From 45465487897a1c6d508b14b904dc5777f7ec7e04 Mon Sep 17 00:00:00 2001 From: Stefani Seibold Date: Mon, 21 Dec 2009 14:37:26 -0800 Subject: kfifo: move struct kfifo in place This is a new generic kernel FIFO implementation. The current kernel fifo API is not very widely used, because it has to many constrains. Only 17 files in the current 2.6.31-rc5 used it. FIFO's are like list's a very basic thing and a kfifo API which handles the most use case would save a lot of development time and memory resources. I think this are the reasons why kfifo is not in use: - The API is to simple, important functions are missing - A fifo can be only allocated dynamically - There is a requirement of a spinlock whether you need it or not - There is no support for data records inside a fifo So I decided to extend the kfifo in a more generic way without blowing up the API to much. The new API has the following benefits: - Generic usage: For kernel internal use and/or device driver. - Provide an API for the most use case. - Slim API: The whole API provides 25 functions. - Linux style habit. - DECLARE_KFIFO, DEFINE_KFIFO and INIT_KFIFO Macros - Direct copy_to_user from the fifo and copy_from_user into the fifo. - The kfifo itself is an in place member of the using data structure, this save an indirection access and does not waste the kernel allocator. - Lockless access: if only one reader and one writer is active on the fifo, which is the common use case, no additional locking is necessary. - Remove spinlock - give the user the freedom of choice what kind of locking to use if one is required. - Ability to handle records. Three type of records are supported: - Variable length records between 0-255 bytes, with a record size field of 1 bytes. - Variable length records between 0-65535 bytes, with a record size field of 2 bytes. - Fixed size records, which no record size field. - Preserve memory resource. - Performance! - Easy to use! This patch: Since most users want to have the kfifo as part of another object, reorganize the code to allow including struct kfifo in another data structure. This requires changing the kfifo_alloc and kfifo_init prototypes so that we pass an existing kfifo pointer into them. This patch changes the implementation and all existing users. [akpm@linux-foundation.org: fix warning] Signed-off-by: Stefani Seibold Acked-by: Greg Kroah-Hartman Acked-by: Mauro Carvalho Chehab Acked-by: Andi Kleen Acked-by: Arnd Bergmann Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/kfifo.h | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) (limited to 'include/linux/kfifo.h') diff --git a/include/linux/kfifo.h b/include/linux/kfifo.h index ad6bdf5a5970..c3f8d82efd34 100644 --- a/include/linux/kfifo.h +++ b/include/linux/kfifo.h @@ -1,6 +1,7 @@ /* - * A simple kernel FIFO implementation. + * A generic kernel FIFO implementation. * + * Copyright (C) 2009 Stefani Seibold * Copyright (C) 2004 Stelian Pop * * This program is free software; you can redistribute it and/or modify @@ -32,10 +33,10 @@ struct kfifo { spinlock_t *lock; /* protects concurrent modifications */ }; -extern struct kfifo *kfifo_init(unsigned char *buffer, unsigned int size, - gfp_t gfp_mask, spinlock_t *lock); -extern struct kfifo *kfifo_alloc(unsigned int size, gfp_t gfp_mask, - spinlock_t *lock); +extern void kfifo_init(struct kfifo *fifo, unsigned char *buffer, + unsigned int size, spinlock_t *lock); +extern __must_check int kfifo_alloc(struct kfifo *fifo, unsigned int size, + gfp_t gfp_mask, spinlock_t *lock); extern void kfifo_free(struct kfifo *fifo); extern unsigned int __kfifo_put(struct kfifo *fifo, const