linux/drivers/dax
Tarun Sahu 46e66dab85 dax/kmem: Pass valid argument to memory_group_register_static
memory_group_register_static takes maximum number of pages as the argument
while dev_dax_kmem_probe passes total_len (in bytes) as the argument.

IIUC, I don't see any crash/panic impact as such. As,
memory_group_register_static just set the max_pages limit which is used in
auto_movable_zone_for_pfn to determine the zone.

which might cause these condition to behave differently,

This will be true always so jump will happen to kernel_zone
    ...
    if (!auto_movable_can_online_movable(NUMA_NO_NODE, group, nr_pages))
        goto kernel_zone;

    ...
    kernel_zone:
        return default_kernel_zone_for_pfn(nid, pfn, nr_pages);

Here, In below, zone_intersects compare range will be larger as nr_pages
will be higher (derived from total_len passed in dev_dax_kmem_probe).

    ...
    static struct zone *default_kernel_zone_for_pfn(int nid, unsigned long start_pfn,
    		unsigned long nr_pages)
    {
    	struct pglist_data *pgdat = NODE_DATA(nid);
    	int zid;

    	for (zid = 0; zid < ZONE_NORMAL; zid++) {
    		struct zone *zone = &pgdat->node_zones[zid];

    		if (zone_intersects(zone, start_pfn, nr_pages))
    			return zone;
    	}

    	return &pgdat->node_zones[ZONE_NORMAL];
    }

Incorrect zone will be returned here, which in later time might cause bigger
problem.

Fixes: eedf634aac ("dax/kmem: use a single static memory group for a single probed unit")
Signed-off-by: Tarun Sahu <tsahu@linux.ibm.com>
Link: https://lore.kernel.org/r/20230621155025.370672-1-tsahu@linux.ibm.com
Reviewed-by: Vishal Verma <vishal.l.verma@intel.com>
Signed-off-by: Vishal Verma <vishal.l.verma@intel.com>
2023-06-23 01:32:06 -06:00
..
hmem dax: Cleanup extra dax_region references 2023-06-23 01:03:50 -06:00
pmem dax: Kill DEV_DAX_PMEM_COMPAT 2021-11-24 19:21:35 -08:00
bus.c dax: Cleanup extra dax_region references 2023-06-23 01:03:50 -06:00
bus.h dax: Cleanup extra dax_region references 2023-06-23 01:03:50 -06:00
cxl.c dax: Cleanup extra dax_region references 2023-06-23 01:03:50 -06:00
dax-private.h dax: Introduce alloc_dev_dax_id() 2023-06-23 01:03:50 -06:00
device.c dax: fix missing-prototype warnings 2023-05-18 17:28:07 -07:00
Kconfig cxl for v6.3 2023-02-25 09:19:23 -08:00
kmem.c dax/kmem: Pass valid argument to memory_group_register_static 2023-06-23 01:32:06 -06:00
Makefile cxl/dax: Create dax devices for CXL RAM regions 2023-02-10 17:33:45 -08:00
pmem.c dax: Cleanup extra dax_region references 2023-06-23 01:03:50 -06:00
super.c dax: super.c: fix kernel-doc bad line warning 2023-01-25 12:36:16 -08:00