locking/atomic, kref: Kill kref_sub()
By general sentiment kref_sub() is a bad interface, make it go away.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
diff --git a/drivers/block/drbd/drbd_req.c b/drivers/block/drbd/drbd_req.c
index 74306c0..b489ac2 100644
--- a/drivers/block/drbd/drbd_req.c
+++ b/drivers/block/drbd/drbd_req.c
@@ -421,7 +421,6 @@ static void mod_rq_state(struct drbd_request *req, struct bio_and_error *m,
struct drbd_peer_device *peer_device = first_peer_device(device);
unsigned s = req->rq_state;
int c_put = 0;
- int k_put = 0;
if (drbd_suspended(device) && !((s | clear) & RQ_COMPLETION_SUSP))
set |= RQ_COMPLETION_SUSP;
@@ -437,6 +436,8 @@ static void mod_rq_state(struct drbd_request *req, struct bio_and_error *m,
/* intent: get references */
+ kref_get(&req->kref);
+
if (!(s & RQ_LOCAL_PENDING) && (set & RQ_LOCAL_PENDING))
atomic_inc(&req->completion_ref);
@@ -473,15 +474,12 @@ static void mod_rq_state(struct drbd_request *req, struct bio_and_error *m,
if (!(s & RQ_LOCAL_ABORTED) && (set & RQ_LOCAL_ABORTED)) {
D_ASSERT(device, req->rq_state & RQ_LOCAL_PENDING);
- /* local completion may still come in later,
- * we need to keep the req object around. */
- kref_get(&req->kref);
++c_put;
}
if ((s & RQ_LOCAL_PENDING) && (clear & RQ_LOCAL_PENDING)) {
if (req->rq_state & RQ_LOCAL_ABORTED)
- ++k_put;
+ kref_put(&req->kref, drbd_req_destroy);
else
++c_put;
list_del_init(&req->req_pending_local);
@@ -503,7 +501,7 @@ static void mod_rq_state(struct drbd_request *req, struct bio_and_error *m,
if (s & RQ_NET_SENT)
atomic_sub(req->i.size >> 9, &device->ap_in_flight);
if (s & RQ_EXP_BARR_ACK)
- ++k_put;
+ kref_put(&req->kref, drbd_req_destroy);
req->net_done_jif = jiffies;
/* in ahead/behind mode, or just in case,
@@ -516,25 +514,16 @@ static void mod_rq_state(struct drbd_request *req, struct bio_and_error *m,
/* potentially complete and destroy */
- if (k_put || c_put) {
- /* Completion does it's own kref_put. If we are going to
- * kref_sub below, we need req to be still around then. */
- int at_least = k_put + !!c_put;
- int refcount = kref_read(&req->kref);
- if (refcount < at_least)
- drbd_err(device,
- "mod_rq_state: Logic BUG: %x -> %x: refcount = %d, should be >= %d\n",
- s, req->rq_state, refcount, at_least);
- }
-
/* If we made progress, retry conflicting peer requests, if any. */
if (req->i.waiting)
wake_up(&device->misc_wait);
- if (c_put)
- k_put += drbd_req_put_completion_ref(req, m, c_put);
- if (k_put)
- kref_sub(&req->kref, k_put, drbd_req_destroy);
+ if (c_put) {
+ if (drbd_req_put_completion_ref(req, m, c_put))
+ kref_put(&req->kref, drbd_req_destroy);
+ } else {
+ kref_put(&req->kref, drbd_req_destroy);
+ }
}
static void drbd_report_io_error(struct drbd_device *device, struct drbd_request *req)