unsigned char *buffer, unsigned int len); -- cgit v1.2.3 From c1e13f25674ed564948ecb7dfe5f83e578892896 Mon Sep 17 00:00:00 2001 From: Stefani Seibold Date: Mon, 21 Dec 2009 14:37:27 -0800 Subject: kfifo: move out spinlock Move the pointer to the spinlock out of struct kfifo. Most users in tree do not actually use a spinlock, so the few exceptions now have to call kfifo_{get,put}_locked, which takes an extra argument to a spinlock. Signed-off-by: Stefani Seibold Acked-by: Greg Kroah-Hartman Acked-by: Mauro Carvalho Chehab Acked-by: Andi Kleen Acked-by: Arnd Bergmann Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/kfifo.h | 80 ++++++++++++++++++++++----------------------------- 1 file changed, 35 insertions(+), 45 deletions(-) (limited to 'include/linux/kfifo.h') diff --git a/include/linux/kfifo.h b/include/linux/kfifo.h index c3f8d82efd34..e0f5c9d4197d 100644 --- a/include/linux/kfifo.h +++ b/include/linux/kfifo.h @@ -30,13 +30,12 @@ struct kfifo { unsigned int size; /* the size of the allocated buffer */ unsigned int in; /* data is added at offset (in % size) */ unsigned int out; /* data is extracted from off. (out % size) */ - spinlock_t *lock; /* protects concurrent modifications */ }; extern void kfifo_init(struct kfifo *fifo, unsigned char *buffer, - unsigned int size, spinlock_t *lock); + unsigned int size); extern __must_check int kfifo_alloc(struct kfifo *fifo, unsigned int size, - gfp_t gfp_mask, spinlock_t *lock); + gfp_t gfp_mask); extern void kfifo_free(struct kfifo *fifo); extern unsigned int __kfifo_put(struct kfifo *fifo, const unsigned char *buffer, unsigned int len); @@ -58,58 +57,67 @@ static inline void __kfifo_reset(struct kfifo *fifo) */ static inline void kfifo_reset(struct kfifo *fifo) { - unsigned long flags; - - spin_lock_irqsave(fifo->lock, flags); - __kfifo_reset(fifo); +} + +/** + * __kfifo_len - returns the number of bytes available in the FIFO + * @fifo: the fifo to be used. + */ +static inline unsigned int __kfifo_len(struct kfifo *fifo) +{ + register unsigned int out; - spin_unlock_irqrestore(fifo->lock, flags); + out = fifo->out; + smp_rmb(); + return fifo->in - out; } /** - * kfifo_put - puts some data into the FIFO + * kfifo_put_locked - puts some data into the FIFO using a spinlock for locking * @fifo: the fifo to be used. - * @buffer: the data to be added. - * @len: the length of the data to be added. + * @from: the data to be added. + * @n: the length of the data to be added. + * @lock: pointer to the spinlock to use for locking. * - * This function copies at most @len bytes from the @buffer into + * This function copies at most @len bytes from the @from buffer into * the FIFO depending on the free space, and returns the number of * bytes copied. */ -static inline unsigned int kfifo_put(struct kfifo *fifo, - const unsigned char *buffer, unsigned int len) +static inline __must_check unsigned int kfifo_put_locked(struct kfifo *fifo, + const unsigned char *from, unsigned int n, spinlock_t *lock) { unsigned long flags; unsigned int ret; - spin_lock_irqsave(fifo->lock, flags); + spin_lock_irqsave(lock, flags); - ret = __kfifo_put(fifo, buffer, len); + ret = __kfifo_put(fifo, from, n); - spin_unlock_irqrestore(fifo->lock, flags); + spin_unlock_irqrestore(lock, flags); return ret; } /** - * kfifo_get - gets some data from the FIFO + * kfifo_get_locked - gets some data from the FIFO using a spinlock for locking * @fifo: the fifo to be used. - * @buffer: where the data must be copied. - * @len: the size of the destination buffer. + * @to: where the data must be copied. + * @n: the size of the destination buffer. + * @lock: pointer