6 files changed, 69 insertions, 137 deletions

diff --git a/drivers/block/drbd/drbd_int.h b/drivers/block/drbd/drbd_int.h
index e9654c8d5b62..485ed8c7d623 100644
--- a/drivers/block/drbd/drbd_int.h
+++ b/drivers/block/drbd/drbd_int.h
@@ -943,8 +943,7 @@ struct drbd_conf {
         struct drbd_work  resync_work,
                           unplug_work,
                           md_sync_work,
-                          delay_probe_work,
-                          uuid_work;
+                          delay_probe_work;
         struct timer_list resync_timer;
         struct timer_list md_sync_timer;
         struct timer_list delay_probe_timer;
@@ -1069,7 +1068,6 @@ struct drbd_conf {
         struct timeval dps_time; /* delay-probes-start-time */
         unsigned int dp_volume_last;  /* send_cnt of last delay probe */
         int c_sync_rate; /* current resync rate after delay_probe magic */
-        atomic_t new_c_uuid;
 };
 
 static inline struct drbd_conf *minor_to_mdev(unsigned int minor)
@@ -1476,7 +1474,6 @@ extern int w_e_end_ov_req(struct drbd_conf *, struct drbd_work *, int);
 extern int w_ov_finished(struct drbd_conf *, struct drbd_work *, int);
 extern int w_resync_inactive(struct drbd_conf *, struct drbd_work *, int);
 extern int w_resume_next_sg(struct drbd_conf *, struct drbd_work *, int);
-extern int w_io_error(struct drbd_conf *, struct drbd_work *, int);
 extern int w_send_write_hint(struct drbd_conf *, struct drbd_work *, int);
 extern int w_make_resync_request(struct drbd_conf *, struct drbd_work *, int);
 extern int w_send_dblock(struct drbd_conf *, struct drbd_work *, int);
@@ -1542,7 +1539,7 @@ static inline void drbd_tcp_nodelay(struct socket *sock)
 
 static inline void drbd_tcp_quickack(struct socket *sock)
 {
-        int __user val = 1;
+        int __user val = 2;
         (void) drbd_setsockopt(sock, SOL_TCP, TCP_QUICKACK,
                         (char __user *)&val, sizeof(val));
 }
@@ -1728,7 +1725,7 @@ static inline void __drbd_chk_io_error_(struct drbd_conf *mdev, int forcedetach,
         switch (mdev->ldev->dc.on_io_error) {
         case EP_PASS_ON:
                 if (!forcedetach) {
-                        if (printk_ratelimit())
+                        if (__ratelimit(&drbd_ratelimit_state))
                                 dev_err(DEV, "Local IO failed in %s."
                                              "Passing error on...\n", where);
                         break;
@@ -2219,8 +2216,6 @@ static inline int __inc_ap_bio_cond(struct drbd_conf *mdev)
                 return 0;
         if (test_bit(BITMAP_IO, &mdev->flags))
                 return 0;
-        if (atomic_read(&mdev->new_c_uuid))
-                return 0;
         return 1;
 }
 
@@ -2241,9 +2236,6 @@ static inline void inc_ap_bio(struct drbd_conf *mdev, int count)
          * to avoid races with the reconnect code,
          * we need to atomic_inc within the spinlock. */
 
-        if (atomic_read(&mdev->new_c_uuid) && atomic_add_unless(&mdev->new_c_uuid, -1, 1))
-                drbd_queue_work_front(&mdev->data.work, &mdev->uuid_work);
-
         spin_lock_irq(&mdev->req_lock);
         while (!__inc_ap_bio_cond(mdev)) {
                 prepare_to_wait(&mdev->misc_wait, &wait, TASK_UNINTERRUPTIBLE);
diff --git a/drivers/block/drbd/drbd_main.c b/drivers/block/drbd/drbd_main.c
index be2d2da9cdba..6b077f93acc6 100644
--- a/drivers/block/drbd/drbd_main.c
+++ b/drivers/block/drbd/drbd_main.c
@@ -1215,18 +1215,17 @@ static void after_state_ch(struct drbd_conf *mdev, union drbd_state os,
              ns.pdsk == D_OUTDATED)) {
                 if (get_ldev(mdev)) {
                         if ((ns.role == R_PRIMARY || ns.peer == R_PRIMARY) &&
-                            mdev->ldev->md.uuid[UI_BITMAP] == 0 && ns.disk >= D_UP_TO_DATE &&
-                            !atomic_read(&mdev->new_c_uuid))
-                                atomic_set(&mdev->new_c_uuid, 2);
+                            mdev->ldev->md.uuid[UI_BITMAP] == 0 && ns.disk >= D_UP_TO_DATE) {
+                                drbd_uuid_new_current(mdev);
+                                drbd_send_uuids(mdev);
+                        }
                         put_ldev(mdev);
                 }
         }
 
