From: Rusty Russell <rusty@rustcorp.com.au>
Date: Thu, 5 Mar 2015 00:19:19 +0000 (+1030)
Subject: cpumask: only allocate nr_cpumask_bits.
X-Git-Tag: v4.1-rc1~71^2~3
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=cdfdef75e795;p=karo-tx-linux.git

cpumask: only allocate nr_cpumask_bits.

Now we'll find out the hard way if anyone has CPUMASK_OFFSTACK and is
returning these or assigning them.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
---

diff --git a/include/linux/cpumask.h b/include/linux/cpumask.h
index 646fadee5caf..4ad2d3c8e21f 100644
--- a/include/linux/cpumask.h
+++ b/include/linux/cpumask.h
@@ -11,6 +11,7 @@
 #include <linux/bitmap.h>
 #include <linux/bug.h>
 
+/* Don't assign or return these: may not be this big! */
 typedef struct cpumask { DECLARE_BITMAP(bits, NR_CPUS); } cpumask_t;
 
 /**
@@ -609,9 +610,7 @@ static inline int cpulist_parse(const char *buf, struct cpumask *dstp)
  */
 static inline size_t cpumask_size(void)
 {
-	/* FIXME: Once all cpumask assignments are eliminated, this
-	 * can be nr_cpumask_bits */
-	return BITS_TO_LONGS(NR_CPUS) * sizeof(long);
+	return BITS_TO_LONGS(nr_cpumask_bits) * sizeof(long);
 }
 
 /*
diff --git a/lib/cpumask.c b/lib/cpumask.c
index b6513a9f2892..ba379d12bb57 100644
--- a/lib/cpumask.c
+++ b/lib/cpumask.c
@@ -89,13 +89,6 @@ bool alloc_cpumask_var_node(cpumask_var_t *mask, gfp_t flags, int node)
 		dump_stack();
 	}
 #endif
-	/* FIXME: Bandaid to save us from old primitives which go to NR_CPUS. */
-	if (*mask) {
-		unsigned char *ptr = (unsigned char *)cpumask_bits(*mask);
-		unsigned int tail;
-		tail = BITS_TO_LONGS(NR_CPUS - nr_cpumask_bits) * sizeof(long);
-		memset(ptr + cpumask_size() - tail, 0, tail);
-	}
 
 	return *mask != NULL;
 }