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Commit | Line | Data |
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2cb7cef9 BS |
1 | From: Gerald Schaefer <geraldsc@de.ibm.com> |
2 | Subject: qdio: proper kill of qdio tasklets | |
3 | References: bnc#484767,LTC#52206 | |
4 | ||
5 | Symptom: kernel BUG at kernel/softirq.c:392! | |
6 | Problem: The queue tasklets were stopped with tasklet_disable. Although | |
7 | tasklet_disable prevents the tasklet from beeing executed it is | |
8 | still possible that a tasklet is scheduled on a CPU at that point. | |
9 | A following qdio_establish calls tasklet_init which clears the | |
10 | tasklet count and the tasklet state leading to the oops. | |
11 | Solution: Use tasklet_kill instead of tasklet_disbale. Since | |
12 | tasklet_schedule must not be called after tasklet_kill use the | |
13 | QDIO_IRQ_STATE_STOPPED to inidicate that a queue is going down | |
14 | and prevent further tasklet schedules in that case. | |
15 | ||
16 | Acked-by: John Jolly <jjolly@suse.de> | |
17 | --- | |
18 | drivers/s390/cio/qdio_main.c | 35 ++++++++++++++++++++++++----------- | |
19 | drivers/s390/cio/qdio_thinint.c | 8 ++++---- | |
20 | 2 files changed, 28 insertions(+), 15 deletions(-) | |
21 | ||
22 | Index: linux-sles11/drivers/s390/cio/qdio_main.c | |
23 | =================================================================== | |
24 | --- linux-sles11.orig/drivers/s390/cio/qdio_main.c | |
25 | +++ linux-sles11/drivers/s390/cio/qdio_main.c | |
26 | @@ -760,21 +760,17 @@ static void __qdio_outbound_processing(s | |
27 | if (qdio_outbound_q_moved(q)) | |
28 | qdio_kick_outbound_handler(q); | |
29 | ||
30 | - if (queue_type(q) == QDIO_ZFCP_QFMT) { | |
31 | + if (queue_type(q) == QDIO_ZFCP_QFMT) | |
32 | if (!pci_out_supported(q) && !qdio_outbound_q_done(q)) | |
33 | - tasklet_schedule(&q->tasklet); | |
34 | - return; | |
35 | - } | |
36 | + goto sched; | |
37 | ||
38 | /* bail out for HiperSockets unicast queues */ | |
39 | if (queue_type(q) == QDIO_IQDIO_QFMT && !multicast_outbound(q)) | |
40 | return; | |
41 | ||
42 | if ((queue_type(q) == QDIO_IQDIO_QFMT) && | |
43 | - (atomic_read(&q->nr_buf_used)) > QDIO_IQDIO_POLL_LVL) { | |
44 | - tasklet_schedule(&q->tasklet); | |
45 | - return; | |
46 | - } | |
47 | + (atomic_read(&q->nr_buf_used)) > QDIO_IQDIO_POLL_LVL) | |
48 | + goto sched; | |
49 | ||
50 | if (q->u.out.pci_out_enabled) | |
51 | return; | |
52 | @@ -792,6 +788,12 @@ static void __qdio_outbound_processing(s | |
53 | qdio_perf_stat_inc(&perf_stats.debug_tl_out_timer); | |
54 | } | |
55 | } | |
56 | + return; | |
57 | + | |
58 | +sched: | |
59 | + if (unlikely(q->irq_ptr->state == QDIO_IRQ_STATE_STOPPED)) | |
60 | + return; | |
61 | + tasklet_schedule(&q->tasklet); | |
62 | } | |
63 | ||
64 | /* outbound tasklet */ | |
65 | @@ -804,6 +806,9 @@ void qdio_outbound_processing(unsigned l | |
66 | void qdio_outbound_timer(unsigned long data) | |
67 | { | |
68 | struct qdio_q *q = (struct qdio_q *)data; | |
69 | + | |
70 | + if (unlikely(q->irq_ptr->state == QDIO_IRQ_STATE_STOPPED)) | |