         if (ns.pdsk < D_INCONSISTENT && get_ldev(mdev)) {
-                /* Diskless peer becomes primary or got connected do diskless, primary peer. */
-                if (ns.peer == R_PRIMARY && mdev->ldev->md.uuid[UI_BITMAP] == 0 &&
-                    !atomic_read(&mdev->new_c_uuid))
-                        atomic_set(&mdev->new_c_uuid, 2);
+                if (ns.peer == R_PRIMARY && mdev->ldev->md.uuid[UI_BITMAP] == 0)
+                        drbd_uuid_new_current(mdev);
 
                 /* D_DISKLESS Peer becomes secondary */
                 if (os.peer == R_PRIMARY && ns.peer == R_SECONDARY)
@@ -1350,24 +1349,6 @@ static void after_state_ch(struct drbd_conf *mdev, union drbd_state os,
         drbd_md_sync(mdev);
 }
 
-static int w_new_current_uuid(struct drbd_conf *mdev, struct drbd_work *w, int cancel)
-{
-        if (get_ldev(mdev)) {
-                if (mdev->ldev->md.uuid[UI_BITMAP] == 0) {
-                        drbd_uuid_new_current(mdev);
-                        if (get_net_conf(mdev)) {
-                                drbd_send_uuids(mdev);
-                                put_net_conf(mdev);
-                        }
-                        drbd_md_sync(mdev);
-                }
-                put_ldev(mdev);
-        }
-        atomic_dec(&mdev->new_c_uuid);
-        wake_up(&mdev->misc_wait);
-
-        return 1;
-}
 
 static int drbd_thread_setup(void *arg)
 {
@@ -2291,9 +2272,9 @@ static int we_should_drop_the_connection(struct drbd_conf *mdev, struct socket *
  * with page_count == 0 or PageSlab.
  */
 static int _drbd_no_send_page(struct drbd_conf *mdev, struct page *page,
-                   int offset, size_t size)
+                   int offset, size_t size, unsigned msg_flags)
 {
-        int sent = drbd_send(mdev, mdev->data.socket, kmap(page) + offset, size, 0);
+        int sent = drbd_send(mdev, mdev->data.socket, kmap(page) + offset, size, msg_flags);
         kunmap(page);
         if (sent == size)
                 mdev->send_cnt += size>>9;
@@ -2301,7 +2282,7 @@ static int _drbd_no_send_page(struct drbd_conf *mdev, struct page *page,
 }
 
 static int _drbd_send_page(struct drbd_conf *mdev, struct page *page,
-                    int offset, size_t size)
+                    int offset, size_t size, unsigned msg_flags)
 {
         mm_segment_t oldfs = get_fs();
         int sent, ok;
@@ -2314,14 +2295,15 @@ static int _drbd_send_page(struct drbd_conf *mdev, struct page *page,
          * __page_cache_release a page that would actually still be referenced
          * by someone, leading to some obscure delayed Oops somewhere else. */
         if (disable_sendpage || (page_count(page) < 1) || PageSlab(page))
-                return _drbd_no_send_page(mdev, page, offset, size);
+                return _drbd_no_send_page(mdev, page, offset, size, msg_flags);
 
