(start_pfn, end_pfn, NULL,
+ ret = walk_memory_range(PFN_DOWN(start), PFN_UP(start + size - 1), NULL,
is_memblock_offlined_cb);
if (ret) {
unlock_memory_hotplug();
- return ret;
+ BUG();
}
/* remove memmap entry */
@@ -1871,17 +1821,12 @@
try_offline_node(nid);
unlock_memory_hotplug();
-
- return 0;
}
#else
int offline_pages(unsigned long start_pfn, unsigned long nr_pages)
{
return -EINVAL;
}
-int remove_memory(int nid, u64 start, u64 size)
-{
- return -EINVAL;
-}
+void remove_memory(int nid, u64 start, u64 size) {}
#endif /* CONFIG_MEMORY_HOTREMOVE */
EXPORT_SYMBOL_GPL(remove_memory);