to the spinlock to use for locking. * * This function copies at most @len bytes from the FIFO into the - * @buffer and returns the number of copied bytes. + * @to buffer and returns the number of copied bytes. */ -static inline unsigned int kfifo_get(struct kfifo *fifo, - unsigned char *buffer, unsigned int len) +static inline __must_check unsigned int kfifo_get_locked(struct kfifo *fifo, + unsigned char *to, unsigned int n, spinlock_t *lock) { unsigned long flags; unsigned int ret; - spin_lock_irqsave(fifo->lock, flags); + spin_lock_irqsave(lock, flags); - ret = __kfifo_get(fifo, buffer, len); + ret = __kfifo_get(fifo, to, n); /* * optimization: if the FIFO is empty, set the indices to 0 @@ -118,36 +126,18 @@ static inline unsigned int kfifo_get(struct kfifo *fifo, if (fifo->in == fifo->out) fifo->in = fifo->out = 0; - spin_unlock_irqrestore(fifo->lock, flags); + spin_unlock_irqrestore(lock, flags); return ret; } -/** - * __kfifo_len - returns the number of bytes available in the FIFO, no locking version - * @fifo: the fifo to be used. - */ -static inline unsigned int __kfifo_len(struct kfifo *fifo) -{ - return fifo->in - fifo->out; -} - /** * kfifo_len - returns the number of bytes available in the FIFO * @fifo: the fifo to be used. */ static inline unsigned int kfifo_len(struct kfifo *fifo) { - unsigned long flags; - unsigned int ret; - - spin_lock_irqsave(fifo->lock, flags); - - ret = __kfifo_len(fifo); - - spin_unlock_irqrestore(fifo->lock, flags); - - return ret; + return __kfifo_len(fifo); } #endif -- cgit v1.2.3 From e64c026dd09b73faf20707711402fc5ed55a8e70 Mon Sep 17 00:00:00 2001 From: Stefani Seibold Date: Mon, 21 Dec 2009 14:37:28 -0800 Subject: kfifo: cleanup namespace change name of __kfifo_* functions to kfifo_*, because the prefix __kfifo should be reserved for internal functions only. Signed-off-by: Stefani Seibold Acked-by: Greg Kroah-Hartman Acked-by: Mauro Carvalho Chehab Acked-by: Andi Kleen Acked-by: Arnd Bergmann Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/kfifo.h | 32 +++++++------------------------- 1 file changed, 7 insertions(+), 25 deletions(-) (limited to 'include/linux/kfifo.h') diff --git a/include/linux/kfifo.h b/include/linux/kfifo.h index e0f5c9d4197d..a893acda3964 100644 --- a/include/linux/kfifo.h +++ b/include/linux/kfifo.h @@ -37,34 +37,25 @@ extern void kfifo_init(struct kfifo *fifo, unsigned char *buffer, extern __must_check int kfifo_alloc(struct kfifo *fifo, unsigned int size, gfp_t gfp_mask); extern void kfifo_free(struct kfifo *fifo); -extern unsigned int __kfifo_put(struct kfifo *fifo, +extern unsigned int kfifo_put(struct kfifo *fifo, const unsigned char *buffer, unsigned int len); -extern unsigned int __kfifo_get(struct kfifo *fifo, +extern unsigned int kfifo_get(struct kfifo *fifo, unsigned char *buffer, unsigned int len); -/** - * __kfifo_reset - removes the entire FIFO contents, no locking version - * @fifo: the fifo to be emptied. - */ -static inline void __kfifo_reset(struct kfifo *fifo) -{ - fifo->in = fifo->out = 0; -} - /** * kfifo_reset - removes the entire FIFO contents * @fifo: the fifo to be emptied. */ static inline void kfifo_reset(struct kfifo *fifo) { - __kfifo_reset(fifo); + fifo->in = fifo->out = 0; } /** - * __kfifo_len - returns the number of bytes available in the FIFO + * kfifo_len - returns the number of used bytes in the FIFO * @fifo: the fifo to be used. */ -static inline unsigned int __kfifo_len(struct kfifo *fifo) +static inline unsigned int kfifo_len(struct kfifo *fifo) { register unsigned int out; @@ -92,7 +83,7 @@ static inline __must_check unsigned int kfifo_put_locked(struct kfifo *fifo, spin_lock_irqsave(lock, flags); - ret = __kfifo_put(fifo, from, n); + ret = kfifo_put(fifo, from, n); spin_unlock_irqrestore(lock, flags); @@ -117,7 +108,7 @@ static inline __must_check unsigned int kfifo_get_locked(struct kfifo *fifo, spin_lock_irqsave(lock, flags); - ret = __kfifo_get(fifo, to, n); + ret = kfifo_get(fifo, to, n); /* * optimization: if the FIFO is empty, set the indices to 0 @@ -131,13 +122,4 @@ static inline __must_check unsigned int kfifo_get_locked(struct kfifo *fifo, return ret; } -/** - * kfifo_len - returns the number of bytes available in the FIFO - * @fifo: the fifo to be used. - */ -static inline unsigned int kfifo_len(struct kfifo *fifo) -{ - return __kfifo_len(fifo); -} - #endif -- cgit v1.2.3 From 7acd72eb85f1c7a15e8b5eb554994949241737f1 Mon Sep 17 00:00:00 2001 From: Stefani Seibold Date: Mon, 21 Dec 2009 14:37:28 -0800 Subject: kfifo: rename kfifo_put... into kfifo_in... and kfifo_get... into kfifo_out... rename kfifo_put... into kfifo_in... to prevent miss use of old non in kernel-tree drivers ditto for kfifo_get... -> kfifo_out... Improve the prototypes of kfifo_in and kfifo_out to make the kerneldoc annotations more readable. Add mini "howto porting to the new API" in kfifo.h Signed-off-by: Stefani Seibold Acked-by: Greg Kroah-Hartman Acked-by: Mauro Carvalho Chehab Acked-by: Andi Kleen Acked-by: Arnd Bergmann Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/kfifo.h | 39 +++++++++++++++++++++++++++++---------- 1 file changed, 29 insertions(+), 10 deletions(-) (limited to 'include/linux/kfifo.h') diff --git a/include/linux/kfifo.h b/include/linux/kfifo.h index a893acda3964..1b59c4a0e85f 100644 --- a/include/linux/kfifo.h +++ b/include/linux/kfifo.h @@ -19,6 +19,25 @@ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. * */ + +/* + * Howto porting drivers to the new generic fifo API: + * + * - Modify the declaration of the "struct kfifo *" object into a + * in-place "struct kfifo" object + * - Init the in-place object with kfifo_alloc() or kfifo_init() + * Note: The address of the in-place "struct kfifo" object must be + * passed as the first argument to this functions + * - Replace the use of __kfifo_put into kfifo_in and __kfifo_get + * into kfifo_out + * - Replace the use of kfifo_put into kfifo_in_locked and kfifo_get + * into kfifo_out_locked + * Note: the spinlock pointer formerly passed to kfifo_init/kfifo_alloc + * must be passed now to the kfifo_in_locked and kfifo_out_locked + * as the last parameter. + * - All formerly name __kfifo_* functions has been renamed into kfifo_* + */ + #ifndef _LINUX_KFIFO_H #define _LINUX_KFIFO_H @@ -37,10 +56,10 @@ extern void kfifo_init(struct kfifo *fifo, unsigned char *buffer, extern __must_check int kfifo_alloc(struct kfifo *fifo, unsigned int size, gfp_t gfp_mask); extern void kfifo_free(struct kfifo *fifo); -extern unsigned int kfifo_put(struct kfifo *fifo, - const unsigned char *buffer, unsigned int len); -extern unsigned int kfifo_get(struct kfifo *fifo, - unsigned char *buffer, unsigned int len); +extern __must_check unsigned int kfifo_in(struct kfifo *fifo, + const unsigned char *from, unsigned int len); +extern __must_check unsigned int kfifo_out(struct kfifo *fifo, + unsigned char *to, unsigned int len); /** * kfifo_reset - removes the entire FIFO contents @@ -65,7 +84,7 @@ static inline unsigned int kfifo_len(struct kfifo *fifo) } /** - * kfifo_put_locked - puts some data into the FIFO using a spinlock for locking + * 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. * @n: the length of the data to be added. @@ -75,7 +94,7 @@ static inline unsigned int