From 1e24edca0557dba6486d39d3c24c288475432bcf Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Mon, 14 Nov 2016 17:12:23 +0100 Subject: locking/atomic, kref: Add KREF_INIT() Since we need to change the implementation, stop exposing internals. Provide KREF_INIT() to allow static initialization of struct kref. Signed-off-by: Peter Zijlstra (Intel) Cc: Andrew Morton Cc: Greg Kroah-Hartman Cc: Linus Torvalds Cc: Paul E. McKenney Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar --- drivers/block/drbd/drbd_bitmap.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers/block') diff --git a/drivers/block/drbd/drbd_bitmap.c b/drivers/block/drbd/drbd_bitmap.c index ab62b81c2ca7..dece26f119d4 100644 --- a/drivers/block/drbd/drbd_bitmap.c +++ b/drivers/block/drbd/drbd_bitmap.c @@ -1070,7 +1070,7 @@ static int bm_rw(struct drbd_device *device, const unsigned int flags, unsigned .done = 0, .flags = flags, .error = 0, - .kref = { ATOMIC_INIT(2) }, + .kref = KREF_INIT(2), }; if (!get_ldev_if_state(device, D_ATTACHING)) { /* put is in drbd_bm_aio_ctx_destroy() */ -- cgit v1.2.3 From 2c935bc57221cc2edc787c72ea0e2d30cdcd3d5e Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Mon, 14 Nov 2016 17:29:48 +0100 Subject: locking/atomic, kref: Add kref_read() Since we need to change the implementation, stop exposing internals. Provide kref_read() to read the current reference count; typically used for debug messages. Kills two anti-patterns: atomic_read(&kref->refcount) kref->refcount.counter Signed-off-by: Peter Zijlstra (Intel) Cc: Andrew Morton Cc: Greg Kroah-Hartman Cc: Linus Torvalds Cc: Paul E. McKenney Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar --- drivers/block/drbd/drbd_req.c | 2 +- drivers/block/rbd.c | 8 ++++---- drivers/block/virtio_blk.c | 2 +- 3 files changed, 6 insertions(+), 6 deletions(-) (limited to 'drivers/block') diff --git a/drivers/block/drbd/drbd_req.c b/drivers/block/drbd/drbd_req.c index de279fe4e4fd..74306c054983 100644 --- a/drivers/block/drbd/drbd_req.c +++ b/drivers/block/drbd/drbd_req.c @@ -520,7 +520,7 @@ static void mod_rq_state(struct drbd_request *req, struct bio_and_error *m, /* 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 = atomic_read(&req->kref.refcount); + 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", diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c index 36d2b9f4e836..436baa66f701 100644 --- a/drivers/block/rbd.c +++ b/drivers/block/rbd.c @@ -1535,7 +1535,7 @@ static bool obj_request_overlaps_parent(struct rbd_obj_request *obj_request) static void rbd_obj_request_get(struct rbd_obj_request *obj_request) { dout("%s: obj %p (was %d)\n", __func__, obj_request, - atomic_read(&obj_request->kref.refcount)); + kref_read(&obj_request->kref)); kref_get(&obj_request->kref); } @@ -1544,14 +1544,14 @@ static void rbd_obj_request_put(struct rbd_obj_request *obj_request) { rbd_assert(obj_request != NULL); dout("%s: obj %p (was %d)\n", __func__, obj_request, - atomic_read(&obj_request->kref.refcount)); + kref_read(&obj_request->kref)); kref_put(&obj_request->kref, rbd_obj_request_destroy); } static void rbd_img_request_get(struct rbd_img_request *img_request) { dout("%s: img %p (was %d)\n", __func__, img_request, - atomic_read(&img_request->kref.refcount)); + kref_read(&img_request->kref)); kref_get(&img_request->kref); } @@ -1562,7 +1562,7 @@ static void rbd_img_request_put(struct rbd_img_request *img_request) { rbd_assert(img_request != NULL); dout("%s: img %p (was %d)\n", __func__, img_request, - atomic_read(&img_request->kref.refcount)); + kref_read(&img_request->kref)); if (img_request_child_test(img_request)) kref_put(&img_request->kref, rbd_parent_request_destroy); else diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c index 5545a679abd8..79a346c97446 100644 --- a/drivers/block/virtio_blk.c +++ b/drivers/block/virtio_blk.c @@ -767,7 +767,7 @@ static void virtblk_remove(struct virtio_device *vdev) /* Stop all the virtqueues. */ vdev->config->reset(vdev); - refc = atomic_read(&disk_to_dev(vblk->disk)->kobj.kref.refcount); + refc = kref_read(&disk_to_dev(vblk->disk)->kobj.kref); put_disk(vblk->disk); vdev->config->del_vqs(vdev); kfree(vblk->vqs); -- cgit v1.2.3 From bdfafc4ffdd24e491119d81f85ddc4393fa49803 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Mon, 14 Nov 2016 17:34:19 +0100 Subject: 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) Cc: Andrew Morton Cc: Greg Kroah-Hartman Cc: Linus Torvalds Cc: Paul E. McKenney Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar --- drivers/block/drbd/drbd_main.c | 7 ++++--- drivers/block/drbd/drbd_req.c | 31 ++++++++++--------------------- 2 files changed, 14 insertions(+), 24 deletions(-) (limited to 'drivers/block') diff --git a/drivers/block/drbd/drbd_main.c b/drivers/block/drbd/drbd_main.c index 83482721bc01..c3ff60c30dde 100644 --- a/drivers/block/drbd/drbd_main.c +++ b/drivers/block/drbd/drbd_main.c @@ -2948,7 +2948,6 @@ void drbd_delete_device(struct drbd_device *device) struct drbd_resource *resource = device->resource; struct drbd_connection *connection; struct drbd_peer_device *peer_device; - int refs = 3; /* move to free_peer_device() */ for_each_peer_device(peer_device, device) @@ -2956,13 +2955,15 @@ void drbd_delete_device(struct drbd_device *device) drbd_debugfs_device_cleanup(device); for_each_connection(connection, resource) { idr_remove(&connection->peer_devices, device->vnr); - refs++; + kref_put(&device->kref, drbd_destroy_device); } idr_remove(&resource->devices, device->vnr); + kref_put(&device->kref, drbd_destroy_device); idr_remove(&drbd_devices, device_to_minor(device)); + kref_put(&device->kref, drbd_destroy_device); del_gendisk(device->vdisk); synchronize_rcu(); - kref_sub(&device->kref, refs, drbd_destroy_device); + kref_put(&device->kref, drbd_destroy_device); } static int __init drbd_init(void) diff --git a/drivers/block/drbd/drbd_req.c b/drivers/block/drbd/drbd_req.c index 74306c054983..b489ac2e9c44 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) -- cgit v1.2.3