From mboxrd@z Thu Jan 1 00:00:00 1970 From: Peter Zijlstra Subject: [RFC][PATCH] wake_up_var() memory ordering Date: Mon, 24 Jun 2019 18:50:12 +0200 Message-ID: <20190624165012.GH3436@hirez.programming.kicks-ass.net> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "Linux-mediatek" Errors-To: linux-mediatek-bounces+glpam-linux-mediatek=m.gmane.org-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org To: Paul McKenney , Will Deacon Cc: Martin Brandenburg , linux-cachefs-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, Mike Snitzer , linux-aio-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org, David Airlie , samba-technical-w/Ol4Ecudpl8XjKLYN78aQ@public.gmane.org, Joonas Lahtinen , dri-devel-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW@public.gmane.org, David Howells , Chris Mason , dm-devel-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, keyrings-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Ingo Molnar , linux-afs-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, Alasdair Kergon , Mike Marshall , linux-cifs-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, rds-devel-N0ozoZBvEnrZJqsBc5GL+g@public.gmane.org, Andreas Gruenbacher , linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, James Morris , cluster-devel-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, Peter Zijlstra , Antti Palosaari , Matthias Brugger , intel-gfx-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW@public.gmane.org, devel-urhm25FSIHzptaDgeN77Px2eb7JE58TQ@public.gmane.org, Serge List-Id: linux-rdma@vger.kernel.org Hi all, I tried using wake_up_var() today and accidentally noticed that it didn't imply an smp_mb() and specifically requires it through wake_up_bit() / waitqueue_active(). Now, wake_up_bit() doesn't imply the barrier because it is assumed to be used with the atomic bitops API which either implies (test_and_clear) or only needs smp_mb__after_atomic(), which is 'much' cheaper than an unconditional smp_mb(). Still, while auditing all that, I found a whole bunch of things that could be improved. There were missing barriers, superfluous barriers and a whole bunch of sites that could use clear_and_wake_up_bit(). So this fixes all wake_up_bit() usage without actually changing semantics of it (which are unfortunate but understandable). This does however change the semantics of wake_up_var(); even though wake_up_var() is most often used with atomics and then the additional smp_mb() is most often superfluous :/ There isn't really a good option here, comments (other than I need to split this up)? --- drivers/bluetooth/btmtksdio.c | 5 +---- drivers/bluetooth/btmtkuart.c | 5 +---- drivers/bluetooth/hci_mrvl.c | 8 ++------ drivers/gpu/drm/i915/i915_reset.c | 6 ++---- drivers/md/dm-bufio.c | 10 ++-------- drivers/media/usb/dvb-usb-v2/dvb_usb_core.c | 15 ++++----------- fs/afs/fs_probe.c | 1 + fs/afs/server.c | 1 + fs/afs/vl_probe.c | 1 + fs/afs/volume.c | 1 + fs/aio.c | 4 +--- fs/block_dev.c | 1 + fs/btrfs/extent_io.c | 4 +--- fs/cachefiles/namei.c | 1 + fs/cifs/connect.c | 3 +-- fs/cifs/misc.c | 15 +++++---------- fs/fscache/cookie.c | 2 ++ fs/fscache/object.c | 2 ++ fs/fscache/page.c | 3 +++ fs/gfs2/glock.c | 8 ++------ fs/gfs2/glops.c | 1 + fs/gfs2/lock_dlm.c | 8 ++------ fs/gfs2/recovery.c | 4 +--- fs/gfs2/super.c | 1 + fs/gfs2/sys.c | 4 +--- fs/nfs/nfs4state.c | 4 +--- fs/nfs/pnfs_nfs.c | 4 +--- fs/nfsd/nfs4recover.c | 4 +--- fs/orangefs/file.c | 2 +- kernel/sched/wait_bit.c | 1 + net/bluetooth/hci_event.c | 5 +---- net/rds/ib_recv.c | 1 + security/keys/gc.c | 5 ++--- 33 files changed, 50 insertions(+), 90 deletions(-) diff --git a/drivers/bluetooth/btmtksdio.c b/drivers/bluetooth/btmtksdio.c index 813338288453..27523cfeac9a 100644 --- a/drivers/bluetooth/btmtksdio.c +++ b/drivers/bluetooth/btmtksdio.c @@ -356,11 +356,8 @@ static int btmtksdio_recv_event(struct hci_dev *hdev, struct sk_buff *skb) if (hdr->evt == HCI_EV_VENDOR) { if (test_and_clear_bit(BTMTKSDIO_TX_WAIT_VND_EVT, - &bdev->tx_state)) { - /* Barrier to sync with other CPUs */ - smp_mb__after_atomic(); + &bdev->tx_state)) wake_up_bit(&bdev->tx_state, BTMTKSDIO_TX_WAIT_VND_EVT); - } } return 0; diff --git a/drivers/bluetooth/btmtkuart.c b/drivers/bluetooth/btmtkuart.c index f5dbeec8e274..7fe324df3799 100644 --- a/drivers/bluetooth/btmtkuart.c +++ b/drivers/bluetooth/btmtkuart.c @@ -340,11 +340,8 @@ static int btmtkuart_recv_event(struct hci_dev *hdev, struct sk_buff *skb) if (hdr->evt == HCI_EV_VENDOR) { if (test_and_clear_bit(BTMTKUART_TX_WAIT_VND_EVT, - &bdev->tx_state)) { - /* Barrier to sync with other CPUs */ - smp_mb__after_atomic(); + &bdev->tx_state)) wake_up_bit(&bdev->tx_state, BTMTKUART_TX_WAIT_VND_EVT); - } } return 0; diff --git a/drivers/bluetooth/hci_mrvl.c b/drivers/bluetooth/hci_mrvl.c index 50212ac629e3..f03294d39d08 100644 --- a/drivers/bluetooth/hci_mrvl.c +++ b/drivers/bluetooth/hci_mrvl.c @@ -157,9 +157,7 @@ static int mrvl_recv_fw_req(struct hci_dev *hdev, struct sk_buff *skb) mrvl->tx_len = le16_to_cpu(pkt->lhs); - clear_bit(STATE_FW_REQ_PENDING, &mrvl->flags); - smp_mb__after_atomic(); - wake_up_bit(&mrvl->flags, STATE_FW_REQ_PENDING); + clear_and_wake_up_bit(STATE_FW_REQ_PENDING, &mrvl->flags); done: kfree_skb(skb); @@ -192,9 +190,7 @@ static int mrvl_recv_chip_ver(struct hci_dev *hdev, struct sk_buff *skb) bt_dev_info(hdev, "Controller id = %x, rev = %x", mrvl->id, mrvl->rev); - clear_bit(STATE_CHIP_VER_PENDING, &mrvl->flags); - smp_mb__after_atomic(); - wake_up_bit(&mrvl->flags, STATE_CHIP_VER_PENDING); + clear_and_wake_up_bit(STATE_CHIP_VER_PENDING, &mrvl->flags); done: kfree_skb(skb); diff --git a/drivers/gpu/drm/i915/i915_reset.c b/drivers/gpu/drm/i915/i915_reset.c index 677d59304e78..6809367dbfa9 100644 --- a/drivers/gpu/drm/i915/i915_reset.c +++ b/drivers/gpu/drm/i915/i915_reset.c @@ -1324,10 +1324,8 @@ void i915_handle_error(struct drm_i915_private *i915, if (i915_reset_engine(engine, msg) == 0) engine_mask &= ~engine->mask; - clear_bit(I915_RESET_ENGINE + engine->id, - &error->flags); - wake_up_bit(&error->flags, - I915_RESET_ENGINE + engine->id); + clear_and_wake_up_bit(I915_RESET_ENGINE + engine->id, + &error->flags); } } diff --git a/drivers/md/dm-bufio.c b/drivers/md/dm-bufio.c index 2a48ea3f1b30..3114836cc717 100644 --- a/drivers/md/dm-bufio.c +++ b/drivers/md/dm-bufio.c @@ -667,10 +667,7 @@ static void write_endio(struct dm_buffer *b, blk_status_t status) BUG_ON(!test_bit(B_WRITING, &b->state)); smp_mb__before_atomic(); - clear_bit(B_WRITING, &b->state); - smp_mb__after_atomic(); - - wake_up_bit(&b->state, B_WRITING); + clear_and_wake_up_bit(B_WRITING, &b->state); } /* @@ -1045,10 +1042,7 @@ static void read_endio(struct dm_buffer *b, blk_status_t status) BUG_ON(!test_bit(B_READING, &b->state)); smp_mb__before_atomic(); - clear_bit(B_READING, &b->state); - smp_mb__after_atomic(); - - wake_up_bit(&b->state, B_READING); + clear_and_wake_up_bit(B_READING, &b->state); } /* diff --git a/drivers/media/usb/dvb-usb-v2/dvb_usb_core.c b/drivers/media/usb/dvb-usb-v2/dvb_usb_core.c index e5e056bf9dfa..fa46bc930704 100644 --- a/drivers/media/usb/dvb-usb-v2/dvb_usb_core.c +++ b/drivers/media/usb/dvb-usb-v2/dvb_usb_core.c @@ -374,9 +374,7 @@ static int dvb_usb_stop_feed(struct dvb_demux_feed *dvbdmxfeed) usb_urb_killv2(&adap->stream); /* clear 'streaming' status bit */ - clear_bit(ADAP_STREAMING, &adap->state_bits); - smp_mb__after_atomic(); - wake_up_bit(&adap->state_bits, ADAP_STREAMING); + clear_and_wake_up_bit(ADAP_STREAMING, &adap->state_bits); skip_feed_stop: if (ret) @@ -578,11 +576,8 @@ static int dvb_usb_fe_init(struct dvb_frontend *fe) goto err; } err: - if (!adap->suspend_resume_active) { - clear_bit(ADAP_INIT, &adap->state_bits); - smp_mb__after_atomic(); - wake_up_bit(&adap->state_bits, ADAP_INIT); - } + if (!adap->suspend_resume_active) + clear_and_wake_up_bit(ADAP_INIT, &adap->state_bits); dev_dbg(&d->udev->dev, "%s: ret=%d\n", __func__, ret); return ret; @@ -619,9 +614,7 @@ static int dvb_usb_fe_sleep(struct dvb_frontend *fe) err: if (!adap->suspend_resume_active) { adap->active_fe = -1; - clear_bit(ADAP_SLEEP, &adap->state_bits); - smp_mb__after_atomic(); - wake_up_bit(&adap->state_bits, ADAP_SLEEP); + clear_and_wake_up_bit(ADAP_SLEEP, &adap->state_bits); } dev_dbg(&d->udev->dev, "%s: ret=%d\n", __func__, ret); diff --git a/fs/afs/fs_probe.c b/fs/afs/fs_probe.c index cfe62b154f68..377ee07d5f76 100644 --- a/fs/afs/fs_probe.c +++ b/fs/afs/fs_probe.c @@ -18,6 +18,7 @@ static bool afs_fs_probe_done(struct afs_server *server) wake_up_var(&server->probe_outstanding); clear_bit_unlock(AFS_SERVER_FL_PROBING, &server->flags); + smp_mb__after_atomic(); wake_up_bit(&server->flags, AFS_SERVER_FL_PROBING); return true; } diff --git a/fs/afs/server.c b/fs/afs/server.c index e900cd74361b..c9b74a397cc1 100644 --- a/fs/afs/server.c +++ b/fs/afs/server.c @@ -569,6 +569,7 @@ bool afs_check_server_record(struct afs_fs_cursor *fc, struct afs_server *server if (!test_and_set_bit_lock(AFS_SERVER_FL_UPDATING, &server->flags)) { success = afs_update_server_record(fc, server); clear_bit_unlock(AFS_SERVER_FL_UPDATING, &server->flags); + smp_mb__after_atomic(); wake_up_bit(&server->flags, AFS_SERVER_FL_UPDATING); _leave(" = %d", success); return success; diff --git a/fs/afs/vl_probe.c b/fs/afs/vl_probe.c index 858498cc1b05..1939624aa147 100644 --- a/fs/afs/vl_probe.c +++ b/fs/afs/vl_probe.c @@ -18,6 +18,7 @@ static bool afs_vl_probe_done(struct afs_vlserver *server) wake_up_var(&server->probe_outstanding); clear_bit_unlock(AFS_VLSERVER_FL_PROBING, &server->flags); + smp_mb__after_atomic(); wake_up_bit(&server->flags, AFS_VLSERVER_FL_PROBING); return true; } diff --git a/fs/afs/volume.c b/fs/afs/volume.c index 08fdb3951c49..b968e4e96f6b 100644 --- a/fs/afs/volume.c +++ b/fs/afs/volume.c @@ -303,6 +303,7 @@ int afs_check_volume_status(struct afs_volume *volume, struct key *key) ret = afs_update_volume_status(volume, key); clear_bit_unlock(AFS_VOLUME_WAIT, &volume->flags); clear_bit_unlock(AFS_VOLUME_UPDATING, &volume->flags); + smp_mb__after_atomic(); wake_up_bit(&volume->flags, AFS_VOLUME_WAIT); _leave(" = %d", ret); return ret; diff --git a/fs/aio.c b/fs/aio.c index 3490d1fa0e16..a21acb7ee2a5 100644 --- a/fs/aio.c +++ b/fs/aio.c @@ -1154,9 +1154,7 @@ static void aio_complete(struct aio_kiocb *iocb) * like in wake_up_bit() where clearing a bit has to be * ordered with the unlocked test. */ - smp_mb(); - - if (waitqueue_active(&ctx->wait)) + if (wq_has_sleeper(&ctx->wait)) wake_up(&ctx->wait); } diff --git a/fs/block_dev.c b/fs/block_dev.c index 749f5984425d..80e35cbfc7cc 100644 --- a/fs/block_dev.c +++ b/fs/block_dev.c @@ -1687,6 +1687,7 @@ int blkdev_get(struct block_device *bdev, fmode_t mode, void *holder) /* tell others that we're done */ BUG_ON(whole->bd_claiming != holder); whole->bd_claiming = NULL; + smp_mb(); wake_up_bit(&whole->bd_claiming, 0); spin_unlock(&bdev_lock); diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c index db337e53aab3..ee1136ae46fd 100644 --- a/fs/btrfs/extent_io.c +++ b/fs/btrfs/extent_io.c @@ -3683,9 +3683,7 @@ static noinline_for_stack int lock_extent_buffer_for_io(struct extent_buffer *eb static void end_extent_buffer_writeback(struct extent_buffer *eb) { - clear_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags); - smp_mb__after_atomic(); - wake_up_bit(&eb->bflags, EXTENT_BUFFER_WRITEBACK); + clear_and_wake_up_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags); } static void set_btree_ioerr(struct page *page) diff --git a/fs/cachefiles/namei.c b/fs/cachefiles/namei.c index ecc8ecbbfa5a..ecebba72ec7d 100644 --- a/fs/cachefiles/namei.c +++ b/fs/cachefiles/namei.c @@ -267,6 +267,7 @@ void cachefiles_mark_object_inactive(struct cachefiles_cache *cache, clear_bit(CACHEFILES_OBJECT_ACTIVE, &object->flags); write_unlock(&cache->active_lock); + smp_mb__after_atomic(); wake_up_bit(&object->flags, CACHEFILES_OBJECT_ACTIVE); /* This object can now be culled, so we need to let the daemon know diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c index 8c4121da624e..8c1115ed1c28 100644 --- a/fs/cifs/connect.c +++ b/fs/cifs/connect.c @@ -5235,8 +5235,7 @@ cifs_sb_tlink(struct cifs_sb_info *cifs_sb) } tlink->tl_tcon = cifs_construct_tcon(cifs_sb, fsuid); - clear_bit(TCON_LINK_PENDING, &tlink->tl_flags); - wake_up_bit(&tlink->tl_flags, TCON_LINK_PENDING); + clear_and_wake_up_bit(TCON_LINK_PENDING, &tlink->tl_flags); if (IS_ERR(tlink->tl_tcon)) { cifs_put_tlink(tlink); diff --git a/fs/cifs/misc.c b/fs/cifs/misc.c index b1a696a73f7c..961751d89113 100644 --- a/fs/cifs/misc.c +++ b/fs/cifs/misc.c @@ -584,10 +584,8 @@ int cifs_get_writer(struct cifsInodeInfo *cinode) /* Check to see if we have started servicing an oplock break */ if (test_bit(CIFS_INODE_PENDING_OPLOCK_BREAK, &cinode->flags)) { cinode->writers--; - if (cinode->writers == 0) { - clear_bit(CIFS_INODE_PENDING_WRITERS, &cinode->flags); - wake_up_bit(&cinode->flags, CIFS_INODE_PENDING_WRITERS); - } + if (cinode->writers == 0) + clear_and_wake_up_bit(CIFS_INODE_PENDING_WRITERS, &cinode->flags); spin_unlock(&cinode->writers_lock); goto start; } @@ -599,10 +597,8 @@ void cifs_put_writer(struct cifsInodeInfo *cinode) { spin_lock(&cinode->writers_lock); cinode->writers--; - if (cinode->writers == 0) { - clear_bit(CIFS_INODE_PENDING_WRITERS, &cinode->flags); - wake_up_bit(&cinode->flags, CIFS_INODE_PENDING_WRITERS); - } + if (cinode->writers == 0) + clear_and_wake_up_bit(CIFS_INODE_PENDING_WRITERS, &cinode->flags); spin_unlock(&cinode->writers_lock); } @@ -630,8 +626,7 @@ void cifs_queue_oplock_break(struct cifsFileInfo *cfile) void cifs_done_oplock_break(struct cifsInodeInfo *cinode) { - clear_bit(CIFS_INODE_PENDING_OPLOCK_BREAK, &cinode->flags); - wake_up_bit(&cinode->flags, CIFS_INODE_PENDING_OPLOCK_BREAK); + clear_and_wake_up_bit(CIFS_INODE_PENDING_OPLOCK_BREAK, &cinode->flags); } bool diff --git a/fs/fscache/cookie.c b/fs/fscache/cookie.c index 0ce39658a620..40ba8957ebf0 100644 --- a/fs/fscache/cookie.c +++ b/fs/fscache/cookie.c @@ -381,6 +381,7 @@ void __fscache_enable_cookie(struct fscache_cookie *cookie, out_unlock: clear_bit_unlock(FSCACHE_COOKIE_ENABLEMENT_LOCK, &cookie->flags); + smp_mb__after_atomic(); wake_up_bit(&cookie->flags, FSCACHE_COOKIE_ENABLEMENT_LOCK); } EXPORT_SYMBOL(__fscache_enable_cookie); @@ -778,6 +779,7 @@ void __fscache_disable_cookie(struct fscache_cookie *cookie, out_unlock_enable: clear_bit_unlock(FSCACHE_COOKIE_ENABLEMENT_LOCK, &cookie->flags); + smp_mb__after_atomic(); wake_up_bit(&cookie->flags, FSCACHE_COOKIE_ENABLEMENT_LOCK); _leave(""); } diff --git a/fs/fscache/object.c b/fs/fscache/object.c index cfeba839a0f2..08b2edec6596 100644 --- a/fs/fscache/object.c +++ b/fs/fscache/object.c @@ -524,6 +524,7 @@ void fscache_object_lookup_negative(struct fscache_object *object) _debug("wake up lookup %p", &cookie->flags); clear_bit_unlock(FSCACHE_COOKIE_LOOKING_UP, &cookie->flags); + smp_mb__after_atomic(); wake_up_bit(&cookie->flags, FSCACHE_COOKIE_LOOKING_UP); } _leave(""); @@ -559,6 +560,7 @@ void fscache_obtained_object(struct fscache_object *object) * to begin shovelling data. */ clear_bit_unlock(FSCACHE_COOKIE_LOOKING_UP, &cookie->flags); + smp_mb__after_atomic(); wake_up_bit(&cookie->flags, FSCACHE_COOKIE_LOOKING_UP); } else { fscache_stat(&fscache_n_object_created); diff --git a/fs/fscache/page.c b/fs/fscache/page.c index 26af6fdf1538..49ef238502a3 100644 --- a/fs/fscache/page.c +++ b/fs/fscache/page.c @@ -113,6 +113,7 @@ bool __fscache_maybe_release_page(struct fscache_cookie *cookie, fscache_stat(&fscache_n_store_vmscan_gone); } + smp_mb(); wake_up_bit(&cookie->flags, 0); trace_fscache_wake_cookie(cookie); if (xpage) @@ -171,6 +172,7 @@ static void fscache_end_page_write(struct fscache_object *object, trace_fscache_page(cookie, page, fscache_page_write_end_pend); } spin_unlock(&cookie->stores_lock); + smp_mb(); wake_up_bit(&cookie->flags, 0); trace_fscache_wake_cookie(cookie); } else { @@ -922,6 +924,7 @@ void fscache_invalidate_writes(struct fscache_cookie *cookie) put_page(results[i]); } + smp_mb(); wake_up_bit(&cookie->flags, 0); trace_fscache_wake_cookie(cookie); diff --git a/fs/gfs2/glock.c b/fs/gfs2/glock.c index f1ebcb42cbf5..8024b6bdb6d4 100644 --- a/fs/gfs2/glock.c +++ b/fs/gfs2/glock.c @@ -302,9 +302,7 @@ static inline int may_grant(const struct gfs2_glock *gl, const struct gfs2_holde static void gfs2_holder_wake(struct gfs2_holder *gh) { - clear_bit(HIF_WAIT, &gh->gh_iflags); - smp_mb__after_atomic(); - wake_up_bit(&gh->gh_iflags, HIF_WAIT); + clear_and_wake_up_bit(HIF_WAIT, &gh->gh_iflags); } /** @@ -436,9 +434,7 @@ static void state_change(struct gfs2_glock *gl, unsigned int new_state) static void gfs2_demote_wake(struct gfs2_glock *gl) { gl->gl_demote_state = LM_ST_EXCLUSIVE; - clear_bit(GLF_DEMOTE, &gl->gl_flags); - smp_mb__after_atomic(); - wake_up_bit(&gl->gl_flags, GLF_DEMOTE); + clear_and_wake_up_bit(GLF_DEMOTE, &gl->gl_flags); } /** diff --git a/fs/gfs2/glops.c b/fs/gfs2/glops.c index cf4c767005b1..666629ea5da7 100644 --- a/fs/gfs2/glops.c +++ b/fs/gfs2/glops.c @@ -227,6 +227,7 @@ static void gfs2_clear_glop_pending(struct gfs2_inode *ip) return; clear_bit_unlock(GIF_GLOP_PENDING, &ip->i_flags); + smp_mb__after_atomic(); wake_up_bit(&ip->i_flags, GIF_GLOP_PENDING); } diff --git a/fs/gfs2/lock_dlm.c b/fs/gfs2/lock_dlm.c index 4361804646d8..0fa1865dd600 100644 --- a/fs/gfs2/lock_dlm.c +++ b/fs/gfs2/lock_dlm.c @@ -1139,9 +1139,7 @@ static void gdlm_recover_done(void *arg, struct dlm_slot *slots, int num_slots, if (!test_bit(DFL_UNMOUNT, &ls->ls_recover_flags)) queue_delayed_work(gfs2_control_wq, &sdp->sd_control_work, 0); - clear_bit(DFL_DLM_RECOVERY, &ls->ls_recover_flags); - smp_mb__after_atomic(); - wake_up_bit(&ls->ls_recover_flags, DFL_DLM_RECOVERY); + clear_and_wake_up_bit(DFL_DLM_RECOVERY, &ls->ls_recover_flags); spin_unlock(&ls->ls_recover_spin); } @@ -1276,9 +1274,7 @@ static int gdlm_mount(struct gfs2_sbd *sdp, const char *table) } ls->ls_first = !!test_bit(DFL_FIRST_MOUNT, &ls->ls_recover_flags); - clear_bit(SDF_NOJOURNALID, &sdp->sd_flags); - smp_mb__after_atomic(); - wake_up_bit(&sdp->sd_flags, SDF_NOJOURNALID); + clear_and_wake_up_bit(SDF_NOJOURNALID, &sdp->sd_flags); return 0; fail_release: diff --git a/fs/gfs2/recovery.c b/fs/gfs2/recovery.c index 2299a3fa1911..ef9a8ef6689b 100644 --- a/fs/gfs2/recovery.c +++ b/fs/gfs2/recovery.c @@ -436,9 +436,7 @@ void gfs2_recover_func(struct work_struct *work) jd->jd_recover_error = error; gfs2_recovery_done(sdp, jd->jd_jid, LM_RD_GAVEUP); done: - clear_bit(JDF_RECOVERY, &jd->jd_flags); - smp_mb__after_atomic(); - wake_up_bit(&jd->jd_flags, JDF_RECOVERY); + clear_and_wake_up_bit(JDF_RECOVERY, &jd->jd_flags); } int gfs2_recover_journal(struct gfs2_jdesc *jd, bool wait) diff --git a/fs/gfs2/super.c b/fs/gfs2/super.c index b70cea5c8c59..28ff2e10bdd9 100644 --- a/fs/gfs2/super.c +++ b/fs/gfs2/super.c @@ -985,6 +985,7 @@ void gfs2_freeze_func(struct work_struct *work) } deactivate_super(sb); clear_bit_unlock(SDF_FS_FROZEN, &sdp->sd_flags); + smp_mb__after_atomic(); wake_up_bit(&sdp->sd_flags, SDF_FS_FROZEN); return; } diff --git a/fs/gfs2/sys.c b/fs/gfs2/sys.c index 159aedf63c2a..b337798d8957 100644 --- a/fs/gfs2/sys.c +++ b/fs/gfs2/sys.c @@ -505,9 +505,7 @@ static ssize_t jid_store(struct gfs2_sbd *sdp, const char *buf, size_t len) if (sdp->sd_args.ar_spectator && jid > 0) rv = jid = -EINVAL; sdp->sd_lockstruct.ls_jid = jid; - clear_bit(SDF_NOJOURNALID, &sdp->sd_flags); - smp_mb__after_atomic(); - wake_up_bit(&sdp->sd_flags, SDF_NOJOURNALID); + clear_and_wake_up_bit(SDF_NOJOURNALID, &sdp->sd_flags); out: spin_unlock(&sdp->sd_jindex_spin); return rv ? rv : len; diff --git a/fs/nfs/nfs4state.c b/fs/nfs/nfs4state.c index e2e3c4f04d3e..a3ed413a38c5 100644 --- a/fs/nfs/nfs4state.c +++ b/fs/nfs/nfs4state.c @@ -1196,9 +1196,7 @@ static int nfs4_run_state_manager(void *); static void nfs4_clear_state_manager_bit(struct nfs_client *clp) { smp_mb__before_atomic(); - clear_bit(NFS4CLNT_MANAGER_RUNNING, &clp->cl_state); - smp_mb__after_atomic(); - wake_up_bit(&clp->cl_state, NFS4CLNT_MANAGER_RUNNING); + clear_and_wake_up_bit(NFS4CLNT_MANAGER_RUNNING, &clp->cl_state); rpc_wake_up(&clp->cl_rpcwaitq); } diff --git a/fs/nfs/pnfs_nfs.c b/fs/nfs/pnfs_nfs.c index c0046c348910..37c4fe5a595c 100644 --- a/fs/nfs/pnfs_nfs.c +++ b/fs/nfs/pnfs_nfs.c @@ -567,9 +567,7 @@ static void nfs4_wait_ds_connect(struct nfs4_pnfs_ds *ds) static void nfs4_clear_ds_conn_bit(struct nfs4_pnfs_ds *ds) { smp_mb__before_atomic(); - clear_bit(NFS4DS_CONNECTING, &ds->ds_state); - smp_mb__after_atomic(); - wake_up_bit(&ds->ds_state, NFS4DS_CONNECTING); + clear_and_wake_up_bit(NFS4DS_CONNECTING, &ds->ds_state); } static struct nfs_client *(*get_v3_ds_connect)( diff --git a/fs/nfsd/nfs4recover.c b/fs/nfsd/nfs4recover.c index 87679557d0d6..0a30f9cdf66a 100644 --- a/fs/nfsd/nfs4recover.c +++ b/fs/nfsd/nfs4recover.c @@ -1638,9 +1638,7 @@ static void nfsd4_cltrack_upcall_unlock(struct nfs4_client *clp) { smp_mb__before_atomic(); - clear_bit(NFSD4_CLIENT_UPCALL_LOCK, &clp->cl_flags); - smp_mb__after_atomic(); - wake_up_bit(&clp->cl_flags, NFSD4_CLIENT_UPCALL_LOCK); + clear_and_wake_up_bit(NFSD4_CLIENT_UPCALL_LOCK, &clp->cl_flags); } static void diff --git a/fs/orangefs/file.c b/fs/orangefs/file.c index a35c17017210..1958bb457143 100644 --- a/fs/orangefs/file.c +++ b/fs/orangefs/file.c @@ -302,7 +302,7 @@ int orangefs_revalidate_mapping(struct inode *inode) orangefs_inode->mapping_time = jiffies + orangefs_cache_timeout_msecs*HZ/1000; - clear_bit(1, bitlock); + clear_bit_unlock(1, bitlock); smp_mb__after_atomic(); wake_up_bit(bitlock, 1); diff --git a/kernel/sched/wait_bit.c b/kernel/sched/wait_bit.c index 45eba18a2898..2662975473e3 100644 --- a/kernel/sched/wait_bit.c +++ b/kernel/sched/wait_bit.c @@ -189,6 +189,7 @@ EXPORT_SYMBOL(init_wait_var_entry); void wake_up_var(void *var) { + smp_mb(); __wake_up_bit(__var_waitqueue(var), var, -1); } EXPORT_SYMBOL(wake_up_var); diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c index 9e4fcf406d9c..4e57f1a1b7a2 100644 --- a/net/bluetooth/hci_event.c +++ b/net/bluetooth/hci_event.c @@ -50,9 +50,7 @@ static void hci_cc_inquiry_cancel(struct hci_dev *hdev, struct sk_buff *skb) if (status) return; - clear_bit(HCI_INQUIRY, &hdev->flags); - smp_mb__after_atomic(); /* wake_up_bit advises about this barrier */ - wake_up_bit(&hdev->flags, HCI_INQUIRY); + clear_and_wake_up_bit(HCI_INQUIRY, &hdev->flags); hci_dev_lock(hdev); /* Set discovery state to stopped if we're not doing LE active @@ -2342,7 +2340,6 @@ static void hci_inquiry_complete_evt(struct hci_dev *hdev, struct sk_buff *skb) if (!test_and_clear_bit(HCI_INQUIRY, &hdev->flags)) return; - smp_mb__after_atomic(); /* wake_up_bit advises about this barrier */ wake_up_bit(&hdev->flags, HCI_INQUIRY); if (!hci_dev_test_flag(hdev, HCI_MGMT)) diff --git a/net/rds/ib_recv.c b/net/rds/ib_recv.c index 3cae88cbdaa0..2c2773172964 100644 --- a/net/rds/ib_recv.c +++ b/net/rds/ib_recv.c @@ -363,6 +363,7 @@ static int acquire_refill(struct rds_connection *conn) static void release_refill(struct rds_connection *conn) { clear_bit(RDS_RECV_REFILL, &conn->c_flags); + smp_mb__after_atomic(); /* We don't use wait_on_bit()/wake_up_bit() because