[PATCH] isdn4linux: Siemens Gigaset drivers: make some variables non-atomic
With Hansjoerg Lipp <hjlipp@web.de>
Replace some atomic_t variables in the Gigaset drivers by non-atomic ones,
using spinlocks instead to assure atomicity, as proposed in discussions on the
linux-kernel mailing list.
Signed-off-by: Hansjoerg Lipp <hjlipp@web.de>
Signed-off-by: Tilman Schmidt <tilman@imap.cc>
Cc: Karsten Keil <kkeil@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/drivers/isdn/gigaset/ev-layer.c b/drivers/isdn/gigaset/ev-layer.c
index 2e826d0..1ba3424 100644
--- a/drivers/isdn/gigaset/ev-layer.c
+++ b/drivers/isdn/gigaset/ev-layer.c
@@ -482,14 +482,6 @@
return v;
}
-static inline void new_index(atomic_t *index, int max)
-{
- if (atomic_read(index) == max) //FIXME race?
- atomic_set(index, 0);
- else
- atomic_inc(index);
-}
-
/* retrieve CID from parsed response
* returns 0 if no CID, -1 if invalid CID, or CID value 1..65535
*/
@@ -581,8 +573,8 @@
}
spin_lock_irqsave(&cs->ev_lock, flags);
- head = atomic_read(&cs->ev_head);
- tail = atomic_read(&cs->ev_tail);
+ head = cs->ev_head;
+ tail = cs->ev_tail;
abort = 1;
curarg = 0;
@@ -715,7 +707,7 @@
break;
}
- atomic_set(&cs->ev_tail, tail);
+ cs->ev_tail = tail;
spin_unlock_irqrestore(&cs->ev_lock, flags);
if (curarg != params)
@@ -734,14 +726,16 @@
struct bc_state *bcs = (*at_state_p)->bcs;
struct cardstate *cs = (*at_state_p)->cs;
- new_index(&(*at_state_p)->seq_index, MAX_SEQ_INDEX);
+ spin_lock_irqsave(&cs->lock, flags);
+ ++(*at_state_p)->seq_index;
/* revert to selected idle mode */
- if (!atomic_read(&cs->cidmode)) {
+ if (!cs->cidmode) {
cs->at_state.pending_commands |= PC_UMMODE;
atomic_set(&cs->commands_pending, 1); //FIXME
gig_dbg(DEBUG_CMD, "Scheduling PC_UMMODE");
}
+ spin_unlock_irqrestore(&cs->lock, flags);
if (bcs) {
/* B channel assigned: invoke hardware specific handler */
@@ -933,17 +927,21 @@
gigaset_i4l_channel_cmd(bcs, ISDN_STAT_BCONN);
}
-static void start_dial(struct at_state_t *at_state, void *data, int seq_index)
+static void start_dial(struct at_state_t *at_state, void *data, unsigned seq_index)
{
struct bc_state *bcs = at_state->bcs;
struct cardstate *cs = at_state->cs;
int retval;
+ unsigned long flags;
bcs->chstate |= CHS_NOTIFY_LL;
- //atomic_set(&bcs->status, BCS_INIT);
- if (atomic_read(&at_state->seq_index) != seq_index)
+ spin_lock_irqsave(&cs->lock, flags);
+ if (at_state->seq_index != seq_index) {
+ spin_unlock_irqrestore(&cs->lock, flags);
goto error;
+ }
+ spin_unlock_irqrestore(&cs->lock, flags);
retval = gigaset_isdn_setup_dial(at_state, data);
if (retval != 0)
@@ -988,6 +986,7 @@
if (atomic_read(&cs->mstate) != MS_LOCKED)
schedule_init(cs, MS_INIT);
+ cs->isdn_up = 1;
gigaset_i4l_cmd(cs, ISDN_STAT_RUN);
// FIXME: not in locked mode
// FIXME 2: only after init sequence
@@ -1003,6 +1002,12 @@
atomic_set(&cs->mode, M_UNKNOWN);
}
+ /* Tell the LL that the device is not available .. */
+ if (cs->isdn_up) {
+ cs->isdn_up = 0;
+ gigaset_i4l_cmd(cs, ISDN_STAT_STOP);
+ }
+
/* The rest is done by cleanup_cs () in user mode. */
cs->cmd_result = -ENODEV;
@@ -1025,6 +1030,12 @@
static void do_stop(struct cardstate *cs)
{
+ unsigned long flags;
+
+ spin_lock_irqsave(&cs->lock, flags);
+ cs->connected = 0;
+ spin_unlock_irqrestore(&cs->lock, flags);
+
do_shutdown(cs);
}
@@ -1153,7 +1164,7 @@
atomic_set(&cs->mstate, MS_UNINITIALIZED);
atomic_set(&cs->mode, M_UNKNOWN);
gigaset_free_channels(cs);
- if (atomic_read(&cs->connected))
+ if (cs->connected)
schedule_init(cs, MS_INIT);
return 0;
@@ -1185,11 +1196,14 @@
cs->at_state.pending_commands &= ~PC_INIT;
cs->cur_at_seq = SEQ_NONE;
atomic_set(&cs->mode, M_UNIMODEM);
- if (!atomic_read(&cs->cidmode)) {
+ spin_lock_irqsave(&cs->lock, flags);
+ if (!cs->cidmode) {
+ spin_unlock_irqrestore(&cs->lock, flags);
gigaset_free_channels(cs);
atomic_set(&cs->mstate, MS_READY);
break;
}
+ spin_unlock_irqrestore(&cs->lock, flags);
cs->at_state.pending_commands |= PC_CIDMODE;
atomic_set(&cs->commands_pending, 1);
gig_dbg(DEBUG_CMD, "Scheduling PC_CIDMODE");
@@ -1536,8 +1550,9 @@
/* events from the proc file system */ // FIXME without ACT_xxxx?
