[PATCH 04/23] net, ceph: convert ceph_snap_context.nref from atomic_t to refcount_t
From: Elena Reshetova <elena.reshetova@intel.com>
Date: 2017-03-17 12:11:30
Also in:
ceph-devel, linux-hams, linux-nfs, linux-rdma, linux-sctp, lkml
Subsystem:
ceph common code (libceph), the rest · Maintainers:
Ilya Dryomov, Alex Markuze, Viacheslav Dubeyko, Linus Torvalds
refcount_t type and corresponding API should be used instead of atomic_t when the variable is used as a reference counter. This allows to avoid accidental refcounter overflows that might lead to use-after-free situations. Signed-off-by: Elena Reshetova <elena.reshetova@intel.com> Signed-off-by: Hans Liljestrand <redacted> Signed-off-by: Kees Cook <redacted> Signed-off-by: David Windsor <redacted> --- include/linux/ceph/libceph.h | 3 ++- net/ceph/snapshot.c | 6 +++--- 2 files changed, 5 insertions(+), 4 deletions(-)
diff --git a/include/linux/ceph/libceph.h b/include/linux/ceph/libceph.h
index 1816c5e..26dc674 100644
--- a/include/linux/ceph/libceph.h
+++ b/include/linux/ceph/libceph.h@@ -14,6 +14,7 @@ #include <linux/wait.h> #include <linux/writeback.h> #include <linux/slab.h> +#include <linux/refcount.h> #include <linux/ceph/types.h> #include <linux/ceph/messenger.h>
@@ -159,7 +160,7 @@ struct ceph_client { * dirtied. */ struct ceph_snap_context { - atomic_t nref; + refcount_t nref; u64 seq; u32 num_snaps; u64 snaps[];
diff --git a/net/ceph/snapshot.c b/net/ceph/snapshot.c
index 705414e..e14a5d0 100644
--- a/net/ceph/snapshot.c
+++ b/net/ceph/snapshot.c@@ -49,7 +49,7 @@ struct ceph_snap_context *ceph_create_snap_context(u32 snap_count, if (!snapc) return NULL; - atomic_set(&snapc->nref, 1); + refcount_set(&snapc->nref, 1); snapc->num_snaps = snap_count; return snapc;
@@ -59,7 +59,7 @@ EXPORT_SYMBOL(ceph_create_snap_context); struct ceph_snap_context *ceph_get_snap_context(struct ceph_snap_context *sc) { if (sc) - atomic_inc(&sc->nref); + refcount_inc(&sc->nref); return sc; } EXPORT_SYMBOL(ceph_get_snap_context);
@@ -68,7 +68,7 @@ void ceph_put_snap_context(struct ceph_snap_context *sc) { if (!sc) return; - if (atomic_dec_and_test(&sc->nref)) { + if (refcount_dec_and_test(&sc->nref)) { /*printk(" deleting snap_context %p\n", sc);*/ kfree(sc); }
--
2.7.4