tree fab1bf78b9d4294786986a692b2ad17467fcf8e2
parent a4f6a0f52a6da052c92ed74cbcfef9bad0bea759
author Finn Thain <fthain@telegraphics.com.au> 1590880333 +1000
committer Greg Kroah-Hartman <gregkh@linuxfoundation.org> 1598000517 +0200

m68k: mac: Don't send IOP message until channel is idle

[ 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/6d667c39e53865661fa5a48f16829d18ed8abe54.1590880333.git.fthain@telegraphics.com.au
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>