+        msg_flags |= MSG_NOSIGNAL;
         drbd_update_congested(mdev);
         set_fs(KERNEL_DS);
         do {
                 sent = mdev->data.socket->ops->sendpage(mdev->data.socket, page,
                                                         offset, len,
-                                                        MSG_NOSIGNAL);
+                                                        msg_flags);
                 if (sent == -EAGAIN) {
                         if (we_should_drop_the_connection(mdev,
                                                           mdev->data.socket))
@@ -2350,9 +2332,11 @@ static int _drbd_send_bio(struct drbd_conf *mdev, struct bio *bio)
 {
         struct bio_vec *bvec;
         int i;
+        /* hint all but last page with MSG_MORE */
         __bio_for_each_segment(bvec, bio, i, 0) {
                 if (!_drbd_no_send_page(mdev, bvec->bv_page,
-                                     bvec->bv_offset, bvec->bv_len))
+                                     bvec->bv_offset, bvec->bv_len,
+                                     i == bio->bi_vcnt -1 ? 0 : MSG_MORE))
                         return 0;
         }
         return 1;
@@ -2362,12 +2346,13 @@ static int _drbd_send_zc_bio(struct drbd_conf *mdev, struct bio *bio)
 {
         struct bio_vec *bvec;
         int i;
+        /* hint all but last page with MSG_MORE */
         __bio_for_each_segment(bvec, bio, i, 0) {
                 if (!_drbd_send_page(mdev, bvec->bv_page,
-                                     bvec->bv_offset, bvec->bv_len))
+                                     bvec->bv_offset, bvec->bv_len,
+                                     i == bio->bi_vcnt -1 ? 0 : MSG_MORE))
                         return 0;
         }
-
         return 1;
 }
 
@@ -2375,9 +2360,11 @@ static int _drbd_send_zc_ee(struct drbd_conf *mdev, struct drbd_epoch_entry *e)
 {
         struct page *page = e->pages;
         unsigned len = e->size;
+        /* hint all but last page with MSG_MORE */
         page_chain_for_each(page) {
                 unsigned l = min_t(unsigned, len, PAGE_SIZE);
-                if (!_drbd_send_page(mdev, page, 0, l))
+                if (!_drbd_send_page(mdev, page, 0, l,
+                                page_chain_next(page) ? MSG_MORE : 0))
                         return 0;
                 len -= l;
         }
@@ -2457,11 +2444,11 @@ int drbd_send_dblock(struct drbd_conf *mdev, struct drbd_request *req)
         p.dp_flags = cpu_to_be32(dp_flags);
         set_bit(UNPLUG_REMOTE, &mdev->flags);
         ok = (sizeof(p) ==
-                drbd_send(mdev, mdev->data.socket, &p, sizeof(p), MSG_MORE));
+                drbd_send(mdev, mdev->data.socket, &p, sizeof(p), dgs ? MSG_MORE : 0));
         if (ok && dgs) {
                 dgb = mdev->int_dig_out;
                 drbd_csum_bio(mdev, mdev->integrity_w_tfm, req->master_bio, dgb);
-                ok = drbd_send(mdev, mdev->data.socket, dgb, dgs, MSG_MORE);
+                ok = drbd_send(mdev, mdev->data.socket, dgb, dgs, 0);
         }
         if (ok) {
                 if (mdev->net_conf->wire_protocol == DRBD_PROT_A)
@@ -2510,11 +2497,11 @@ int drbd_send_block(struct drbd_conf *mdev, enum drbd_packets cmd,
                 return 0;
 
         ok = sizeof(p) == drbd_send(mdev, mdev->data.socket, &p,
-                                        sizeof(p), MSG_MORE);
+                                        sizeof(p), dgs ? MSG_MORE : 0);
         if (ok && dgs) {
                 dgb = mdev->int_dig_out;
                 drbd_csum_ee(mdev, mdev->integrity_w_tfm, e, dgb);
-                ok = drbd_send(mdev, mdev->data.socket, dgb, dgs, MSG_MORE);
+                ok = drbd_send(mdev, mdev->data.socket, dgb, dgs, 0);
         }
         if (ok)
                 ok = _drbd_send_zc_ee(mdev, e);
@@ -2708,7 +2695,6 @@ void drbd_init_set_defaults(struct drbd_conf *mdev)
         atomic_set(&mdev->net_cnt, 0);
         atomic_set(&mdev->packet_seq, 0);
         atomic_set(&mdev->pp_in_use, 0);
-        atomic_set(&mdev->new_c_uuid, 0);
 
         mutex_init(&mdev->md_io_mutex);
         mutex_init(&mdev->data.mutex);
@@ -2739,14 +2725,12 @@ void drbd_init_set_defaults(struct drbd_conf *mdev)
         INIT_LIST_HEAD(&mdev->bm_io_work.w.list);
         INIT_LIST_HEAD(&mdev->delay_probes);
         INIT_LIST_HEAD(&mdev->delay_probe_work.list);
-        INIT_LIST_HEAD(&mdev->uuid_work.list);
 
