x86/mm: Cleanup prctl_enable_tagged_addr() nr_bits error checking

There are two separate checks in prctl_enable_tagged_addr() that nr_bits
is in the correct range. The checks are arranged such the correct case
is sandwiched between both error cases, which do exactly the same thing.

Simplify the if condition and pull the correct case outside with the
rest of the success code path.

Signed-off-by: Yosry Ahmed <yosryahmed@google.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Link: https://lore.kernel.org/all/20240702132139.3332013-4-yosryahmed%40google.com

diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index e9f7cfdb94202df91c72362e939f8d1abd458e7f..226472332a70dd02902f81c21207d770e698aeed 100644 (file)
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -812,6 +812,9 @@ static void enable_lam_func(void *__mm)
 
 static void mm_enable_lam(struct mm_struct *mm)
 {
+       mm->context.lam_cr3_mask = X86_CR3_LAM_U57;
+       mm->context.untag_mask =  ~GENMASK(62, 57);
+
        /*
         * Even though the process must still be single-threaded at this
         * point, kernel threads may be using the mm.  IPI those kernel
@@ -846,13 +849,7 @@ static int prctl_enable_tagged_addr(struct mm_struct *mm, unsigned long nr_bits)
                return -EBUSY;
        }
 
-       if (!nr_bits) {
-               mmap_write_unlock(mm);
-               return -EINVAL;
-       } else if (nr_bits <= LAM_U57_BITS) {
-               mm->context.lam_cr3_mask = X86_CR3_LAM_U57;
-               mm->context.untag_mask =  ~GENMASK(62, 57);
-       } else {
+       if (!nr_bits || nr_bits > LAM_U57_BITS) {
                mmap_write_unlock(mm);
                return -EINVAL;
        }