our waking is in a * hot path and finding waiters is very rare. We don't want to walk diff --git a/security/keys/gc.c b/security/keys/gc.c index 44e58a3e5663..f452816bd7d0 100644 --- a/security/keys/gc.c +++ b/security/keys/gc.c @@ -308,9 +308,8 @@ static void key_garbage_collector(struct work_struct *work) if (unlikely(gc_state & KEY_GC_REAPING_DEAD_3)) { kdebug("dead wake"); - smp_mb(); - clear_bit(KEY_GC_REAPING_KEYTYPE, &key_gc_flags); - wake_up_bit(&key_gc_flags, KEY_GC_REAPING_KEYTYPE); + smp_mb__before_atomic(); + clear_and_wake_up_bit(KEY_GC_REAPING_KEYTYPE, &key_gc_flags); } if (gc_state & KEY_GC_REAP_AGAIN) From mboxrd@z Thu Jan 1 00:00:00 1970 From: Peter Zijlstra Date: Mon, 24 Jun 2019 18:50:12 +0200 Subject: [Cluster-devel] [RFC][PATCH] wake_up_var() memory ordering Message-ID: <20190624165012.GH3436@hirez.programming.kicks-ass.net> List-Id: To: cluster-devel.redhat.com MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Hi all, I tried using wake_up_var() today and accidentally noticed that it didn't imply an smp_mb() and specifically requires it through wake_up_bit() / waitqueue_active(). Now, wake_up_bit() doesn't imply the barrier because it is assumed to be used with the atomic bitops API which either implies (test_and_clear) or only needs smp_mb__after_atomic(), which is 'much' cheaper than an unconditional smp_mb(). Still, while auditing all that, I found a whole bunch of things that could be improved. There were missing barriers, superfluous barriers and a whole bunch of sites that could use clear_and_wake_up_bit(). So this fixes all wake_up_bit() usage without actually changing semantics of it (which are unfortunate but understandable). This does however change the semantics of wake_up_var(); even though wake_up_var() is most often used with atomics and then the additional smp_mb() is most often superfluous :/ There isn't really a good option here, comments (other than I need to split this up)? --- drivers/bluetooth/btmtksdio.c | 5 +---- drivers/bluetooth/btmtkuart.c | 5 +---- drivers/bluetooth/hci_mrvl.c | 8 ++------ drivers/gpu/drm/i915/i915_reset.c | 6 ++---- drivers/md/dm-bufio.c | 10 ++-------- drivers/media/usb/dvb-usb-v2/dvb_usb_core.c | 15 ++++----------- fs/afs/fs_probe.c | 1 + fs/afs/server.c | 1 + fs/afs/vl_probe.c | 1 + fs/afs/volume.c | 1 + fs/aio.c | 4 +--- fs/block_dev.c | 1 + fs/btrfs/extent_io.c | 4 +--- fs/cachefiles/namei.c | 1 + fs/cifs/connect.c | 3 +-- fs/cifs/misc.c | 15 +++++---------- fs/fscache/cookie.c | 2 ++ fs/fscache/object.c | 2 ++ fs/fscache/page.c | 3 +++ fs/gfs2/glock.c | 8 ++------ fs/gfs2/glops.c | 1 + fs/gfs2/lock_dlm.c | 8 ++------ fs/gfs2/recovery.c | 4 +--- fs/gfs2/super.c | 1 + fs/gfs2/sys.c | 4 +--- fs/nfs/nfs4state.c | 4 +--- fs/nfs/pnfs_nfs.c | 4 +--- fs/nfsd/nfs4recover.c | 4 +--- fs/orangefs/file.c | 2 +- kernel/sched/wait_bit.c | 1 + net/bluetooth/hci_event.c | 5 +---- net/rds/ib_recv.c | 1 + security/keys/gc.c | 5 ++--- 33 files changed, 50 insertions(+), 90 deletions(-) diff --git a/drivers/bluetooth/btmtksdio.c b/drivers/bluetooth/btmtksdio.c index 813338288453..27523cfeac9a 100644 --- a/drivers/bluetooth/btmtksdio.c +++ b/drivers/bluetooth/btmtksdio.c @@ -356,11 +356,8 @@ static int btmtksdio_recv_event(struct hci_dev *hdev, struct sk_buff *skb) if (hdr->evt == HCI_EV_VENDOR) { if (test_and_clear_bit(BTMTKSDIO_TX_WAIT_VND_EVT, - &bdev->tx_state)) { - /* Barrier to sync with other CPUs */ - smp_mb__after_atomic(); + &bdev->tx_state)) wake_up_bit(&bdev->tx_state, BTMTKSDIO_TX_WAIT_VND_EVT); - } } return 0; diff --git a/drivers/bluetooth/btmtkuart.c b/drivers/bluetooth/btmtkuart.c index f5dbeec8e274..7fe324df3799 100644 --- a/drivers/bluetooth/btmtkuart.c +++ b/drivers/bluetooth/btmtkuart.c @@ -340,11 +340,8 @@ static int btmtkuart_recv_event(struct hci_dev *hdev, struct sk_buff *skb) if (hdr->evt == HCI_EV_VENDOR) { if (test_and_clear_bit(BTMTKUART_TX_WAIT_VND_EVT, - &bdev->tx_state)) { - /* Barrier to sync with other CPUs */ - smp_mb__after_atomic(); + &bdev->tx_state)) wake_up_bit(&bdev->tx_state, BTMTKUART_TX_WAIT_VND_EVT); - } } return 0; diff --git a/drivers/bluetooth/hci_mrvl.c b/drivers/bluetooth/hci_mrvl.c index 50212ac629e3..f03294d39d08 100644 --- a/drivers/bluetooth/hci_mrvl.c +++ b/drivers/bluetooth/hci_mrvl.c @@ -157,9 +157,7 @@ static int mrvl_recv_fw_req(struct hci_dev *hdev, struct sk_buff *skb) mrvl->tx_len = le16_to_cpu(pkt->lhs); - clear_bit(STATE_FW_REQ_PENDING, &mrvl->flags); - smp_mb__after_atomic(); - wake_up_bit(&mrvl->flags, STATE_FW_REQ_PENDING); + clear_and_wake_up_bit(STATE_FW_REQ_PENDING, &mrvl->flags); done: kfree_skb(skb); @@ -192,9 +190,7 @@ static int mrvl_recv_chip_ver(struct hci_dev *hdev, struct sk_buff *skb) bt_dev_info(hdev, "Controller id = %x, rev = %x", mrvl->id, mrvl->rev); - clear_bit(STATE_CHIP_VER_PENDING, &mrvl->flags); - smp_mb__after_atomic(); - wake_up_bit(&mrvl->flags, STATE_CHIP_VER_PENDING); + clear_and_wake_up_bit(STATE_CHIP_VER_PENDING, &mrvl->flags); done: kfree_skb(skb); diff --git a/drivers/gpu/drm/i915/i915_reset.c b/drivers/gpu/drm/i915/i915_reset.c index 677d59304e78..6809367dbfa9 100644 --- a/drivers/gpu/drm/i915/i915_reset.c +++ b/drivers/gpu/drm/i915/i915_reset.c @@ -1324,10 +1324,8 @@ void i915_handle_error(struct drm_i915_private *i915, if (i915_reset_engine(engine, msg) == 0) engine_mask &= ~engine->mask; - clear_bit(I915_RESET_ENGINE + engine->id, - &error->flags); - wake_up_bit(&error->flags, - I915_RESET_ENGINE + engine->id); + clear_and_wake_up_bit(I915_RESET_ENGINE + engine->id, + &error->flags); } } diff --git a/drivers/md/dm-bufio.c b/drivers/md/dm-bufio.c index 2a48ea3f1b30..3114836cc717 100644 --- a/drivers/md/dm-bufio.c +++ b/drivers/md/dm-bufio.c @@ -667,10 +667,7 @@ static void write_endio(struct dm_buffer *b, blk_status_t