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Subject[char-misc-next 3/8] mei: drop read complete queue emptiness check
Date
From: Alexander Usyskin <alexander.usyskin@intel.com>

In the course of the read flow we want to wait for read completion only
if the read queue is empty.
However the calling list_empty(&cl->rd_completed) is a duplication as the
same check was performed by mei_cl_read_cb() and the waiting is skipped
if it returns not NULL.

Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
---
drivers/misc/mei/bus.c | 3 ++-
drivers/misc/mei/main.c | 3 ++-
2 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/misc/mei/bus.c b/drivers/misc/mei/bus.c
index 1f33fea9299f..63411ddfb83d 100644
--- a/drivers/misc/mei/bus.c
+++ b/drivers/misc/mei/bus.c
@@ -126,7 +126,8 @@ ssize_t __mei_cl_recv(struct mei_cl *cl, u8 *buf, size_t length)
goto out;

/* wait on event only if there is no other waiter */
- if (list_empty(&cl->rd_completed) && !waitqueue_active(&cl->rx_wait)) {
+ /* synchronized under device mutex */
+ if (!waitqueue_active(&cl->rx_wait)) {

mutex_unlock(&bus->device_lock);

diff --git a/drivers/misc/mei/main.c b/drivers/misc/mei/main.c
index a8d0471f817f..3326bde7fba1 100644
--- a/drivers/misc/mei/main.c
+++ b/drivers/misc/mei/main.c
@@ -183,7 +183,8 @@ static ssize_t mei_read(struct file *file, char __user *ubuf,
goto out;
}

- if (list_empty(&cl->rd_completed) && !waitqueue_active(&cl->rx_wait)) {
+ /* synchronized under device mutex */
+ if (!waitqueue_active(&cl->rx_wait)) {
if (file->f_flags & O_NONBLOCK) {
rets = -EAGAIN;
goto out;
--
2.5.5
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