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Subject[PATCH 13/16] isdn: hisax/elsa: fix sleep_on race in elsa FSM
Date
The state machine code in the elsa driver uses interruptible_sleep_on
to wait for state changes, which is racy. A closer look at the possible
states reveals that it is always used to wait for getting back into
ARCOFI_NOP, so we can use wait_event_interruptible instead.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Karsten Keil <isdn@linux-pingi.de>
Cc: netdev@vger.kernel.org
---
drivers/isdn/hisax/elsa.c | 9 ++++++---
drivers/isdn/hisax/elsa_ser.c | 3 ++-
2 files changed, 8 insertions(+), 4 deletions(-)

diff --git a/drivers/isdn/hisax/elsa.c b/drivers/isdn/hisax/elsa.c
index 2be1c8a..d8ef64d 100644
--- a/drivers/isdn/hisax/elsa.c
+++ b/drivers/isdn/hisax/elsa.c
@@ -509,7 +509,8 @@ static void
set_arcofi(struct IsdnCardState *cs, int bc) {
cs->dc.isac.arcofi_bc = bc;
arcofi_fsm(cs, ARCOFI_START, &ARCOFI_COP_5);
- interruptible_sleep_on(&cs->dc.isac.arcofi_wait);
+ wait_event_interruptible(cs->dc.isac.arcofi_wait,
+ cs->dc.isac.arcofi_state == ARCOFI_NOP);
}

static int
@@ -528,7 +529,8 @@ check_arcofi(struct IsdnCardState *cs)
}
cs->dc.isac.arcofi_bc = 0;
arcofi_fsm(cs, ARCOFI_START, &ARCOFI_VERSION);
- interruptible_sleep_on(&cs->dc.isac.arcofi_wait);
+ wait_event_interruptible(cs->dc.isac.arcofi_wait,
+ cs->dc.isac.arcofi_state == ARCOFI_NOP);
if (!test_and_clear_bit(FLG_ARCOFI_ERROR, &cs->HW_Flags)) {
debugl1(cs, "Arcofi response received %d bytes", cs->dc.isac.mon_rxp);
p = cs->dc.isac.mon_rx;
@@ -595,7 +597,8 @@ check_arcofi(struct IsdnCardState *cs)
Elsa_Types[cs->subtyp],
cs->hw.elsa.base + 8);
arcofi_fsm(cs, ARCOFI_START, &ARCOFI_XOP_0);
- interruptible_sleep_on(&cs->dc.isac.arcofi_wait);
+ wait_event_interruptible(cs->dc.isac.arcofi_wait,
+ cs->dc.isac.arcofi_state == ARCOFI_NOP);
return (1);
}
return (0);
diff --git a/drivers/isdn/hisax/elsa_ser.c b/drivers/isdn/hisax/elsa_ser.c
index 3f84dd8..a2a358c 100644
--- a/drivers/isdn/hisax/elsa_ser.c
+++ b/drivers/isdn/hisax/elsa_ser.c
@@ -573,7 +573,8 @@ modem_l2l1(struct PStack *st, int pr, void *arg)
test_and_clear_bit(BC_FLG_ACTIV, &bcs->Flag);
bcs->cs->dc.isac.arcofi_bc = st->l1.bc;
arcofi_fsm(bcs->cs, ARCOFI_START, &ARCOFI_XOP_0);
- interruptible_sleep_on(&bcs->cs->dc.isac.arcofi_wait);
+ wait_event_interruptible(bcs->cs->dc.isac.arcofi_wait,
+ bcs->cs->dc.isac.arcofi_state == ARCOFI_NOP);
bcs->cs->hw.elsa.MFlag = 1;
} else {
printk(KERN_WARNING "ElsaSer: unknown pr %x\n", pr);
--
1.8.3.2


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