case ACT_PROC_CIDMODE:
- if (ev->parameter != atomic_read(&cs->cidmode)) {
- atomic_set(&cs->cidmode, ev->parameter);
+ spin_lock_irqsave(&cs->lock, flags);
+ if (ev->parameter != cs->cidmode) {
+ cs->cidmode = ev->parameter;
if (ev->parameter) {
cs->at_state.pending_commands |= PC_CIDMODE;
gig_dbg(DEBUG_CMD, "Scheduling PC_CIDMODE");
@@ -1547,6 +1562,7 @@
}
atomic_set(&cs->commands_pending, 1);
}
+ spin_unlock_irqrestore(&cs->lock, flags);
cs->waiting = 0;
wake_up(&cs->waitqueue);
break;
@@ -1615,8 +1631,9 @@
/* Setting the pointer to the dial array */
rep = at_state->replystruct;
+ spin_lock_irqsave(&cs->lock, flags);
if (ev->type == EV_TIMEOUT) {
- if (ev->parameter != atomic_read(&at_state->timer_index)
+ if (ev->parameter != at_state->timer_index
|| !at_state->timer_active) {
ev->type = RSP_NONE; /* old timeout */
gig_dbg(DEBUG_ANY, "old timeout");
@@ -1625,6 +1642,7 @@
else
gig_dbg(DEBUG_ANY, "stopped waiting");
}
+ spin_unlock_irqrestore(&cs->lock, flags);
/* if the response belongs to a variable in at_state->int_var[VAR_XXXX]
or at_state->str_var[STR_XXXX], set it */
@@ -1686,7 +1704,7 @@
} else {
/* Send command to modem if not NULL... */
if (p_command/*rep->command*/) {
- if (atomic_read(&cs->connected))
+ if (cs->connected)
send_command(cs, p_command,
sendcid, cs->dle,
GFP_ATOMIC);
@@ -1703,8 +1721,7 @@
} else if (rep->timeout > 0) { /* new timeout */
at_state->timer_expires = rep->timeout * 10;
at_state->timer_active = 1;
- new_index(&at_state->timer_index,
- MAX_TIMER_INDEX);
+ ++at_state->timer_index;
}
spin_unlock_irqrestore(&cs->lock, flags);
}
@@ -1724,6 +1741,7 @@
struct bc_state *bcs;
int i;
int sequence;
+ unsigned long flags;
atomic_set(&cs->commands_pending, 0);
@@ -1773,8 +1791,9 @@
}
/* only switch back to unimodem mode, if no commands are pending and no channels are up */
+ spin_lock_irqsave(&cs->lock, flags);
if (cs->at_state.pending_commands == PC_UMMODE
- && !atomic_read(&cs->cidmode)
+ && !cs->cidmode
&& list_empty(&cs->temp_at_states)
&& atomic_read(&cs->mode) == M_CID) {
sequence = SEQ_UMMODE;
@@ -1788,6 +1807,7 @@
}
}
}
+ spin_unlock_irqrestore(&cs->lock, flags);
cs->at_state.pending_commands &= ~PC_UMMODE;
if (sequence != SEQ_NONE) {
schedule_sequence(cs, at_state, sequence);
@@ -1900,18 +1920,21 @@
int i;
int check_flags = 0;
int was_busy;
+ unsigned long flags;
- /* no locking needed (only one reader) */
- head = atomic_read(&cs->ev_head);
+ spin_lock_irqsave(&cs->ev_lock, flags);
+ head = cs->ev_head;
for (i = 0; i < 2 * MAX_EVENTS; ++i) {
- tail = atomic_read(&cs->ev_tail);
+ tail = cs->ev_tail;
if (tail == head) {
if (!check_flags && !atomic_read(&cs->commands_pending))
break;
check_flags = 0;
+ spin_unlock_irqrestore(&cs->ev_lock, flags);
process_command_flags(cs);
- tail = atomic_read(&cs->ev_tail);
+ spin_lock_irqsave(&cs->ev_lock, flags);
+ tail = cs->ev_tail;
if (tail == head) {
if (!atomic_read(&cs->commands_pending))
break;
@@ -1921,16 +1944,20 @@
ev = cs->events + head;
was_busy = cs->cur_at_seq != SEQ_NONE;
+ spin_unlock_irqrestore(&cs->ev_lock, flags);
process_event(cs, ev);
+ spin_lock_irqsave(&cs->ev_lock, flags);
kfree(ev->ptr);
ev->ptr = NULL;
if (was_busy && cs->cur_at_seq == SEQ_NONE)
check_flags = 1;
head = (head + 1) % MAX_EVENTS;
- atomic_set(&cs->ev_head, head);
+ cs->ev_head = head;
}
+ spin_unlock_irqrestore(&cs->ev_lock, flags);
+
if (i == 2 * MAX_EVENTS) {
dev_err(cs->dev,
"infinite loop in process_events; aborting.\n");