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Commit c728cc88 authored by Arnd Bergmann's avatar Arnd Bergmann Committed by David S. Miller
Browse files

isdn: hisax/elsa: fix sleep_on race in elsa FSM 



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: default avatarArnd Bergmann <arnd@arndb.de>
Cc: Karsten Keil <isdn@linux-pingi.de>
Cc: netdev@vger.kernel.org
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent e5b3fa15

drivers/isdn/hisax/elsa.c

+6 −3
Original line number Diff line number Diff line
@@ -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);

drivers/isdn/hisax/elsa_ser.c

+2 −1
Original line number Diff line number Diff line
@@ -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);