HID: cp2112: fix sleep-while-atomic

A recent commit fixing DMA-buffers on stack added a shared transfer
buffer protected by a spinlock. This is broken as the USB HID request
callbacks can sleep. Fix this up by replacing the spinlock with a mutex.

Fixes: 1ffb3c40ffb5 ("HID: cp2112: make transfer buffers DMA capable")
Cc: stable <stable@vger.kernel.org>	# 4.9
Signed-off-by: Johan Hovold <johan@kernel.org>
Reviewed-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

1 files changed, 5 insertions, 2 deletions

diff --git a/trafgen.c b/trafgen.c
index 3b2f471..ce2967d 100644
--- a/trafgen.c
+++ b/trafgen.c
@@ -342,11 +342,11 @@ static void apply_csum16(int csum_id)
 		struct csum16 *csum = &packet_dyn[i].csum[j];
 
 		fmemset(&packets[i].payload[csum->off], 0, sizeof(sum));
+		if (unlikely(csum->to >= packets[i].len))
+			csum->to = packets[i].len - 1;
 
 		switch (csum->which) {
 		case CSUM_IP:
-			if (csum->to >= packets[i].len)
-				csum->to = packets[i].len - 1;
 			sum = calc_csum(packets[i].payload + csum->from,
 					csum->to - csum->from + 1, 0);
 			break;
@@ -362,6 +362,9 @@ static void apply_csum16(int csum_id)
 				      (packets[i].len - csum->to),
 				      IPPROTO_TCP);
 			break;
+		default:
+			bug();
+			break;
 		}
 
 		fmemcpy(&packets[i].payload[csum->off], &sum, sizeof(sum));