         mdev->resync_work.cb  = w_resync_inactive;
         mdev->unplug_work.cb  = w_send_write_hint;
         mdev->md_sync_work.cb = w_md_sync;
         mdev->bm_io_work.w.cb = w_bitmap_io;
         mdev->delay_probe_work.cb = w_delay_probes;
-        mdev->uuid_work.cb = w_new_current_uuid;
         init_timer(&mdev->resync_timer);
         init_timer(&mdev->md_sync_timer);
         init_timer(&mdev->delay_probe_timer);
@@ -3799,7 +3783,7 @@ _drbd_insert_fault(struct drbd_conf *mdev, unsigned int type)
         if (ret) {
                 fault_count++;
 
-                if (printk_ratelimit())
+                if (__ratelimit(&drbd_ratelimit_state))
                         dev_warn(DEV, "***Simulating %s failure\n",
                                 _drbd_fault_str(type));
         }
diff --git a/drivers/block/drbd/drbd_receiver.c b/drivers/block/drbd/drbd_receiver.c
index bc9ab7fb2cc7..dff48701b84d 100644
--- a/drivers/block/drbd/drbd_receiver.c
+++ b/drivers/block/drbd/drbd_receiver.c
@@ -42,7 +42,6 @@
 #include <linux/unistd.h>
 #include <linux/vmalloc.h>
 #include <linux/random.h>
-#include <linux/mm.h>
 #include <linux/string.h>
 #include <linux/scatterlist.h>
 #include "drbd_int.h"
@@ -571,6 +570,25 @@ static int drbd_recv(struct drbd_conf *mdev, void *buf, size_t size)
         return rv;
 }
 
+/* quoting tcp(7):
+ *   On individual connections, the socket buffer size must be set prior to the
+ *   listen(2) or connect(2) calls in order to have it take effect.
+ * This is our wrapper to do so.
+ */
+static void drbd_setbufsize(struct socket *sock, unsigned int snd,
+                unsigned int rcv)
+{
+        /* open coded SO_SNDBUF, SO_RCVBUF */
+        if (snd) {
+                sock->sk->sk_sndbuf = snd;
+                sock->sk->sk_userlocks |= SOCK_SNDBUF_LOCK;
+        }
+        if (rcv) {
+                sock->sk->sk_rcvbuf = rcv;
+                sock->sk->sk_userlocks |= SOCK_RCVBUF_LOCK;
+        }
+}
+
 static struct socket *drbd_try_connect(struct drbd_conf *mdev)
 {
         const char *what;
@@ -592,6 +610,8 @@ static struct socket *drbd_try_connect(struct drbd_conf *mdev)
 
         sock->sk->sk_rcvtimeo =
         sock->sk->sk_sndtimeo =  mdev->net_conf->try_connect_int*HZ;
+        drbd_setbufsize(sock, mdev->net_conf->sndbuf_size,
+                        mdev->net_conf->rcvbuf_size);
 
        /* explicitly bind to the configured IP as source IP
         *  for the outgoing connections.
@@ -670,6 +690,8 @@ static struct socket *drbd_wait_for_connect(struct drbd_conf *mdev)
         s_listen->sk->sk_reuse    = 1; /* SO_REUSEADDR */
         s_listen->sk->sk_rcvtimeo = timeo;
         s_listen->sk->sk_sndtimeo = timeo;
+        drbd_setbufsize(s_listen, mdev->net_conf->sndbuf_size,
+                        mdev->net_conf->rcvbuf_size);
 
         what = "bind before listen";
         err = s_listen->ops->bind(s_listen,
@@ -856,16 +878,6 @@ retry:
         sock->sk->sk_priority = TC_PRIO_INTERACTIVE_BULK;
         msock->sk->sk_priority = TC_PRIO_INTERACTIVE;
 