71 | + return; | |
72 | tasklet_schedule(&q->tasklet); | |
73 | } | |
74 | ||
75 | @@ -845,6 +850,9 @@ static void qdio_int_handler_pci(struct | |
76 | int i; | |
77 | struct qdio_q *q; | |
78 | ||
79 | + if (unlikely(irq_ptr->state == QDIO_IRQ_STATE_STOPPED)) | |
80 | + return; | |
81 | + | |
82 | qdio_perf_stat_inc(&perf_stats.pci_int); | |
83 | ||
84 | for_each_input_queue(irq_ptr, q, i) | |
85 | @@ -1072,11 +1080,11 @@ static void qdio_shutdown_queues(struct | |
86 | int i; | |
87 | ||
88 | for_each_input_queue(irq_ptr, q, i) | |
89 | - tasklet_disable(&q->tasklet); | |
90 | + tasklet_kill(&q->tasklet); | |
91 | ||
92 | for_each_output_queue(irq_ptr, q, i) { | |
93 | - tasklet_disable(&q->tasklet); | |
94 | del_timer(&q->u.out.timer); | |
95 | + tasklet_kill(&q->tasklet); | |
96 | } | |
97 | } | |
98 | ||
99 | @@ -1107,6 +1115,12 @@ int qdio_shutdown(struct ccw_device *cde | |
100 | return 0; | |
101 | } | |
102 | ||
103 | + /* | |
104 | + * Indicate that the device is going down. Scheduling the queue | |
105 | + * tasklets is forbidden from here on. | |
106 | + */ | |
107 | + qdio_set_state(irq_ptr, QDIO_IRQ_STATE_STOPPED); | |
108 | + | |
109 | tiqdio_remove_input_queues(irq_ptr); | |
110 | qdio_shutdown_queues(cdev); | |
111 | qdio_shutdown_debug_entries(irq_ptr, cdev); | |
112 | @@ -1526,7 +1540,6 @@ static int handle_outbound(struct qdio_q | |
113 | qdio_perf_stat_inc(&perf_stats.fast_requeue); | |
114 | } | |
115 | out: | |
116 | - /* Fixme: could wait forever if called from process context */ | |
117 | tasklet_schedule(&q->tasklet); | |
118 | return rc; | |
119 | } | |
120 | Index: linux-sles11/drivers/s390/cio/qdio_thinint.c | |
121 | =================================================================== | |
122 | --- linux-sles11.orig/drivers/s390/cio/qdio_thinint.c | |
123 | +++ linux-sles11/drivers/s390/cio/qdio_thinint.c | |
124 | @@ -101,7 +101,6 @@ void tiqdio_add_input_queues(struct qdio | |
125 | list_add_rcu(&q->entry, &tiq_list); | |
126 | mutex_unlock(&tiq_list_lock); | |
127 | xchg(irq_ptr->dsci, 1); | |
128 | - tasklet_schedule(&tiqdio_tasklet); | |
129 | } | |
130 | ||
131 | /* | |
132 | @@ -159,7 +158,6 @@ static void __tiqdio_inbound_processing( | |
133 | */ | |
134 | qdio_check_outbound_after_thinint(q); | |
135 | ||
136 | -again: | |
137 | if (!qdio_inbound_q_moved(q)) | |
138 | return; | |
139 | ||
140 | @@ -167,7 +165,8 @@ again: | |
141 | ||
142 | if (!tiqdio_inbound_q_done(q)) { | |
143 | qdio_perf_stat_inc(&perf_stats.thinint_inbound_loop); | |
144 | - goto again; | |
145 | + if (likely(q->irq_ptr->state != QDIO_IRQ_STATE_STOPPED)) | |
146 | + tasklet_schedule(&q->tasklet); | |
147 | } | |
148 | ||
149 | qdio_stop_polling(q); | |
150 | @@ -177,7 +176,8 @@ again: | |
151 | */ | |
152 | if (!tiqdio_inbound_q_done(q)) { | |
153 | qdio_perf_stat_inc(&perf_stats.thinint_inbound_loop2); | |
154 | - goto again; | |
155 | + if (likely(q->irq_ptr->state != QDIO_IRQ_STATE_STOPPED)) | |
156 | + tasklet_schedule(&q->tasklet); | |
157 | } | |
158 | } | |
159 |