@@ -224,6 +224,7 @@ static bool pages_correctly_reserved(unsigned long start_pfn)
/*
* MEMORY_HOTPLUG depends on SPARSEMEM in mm/Kconfig, so it is
* OK to have direct references to sparsemem variables in here.
+ * Must already be protected by mem_hotplug_begin().
*/
static int
memory_block_action(unsigned long phys_index, unsigned long action, int online_type)
@@ -289,6 +290,7 @@ static int memory_subsys_online(struct device *dev)
if (mem->online_type < 0)
mem->online_type = MMOP_ONLINE_KEEP;
+ /* Already under protection of mem_hotplug_begin() */
ret = memory_block_change_state(mem, MEM_ONLINE, MEM_OFFLINE);
/* clear online_type */
@@ -335,11 +337,19 @@ store_mem_state(struct device *dev,
goto err;
}
+ /*
+ * Memory hotplug needs to hold mem_hotplug_begin() for probe to find
+ * the correct memory block to online before doing device_online(dev),
+ * which will take dev->mutex. Take the lock early to prevent an
+ * inversion, memory_subsys_online() callbacks will be implemented by
+ * assuming it's already protected.
+ */
+ mem_hotplug_begin();
+
switch (online_type) {
case MMOP_ONLINE_KERNEL:
case MMOP_ONLINE_MOVABLE:
case MMOP_ONLINE_KEEP:
- /* mem->online_type is protected by device_hotplug_lock */
mem->online_type = online_type;
ret = device_online(&mem->dev);
break;
@@ -350,6 +360,7 @@ store_mem_state(struct device *dev,
ret = -EINVAL; /* should never happen */
}
+ mem_hotplug_done();
err:
unlock_device_hotplug();
@@ -881,6 +881,7 @@ static struct zone * __meminit move_pfn_range(int online_type, int nid,
return zone;
}
+/* Must be protected by mem_hotplug_begin() or a device_lock */
int __ref online_pages(unsigned long pfn, unsigned long nr_pages, int online_type)
{
unsigned long flags;
@@ -904,8 +905,6 @@ int __ref online_pages(unsigned long pfn, unsigned long nr_pages, int online_typ
if (ret)
goto failed_addition;
- mem_hotplug_begin();
-
/*
* If this zone is not populated, then it is not in zonelist.
* This means the page allocator ignores this zone.
@@ -951,7 +950,6 @@ int __ref online_pages(unsigned long pfn, unsigned long nr_pages, int online_typ
if (onlined_pages)
memory_notify(MEM_ONLINE, &arg);
- mem_hotplug_done();
return 0;
failed_addition:
@@ -959,7 +957,6 @@ int __ref online_pages(unsigned long pfn, unsigned long nr_pages, int online_typ
(unsigned long long) pfn << PAGE_SHIFT,
(((unsigned long long) pfn + nr_pages) << PAGE_SHIFT) - 1);
memory_notify(MEM_CANCEL_ONLINE, &arg);
- mem_hotplug_done();
return ret;
}
#endif /* CONFIG_MEMORY_HOTPLUG_SPARSE */
@@ -1170,22 +1167,20 @@ int __ref add_memory_resource(int nid, struct resource *res, bool online)
/* create new memmap entry */
firmware_map_add_hotplug(start, start + size, "System RAM");
- /* device_online() will take the lock when calling online_pages() */
- mem_hotplug_done();
-
/* online pages if requested */
if (online)
walk_memory_range(PFN_DOWN(start), PFN_UP(start + size - 1),
NULL, online_memory_block);
-
- return ret;
+ goto out;
error:
/* rollback pgdat allocation and others */
if (new_pgdat && pgdat)
rollback_node_hotadd(nid, pgdat);
memblock_remove(start, size);
+
+out:
mem_hotplug_done();
return ret;
}
@@ -1626,16 +1621,10 @@ static int __ref __offline_pages(unsigned long start_pfn,
return -EINVAL;
if (!IS_ALIGNED(end_pfn, pageblock_nr_pages))
return -EINVAL;
-
- mem_hotplug_begin();
-
/* This makes hotplug much easier...and readable.
we assume this for now. .*/
- if (!test_pages_in_a_zone(start_pfn, end_pfn, &valid_start,
- &valid_end)) {
- mem_hotplug_done();
+ if (!test_pages_in_a_zone(start_pfn, end_pfn, &valid_start, &valid_end))
return -EINVAL;
- }
zone = page_zone(pfn_to_page(valid_start));
node = zone_to_nid(zone);
@@ -1644,10 +1633,8 @@ static int __ref __offline_pages(unsigned long start_pfn,
/* set above range as isolated */
ret = start_isolate_page_range(start_pfn, end_pfn,
MIGRATE_MOVABLE, true);
- if (ret) {
- mem_hotplug_done();
+ if (ret)
return ret;
- }
arg.start_pfn = start_pfn;
arg.nr_pages = nr_pages;
@@ -1718,7 +1705,6 @@ static int __ref __offline_pages(unsigned long start_pfn,
writeback_set_ratelimit();
memory_notify(MEM_OFFLINE, &arg);
- mem_hotplug_done();
return 0;
failed_removal:
@@ -1728,10 +1714,10 @@ static int __ref __offline_pages(unsigned long start_pfn,
memory_notify(MEM_CANCEL_OFFLINE, &arg);
/* pushback to free area */
undo_isolate_page_range(start_pfn, end_pfn, MIGRATE_MOVABLE);
- mem_hotplug_done();
return ret;
}
+/* Must be protected by mem_hotplug_begin() or a device_lock */
int offline_pages(unsigned long start_pfn, unsigned long nr_pages)
{
return __offline_pages(start_pfn, start_pfn + nr_pages);
BugLink: https://bugs.launchpad.net/bugs/1862312 This reverts commit 483735440add2530c03da656ede83ee81414a566. The backport for upstream commit 381eab4a6ee8 (mm/memory_hotplug: fix online/offline_pages called w.o. mem_hotplug_lock) placed the call to mem_hotplug_begin() on the wrong location and caused a regression. Signed-off-by: Marcelo Henrique Cerri <marcelo.cerri@canonical.com> --- drivers/base/memory.c | 13 ++++++++++++- mm/memory_hotplug.c | 28 +++++++--------------------- 2 files changed, 19 insertions(+), 22 deletions(-)