-        if (mdev->net_conf->sndbuf_size) {
-                sock->sk->sk_sndbuf = mdev->net_conf->sndbuf_size;
-                sock->sk->sk_userlocks |= SOCK_SNDBUF_LOCK;
-        }
-
-        if (mdev->net_conf->rcvbuf_size) {
-                sock->sk->sk_rcvbuf = mdev->net_conf->rcvbuf_size;
-                sock->sk->sk_userlocks |= SOCK_RCVBUF_LOCK;
-        }
-
         /* NOT YET ...
          * sock->sk->sk_sndtimeo = mdev->net_conf->timeout*HZ/10;
          * sock->sk->sk_rcvtimeo = MAX_SCHEDULE_TIMEOUT;
@@ -1154,17 +1166,6 @@ int drbd_submit_ee(struct drbd_conf *mdev, struct drbd_epoch_entry *e,
         unsigned n_bios = 0;
         unsigned nr_pages = (ds + PAGE_SIZE -1) >> PAGE_SHIFT;
 
-        if (atomic_read(&mdev->new_c_uuid)) {
-                if (atomic_add_unless(&mdev->new_c_uuid, -1, 1)) {
-                        drbd_uuid_new_current(mdev);
-                        drbd_md_sync(mdev);
-
-                        atomic_dec(&mdev->new_c_uuid);
-                        wake_up(&mdev->misc_wait);
-                }
-                wait_event(mdev->misc_wait, !atomic_read(&mdev->new_c_uuid));
-        }
-
         /* In most cases, we will only need one bio.  But in case the lower
          * level restrictions happen to be different at this offset on this
          * side than those of the sending peer, we may need to submit the
diff --git a/drivers/block/drbd/drbd_req.c b/drivers/block/drbd/drbd_req.c
index 3397f11d0ba9..654f1ef5cbb0 100644
--- a/drivers/block/drbd/drbd_req.c
+++ b/drivers/block/drbd/drbd_req.c
@@ -102,32 +102,7 @@ static void _req_is_done(struct drbd_conf *mdev, struct drbd_request *req, const
                 }
         }
 
-        /* if it was a local io error, we want to notify our
-         * peer about that, and see if we need to
-         * detach the disk and stuff.
-         * to avoid allocating some special work
-         * struct, reuse the request. */
-
-        /* THINK
-         * why do we do this not when we detect the error,
-         * but delay it until it is "done", i.e. possibly
-         * until the next barrier ack? */
-
-        if (rw == WRITE &&
-            ((s & RQ_LOCAL_MASK) && !(s & RQ_LOCAL_OK))) {
-                if (!(req->w.list.next == LIST_POISON1 ||
-                      list_empty(&req->w.list))) {
-                        /* DEBUG ASSERT only; if this triggers, we
-                         * probably corrupt the worker list here */
-                        dev_err(DEV, "req->w.list.next = %p\n", req->w.list.next);
-                        dev_err(DEV, "req->w.list.prev = %p\n", req->w.list.prev);
-                }
-                req->w.cb = w_io_error;
-                drbd_queue_work(&mdev->data.work, &req->w);
-                /* drbd_req_free() is done in w_io_error */
-        } else {
-                drbd_req_free(req);
-        }
+        drbd_req_free(req);
 }
 
 static void queue_barrier(struct drbd_conf *mdev)
@@ -453,9 +428,6 @@ void __req_mod(struct drbd_request *req, enum drbd_req_event what,
                 req->rq_state |= RQ_LOCAL_COMPLETED;
                 req->rq_state &= ~RQ_LOCAL_PENDING;
 
-                dev_alert(DEV, "Local WRITE failed sec=%llus size=%u\n",
-                      (unsigned long long)req->sector, req->size);
-                /* and now: check how to handle local io error. */
                 __drbd_chk_io_error(mdev, FALSE);
                 _req_may_be_done(req, m);
                 put_ldev(mdev);
@@ -475,22 +447,21 @@ void __req_mod(struct drbd_request *req, enum drbd_req_event what,
                 req->rq_state |= RQ_LOCAL_COMPLETED;
                 req->rq_state &= ~RQ_LOCAL_PENDING;
 
-                dev_alert(DEV, "Local READ failed sec=%llus size=%u\n",
-                      (unsigned long long)req->sector, req->size);
-                /* _req_mod(req,to_be_send); oops, recursion... */
                 D_ASSERT(!(req->rq_state & RQ_NET_MASK));
-                req->rq_state |= RQ_NET_PENDING;
-                inc_ap_pending(mdev);
 