kfifo_len(struct kfifo *fifo) * the FIFO depending on the free space, and returns the number of * bytes copied. */ -static inline __must_check unsigned int kfifo_put_locked(struct kfifo *fifo, +static inline __must_check unsigned int kfifo_in_locked(struct kfifo *fifo, const unsigned char *from, unsigned int n, spinlock_t *lock) { unsigned long flags; @@ -83,7 +102,7 @@ static inline __must_check unsigned int kfifo_put_locked(struct kfifo *fifo, spin_lock_irqsave(lock, flags); - ret = kfifo_put(fifo, from, n); + ret = kfifo_in(fifo, from, n); spin_unlock_irqrestore(lock, flags); @@ -91,7 +110,7 @@ static inline __must_check unsigned int kfifo_put_locked(struct kfifo *fifo, } /** - * kfifo_get_locked - gets some data from the FIFO using a spinlock for locking + * kfifo_out_locked - gets some data from the FIFO using a spinlock for locking * @fifo: the fifo to be used. * @to: where the data must be copied. * @n: the size of the destination buffer. @@ -100,7 +119,7 @@ static inline __must_check unsigned int kfifo_put_locked(struct kfifo *fifo, * This function copies at most @len bytes from the FIFO into the * @to buffer and returns the number of copied bytes. */ -static inline __must_check unsigned int kfifo_get_locked(struct kfifo *fifo, +static inline __must_check unsigned int kfifo_out_locked(struct kfifo *fifo, unsigned char *to, unsigned int n, spinlock_t *lock) { unsigned long flags; @@ -108,7 +127,7 @@ static inline __must_check unsigned int kfifo_get_locked(struct kfifo *fifo, spin_lock_irqsave(lock, flags); - ret = kfifo_get(fifo, to, n); + ret = kfifo_out(fifo, to, n); /* * optimization: if the FIFO is empty, set the indices to 0 -- cgit v1.2.3 From 9842c38e917636fa7dc6b88aff17a8f1fd7f0cc0 Mon Sep 17 00:00:00 2001 From: Stefani Seibold Date: Mon, 21 Dec 2009 14:37:29 -0800 Subject: kfifo: fix warn_unused_result Fix the "ignoring return value of '...', declared with attribute warn_unused_result" compiler warning in several users of the new kfifo API. It removes the __must_check attribute from kfifo_in() and kfifo_in_locked() which must not necessary performed. Fix the allocation bug in the nozomi driver file, by moving out the kfifo_alloc from the interrupt handler into the probe function. Fix the kfifo_out() and kfifo_out_locked() users to handle a unexpected end of fifo. Signed-off-by: Stefani Seibold Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/kfifo.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'include/linux/kfifo.h') diff --git a/include/linux/kfifo.h b/include/linux/kfifo.h index 1b59c4a0e85f..5ed2565c89b6 100644 --- a/include/linux/kfifo.h +++ b/include/linux/kfifo.h @@ -56,7 +56,7 @@ extern void kfifo_init(struct kfifo *fifo, unsigned char *buffer, extern __must_check int kfifo_alloc(struct kfifo *fifo, unsigned int size, gfp_t gfp_mask); extern void kfifo_free(struct kfifo *fifo); -extern __must_check unsigned int kfifo_in(struct kfifo *fifo, +extern unsigned int kfifo_in(struct kfifo *fifo, const unsigned char *from, unsigned int len); extern __must_check unsigned int kfifo_out(struct kfifo *fifo, unsigned char *to, unsigned int len); @@ -94,7 +94,7 @@ static inline unsigned int kfifo_len(struct kfifo *fifo) * the FIFO depending on the free space, and returns the number of * bytes copied. */ -static inline __must_check unsigned int kfifo_in_locked(struct kfifo *fifo, +static inline unsigned int kfifo_in_locked(struct kfifo *fifo, const unsigned char *from, unsigned int n, spinlock_t *lock) { unsigned long flags; -- cgit v1.2.3 From 37bdfbbfaab47811fcec84dff23c4e8da1a09f9e Mon Sep 17 00:00:00 2001 From: Stefani Seibold Date: Mon, 21 Dec 2009 