status) BUG_ON(!test_bit(B_WRITING, &b->state)); smp_mb__before_atomic(); - clear_bit(B_WRITING, &b->state); - smp_mb__after_atomic(); - - wake_up_bit(&b->state, B_WRITING); + clear_and_wake_up_bit(B_WRITING, &b->state); } /* @@ -1045,10 +1042,7 @@ static void read_endio(struct dm_buffer *b, blk_status_t status) BUG_ON(!test_bit(B_READING, &b->state)); smp_mb__before_atomic(); - clear_bit(B_READING, &b->state); - smp_mb__after_atomic(); - - wake_up_bit(&b->state, B_READING); + clear_and_wake_up_bit(B_READING, &b->state); } /* diff --git a/drivers/media/usb/dvb-usb-v2/dvb_usb_core.c b/drivers/media/usb/dvb-usb-v2/dvb_usb_core.c index e5e056bf9dfa..fa46bc930704 100644 --- a/drivers/media/usb/dvb-usb-v2/dvb_usb_core.c +++ b/drivers/media/usb/dvb-usb-v2/dvb_usb_core.c @@ -374,9 +374,7 @@ static int dvb_usb_stop_feed(struct dvb_demux_feed *dvbdmxfeed) usb_urb_killv2(&adap->stream); /* clear 'streaming' status bit */ - clear_bit(ADAP_STREAMING, &adap->state_bits); - smp_mb__after_atomic(); - wake_up_bit(&adap->state_bits, ADAP_STREAMING); + clear_and_wake_up_bit(ADAP_STREAMING, &adap->state_bits); skip_feed_stop: if (ret) @@ -578,11 +576,8 @@ static int dvb_usb_fe_init(struct dvb_frontend *fe) goto err; } err: - if (!adap->suspend_resume_active) { - clear_bit(ADAP_INIT, &adap->state_bits); - smp_mb__after_atomic(); - wake_up_bit(&adap->state_bits, ADAP_INIT); - } + if (!adap->suspend_resume_active) + clear_and_wake_up_bit(ADAP_INIT, &adap->state_bits); dev_dbg(&d->udev->dev, "%s: ret=%d\n", __func__, ret); return ret; @@ -619,9 +614,7 @@ static int dvb_usb_fe_sleep(struct dvb_frontend *fe) err: if (!adap->suspend_resume_active) { adap->active_fe = -1; - clear_bit(ADAP_SLEEP, &adap->state_bits); - smp_mb__after_atomic(); - wake_up_bit(&adap->state_bits, ADAP_SLEEP); + clear_and_wake_up_bit(ADAP_SLEEP, &adap->state_bits); } dev_dbg(&d->udev->dev, "%s: ret=%d\n", __func__, ret); diff --git a/fs/afs/fs_probe.c b/fs/afs/fs_probe.c index cfe62b154f68..377ee07d5f76 100644 --- a/fs/afs/fs_probe.c +++ b/fs/afs/fs_probe.c @@ -18,6 +18,7 @@ static bool afs_fs_probe_done(struct afs_server *server) wake_up_var(&server->probe_outstanding); clear_bit_unlock(AFS_SERVER_FL_PROBING, &server->flags); + smp_mb__after_atomic(); wake_up_bit(&server->flags, AFS_SERVER_FL_PROBING); return true; } diff --git a/fs/afs/server.c b/fs/afs/server.c index e900cd74361b..c9b74a397cc1 100644 --- a/fs/afs/server.c +++ b/fs/afs/server.c @@ -569,6 +569,7 @@ bool afs_check_server_record(struct afs_fs_cursor *fc, struct afs_server *server if (!test_and_set_bit_lock(AFS_SERVER_FL_UPDATING, &server->flags)) { success = afs_update_server_record(fc, server); clear_bit_unlock(AFS_SERVER_FL_UPDATING, &server->flags); + smp_mb__after_atomic(); wake_up_bit(&server->flags, AFS_SERVER_FL_UPDATING); _leave(" = %d", success); return success; diff --git a/fs/afs/vl_probe.c b/fs/afs/vl_probe.c index 858498cc1b05..1939624aa147 100644 --- a/fs/afs/vl_probe.c +++ b/fs/afs/vl_probe.c @@ -18,6 +18,7 @@ static bool afs_vl_probe_done(struct afs_vlserver *server) wake_up_var(&server->probe_outstanding); clear_bit_unlock(AFS_VLSERVER_FL_PROBING, &server->flags); + smp_mb__after_atomic(); wake_up_bit(&server->flags, AFS_VLSERVER_FL_PROBING); return true; } diff --git a/fs/afs/volume.c b/fs/afs/volume.c index 08fdb3951c49..b968e4e96f6b 100644 --- a/fs/afs/volume.c +++ b/fs/afs/volume.c @@ -303,6 +303,7 @@ int afs_check_volume_status(struct afs_volume *volume, struct key *key) ret = afs_update_volume_status(volume, key); clear_bit_unlock(AFS_VOLUME_WAIT, &volume->flags); clear_bit_unlock(AFS_VOLUME_UPDATING, &volume->flags); + smp_mb__after_atomic(); wake_up_bit(&volume->flags, AFS_VOLUME_WAIT); _leave(" = %d", ret); return ret; diff --git a/fs/aio.c b/fs/aio.c index 3490d1fa0e16..a21acb7ee2a5 100644 --- a/fs/aio.c +++ b/fs/aio.c @@ -1154,9 +1154,7 @@ static void aio_complete(struct aio_kiocb *iocb) * like in wake_up_bit() where clearing a bit has to be * ordered with the unlocked test. */ - smp_mb(); - - if (waitqueue_active(&ctx->wait)) + if (wq_has_sleeper(&ctx->wait)) wake_up(&ctx->wait); } diff --git a/fs/block_dev.c b/fs/block_dev.c index 749f5984425d..80e35cbfc7cc 100644 --- a/fs/block_dev.c +++ b/fs/block_dev.c @@ -1687,6 +1687,7 @@ int blkdev_get(struct block_device *bdev, fmode_t mode, void *holder) /* tell others that we're done */ BUG_ON(whole->bd_claiming != holder); whole->bd_claiming = NULL; + smp_mb(); wake_up_bit(&whole->bd_claiming, 0); spin_unlock(&bdev_lock); diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c index db337e53aab3..ee1136ae46fd 100644 --- a/fs/btrfs/extent_io.c +++ b/fs/btrfs/extent_io.c @@ -3683,9 +3683,7 @@ static noinline_for_stack int lock_extent_buffer_for_io(struct extent_buffer *eb static void end_extent_buffer_writeback(struct extent_buffer *eb) { - clear_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags); - smp_mb__after_atomic(); - wake_up_bit(&eb->bflags, EXTENT_BUFFER_WRITEBACK); + clear_and_wake_up_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags); } static void set_btree_ioerr(struct page *page) diff --git a/fs/cachefiles/namei.c b/fs/cachefiles/namei.c index ecc8ecbbfa5a..ecebba72ec7d 100644 --- a/fs/cachefiles/namei.c +++ b/fs/cachefiles/namei.c @@ -267,6 +267,7 @@ void cachefiles_mark_object_inactive(struct cachefiles_cache *cache, clear_bit(CACHEFILES_OBJECT_ACTIVE, &object->flags); write_unlock(&cache->active_lock); + smp_mb__after_atomic(); wake_up_bit(&object->flags, CACHEFILES_OBJECT_ACTIVE); /* This object can now be culled, so we need to let the daemon know diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c index 8c4121da624e..8c1115ed1c28 100644 --- a/fs/cifs/connect.c +++ b/fs/cifs/connect.c @@ -5235,8 +5235,7 @@ cifs_sb_tlink(struct cifs_sb_info *cifs_sb) } tlink->tl_tcon = cifs_construct_tcon(cifs_sb, fsuid); - clear_bit(TCON_LINK_PENDING, &tlink->tl_flags); - wake_up_bit(&tlink->tl_flags, TCON_LINK_PENDING); + clear_and_wake_up_bit(TCON_LINK_PENDING, &tlink->tl_flags); if (IS_ERR(tlink->tl_tcon)) { cifs_put_tlink(tlink); diff --git a/fs/cifs/misc.c b/fs/cifs/misc.c index b1a696a73f7c..961751d89113 100644 --- a/fs/cifs/misc.c +++ b/fs/cifs/misc.c @@ -584,10 +584,8 @@ int cifs_get_writer(struct cifsInodeInfo *cinode) /* Check to see if we have started servicing an oplock break */ if (test_bit(CIFS_INODE_PENDING_OPLOCK_BREAK, &cinode->flags)) { cinode->writers--; - if (cinode->writers == 0) { - clear_bit(CIFS_INODE_PENDING_WRITERS, &cinode->flags); - wake_up_bit(&cinode->flags, CIFS_INODE_PENDING_WRITERS); - } + if (cinode->writers == 0) + clear_and_wake_up_bit(CIFS_INODE_PENDING_WRITERS, &cinode->flags); spin_unlock(&cinode->writers_lock); goto start; } @@ -599,10 +597,8 @@ void cifs_put_writer(struct cifsInodeInfo *cinode) { spin_lock(&cinode->writers_lock); cinode->writers--; - if (cinode->writers == 0) { - clear_bit(CIFS_INODE_PENDING_WRITERS, &cinode->flags); - wake_up_bit(&cinode->flags, CIFS_INODE_PENDING_WRITERS); - } + if (cinode->writers == 0) + clear_and_wake_up_bit(CIFS_INODE_PENDING_WRITERS, &cinode->flags); spin_unlock(&cinode->writers_lock); } @@ -630,8 +626,7 @@ void cifs_queue_oplock_break(struct cifsFileInfo *cfile) void cifs_done_oplock_break(struct cifsInodeInfo *cinode) { - clear_bit(CIFS_INODE_PENDING_OPLOCK_BREAK, &cinode->flags); - wake_up_bit(&cinode->flags, CIFS_INODE_PENDING_OPLOCK_BREAK); + clear_and_wake_up_bit(CIFS_INODE_PENDING_OPLOCK_BREAK, &cinode->flags); } bool diff --git a/fs/fscache/cookie.c b/fs/fscache/cookie.c index 0ce39658a620..40ba8957ebf0 100644 --- a/fs/fscache/cookie.c +++ b/fs/fscache/cookie.c @@ -381,6 +381,7 @@ void __fscache_enable_cookie(struct fscache_cookie *cookie, out_unlock: clear_bit_unlock(FSCACHE_COOKIE_ENABLEMENT_LOCK, &cookie->flags); + smp_mb__after_atomic(); wake_up_bit(&cookie->flags, FSCACHE_COOKIE_ENABLEMENT_LOCK); } EXPORT_SYMBOL(__fscache_enable_cookie); @@ -778,6 +779,7 @@ void __fscache_disable_cookie(struct fscache_cookie *cookie, out_unlock_enable: clear_bit_unlock(FSCACHE_COOKIE_ENABLEMENT_LOCK, &cookie->flags); + smp_mb__after_atomic(); wake_up_bit(&cookie->flags, FSCACHE_COOKIE_ENABLEMENT_LOCK); _leave(""); } diff --git a/fs/fscache/object.c b/fs/fscache/object.c index cfeba839a0f2..08b2edec6596 100644 --- a/fs/fscache/object.c +++ b/fs/fscache/object.c @@ -524,6 +524,7 @@ void fscache_object_lookup_negative(struct fscache_object *object) _debug("wake up lookup %p", &cookie->flags); clear_bit_unlock(FSCACHE_COOKIE_LOOKING_UP, &cookie->flags); + smp_mb__after_atomic(); wake_up_bit(&cookie->flags, FSCACHE_COOKIE_LOOKING_UP); } _leave(""); @@ -559,6 +560,7 @@ void fscache_obtained_object(struct fscache_object *object) * to begin shovelling data. */ clear_bit_unlock(FSCACHE_COOKIE_LOOKING_UP, &cookie->flags); + smp_mb__after_atomic(); wake_up_bit(&cookie->flags, FSCACHE_COOKIE_LOOKING_UP); } else { fscache_stat(&fscache_n_object_created); diff --git a/fs/fscache/page.c b/fs/fscache/page.c index 26af6fdf1538..49ef238502a3 100644 --- a/fs/fscache/page.c +++ b/fs/fscache/page.c @@ -113,6 +113,7 @@ bool __fscache_maybe_release_page(struct fscache_cookie *cookie, fscache_stat(&fscache_n_store_vmscan_gone); } + smp_mb(); wake_up_bit(&cookie->flags, 0); trace_fscache_wake_cookie(cookie); if (xpage) @@ -171,6 +172,7 @@ static void fscache_end_page_write(struct fscache_object *object, trace_fscache_page(cookie, page, fscache_page_write_end_pend); } spin_unlock(&cookie->stores_lock); + smp_mb(); wake_up_bit(&cookie->flags, 0); trace_fscache_wake_cookie(cookie); } else { @@ -922,6 +924,7 @@ void fscache_invalidate_writes(struct fscache_cookie *cookie) put_page(results[i]); } + smp_mb(); wake_up_bit(&cookie->flags, 0); trace_fscache_wake_cookie(cookie); diff --git a/fs/gfs2/glock.c b/fs/gfs2/glock.c index f1ebcb42cbf5..8024b6bdb6d4 100644 --- a/fs/gfs2/glock.c +++ b/fs/gfs2/glock.c @@ -302,9 +302,7 @@ static inline int may_grant(const struct gfs2_glock *gl, const struct gfs2_holde static void gfs2_holder_wake(struct gfs2_holder *gh) { - clear_bit(HIF_WAIT, &gh->gh_iflags); - smp_mb__after_atomic(); - wake_up_bit(&gh->gh_iflags, HIF_WAIT); + clear_and_wake_up_bit(HIF_WAIT, &gh->gh_iflags); } /** @@ -436,9 +434,7 @@ static void state_change(struct gfs2_glock *gl, unsigned int new_state) static void gfs2_demote_wake(struct gfs2_glock *gl) { gl->gl_demote_state = LM_ST_EXCLUSIVE; - clear_bit(GLF_DEMOTE, &gl->gl_flags); - smp_mb__after_atomic(); - wake_up_bit(&gl->gl_flags, GLF_DEMOTE); + clear_and_wake_up_bit(GLF_DEMOTE, &gl->gl_flags); } /** diff --git a/fs/gfs2/glops.c b/fs/gfs2/glops.c index cf4c767005b1..666629ea5da7 100644 --- a/fs/gfs2/glops.c +++ b/fs/gfs2/glops.c @@ -227,6 +227,7 @@ static void gfs2_clear_glop_pending(struct gfs2_inode *ip) return; clear_bit_unlock(GIF_GLOP_PENDING, &ip->i_flags); + smp_mb__after_atomic(); wake_up_bit(&ip->i_flags, GIF_GLOP_PENDING); } diff --git a/fs/gfs2/lock_dlm.c b/fs/gfs2/lock_dlm.c index 4361804646d8..0fa1865dd600 100644 --- a/fs/gfs2/lock_dlm.c +++ b/fs/gfs2/lock_dlm.c @@ -1139,9 +1139,7 @@ static void gdlm_recover_done(void *arg, struct dlm_slot *slots, int num_slots, if (!test_bit(DFL_UNMOUNT, &ls->ls_recover_flags)) queue_delayed_work(gfs2_control_wq, &sdp->sd_control_work, 0); - clear_bit(DFL_DLM_RECOVERY, &ls->ls_recover_flags); - smp_mb__after_atomic(); - wake_up_bit(&ls->ls_recover_flags, DFL_DLM_RECOVERY); + clear_and_wake_up_bit(DFL_DLM_RECOVERY, &ls->ls_recover_flags); spin_unlock(&ls->ls_recover_spin); } @@ -1276,9 +1274,7 @@ static int gdlm_mount(struct gfs2_sbd *sdp, const char *table) } ls->ls_first = !!test_bit(DFL_FIRST_MOUNT, &ls->ls_recover_flags); - clear_bit(SDF_NOJOURNALID, &sdp->sd_flags); - smp_mb__after_atomic(); - wake_up_bit(&sdp->sd_flags, SDF_NOJOURNALID); + clear_and_wake_up_bit(SDF_NOJOURNALID, &sdp->sd_flags); return 0; fail_release: diff --git a/fs/gfs2/recovery.c b/fs/gfs2/recovery.c index 2299a3fa1911..ef9a8ef6689b 100644 --- a/fs/gfs2/recovery.c +++ b/fs/gfs2/recovery.c @@ -436,9 +436,7 @@ void gfs2_recover_func(struct work_struct *work) jd->jd_recover_error = error; gfs2_recovery_done(sdp, jd->jd_jid, LM_RD_GAVEUP); done: - clear_bit(JDF_RECOVERY, &jd->jd_flags); - smp_mb__after_atomic(); - wake_up_bit(&jd->jd_flags, JDF_RECOVERY); + clear_and_wake_up_bit(JDF_RECOVERY, &jd->jd_flags); } int gfs2_recover_journal(struct gfs2_jdesc *jd, bool wait) diff --git a/fs/gfs2/super.c b/fs/gfs2/super.c index b70cea5c8c59..28ff2e10bdd9 100644 --- a/fs/gfs2/super.c +++ b/fs/gfs2/super.c @@ -985,6 +985,7 @@ void gfs2_freeze_func(struct work_struct *work) } deactivate_super(sb); clear_bit_unlock(SDF_FS_FROZEN, &sdp->sd_flags); + smp_mb__after_atomic(); wake_up_bit(&sdp->sd_flags, SDF_FS_FROZEN); return; } diff --git a/fs/gfs2/sys.c b/fs/gfs2/sys.c index 159aedf63c2a..b337798d8957 100644 --- a/fs/gfs2/sys.c +++ b/fs/gfs2/sys.c @@ -505,9 +505,7 @@ static ssize_t jid_store(struct gfs2_sbd *sdp, const char *buf, size_t len) if (sdp->sd_args.ar_spectator && jid > 0) rv = jid = -EINVAL; sdp->sd_lockstruct.ls_jid = jid; - clear_bit(SDF_NOJOURNALID, &sdp->sd_flags); - smp_mb__after_atomic(); - wake_up_bit(&sdp->sd_flags, SDF_NOJOURNALID); + clear_and_wake_up_bit(SDF_NOJOURNALID, &sdp->sd_flags); out: spin_unlock(&sdp->sd_jindex_spin); return rv ? rv : len; diff --git a/fs/nfs/nfs4state.c b/fs/nfs/nfs4state.c index e2e3c4f04d3e..a3ed413a38c5 100644 --- a/fs/nfs/nfs4state.c +++ b/fs/nfs/nfs4state.c @@ -1196,9 +1196,7 @@ static int nfs4_run_state_manager(void *); static void nfs4_clear_state_manager_bit(struct nfs_client *clp) { smp_mb__before_atomic(); - clear_bit(NFS4CLNT_MANAGER_RUNNING, &clp->cl_state); - smp_mb__after_atomic(); - wake_up_bit(&clp->cl_state, NFS4CLNT_MANAGER_RUNNING); + clear_and_wake_up_bit(NFS4CLNT_MANAGER_RUNNING, &clp->cl_state); rpc_wake_up(&clp->cl_rpcwaitq); } diff --git a/fs/nfs/pnfs_nfs.c b/fs/nfs/pnfs_nfs.c index c0046c348910..37c4fe5a595c 100644 --- a/fs/nfs/pnfs_nfs.c +++ b/fs/nfs/pnfs_nfs.c @@ -567,9 +567,7 @@ static void nfs4_wait_ds_connect(struct nfs4_pnfs_ds *ds) static void nfs4_clear_ds_conn_bit(struct nfs4_pnfs_ds *ds) { smp_mb__before_atomic(); - clear_bit(NFS4DS_CONNECTING, &ds->ds_state); - smp_mb__after_atomic(); - wake_up_bit(&ds->ds_state, NFS4DS_CONNECTING); + clear_and_wake_up_bit(NFS4DS_CONNECTING, &ds->ds_state); } static struct nfs_client *(*get_v3_ds_connect)( diff --git a/fs/nfsd/nfs4recover.c b/fs/nfsd/nfs4recover.c index 87679557d0d6..0a30f9cdf66a 100644 --- a/fs/nfsd/nfs4recover.c +++ b/fs/nfsd/nfs4recover.c @@ -1638,9 +1638,7 @@ static void nfsd4_cltrack_upcall_unlock(struct nfs4_client *clp) { smp_mb__before_atomic(); - clear_bit(NFSD4_CLIENT_UPCALL_LOCK, &clp->cl_flags); - smp_mb__after_atomic(); - wake_up_bit(&clp->cl_flags, NFSD4_CLIENT_UPCALL_LOCK); + clear_and_wake_up_bit(NFSD4_CLIENT_UPCALL_LOCK, &clp->cl_flags); } static void diff --git a/fs/orangefs/file.c b/fs/orangefs/file.c index a35c17017210..1958bb457143 100644 --- a/fs/orangefs/file.c +++ b/fs/orangefs/file.c @@ -302,7 +302,7 @@ int orangefs_revalidate_mapping(struct inode *inode) orangefs_inode->mapping_time = jiffies + orangefs_cache_timeout_msecs*HZ/1000; - clear_bit(1, bitlock); + clear_bit_unlock(1, bitlock); smp_mb__after_atomic(); wake_up_bit(bitlock, 1); diff --git a/kernel/sched/wait_bit.c b/kernel/sched/wait_bit.c index 45eba18a2898..2662975473e3 100644 --- a/kernel/sched/wait_bit.c +++ b/kernel/sched/wait_bit.c @@ -189,6 +189,7 @@ EXPORT_SYMBOL(init_wait_var_entry); void wake_up_var(void *var) { + smp_mb(); __wake_up_bit(__var_waitqueue(var), var, -1); } EXPORT_SYMBOL(wake_up_var); diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c index 9e4fcf406d9c..4e57f1a1b7a2 100644 --- a/net/bluetooth/hci_event.c +++ b/net/bluetooth/hci_event.c @@ -50,9 +50,7 @@ static void hci_cc_inquiry_cancel(struct hci_dev *hdev, struct sk_buff *skb) if (status) return; - clear_bit(HCI_INQUIRY, &hdev->flags); - smp_mb__after_atomic(); /* wake_up_bit advises about this barrier */ - wake_up_bit(&hdev->flags, HCI_INQUIRY); + clear_and_wake_up_bit(HCI_INQUIRY, &hdev->flags); hci_dev_lock(hdev); /* Set discovery state to stopped if we're not doing LE active @@ -2342,7 +2340,6 @@ static void hci_inquiry_complete_evt(struct hci_dev *hdev, struct sk_buff *skb) if (!test_and_clear_bit(HCI_INQUIRY, &hdev->flags)) return; - smp_mb__after_atomic(); /* wake_up_bit advises about this barrier */ wake_up_bit(&hdev->flags, HCI_INQUIRY); if (!hci_dev_test_flag(hdev, HCI_MGMT)) diff --git a/net/rds/ib_recv.c b/net/rds/ib_recv.c index 3cae88cbdaa0..2c2773172964 100644 --- a/net/rds/ib_recv.c +++ b/net/rds/ib_recv.c @@ -363,6 +363,7 @@ static int acquire_refill(struct rds_connection *conn) static void release_refill(struct rds_connection *conn) { clear_bit(RDS_RECV_REFILL, &conn->c_flags); + smp_mb__after_atomic(); /* We don't use wait_on_bit()/wake_up_bit() because our waking is in a * hot path and finding waiters is very rare. We don't want to walk diff --git a/security/keys/gc.c b/security/keys/gc.c index 44e58a3e5663..f452816bd7d0 100644 --- a/security/keys/gc.c +++ b/security/keys/gc.c @@ -308,9 +308,8 @@ static void key_garbage_collector(struct work_struct *work) if (unlikely(gc_state & KEY_GC_REAPING_DEAD_3)) { kdebug("dead wake"); - smp_mb(); - clear_bit(KEY_GC_REAPING_KEYTYPE, &key_gc_flags); - wake_up_bit(&key_gc_flags, KEY_GC_REAPING_KEYTYPE); + smp_mb__before_atomic(); + clear_and_wake_up_bit(KEY_GC_REAPING_KEYTYPE, &key_gc_flags); } if (gc_state & KEY_GC_REAP_AGAIN)