kfifo API type safety

This patch enhances the type safety for the kfifo API.  It is now safe to
put const data into a non const FIFO and the API will now generate a
compiler warning when reading from the fifo where the destination address
is pointing to a const variable.

As a side effect the kfifo_put() does now expect the value of an element
instead a pointer to the element.  This was suggested Russell King.  It
make the handling of the kfifo_put easier since there is no need to create
a helper variable for getting the address of a pointer or to pass integers
of different sizes.

IMHO the API break is okay, since there are currently only six users of
kfifo_put().

The code is also cleaner by kicking out the "if (0)" expressions.

Signed-off-by: Stefani Seibold <stefani@seibold.net>
Cc: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

5 files changed, 5 insertions, 5 deletions

diff --git a/drivers/gpu/drm/drm_flip_work.c b/drivers/gpu/drm/drm_flip_work.c
index e788882d9021..f9c7fa3d0012 100644
--- a/drivers/gpu/drm/drm_flip_work.c
+++ b/drivers/gpu/drm/drm_flip_work.c
@@ -34,7 +34,7 @@
  */
 void drm_flip_work_queue(struct drm_flip_work *work, void *val)
 {
-	if (kfifo_put(&work->fifo, (const void **)&val)) {
+	if (kfifo_put(&work->fifo, val)) {
 		atomic_inc(&work->pending);
 	} else {
 		DRM_ERROR("%s fifo full!\n", work->name);
diff --git a/drivers/iio/industrialio-event.c b/drivers/iio/industrialio-event.c
index 6be65ef5faa9..343144343384 100644
--- a/drivers/iio/industrialio-event.c
+++ b/drivers/iio/industrialio-event.c
@@ -56,7 +56,7 @@ int iio_push_event(struct iio_dev *indio_dev, u64 ev_code, s64 timestamp)
 		ev.id = ev_code;
 		ev.timestamp = timestamp;
 
-		copied = kfifo_put(&ev_int->det_events, &ev);
+		copied = kfifo_put(&ev_int->det_events, ev);
 		if (copied != 0)
 			wake_up_locked_poll(&ev_int->wait, POLLIN);
 	}
diff --git a/drivers/net/wireless/rt2x00/rt2800pci.c b/drivers/net/wireless/rt2x00/rt2800pci.c
index f8f2abbfbb65..fce25ee634a9 100644
--- a/drivers/net/wireless/rt2x00/rt2800pci.c
+++ b/drivers/net/wireless/rt2x00/rt2800pci.c
@@ -1025,7 +1025,7 @@ static void rt2800pci_txstatus_interrupt(struct rt2x00_dev *rt2x00dev)
 		if (!rt2x00_get_field32(status, TX_STA_FIFO_VALID))
 			break;
 
-		if (!kfifo_put(&rt2x00dev->txstatus_fifo, &status)) {
+		if (!kfifo_put(&rt2x00dev->txstatus_fifo, status)) {
 			rt2x00_warn(rt2x00dev, "TX status FIFO overrun, drop tx status report\n");
 			break;
 		}
diff --git a/drivers/net/wireless/rt2x00/rt2800usb.c b/drivers/net/wireless/rt2x00/rt2800usb.c
index 96961b9a395c..52eae828aa7f 100644
--- a/drivers/net/wireless/rt2x00/rt2800usb.c
+++ b/drivers/net/wireless/rt2x00/rt2800usb.c
@@ -162,7 +162,7 @@ static bool rt2800usb_tx_sta_fifo_read_completed(struct rt2x00_dev *rt2x00dev,
 
 	valid = rt2x00_get_field32(tx_status, TX_STA_FIFO_VALID);
 	if (valid) {
-		if (!kfifo_put(&rt2x00dev->txstatus_fifo, &tx_status))
+		if (!kfifo_put(&rt2x00dev->txstatus_fifo, tx_status))
 			rt2x00_warn(rt2x00dev, "TX status FIFO overrun\n");
 
 		queue_work(rt2x00dev->workqueue, &rt2x00dev->txdone_work);
diff --git a/drivers/pci/pcie/aer/aerdrv_core.c b/drivers/pci/pcie/aer/aerdrv_core.c
index 85ca36f2136d..6b3a958e1be6 100644
--- a/drivers/pci/pcie/aer/aerdrv_core.c
+++ b/drivers/pci/pcie/aer/aerdrv_core.c
@@ -574,7 +574,7 @@ void aer_recover_queue(int domain, unsigned int bus, unsigned int devfn,
 	};
 
 	spin_lock_irqsave(&aer_recover_ring_lock, flags);
-	if (kfifo_put(&aer_recover_ring, &entry))
+	if (kfifo_put(&aer_recover_ring, entry))
 		schedule_work(&aer_recover_work);
 	else
 		pr_err("AER recover: Buffer overflow when recovering AER for %04x:%02x:%02x:%x\n",