linux-kernel - [PATCH] mmap_region: cleanup, remove unneeded file != NULL check

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Date:	Sun, 3 Feb 2008 21:01:22 +0300
From:	Oleg Nesterov <oleg@...sign.ru>
To:	Andrew Morton <akpm@...ux-foundation.org>
Cc:	Miklos Szeredi <mszeredi@...e.cz>, linux-kernel@...r.kernel.org
Subject: [PATCH] mmap_region: cleanup, remove unneeded file != NULL check

mmap_region() checks "file != NULL" when we know "file && vma_merge() == T".
Also, swap these if/else branches, imho make the code a bit more readable.

Signed-off-by: Oleg Nesterov <oleg@...sign.ru>

--- MM/mm/mmap.c~1_MMAP	2008-01-27 17:09:47.000000000 +0300
+++ MM/mm/mmap.c	2008-02-03 20:49:39.000000000 +0300
@@ -1189,22 +1189,20 @@ munmap_back:
 	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))) {
+		mpol_free(vma_policy(vma));
+		kmem_cache_free(vm_area_cachep, vma);
+		if (correct_wcount)
+			atomic_inc(&inode->i_writecount);
+		fput(file);
+	} else {
 		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);
 	}
-out:	
+out:
 	mm->total_vm += len >> PAGE_SHIFT;
 	vm_stat_account(mm, vm_flags, file, len >> PAGE_SHIFT);
 	if (vm_flags & VM_LOCKED) {

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