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[RESEND,v5,2/7] kfifo: provide kfifo_is_empty_spinlocked()

Message ID 20200123140506.29275-3-brgl@bgdev.pl
State New
Headers show
Series gpiolib: add an ioctl() for monitoring line status changes | expand

Commit Message

Bartosz Golaszewski Jan. 23, 2020, 2:05 p.m. UTC 
From: Bartosz Golaszewski <bgolaszewski@baylibre.com>

Provide two spinlocked versions of kfifo_is_empty() to be used with
spinlocked variants of kfifo_in() and kfifo_out().

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
---
 include/linux/kfifo.h | 31 +++++++++++++++++++++++++++++++
 1 file changed, 31 insertions(+)
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Patch

diff --git a/include/linux/kfifo.h b/include/linux/kfifo.h
index 123c200ed7cb..86249476b57f 100644
--- a/include/linux/kfifo.h
+++ b/include/linux/kfifo.h
@@ -246,6 +246,37 @@  __kfifo_int_must_check_helper(int val)
 	__tmpq->kfifo.in == __tmpq->kfifo.out; \
 })
 
+/**
+ * kfifo_is_empty_spinlocked - returns true if the fifo is empty using
+ * a spinlock for locking
+ * @fifo: address of the fifo to be used
+ * @lock: spinlock to be used for locking
+ */
+#define kfifo_is_empty_spinlocked(fifo, lock) \
+({ \
+	unsigned long __flags; \
+	bool __ret; \
+	spin_lock_irqsave(lock, __flags); \
+	__ret = kfifo_is_empty(fifo); \
+	spin_unlock_irqrestore(lock, __flags); \
+	__ret; \
+})
+
+/**
+ * kfifo_is_empty_spinlocked_noirqsave  - returns true if the fifo is empty
+ * using a spinlock for locking, doesn't disable interrupts
+ * @fifo: address of the fifo to be used
+ * @lock: spinlock to be used for locking
+ */
+#define kfifo_is_empty_spinlocked_noirqsave(fifo, lock) \
+({ \
+	bool __ret; \
+	spin_lock(lock); \
+	__ret = kfifo_is_empty(fifo); \
+	spin_unlock(lock); \
+	__ret; \
+})
+
 /**
  * kfifo_is_full - returns true if the fifo is full
  * @fifo: address of the fifo to be used