linux-kernel - lib/bitmap.c: quiet sparse noise about address space

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Date:	Wed, 31 Aug 2011 18:13:38 -0700
From:	H Hartley Sweeten <hartleys@...ionengravers.com>
To:	Linux Kernel <linux-kernel@...r.kernel.org>
CC:	<akpm@...ux-foundation.org>, <len.brown@...el.com>,
	<ying.huang@...el.com>, <andy.shevchenko@...il.com>,
	<ak@...ux.intel.com>
Subject: lib/bitmap.c: quiet sparse noise about address space

The functions __bitmap_parse and __bitmap_parselist both take a pointer
to a kernel buffer as a parameter and then cast it to a pointer to user
buffer for use in cases when the parameter is_user indicates that the
buffer is actually located in user space. This casting, and the casts
in the callers, results in sparse noise like the following:

	warning: incorrect type in initializer (different address spaces)
	  expected char const [noderef] <asn:1>*ubuf
	  got char const *buf
	warning: cast removes address space of expression

Since these casts are intentional, use __force to quiet the noise.

Signed-off-by: H Hartley Sweeten <hsweeten@...ionengravers.com>
Cc: Andrew Morton <akpm@...ux-foundation.org>
Cc: Len Brown <len.brown@...el.com>
Cc: Huang Ying <ying.huang@...el.com>
Cc: Andy Shevchenko <andy.shevchenko@...il.com>
Cc: Andi Kleen <ak@...ux.intel.com>

---

diff --git a/lib/bitmap.c b/lib/bitmap.c
index 2f4412e..b7b71bd 100644
--- a/lib/bitmap.c
+++ b/lib/bitmap.c
@@ -419,7 +419,7 @@ int __bitmap_parse(const char *buf, unsigned int buflen,
 {
 	int c, old_c, totaldigits, ndigits, nchunks, nbits;
 	u32 chunk;
-	const char __user *ubuf = buf;
+	const char __user __force *ubuf = buf;
 
 	bitmap_zero(maskp, nmaskbits);
 
@@ -504,7 +504,9 @@ int bitmap_parse_user(const char __user *ubuf,
 {
 	if (!access_ok(VERIFY_READ, ubuf, ulen))
 		return -EFAULT;
-	return __bitmap_parse((const char *)ubuf, ulen, 1, maskp, nmaskbits);
+	return __bitmap_parse((const char __force *)ubuf,
+				ulen, 1, maskp, nmaskbits);
+
 }
 EXPORT_SYMBOL(bitmap_parse_user);
 
@@ -594,7 +596,7 @@ static int __bitmap_parselist(const char *buf, unsigned int buflen,
 {
 	unsigned a, b;
 	int c, old_c, totaldigits;
-	const char __user *ubuf = buf;
+	const char __user __force *ubuf = buf;
 	int exp_digit, in_range;
 
 	totaldigits = c = 0;
@@ -694,7 +696,7 @@ int bitmap_parselist_user(const char __user *ubuf,
 {
 	if (!access_ok(VERIFY_READ, ubuf, ulen))
 		return -EFAULT;
-	return __bitmap_parselist((const char *)ubuf,
+	return __bitmap_parselist((const char __force *)ubuf,
 					ulen, 1, maskp, nmaskbits);
 }
 EXPORT_SYMBOL(bitmap_parselist_user);
--
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