From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753096AbdLBQSf (ORCPT ); Sat, 2 Dec 2017 11:18:35 -0500 Received: from omzsmtpe01.verizonbusiness.com ([199.249.25.210]:62168 "EHLO omzsmtpe01.verizonbusiness.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752494AbdLBPwr (ORCPT ); Sat, 2 Dec 2017 10:52:47 -0500 From: alexander.levin@verizon.com Cc: Sudeep Holla , Jassi Brar , alexander.levin@verizon.com X-Host: pioneer.tdc.vzwcorp.com To: "linux-kernel@vger.kernel.org" , "stable@vger.kernel.org" Subject: [PATCH AUTOSEL for 4.14 42/64] mailbox: mailbox-test: don't rely on rx_buffer content to signal data ready Thread-Topic: [PATCH AUTOSEL for 4.14 42/64] mailbox: mailbox-test: don't rely on rx_buffer content to signal data ready Thread-Index: AQHTa4VuHUwRUv4rIU29xWsT0RM9xw== Date: Sat, 2 Dec 2017 15:51:34 +0000 Message-ID: <20171202155101.7573-42-alexander.levin@verizon.com> References: <20171202155101.7573-1-alexander.levin@verizon.com> In-Reply-To: <20171202155101.7573-1-alexander.levin@verizon.com> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-ms-exchange-messagesentrepresentingtype: 1 x-ms-exchange-transport-fromentityheader: Hosted x-originating-ip: [10.144.60.250] Content-Type: text/plain; charset="iso-8859-1" MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from quoted-printable to 8bit by nfs id vB2GIeAE028897 From: Sudeep Holla [ Upstream commit e339c80af95e14de3712d69ddea09a3868fa14cd ] Currently we rely on the first byte of the Rx buffer to check if there's any data available to be read. If the first byte of the received buffer is zero (i.e. null character), then we fail to signal that data is available even when it's available. Instead introduce a boolean variable to track the data availability and update it in the channel receive callback as ready and clear it when the data is read. Signed-off-by: Sudeep Holla Signed-off-by: Jassi Brar Signed-off-by: Sasha Levin --- drivers/mailbox/mailbox-test.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) diff --git a/drivers/mailbox/mailbox-test.c b/drivers/mailbox/mailbox-test.c index 97fb956bb6e0..93f3d4d61fa7 100644 --- a/drivers/mailbox/mailbox-test.c +++ b/drivers/mailbox/mailbox-test.c @@ -30,6 +30,7 @@ #define MBOX_HEXDUMP_MAX_LEN (MBOX_HEXDUMP_LINE_LEN * \ (MBOX_MAX_MSG_LEN / MBOX_BYTES_PER_LINE)) +static bool mbox_data_ready; static struct dentry *root_debugfs_dir; struct mbox_test_device { @@ -152,16 +153,14 @@ out: static bool mbox_test_message_data_ready(struct mbox_test_device *tdev) { - unsigned char data; + bool data_ready; unsigned long flags; spin_lock_irqsave(&tdev->lock, flags); - data = tdev->rx_buffer[0]; + data_ready = mbox_data_ready; spin_unlock_irqrestore(&tdev->lock, flags); - if (data != '\0') - return true; - return false; + return data_ready; } static ssize_t mbox_test_message_read(struct file *filp, char __user *userbuf, @@ -223,6 +222,7 @@ static ssize_t mbox_test_message_read(struct file *filp, char __user *userbuf, *(touser + l) = '\0'; memset(tdev->rx_buffer, 0, MBOX_MAX_MSG_LEN); + mbox_data_ready = false; spin_unlock_irqrestore(&tdev->lock, flags); @@ -292,6 +292,7 @@ static void mbox_test_receive_message(struct mbox_client *client, void *message) message, MBOX_MAX_MSG_LEN); memcpy(tdev->rx_buffer, message, MBOX_MAX_MSG_LEN); } + mbox_data_ready = true; spin_unlock_irqrestore(&tdev->lock, flags); wake_up_interruptible(&tdev->waitq); -- 2.11.0