um: Update min_low_pfn to match changes in uml_reserved

[ Upstream commit e82cf3051e6193f61e03898f8dba035199064d36 ]

When uml_reserved is updated, min_low_pfn must also be updated
accordingly. Otherwise, min_low_pfn will not accurately reflect
the lowest available PFN.

Signed-off-by: Tiwei Bie <tiwei.btw@antgroup.com>
Link: https://patch.msgid.link/20250221041855.1156109-1-tiwei.btw@antgroup.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/arch/um/kernel/mem.c b/arch/um/kernel/mem.c
index 38d5a71a579bcb56595d64f07159f5f321c6662f..f6c766b2bdf5e4343545c2ba5c48840c603e846e 100644 (file)
--- a/arch/um/kernel/mem.c
+++ b/arch/um/kernel/mem.c
@@ -68,6 +68,7 @@ void __init mem_init(void)
        map_memory(brk_end, __pa(brk_end), uml_reserved - brk_end, 1, 1, 0);
        memblock_free((void *)brk_end, uml_reserved - brk_end);
        uml_reserved = brk_end;
+       min_low_pfn = PFN_UP(__pa(uml_reserved));
 
        /* this will put all low memory onto the freelists */
        memblock_free_all();