mm, treewide: rename kzfree() to kfree_sensitive()

As said by Linus:

  A symmetric naming is only helpful if it implies symmetries in use.
  Otherwise it's actively misleading.

  In "kzalloc()", the z is meaningful and an important part of what the
  caller wants.

  In "kzfree()", the z is actively detrimental, because maybe in the
  future we really _might_ want to use that "memfill(0xdeadbeef)" or
  something. The "zero" part of the interface isn't even _relevant_.

The main reason that kzfree() exists is to clear sensitive information
that should not be leaked to other future users of the same memory
objects.

Rename kzfree() to kfree_sensitive() to follow the example of the recently
added kvfree_sensitive() and make the intention of the API more explicit.
In addition, memzero_explicit() is used to clear the memory to make sure
that it won't get optimized away by the compiler.

The renaming is done by using the command sequence:

  git grep -w --name-only kzfree |\
  xargs sed -i 's/kzfree/kfree_sensitive/'

followed by some editing of the kfree_sensitive() kerneldoc and adding
a kzfree backward compatibility macro in slab.h.

[[email protected]: fs/crypto/inline_crypt.c needs linux/slab.h]
[[email protected]: fix fs/crypto/inline_crypt.c some more]

Suggested-by: Joe Perches <[email protected]>
Signed-off-by: Waiman Long <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Acked-by: David Howells <[email protected]>
Acked-by: Michal Hocko <[email protected]>
Acked-by: Johannes Weiner <[email protected]>
Cc: Jarkko Sakkinen <[email protected]>
Cc: James Morris <[email protected]>
Cc: "Serge E. Hallyn" <[email protected]>
Cc: Joe Perches <[email protected]>
Cc: Matthew Wilcox <[email protected]>
Cc: David Rientjes <[email protected]>
Cc: Dan Carpenter <[email protected]>
Cc: "Jason A . Donenfeld" <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Linus Torvalds <[email protected]>

4 files changed, 8 insertions, 8 deletions

diff --git a/scripts/coccinelle/free/devm_free.cocci b/scripts/coccinelle/free/devm_free.cocci
index 3357bf4dbd7c..da80050b91ff 100644
--- a/scripts/coccinelle/free/devm_free.cocci
+++ b/scripts/coccinelle/free/devm_free.cocci
@@ -89,7 +89,7 @@ position p;
 (
  kfree@p(x)
 |
- kzfree@p(x)
+ kfree_sensitive@p(x)
 |
  krealloc@p(x, ...)
 |
@@ -112,7 +112,7 @@ position p != safe.p;
 (
 * kfree@p(x)
 |
-* kzfree@p(x)
+* kfree_sensitive@p(x)
 |
 * krealloc@p(x, ...)
 |
diff --git a/scripts/coccinelle/free/ifnullfree.cocci b/scripts/coccinelle/free/ifnullfree.cocci
index b3290c4ee239..2045391e36a0 100644
--- a/scripts/coccinelle/free/ifnullfree.cocci
+++ b/scripts/coccinelle/free/ifnullfree.cocci
@@ -21,7 +21,7 @@ expression E;
 (
   kfree(E);
 |
-  kzfree(E);
+  kfree_sensitive(E);
 |
   debugfs_remove(E);
 |
@@ -42,7 +42,7 @@ position p;
 @@
 
 * if (E != NULL)
-*	\(kfree@p\|kzfree@p\|debugfs_remove@p\|debugfs_remove_recursive@p\|
+*	\(kfree@p\|kfree_sensitive@p\|debugfs_remove@p\|debugfs_remove_recursive@p\|
 *         usb_free_urb@p\|kmem_cache_destroy@p\|mempool_destroy@p\|
 *         dma_pool_destroy@p\)(E);
 
diff --git a/scripts/coccinelle/free/kfree.cocci b/scripts/coccinelle/free/kfree.cocci
index e9d50e718e46..168568386034 100644
--- a/scripts/coccinelle/free/kfree.cocci
+++ b/scripts/coccinelle/free/kfree.cocci
@@ -24,7 +24,7 @@ position p1;
 (
 * kfree@p1(E)
 |
-* kzfree@p1(E)
+* kfree_sensitive@p1(E)
 )
 
 @print expression@
@@ -68,7 +68,7 @@ while (1) { ...
 (
 * kfree@ok(E)
 |
-* kzfree@ok(E)
+* kfree_sensitive@ok(E)
 )
   ... when != break;
       when != goto l;
@@ -86,7 +86,7 @@ position free.p1!=loop.ok,p2!={print.p,sz.p};
 (
 * kfree@p1(E,...)
 |
-* kzfree@p1(E,...)
+* kfree_sensitive@p1(E,...)
 )
 ...
 (
diff --git a/scripts/coccinelle/free/kfreeaddr.cocci b/scripts/coccinelle/free/kfreeaddr.cocci
index cfaf308328d8..142af6337a04 100644
--- a/scripts/coccinelle/free/kfreeaddr.cocci
+++ b/scripts/coccinelle/free/kfreeaddr.cocci
@@ -20,7 +20,7 @@ position p;
 (
 * kfree@p(&e->f)
 |
-* kzfree@p(&e->f)
+* kfree_sensitive@p(&e->f)
 )
 
 @script:python depends on org@