4.14-stable review patch. If anyone has any objections, please let me know.
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From: Sudeep Holla sudeep.holla@arm.com
[ 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 sudeep.holla@arm.com Signed-off-by: Jassi Brar jaswinder.singh@linaro.org Signed-off-by: Sasha Levin alexander.levin@verizon.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/mailbox/mailbox-test.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-)
--- 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(st *(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(st 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);