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Commit 4d3d5b41 authored by Oleg Nesterov's avatar Oleg Nesterov Committed by Linus Torvalds
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mmap_region: cleanup the final vma_merge() related code 



It is not easy to actually understand the "if (!file || !vma_merge())"
code, turn it into "if (file && vma_merge())".  This makes immediately
obvious that the subsequent "if (file)" is superfluous.

As Hugh Dickins pointed out, we can also factor out the ->i_writecount
corrections, and add a small comment about that.

Signed-off-by: default avatarOleg Nesterov <oleg@tv-sign.ru>
Cc: Miklos Szeredi <miklos@szeredi.hu>
Cc: Hugh Dickins <hugh@veritas.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 0dd1334f

mm/mmap.c

+10 −13
Original line number Diff line number Diff line
@@ -1068,7 +1068,6 @@ int vma_wants_writenotify(struct vm_area_struct *vma) 
		mapping_cap_account_dirty(vma->vm_file->f_mapping);

}





unsigned long mmap_region(struct file *file, unsigned long addr,

			  unsigned long len, unsigned long flags,

			  unsigned int vm_flags, unsigned long pgoff,
@@ -1181,21 +1180,19 @@ unsigned long mmap_region(struct file *file, unsigned long addr, 
	if (vma_wants_writenotify(vma))

		vma->vm_page_prot = vm_get_page_prot(vm_flags & ~VM_SHARED);



	if (!file || !vma_merge(mm, prev, addr, vma->vm_end,

	if (file && vma_merge(mm, prev, addr, vma->vm_end,

			vma->vm_flags, NULL, file, pgoff, vma_policy(vma))) {

		file = vma->vm_file;

		vma_link(mm, vma, prev, rb_link, rb_parent);

		if (correct_wcount)

			atomic_inc(&inode->i_writecount);

	} else {

		if (file) {

			if (correct_wcount)

				atomic_inc(&inode->i_writecount);

			fput(file);

		}

		mpol_free(vma_policy(vma));

		kmem_cache_free(vm_area_cachep, vma);

		fput(file);

	} else {

		vma_link(mm, vma, prev, rb_link, rb_parent);

		file = vma->vm_file;

	}



	/* Once vma denies write, undo our temporary denial count */

	if (correct_wcount)

		atomic_inc(&inode->i_writecount);

out:

	mm->total_vm += len >> PAGE_SHIFT;

	vm_stat_account(mm, vm_flags, file, len >> PAGE_SHIFT);