[PATCH 1/3] vmalloc: ignore vmalloc area holes in vwrite()

[Wu Fengguang <fengguang.wu@intel.com>]

[-- Attachment #1: vwrite-ret.patch --]
[-- Type: text/plain, Size: 1970 bytes --]

Siliently ignore all vmalloc area holes in vwrite(),
and report success to the caller even if nothing is written.

CC: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
---
 mm/vmalloc.c |   13 ++-----------
 1 file changed, 2 insertions(+), 11 deletions(-)

--- linux-mm.orig/mm/vmalloc.c	2009-09-15 10:08:33.000000000 +0800
+++ linux-mm/mm/vmalloc.c	2009-09-15 10:14:18.000000000 +0800
@@ -1805,10 +1805,8 @@ finished:
  *	@addr:		vm address.
  *	@count:		number of bytes to be read.
  *
- *	Returns # of bytes which addr and buf should be incresed.
+ *	Returns # of bytes which addr and buf should be increased.
  *	(same number to @count).
- *	If [addr...addr+count) doesn't includes any intersect with valid
- *	vmalloc area, returns 0.
  *
  *	This function checks that addr is a valid vmalloc'ed area, and
  *	copy data from a buffer to the given addr. If specified range of
@@ -1816,8 +1814,6 @@ finished:
  *	proper area of @buf. If there are memory holes, no copy to hole.
  *	IOREMAP area is treated as memory hole and no copy is done.
  *
- *	If [addr...addr+count) doesn't includes any intersects with alive
- *	vm_struct area, returns 0.
  *	@buf should be kernel's buffer. Because	this function uses KM_USER0,
  *	the caller should guarantee KM_USER0 is not used.
  *
@@ -1834,7 +1830,6 @@ long vwrite(char *buf, char *addr, unsig
 	struct vm_struct *tmp;
 	char *vaddr;
 	unsigned long n, buflen;
-	int copied = 0;
 
 	/* Don't allow overflow */
 	if ((unsigned long) addr + count < count)
@@ -1856,18 +1851,14 @@ long vwrite(char *buf, char *addr, unsig
 		n = vaddr + tmp->size - PAGE_SIZE - addr;
 		if (n > count)
 			n = count;
-		if (!(tmp->flags & VM_IOREMAP)) {
+		if (!(tmp->flags & VM_IOREMAP))
 			aligned_vwrite(buf, addr, n);
-			copied++;
-		}
 		buf += n;
 		addr += n;
 		count -= n;
 	}
 finished:
 	read_unlock(&vmlist_lock);
-	if (!copied)
-		return 0;
 	return buflen;
 }
 

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