From: Finn Thain fthain@telegraphics.com.au
[ Upstream commit aeb445bf2194d83e12e85bf5c65baaf1f093bd8f ]
In the following sequence of calls, iop_do_send() gets called when the "send" channel is not in the IOP_MSG_IDLE state:
iop_ism_irq() iop_handle_send() (msg->handler)() iop_send_message() iop_do_send()
Avoid this by testing the channel state before calling iop_do_send().
When sending, and iop_send_queue is empty, call iop_do_send() because the channel is idle. If iop_send_queue is not empty, iop_do_send() will get called later by iop_handle_send().
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Finn Thain fthain@telegraphics.com.au Tested-by: Stan Johnson userm57@yahoo.com Cc: Joshua Thompson funaho@jurai.org Link: https://lore.kernel.org/r/6d667c39e53865661fa5a48f16829d18ed8abe54.159088033... Signed-off-by: Geert Uytterhoeven geert@linux-m68k.org Signed-off-by: Sasha Levin sashal@kernel.org Signed-off-by: Yang Yingliang yangyingliang@huawei.com --- arch/m68k/mac/iop.c | 9 +++------ 1 file changed, 3 insertions(+), 6 deletions(-)
diff --git a/arch/m68k/mac/iop.c b/arch/m68k/mac/iop.c index 9bfa170157688..d8f2282978f9c 100644 --- a/arch/m68k/mac/iop.c +++ b/arch/m68k/mac/iop.c @@ -416,7 +416,8 @@ static void iop_handle_send(uint iop_num, uint chan) msg->status = IOP_MSGSTATUS_UNUSED; msg = msg->next; iop_send_queue[iop_num][chan] = msg; - if (msg) iop_do_send(msg); + if (msg && iop_readb(iop, IOP_ADDR_SEND_STATE + chan) == IOP_MSG_IDLE) + iop_do_send(msg); }
/* @@ -490,16 +491,12 @@ int iop_send_message(uint iop_num, uint chan, void *privdata,
if (!(q = iop_send_queue[iop_num][chan])) { iop_send_queue[iop_num][chan] = msg; + iop_do_send(msg); } else { while (q->next) q = q->next; q->next = msg; }
- if (iop_readb(iop_base[iop_num], - IOP_ADDR_SEND_STATE + chan) == IOP_MSG_IDLE) { - iop_do_send(msg); - } - return 0; }