atomic_t variables are currently used to implement reference
counters with the following properties:
- counter is initialized to 1 using atomic_set()
- a resource is freed upon counter reaching zero
- once counter reaches zero, its further
increments aren't allowed
- counter schema uses basic atomic operations
(set, inc, inc_not_zero, dec_and_test, etc.)
Such atomic variables should be converted to a newly provided
refcount_t type and API that prevents accidental counter overflows
and underflows. This is important since overflows and underflows
can lead to use-after-free situation and be exploitable.
The variable mlx4_cq.refcount is used as pure reference counter.
Convert it to refcount_t and fix up the operations.
Suggested-by: Kees Cook <keescook@chromium.org>
Reviewed-by: David Windsor <dwindsor@gmail.com>
Reviewed-by: Hans Liljestrand <ishkamiel@gmail.com>
Signed-off-by: Elena Reshetova <elena.reshetova@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
list_for_each_entry_safe(mcq, temp, &ctx->process_list, tasklet_ctx.list) {
list_del_init(&mcq->tasklet_ctx.list);
mcq->tasklet_ctx.comp(mcq);
list_for_each_entry_safe(mcq, temp, &ctx->process_list, tasklet_ctx.list) {
list_del_init(&mcq->tasklet_ctx.list);
mcq->tasklet_ctx.comp(mcq);
- if (atomic_dec_and_test(&mcq->refcount))
+ if (refcount_dec_and_test(&mcq->refcount))
complete(&mcq->free);
if (time_after(jiffies, end))
break;
complete(&mcq->free);
if (time_after(jiffies, end))
break;
* still arrive.
*/
if (list_empty_careful(&cq->tasklet_ctx.list)) {
* still arrive.
*/
if (list_empty_careful(&cq->tasklet_ctx.list)) {
- atomic_inc(&cq->refcount);
+ refcount_inc(&cq->refcount);
kick = list_empty(&tasklet_ctx->list);
list_add_tail(&cq->tasklet_ctx.list, &tasklet_ctx->list);
if (kick)
kick = list_empty(&tasklet_ctx->list);
list_add_tail(&cq->tasklet_ctx.list, &tasklet_ctx->list);
if (kick)
cq->cons_index = 0;
cq->arm_sn = 1;
cq->uar = uar;
cq->cons_index = 0;
cq->arm_sn = 1;
cq->uar = uar;
- atomic_set(&cq->refcount, 1);
+ refcount_set(&cq->refcount, 1);
init_completion(&cq->free);
cq->comp = mlx4_add_cq_to_tasklet;
cq->tasklet_ctx.priv =
init_completion(&cq->free);
cq->comp = mlx4_add_cq_to_tasklet;
cq->tasklet_ctx.priv =
priv->eq_table.eq[MLX4_EQ_ASYNC].irq)
synchronize_irq(priv->eq_table.eq[MLX4_EQ_ASYNC].irq);
priv->eq_table.eq[MLX4_EQ_ASYNC].irq)
synchronize_irq(priv->eq_table.eq[MLX4_EQ_ASYNC].irq);
- if (atomic_dec_and_test(&cq->refcount))
+ if (refcount_dec_and_test(&cq->refcount))
complete(&cq->free);
wait_for_completion(&cq->free);
complete(&cq->free);
wait_for_completion(&cq->free);
#include <linux/cpu_rmap.h>
#include <linux/crash_dump.h>
#include <linux/cpu_rmap.h>
#include <linux/crash_dump.h>
-#include <linux/atomic.h>
+#include <linux/refcount.h>
#include <linux/timecounter.h>
#include <linux/timecounter.h>
int cqn;
unsigned vector;
int cqn;
unsigned vector;
struct completion free;
struct {
struct list_head list;
struct completion free;
struct {
struct list_head list;