mm: fix build warning for uninitialized value (1756954c) · Commits · 戴 / test

do_wp_page() sets mmun_called if mmun_start and mmun_end were initialized and, if so, may call mmu_notifier_invalidate_range_end() with these values. This doesn't prevent gcc from emitting a build warning though: mm/memory.c: In function `do_wp_page': mm/memory.c:2530: warning: `mmun_start' may be used uninitialized in this function mm/memory.c:2531: warning: `mmun_end' may be used uninitialized in this function It's much easier to initialize the variables to impossible values and do a simple comparison to determine if they were initialized to remove the bool entirely. Signed-off-by:

David Rientjes <rientjes@google.com> Signed-off-by:

Andrew Morton <akpm@linux-foundation.org> Signed-off-by:

Linus Torvalds <torvalds@linux-foundation.org>

mm/memory.c

+4 −6

Original line number	Diff line number	Diff line
		@@ -2527,9 +2527,8 @@ static int do_wp_page(struct mm_struct mm, struct vm_area_struct vma,
		int ret = 0;
		int page_mkwrite = 0;
		struct page *dirty_page = NULL;
		unsigned long mmun_start; /* For mmu_notifiers */
		unsigned long mmun_end; /* For mmu_notifiers */
		bool mmun_called = false; /* For mmu_notifiers */
		unsigned long mmun_start = 0; /* For mmu_notifiers */
		unsigned long mmun_end = 0; /* For mmu_notifiers */

		old_page = vm_normal_page(vma, address, orig_pte);
		if (!old_page) {
		@@ -2708,8 +2707,7 @@ gotten:
		goto oom_free_new;

		mmun_start = address & PAGE_MASK;
		mmun_end = (address & PAGE_MASK) + PAGE_SIZE;
		mmun_called = true;
		mmun_end = mmun_start + PAGE_SIZE;
		mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end);

		/*
		@@ -2778,7 +2776,7 @@ gotten:
		page_cache_release(new_page);
		unlock:
		pte_unmap_unlock(page_table, ptl);
		if (mmun_called)
		if (mmun_end > mmun_start)
		mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
		if (old_page) {
		/*

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