RDMA/cxgb4: DB Drop Recovery for RDMA and LLD queues
Add module option db_fc_threshold which is the count of active QPs that trigger automatic db flow control mode. Automatically transition to/from flow control mode when the active qp count crosses db_fc_theshold. Add more db debugfs stats On DB DROP event from the LLD, recover all the iwarp queues. Signed-off-by: Vipul Pandya <vipul@chelsio.com> Signed-off-by: Steve Wise <swise@opengridcomputing.com> Signed-off-by: Roland Dreier <roland@purestorage.com>
This commit is contained in:

committed by
Roland Dreier

parent
4984037bef
commit
422eea0a8c
@@ -246,6 +246,8 @@ static const struct file_operations stag_debugfs_fops = {
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.llseek = default_llseek,
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};
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static char *db_state_str[] = {"NORMAL", "FLOW_CONTROL", "RECOVERY"};
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static int stats_show(struct seq_file *seq, void *v)
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{
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struct c4iw_dev *dev = seq->private;
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@@ -272,6 +274,9 @@ static int stats_show(struct seq_file *seq, void *v)
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seq_printf(seq, " DB FULL: %10llu\n", dev->rdev.stats.db_full);
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seq_printf(seq, " DB EMPTY: %10llu\n", dev->rdev.stats.db_empty);
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seq_printf(seq, " DB DROP: %10llu\n", dev->rdev.stats.db_drop);
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seq_printf(seq, " DB State: %s Transitions %llu\n",
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db_state_str[dev->db_state],
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dev->rdev.stats.db_state_transitions);
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return 0;
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}
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@@ -295,6 +300,7 @@ static ssize_t stats_clear(struct file *file, const char __user *buf,
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dev->rdev.stats.db_full = 0;
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dev->rdev.stats.db_empty = 0;
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dev->rdev.stats.db_drop = 0;
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dev->rdev.stats.db_state_transitions = 0;
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mutex_unlock(&dev->rdev.stats.lock);
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return count;
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}
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@@ -677,8 +683,11 @@ static int disable_qp_db(int id, void *p, void *data)
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static void stop_queues(struct uld_ctx *ctx)
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{
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spin_lock_irq(&ctx->dev->lock);
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ctx->dev->db_state = FLOW_CONTROL;
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idr_for_each(&ctx->dev->qpidr, disable_qp_db, NULL);
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if (ctx->dev->db_state == NORMAL) {
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ctx->dev->rdev.stats.db_state_transitions++;
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ctx->dev->db_state = FLOW_CONTROL;
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idr_for_each(&ctx->dev->qpidr, disable_qp_db, NULL);
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}
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spin_unlock_irq(&ctx->dev->lock);
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}
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@@ -693,11 +702,167 @@ static int enable_qp_db(int id, void *p, void *data)
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static void resume_queues(struct uld_ctx *ctx)
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{
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spin_lock_irq(&ctx->dev->lock);
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ctx->dev->db_state = NORMAL;
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idr_for_each(&ctx->dev->qpidr, enable_qp_db, NULL);
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if (ctx->dev->qpcnt <= db_fc_threshold &&
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ctx->dev->db_state == FLOW_CONTROL) {
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ctx->dev->db_state = NORMAL;
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ctx->dev->rdev.stats.db_state_transitions++;
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idr_for_each(&ctx->dev->qpidr, enable_qp_db, NULL);
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}
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spin_unlock_irq(&ctx->dev->lock);
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}
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struct qp_list {
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unsigned idx;
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struct c4iw_qp **qps;
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};
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static int add_and_ref_qp(int id, void *p, void *data)
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{
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struct qp_list *qp_listp = data;
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struct c4iw_qp *qp = p;
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c4iw_qp_add_ref(&qp->ibqp);
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qp_listp->qps[qp_listp->idx++] = qp;
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return 0;
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}
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static int count_qps(int id, void *p, void *data)
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{
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unsigned *countp = data;
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(*countp)++;
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return 0;
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}
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static void deref_qps(struct qp_list qp_list)
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{
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int idx;
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for (idx = 0; idx < qp_list.idx; idx++)
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c4iw_qp_rem_ref(&qp_list.qps[idx]->ibqp);
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}
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static void recover_lost_dbs(struct uld_ctx *ctx, struct qp_list *qp_list)
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{
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int idx;
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int ret;
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for (idx = 0; idx < qp_list->idx; idx++) {
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struct c4iw_qp *qp = qp_list->qps[idx];
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ret = cxgb4_sync_txq_pidx(qp->rhp->rdev.lldi.ports[0],
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qp->wq.sq.qid,
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t4_sq_host_wq_pidx(&qp->wq),
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t4_sq_wq_size(&qp->wq));
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if (ret) {
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printk(KERN_ERR MOD "%s: Fatal error - "
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"DB overflow recovery failed - "
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"error syncing SQ qid %u\n",
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pci_name(ctx->lldi.pdev), qp->wq.sq.qid);
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return;
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}
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ret = cxgb4_sync_txq_pidx(qp->rhp->rdev.lldi.ports[0],
