[PATCH] Bluetooth: hidp: Fix assumptions on the return value of hidp_send_message

From: Dan Elkouby <streetwalkermc@gmail.com>
To: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Dan Elkouby <streetwalkermc@gmail.com>,
	Jiri Kosina <jikos@kernel.org>,
	Benjamin Tissoires <benjamin.tissoires@redhat.com>,
	Marcel Holtmann <marcel@holtmann.org>,
	Johan Hedberg <johan.hedberg@gmail.com>,
	"David S. Miller" <davem@davemloft.net>,
	Brian Norris <computersforpeace@gmail.com>,
	Fabian Henneke <fabian.henneke@gmail.com>,
	Al Viro <viro@zeniv.linux.org.uk>,
	Andrea Parri <andrea.parri@amarulasolutions.com>,
	linux-input@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-bluetooth@vger.kernel.org, netdev@vger.kernel.org
Subject: [PATCH] Bluetooth: hidp: Fix assumptions on the return value of hidp_send_message
Date: Fri,  6 Sep 2019 14:06:44 +0300	[thread overview]
Message-ID: <20190906110645.27601-1-streetwalkermc@gmail.com> (raw)
In-Reply-To: <20190906101306.GA12017@kadam>

hidp_send_message was changed to return non-zero values on success,
which some other bits did not expect. This caused spurious errors to be
propagated through the stack, breaking some drivers, such as hid-sony
for the Dualshock 4 in Bluetooth mode.

As pointed out by Dan Carpenter, hid-microsoft directly relied on that
assumption as well.

Fixes: 48d9cc9d85dd ("Bluetooth: hidp: Let hidp_send_message return number of queued bytes")

Signed-off-by: Dan Elkouby <streetwalkermc@gmail.com>
---
 drivers/hid/hid-microsoft.c | 2 +-
 net/bluetooth/hidp/core.c   | 4 ++--
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/hid/hid-microsoft.c b/drivers/hid/hid-microsoft.c
index 8b3a922bdad3..2cf83856f2e4 100644
--- a/drivers/hid/hid-microsoft.c
+++ b/drivers/hid/hid-microsoft.c
@@ -303,7 +303,7 @@ static void ms_ff_worker(struct work_struct *work)
 	r->magnitude[MAGNITUDE_WEAK] = ms->weak;     /* right actuator */
 
 	ret = hid_hw_output_report(hdev, (__u8 *)r, sizeof(*r));
-	if (ret)
+	if (ret < 0)
 		hid_warn(hdev, "failed to send FF report\n");
 }
 
diff --git a/net/bluetooth/hidp/core.c b/net/bluetooth/hidp/core.c
index 8d889969ae7e..bef84b95e2c4 100644
--- a/net/bluetooth/hidp/core.c
+++ b/net/bluetooth/hidp/core.c
@@ -267,7 +267,7 @@ static int hidp_get_raw_report(struct hid_device *hid,
 	set_bit(HIDP_WAITING_FOR_RETURN, &session->flags);
 	data[0] = report_number;
 	ret = hidp_send_ctrl_message(session, report_type, data, 1);
-	if (ret)
+	if (ret < 0)
 		goto err;
 
 	/* Wait for the return of the report. The returned report
@@ -343,7 +343,7 @@ static int hidp_set_raw_report(struct hid_device *hid, unsigned char reportnum,
 	data[0] = reportnum;
 	set_bit(HIDP_WAITING_FOR_SEND_ACK, &session->flags);
 	ret = hidp_send_ctrl_message(session, report_type, data, count);
-	if (ret)
+	if (ret < 0)
 		goto err;
 
 	/* Wait for the ACK from the device. */
-- 
2.23.0

