mm: remove can_modify_mm()

With no more users in the tree, we can finally remove can_modify_mm().

Link: https://lkml.kernel.org/r/20240817-mseal-depessimize-v3-6-d8d2e037df30@gmail.comSigned-off-by: Pedro Falcato <pedro.falcato@gmail.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Jeff Xu <jeffxu@chromium.org>
Cc: Kees Cook <kees@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/internal.h

@@ -1359,25 +1359,11 @@ static inline int can_do_mseal(unsigned long flags)
 	return 0;
 }
 
-bool can_modify_mm(struct mm_struct *mm, unsigned long start,
-		unsigned long end);
 #else
 static inline int can_do_mseal(unsigned long flags)
 {
 	return -EPERM;
 }
-
-static inline bool can_modify_mm(struct mm_struct *mm, unsigned long start,
-		unsigned long end)
-{
-	return true;
-}
-
-static inline bool can_modify_mm_madv(struct mm_struct *mm, unsigned long start,
-		unsigned long end, int behavior)
-{
-	return true;
-}
 #endif
 
 #ifdef CONFIG_SHRINKER_DEBUG

mm/mseal.c

@@ -53,27 +53,6 @@ static bool is_ro_anon(struct vm_area_struct *vma)
 	return false;
 }
 
-/*
- * Check if the vmas of a memory range are allowed to be modified.
- * the memory ranger can have a gap (unallocated memory).
- * return true, if it is allowed.
- */
-bool can_modify_mm(struct mm_struct *mm, unsigned long start, unsigned long end)
-{
-	struct vm_area_struct *vma;
-
-	VMA_ITERATOR(vmi, mm, start);
-
-	/* going through each vma to check. */
-	for_each_vma_range(vmi, vma, end) {
-		if (unlikely(!can_modify_vma(vma)))
-			return false;
-	}
-
-	/* Allow by default. */
-	return true;
-}
-
 /*
  * Check if a vma is allowed to be modified by madvise.
  */