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qp->wq.rq.qid,
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t4_rq_host_wq_pidx(&qp->wq),
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t4_rq_wq_size(&qp->wq));
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if (ret) {
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printk(KERN_ERR MOD "%s: Fatal error - "
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"DB overflow recovery failed - "
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"error syncing RQ qid %u\n",
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pci_name(ctx->lldi.pdev), qp->wq.rq.qid);
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return;
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}
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/* Wait for the dbfifo to drain */
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while (cxgb4_dbfifo_count(qp->rhp->rdev.lldi.ports[0], 1) > 0) {
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set_current_state(TASK_UNINTERRUPTIBLE);
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schedule_timeout(usecs_to_jiffies(10));
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}
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}
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}
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static void recover_queues(struct uld_ctx *ctx)
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{
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int count = 0;
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struct qp_list qp_list;
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int ret;
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/* lock out kernel db ringers */
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mutex_lock(&ctx->dev->db_mutex);
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/* put all queues in to recovery mode */
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spin_lock_irq(&ctx->dev->lock);
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ctx->dev->db_state = RECOVERY;
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ctx->dev->rdev.stats.db_state_transitions++;
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idr_for_each(&ctx->dev->qpidr, disable_qp_db, NULL);
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spin_unlock_irq(&ctx->dev->lock);
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/* slow everybody down */
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set_current_state(TASK_UNINTERRUPTIBLE);
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schedule_timeout(usecs_to_jiffies(1000));
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/* Wait for the dbfifo to completely drain. */
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while (cxgb4_dbfifo_count(ctx->dev->rdev.lldi.ports[0], 1) > 0) {
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set_current_state(TASK_UNINTERRUPTIBLE);
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schedule_timeout(usecs_to_jiffies(10));
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}
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/* flush the SGE contexts */
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ret = cxgb4_flush_eq_cache(ctx->dev->rdev.lldi.ports[0]);
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if (ret) {
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printk(KERN_ERR MOD "%s: Fatal error - DB overflow recovery failed\n",
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pci_name(ctx->lldi.pdev));
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goto out;
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}
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/* Count active queues so we can build a list of queues to recover */
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spin_lock_irq(&ctx->dev->lock);
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idr_for_each(&ctx->dev->qpidr, count_qps, &count);
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qp_list.qps = kzalloc(count * sizeof *qp_list.qps, GFP_ATOMIC);
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if (!qp_list.qps) {
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printk(KERN_ERR MOD "%s: Fatal error - DB overflow recovery failed\n",
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pci_name(ctx->lldi.pdev));
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spin_unlock_irq(&ctx->dev->lock);
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goto out;
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}
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qp_list.idx = 0;
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/* add and ref each qp so it doesn't get freed */
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idr_for_each(&ctx->dev->qpidr, add_and_ref_qp, &qp_list);
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spin_unlock_irq(&ctx->dev->lock);
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/* now traverse the list in a safe context to recover the db state*/
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recover_lost_dbs(ctx, &qp_list);
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/* we're almost done! deref the qps and clean up */
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deref_qps(qp_list);
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kfree(qp_list.qps);
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/* Wait for the dbfifo to completely drain again */
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while (cxgb4_dbfifo_count(ctx->dev->rdev.lldi.ports[0], 1) > 0) {
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set_current_state(TASK_UNINTERRUPTIBLE);
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schedule_timeout(usecs_to_jiffies(10));
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}
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/* resume the queues */
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spin_lock_irq(&ctx->dev->lock);
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if (ctx->dev->qpcnt > db_fc_threshold)
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ctx->dev->db_state = FLOW_CONTROL;
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else {
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ctx->dev->db_state = NORMAL;
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idr_for_each(&ctx->dev->qpidr, enable_qp_db, NULL);
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}
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ctx->dev->rdev.stats.db_state_transitions++;
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spin_unlock_irq(&ctx->dev->lock);
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out:
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/* start up kernel db ringers again */
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mutex_unlock(&ctx->dev->db_mutex);
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}
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static int c4iw_uld_control(void *handle, enum cxgb4_control control, ...)
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{
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struct uld_ctx *ctx = handle;
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@@ -716,8 +881,7 @@ static int c4iw_uld_control(void *handle, enum cxgb4_control control, ...)
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mutex_unlock(&ctx->dev->rdev.stats.lock);
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break;
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case CXGB4_CONTROL_DB_DROP:
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printk(KERN_WARNING MOD "%s: Fatal DB DROP\n",
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pci_name(ctx->lldi.pdev));
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recover_queues(ctx);
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mutex_lock(&ctx->dev->rdev.stats.lock);
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ctx->dev->rdev.stats.db_drop++;
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mutex_unlock(&ctx->dev->rdev.stats.lock);
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