[PATCH AUTOSEL 3.18 30/98] USB: EHCI: adjust error return code

Sasha Levin
2018-10-25T14:17:45Z

From: Alan Stern <stern@rowland.harvard.edu>

[ Upstream commit c401e7b4a808d50ab53ef45cb8d0b99b238bf2c9 ]

The USB stack uses error code -ENOSPC to indicate that the periodic
schedule is too full, with insufficient bandwidth to accommodate a new
allocation. It uses -EFBIG to indicate that an isochronous transfer
could not be linked into the schedule because it would exceed the
number of isochronous packets the host controller driver can handle
(generally because the new transfer would extend too far into the
future).

ehci-hcd uses the wrong error code at one point. This patch fixes it,
along with a misleading comment and debugging message.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/usb/host/ehci-sched.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/usb/host/ehci-sched.c b/drivers/usb/host/ehci-sched.c
index c399606f154e..f9a332775c47 100644
--- a/drivers/usb/host/ehci-sched.c
+++ b/drivers/usb/host/ehci-sched.c
@@ -1604,11 +1604,11 @@ iso_stream_schedule (
*/
now2 = (now - base) & (mod - 1);

- /* Is the schedule already full? */
+ /* Is the schedule about to wrap around? */
if (unlikely(!empty && start < period)) {
- ehci_dbg(ehci, "iso sched full %p (%u-%u < %u mod %u)\n",
+ ehci_dbg(ehci, "request %p would overflow (%u-%u < %u mod %u)\n",
urb, stream->next_uframe, base, period, mod);
- status = -ENOSPC;
+ status = -EFBIG;
goto fail;
}

--
2.17.1