[PATCH net-next 02/14] net: cdc_ncm: use device rx_max value if update failed

["Bjørn Mork" <bjorn@mork.no>]

If the device refuses our updated value, then we must be prepared
to receive URBs as big as the device wants to send.  Set rx_max
to the device provided value on error.

Signed-off-by: Bjørn Mork <bjorn@mork.no>
---
 drivers/net/usb/cdc_ncm.c |    7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/net/usb/cdc_ncm.c b/drivers/net/usb/cdc_ncm.c
index 4cd582a..6a65662 100644
--- a/drivers/net/usb/cdc_ncm.c
+++ b/drivers/net/usb/cdc_ncm.c
@@ -251,8 +251,11 @@ static u8 cdc_ncm_setup(struct cdc_ncm_ctx *ctx)
 			kfree(dwNtbInMaxSize);
 		}
 size_err:
-		if (err < 0)
-			pr_debug("Setting NTB Input Size failed\n");
+		if (err < 0) {
+			/* failed, so attempt to use the device suggested size */
+			ctx->rx_max = le32_to_cpu(ctx->ncm_parm.dwNtbInMaxSize);
+			pr_debug("Setting NTB Input Size failed, reverting to %u\n", ctx->rx_max);
+		}
 	}
 
 	/* verify maximum size of transmitted NTB in bytes */
-- 
1.7.10.4