From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755900AbZHPU5M (ORCPT ); Sun, 16 Aug 2009 16:57:12 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755545AbZHPU5L (ORCPT ); Sun, 16 Aug 2009 16:57:11 -0400 Received: from www84.your-server.de ([213.133.104.84]:43043 "EHLO www84.your-server.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755393AbZHPU5K (ORCPT ); Sun, 16 Aug 2009 16:57:10 -0400 Subject: Re: [PATCH 5/7] kfifo: add DEFINE_KFIFO and friends, add very tiny functions From: Stefani Seibold To: linux-kernel Cc: Andrew Morton , Arnd Bergmann , Andi Kleen , Amerigo Wang , Joe Perches In-Reply-To: <1250455161.28540.4.camel@wall-e> References: <1250455161.28540.4.camel@wall-e> Content-Type: text/plain Date: Sun, 16 Aug 2009 22:57:01 +0200 Message-Id: <1250456221.28540.22.camel@wall-e> Mime-Version: 1.0 X-Mailer: Evolution 2.26.3 Content-Transfer-Encoding: 7bit X-Authenticated-Sender: stefani@seibold.net Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Add DECLARE_KFIFO - macro to declare a kfifo and the associated buffer inside a struct Add INIT_KFIFO - Initialize a kfifo declared by DECLARED_KFIFO Add DEFINE_KFIFO - macro to define and initialize a kfifo as a global or local object Add kfifo_size() - returns the size of the fifo in bytes Add kfifo_is_empty() - returns true if the fifo is empty Add kfifo_is_full() - returns true if the fifo is full Add kfifo_avail() - returns the number of bytes available in the FIFO Do some code cleanup Signed-off-by: Stefani Seibold --- kfifo.h | 85 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 83 insertions(+), 2 deletions(-) diff -u -N -r linux-2.6.31-rc4-kfifo4/include/linux/kfifo.h linux-2.6.31-rc4-kfifo5/include/linux/kfifo.h --- linux-2.6.31-rc4-kfifo4/include/linux/kfifo.h 2009-08-16 22:16:13.000000000 +0200 +++ linux-2.6.31-rc4-kfifo5/include/linux/kfifo.h 2009-08-16 22:16:43.000000000 +0200 @@ -32,6 +32,51 @@ unsigned int out; /* data is extracted from off. (out % size) */ }; +/* + * Macros for declaration and initialization of the kfifo datatype + */ + +#define __kfifo_initializer(s, b) \ + (struct kfifo) { \ + .size = s, \ + .in = 0, \ + .out = 0, \ + .buffer = b \ + } + +/** + * DECLARE_KFIFO - macro to declare a kfifo and the associated buffer + * @name: name of the declared kfifo datatype + * @size: size of the fifo buffer + * + * Note: the macro can be used inside struct or union declaration + */ +#define DECLARE_KFIFO(name, size) \ +union { \ + struct kfifo name; \ + unsigned char name##kfifo_buffer[size + sizeof(struct kfifo)]; \ +} + +/** + * INIT_KFIFO - Initialize a kfifo declared by DECLARED_KFIFO + * @name: name of the declared kfifo datatype + * @size: size of the fifo buffer + */ +#define INIT_KFIFO(name) \ + name = __kfifo_initializer(sizeof(name##kfifo_buffer) - \ + sizeof(struct kfifo), name##kfifo_buffer) + +/** + * DEFINE_KFIFO - macro to define and initialize a kfifo + * @name: name of the declared kfifo datatype + * @size: size of the fifo buffer + * + * Note: the macro can be used for global and local kfifo data type variables + */ +#define DEFINE_KFIFO(name, size) \ + unsigned char name##kfifo_buffer[size]; \ + struct kfifo name = __kfifo_initializer(size, name##kfifo_buffer) + extern void kfifo_init(struct kfifo *fifo, unsigned char *buffer, unsigned int size); extern __must_check int kfifo_alloc(struct kfifo *fifo, unsigned int size, @@ -52,6 +97,15 @@ } /** + * kfifo_size - returns the size of the fifo in bytes + * @fifo: the fifo to be used. + */ +static inline __must_check unsigned int kfifo_size(struct kfifo *fifo) +{ + return fifo->size; +} + +/** * kfifo_len - returns the number of used bytes in the FIFO * @fifo: the fifo to be used. */ @@ -65,6 +119,33 @@ } /** + * kfifo_is_empty - returns true if the fifo is empty + * @fifo: the fifo to be used. + */ +static inline __must_check int kfifo_is_empty(struct kfifo *fifo) +{ + return fifo->in == fifo->out; +} + +/** + * kfifo_is_full - returns true if the fifo is full + * @fifo: the fifo to be used. + */ +static inline __must_check int kfifo_is_full(struct kfifo *fifo) +{ + return kfifo_len(fifo) == kfifo_size(fifo); +} + +/** + * kfifo_avail - returns the number of bytes available in the FIFO + * @fifo: the fifo to be used. + */ +static inline __must_check unsigned int kfifo_avail(struct kfifo *fifo) +{ + return kfifo_size(fifo) - kfifo_len(fifo); +} + +/** * kfifo_in_locked - puts some data into the FIFO using a spinlock for locking * @fifo: the fifo to be used. * @from: the data to be added. @@ -114,8 +195,8 @@ * optimization: if the FIFO is empty, set the indices to 0 * so we don't wrap the next time */ - if (fifo->in == fifo->out) - fifo->in = fifo->out = 0; + if (kfifo_is_empty(fifo)) + kfifo_reset(fifo); spin_unlock_irqrestore(lock, flags);