mm/mmap: use vms accounted pages in mmap_region()

Change from nr_pages variable to vms.nr_accounted for the charged pages
calculation.  This is necessary for a future patch.

This also avoids checking security_vm_enough_memory_mm() if the amount of
memory won't change.

Link: https://lkml.kernel.org/r/20240830040101.822209-18-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Reviewed-by: Kees Cook <kees@kernel.org>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Reviewed-by: Suren Baghdasaryan <surenb@google.com>
Acked-by: Paul Moore <paul@paul-moore.com>	[LSM]
Cc: Kees Cook <kees@kernel.org>
Cc: Bert Karwatzki <spasswolf@web.de>
Cc: Jeff Xu <jeffxu@chromium.org>
Cc: Jiri Olsa <olsajiri@gmail.com>
Cc: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Mark Brown <broonie@kernel.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: "Paul E. McKenney" <paulmck@kernel.org>
Cc: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/mm/mmap.c b/mm/mmap.c
index cd09dd164e852cb68eb77dea83499b4888d6c145..4faadc54e89db953eb4ba47f0fba090f7a06bc56 100644 (file)
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -1414,9 +1414,10 @@ unsigned long mmap_region(struct file *file, unsigned long addr,
         */
        if (accountable_mapping(file, vm_flags)) {
                charged = pglen;
-               charged -= nr_accounted;
-               if (security_vm_enough_memory_mm(mm, charged))
+               charged -= vms.nr_accounted;
+               if (charged && security_vm_enough_memory_mm(mm, charged))
                        goto abort_munmap;
+
                vms.nr_accounted = 0;
                vm_flags |= VM_ACCOUNT;
        }