2 files changed, 20 insertions, 4 deletions

diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
index 80b11521627a..4c46ff6f2242 100644
--- a/drivers/firmware/efi/efi.c
+++ b/drivers/firmware/efi/efi.c
@@ -997,8 +997,8 @@ static int __init efi_memreserve_map_root(void)
 int __ref efi_mem_reserve_persistent(phys_addr_t addr, u64 size)
 {
         struct linux_efi_memreserve *rsv;
-        int rsvsize = EFI_MEMRESERVE_SIZE(1);
-        int rc;
+        unsigned long prsv;
+        int rc, index;
 
         if (efi_memreserve_root == (void *)ULONG_MAX)
                 return -ENODEV;
@@ -1009,11 +1009,24 @@ int __ref efi_mem_reserve_persistent(phys_addr_t addr, u64 size)
                         return rc;
         }
 
-        rsv = kmalloc(rsvsize, GFP_ATOMIC);
+        /* first try to find a slot in an existing linked list entry */
+        for (prsv = efi_memreserve_root->next; prsv; prsv = rsv->next) {
+                rsv = __va(prsv);
+                index = atomic_fetch_add_unless(&rsv->count, 1, rsv->size);
+                if (index < rsv->size) {
+                        rsv->entry[index].base = addr;
+                        rsv->entry[index].size = size;
+
+                        return 0;
+                }
+        }
+
+        /* no slot found - allocate a new linked list entry */
+        rsv = (struct linux_efi_memreserve *)__get_free_page(GFP_ATOMIC);
         if (!rsv)
                 return -ENOMEM;
 
-        rsv->size = 1;
+        rsv->size = EFI_MEMRESERVE_COUNT(PAGE_SIZE);
         atomic_set(&rsv->count, 1);
         rsv->entry[0].base = addr;
         rsv->entry[0].size = size;
diff --git a/include/linux/efi.h b/include/linux/efi.h
index 4f27640fdcdc..becd5d76a207 100644
--- a/include/linux/efi.h
+++ b/include/linux/efi.h
@@ -1724,4 +1724,7 @@ struct linux_efi_memreserve {
 #define EFI_MEMRESERVE_SIZE(count) (sizeof(struct linux_efi_memreserve) + \
         (count) * sizeof(((struct linux_efi_memreserve *)0)->entry[0]))
 
+#define EFI_MEMRESERVE_COUNT(size) (((size) - sizeof(struct linux_efi_memreserve)) \
+        / sizeof(((struct linux_efi_memreserve *)0)->entry[0]))
+
 #endif /* _LINUX_EFI_H */