Commit cc8d1b09 authored by Liam R. Howlett's avatar Liam R. Howlett Committed by Andrew Morton
Browse files

mmap: clean up mmap_region() unrolling 

Move logic of unrolling to the error path as apposed to duplicating it
within the function body.  This reduces the potential of missing an update
to one path when making changes.

Link: https://lkml.kernel.org/r/20230120162650.984577-38-Liam.Howlett@oracle.com


Signed-off-by: default avatarLiam R. Howlett <Liam.Howlett@oracle.com>
Cc: Li Zetao <lizetao1@huawei.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent b373037f

mm/mmap.c

+18 −27
Original line number Diff line number Diff line
@@ -2601,12 +2601,11 @@ unsigned long mmap_region(struct file *file, unsigned long addr, 
		 * Expansion is handled above, merging is handled below.

		 * Drivers should not alter the address of the VMA.

		 */

		if (WARN_ON((addr != vma->vm_start))) {

		error = -EINVAL;

		if (WARN_ON((addr != vma->vm_start)))

			goto close_and_free_vma;

		}

		vma_iter_set(&vmi, addr);



		vma_iter_set(&vmi, addr);

		/*

		 * If vm_flags changed after call_mmap(), we should try merge

		 * vma again as we may succeed this time.
@@ -2653,25 +2652,13 @@ unsigned long mmap_region(struct file *file, unsigned long addr, 
	}



	/* Allow architectures to sanity-check the vm_flags */

	if (!arch_validate_flags(vma->vm_flags)) {

	error = -EINVAL;

		if (file)

	if (!arch_validate_flags(vma->vm_flags))

		goto close_and_free_vma;

		else if (vma->vm_file)

			goto unmap_and_free_vma;

		else

			goto free_vma;

	}



	if (vma_iter_prealloc(&vmi)) {

	error = -ENOMEM;

		if (file)

	if (vma_iter_prealloc(&vmi))

		goto close_and_free_vma;

		else if (vma->vm_file)

			goto unmap_and_free_vma;

		else

			goto free_vma;

	}



	if (vma->vm_file)

		i_mmap_lock_write(vma->vm_file->f_mapping);
@@ -2730,14 +2717,18 @@ unsigned long mmap_region(struct file *file, unsigned long addr, 
	return addr;



close_and_free_vma:

	if (vma->vm_ops && vma->vm_ops->close)

	if (file && vma->vm_ops && vma->vm_ops->close)

		vma->vm_ops->close(vma);



	if (file || vma->vm_file) {

unmap_and_free_vma:

		fput(vma->vm_file);

		vma->vm_file = NULL;



		/* Undo any partial mapping done by a device driver. */

	unmap_region(mm, &mm->mm_mt, vma, prev, next, vma->vm_start, vma->vm_end);

		unmap_region(mm, &mm->mm_mt, vma, prev, next, vma->vm_start,

			     vma->vm_end);

	}

	if (file && (vm_flags & VM_SHARED))

		mapping_unmap_writable(file->f_mapping);

free_vma: