From: Matt Mackall <mpm@selenic.com>
Date: Wed, 8 Oct 2008 19:51:57 +0000 (-0500)
Subject: SLOB: fix bogus ksize calculation fix
X-Git-Tag: v2.6.27~4
X-Git-Url: http://pilppa.com/gitweb/?a=commitdiff_plain;h=70096a561d1e09120bae1f293f3632cedbfd5c68;p=linux-2.6-omap-h63xx.git

SLOB: fix bogus ksize calculation fix

This fixes the previous fix, which was completely wrong on closer
inspection. This version has been manually tested with a user-space
test harness and generates sane values. A nearly identical patch has
been boot-tested.

The problem arose from changing how kmalloc/kfree handled alignment
padding without updating ksize to match. This brings it in sync.

Signed-off-by: Matt Mackall <mpm@selenic.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---

diff --git a/mm/slob.c b/mm/slob.c
index 62b679dc660..cb675d12679 100644
--- a/mm/slob.c
+++ b/mm/slob.c
@@ -514,9 +514,11 @@ size_t ksize(const void *block)
 		return 0;
 
 	sp = (struct slob_page *)virt_to_page(block);
-	if (slob_page(sp))
-		return (((slob_t *)block - 1)->units - 1) * SLOB_UNIT;
-	else
+	if (slob_page(sp)) {
+		int align = max(ARCH_KMALLOC_MINALIGN, ARCH_SLAB_MINALIGN);
+		unsigned int *m = (unsigned int *)(block - align);
+		return SLOB_UNITS(*m) * SLOB_UNIT;
+	} else
 		return sp->page.private;
 }