                 __drbd_chk_io_error(mdev, FALSE);
                 put_ldev(mdev);
-                /* NOTE: if we have no connection,
-                 * or know the peer has no good data either,
-                 * then we don't actually need to "queue_for_net_read",
-                 * but we do so anyways, since the drbd_io_error()
-                 * and the potential state change to "Diskless"
-                 * needs to be done from process context */
 
+                /* no point in retrying if there is no good remote data,
+                 * or we have no connection. */
+                if (mdev->state.pdsk != D_UP_TO_DATE) {
+                        _req_may_be_done(req, m);
+                        break;
+                }
+
+                /* _req_mod(req,to_be_send); oops, recursion... */
+                req->rq_state |= RQ_NET_PENDING;
+                inc_ap_pending(mdev);
                 /* fall through: _req_mod(req,queue_for_net_read); */
 
         case queue_for_net_read:
@@ -600,6 +571,9 @@ void __req_mod(struct drbd_request *req, enum drbd_req_event what,
                 _req_may_be_done(req, m);
                 break;
 
+        case read_retry_remote_canceled:
+                req->rq_state &= ~RQ_NET_QUEUED;
+                /* fall through, in case we raced with drbd_disconnect */
         case connection_lost_while_pending:
                 /* transfer log cleanup after connection loss */
                 /* assert something? */
diff --git a/drivers/block/drbd/drbd_req.h b/drivers/block/drbd/drbd_req.h
index 16119d7056cc..02d575d24518 100644
--- a/drivers/block/drbd/drbd_req.h
+++ b/drivers/block/drbd/drbd_req.h
@@ -91,6 +91,7 @@ enum drbd_req_event {
         send_failed,
         handed_over_to_network,
         connection_lost_while_pending,
+        read_retry_remote_canceled,
         recv_acked_by_peer,
         write_acked_by_peer,
         write_acked_by_peer_and_sis, /* and set_in_sync */
diff --git a/drivers/block/drbd/drbd_worker.c b/drivers/block/drbd/drbd_worker.c
index 727ff6339754..b623ceee2a4a 100644
--- a/drivers/block/drbd/drbd_worker.c
+++ b/drivers/block/drbd/drbd_worker.c
@@ -224,9 +224,6 @@ void drbd_endio_pri(struct bio *bio, int error)
         enum drbd_req_event what;
         int uptodate = bio_flagged(bio, BIO_UPTODATE);
 
-        if (error)
-                dev_warn(DEV, "p %s: error=%d\n",
-                         bio_data_dir(bio) == WRITE ? "write" : "read", error);
         if (!error && !uptodate) {
                 dev_warn(DEV, "p %s: setting error to -EIO\n",
                          bio_data_dir(bio) == WRITE ? "write" : "read");
@@ -257,20 +254,6 @@ void drbd_endio_pri(struct bio *bio, int error)
                 complete_master_bio(mdev, &m);
 }
 
-int w_io_error(struct drbd_conf *mdev, struct drbd_work *w, int cancel)
-{
-        struct drbd_request *req = container_of(w, struct drbd_request, w);
-
-        /* NOTE: mdev->ldev can be NULL by the time we get here! */
-        /* D_ASSERT(mdev->ldev->dc.on_io_error != EP_PASS_ON); */
-
-        /* the only way this callback is scheduled is from _req_may_be_done,
-         * when it is done and had a local write error, see comments there */
-        drbd_req_free(req);
-
-        return TRUE;
-}
-
 int w_read_retry_remote(struct drbd_conf *mdev, struct drbd_work *w, int cancel)
 {
         struct drbd_request *req = container_of(w, struct drbd_request, w);
@@ -280,12 +263,9 @@ int w_read_retry_remote(struct drbd_conf *mdev, struct drbd_work *w, int cancel)
          * to give the disk the chance to relocate that block */
 
         spin_lock_irq(&mdev->req_lock);
-        if (cancel ||
-            mdev->state.conn < C_CONNECTED ||
-            mdev->state.pdsk <= D_INCONSISTENT) {
-                _req_mod(req, send_canceled);
+        if (cancel || mdev->state.pdsk != D_UP_TO_DATE) {
+                _req_mod(req, read_retry_remote_canceled);
                 spin_unlock_irq(&mdev->req_lock);
-                dev_alert(DEV, "WE ARE LOST. Local IO failure, no peer.\n");
                 return 1;
         }
         spin_unlock_irq(&mdev->req_lock);