14:37:30 -0800 Subject: kfifo: add DEFINE_KFIFO and friends, add very tiny functions 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 Acked-by: Greg Kroah-Hartman Acked-by: Mauro Carvalho Chehab Acked-by: Andi Kleen Acked-by: Arnd Bergmann Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/kfifo.h | 94 +++++++++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 92 insertions(+), 2 deletions(-) (limited to 'include/linux/kfifo.h') diff --git a/include/linux/kfifo.h b/include/linux/kfifo.h index 5ed2565c89b6..dd53eed3e2af 100644 --- a/include/linux/kfifo.h +++ b/include/linux/kfifo.h @@ -51,6 +51,60 @@ struct kfifo { unsigned int out; /* data is extracted from off. (out % size) */ }; +/* + * Macros for declaration and initialization of the kfifo datatype + */ + +/* helper macro */ +#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 + * Note: the macro creates two objects: + * A kfifo object with the given name and a buffer for the kfifo + * object named name##kfifo_buffer + */ +#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 + * Note: the macro creates two objects: + * A kfifo object with the given name and a buffer for the kfifo + * object named name##kfifo_buffer + */ +#define DEFINE_KFIFO(name, size) \ + unsigned char name##kfifo_buffer[size]; \ + struct kfifo name = __kfifo_initializer(size, name##kfifo_buffer) + +#undef __kfifo_initializer + 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, @@ -70,6 +124,15 @@ static inline void kfifo_reset(struct kfifo *fifo) fifo->in = fifo->out = 0; } +/** + * 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. @@ -83,6 +146,33 @@ static inline unsigned int kfifo_len(struct kfifo *fifo) return fifo->in - out; } +/** + * 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. @@ -133,8 +223,8 @@ static inline __must_check unsigned int kfifo_out_locked(struct kfifo *fifo, * 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); -- cgit v1.2.3 From a121f24accac1600bf5b6fb1e12eeabdfed7cb1a Mon Sep 17 00:00:00 2001 From: Stefani Seibold Date: Mon, 21 Dec 2009 14:37:31 -0800 Subject: kfifo: add kfifo_skip, kfifo_from_user and kfifo_to_user Add kfifo_reset_out() for save lockless discard the fifo output Add kfifo_skip() to skip a number of output bytes Add kfifo_from_user() to copy user space data into the fifo Add kfifo_to_user() to copy fifo data to user space Signed-off-by: Stefani Seibold Acked-by: Greg Kroah-Hartman Acked-by: Mauro Carvalho Chehab Acked-by: Andi Kleen Acked-by: Arnd Bergmann Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/kfifo.h | 47 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 47 insertions(+) (limited to 'include/linux/kfifo.h') diff --git a/include/linux/kfifo.h b/include/linux/kfifo.h index dd53eed3e2af..d3230fb08bc7 100644 --- a/include/linux/kfifo.h +++ b/include/linux/kfifo.h @@ -124,6 +124,16 @@ static inline void kfifo_reset(struct kfifo *fifo) fifo->in = fifo->out = 0; } +/** + * kfifo_reset_out - skip FIFO contents + * @fifo: the fifo to be emptied. + */ +static inline void kfifo_reset_out(struct kfifo *fifo) +{ + smp_mb(); + fifo->out = fifo->in; +} + /** * kfifo_size - returns the size of the fifo in bytes * @fifo: the fifo to be used. @@ -231,4 +241,41 @@ static inline __must_check unsigned int kfifo_out_locked(struct kfifo *fifo, return ret; } +extern void kfifo_skip(struct kfifo *fifo, unsigned int len); + +extern __must_check unsigned int kfifo_from_user(struct kfifo *fifo, + const void __user *from, unsigned int n); + +extern __must_check unsigned int kfifo_to_user(struct kfifo *fifo, + void __user *to, unsigned int n); + +/** + * __kfifo_add_out internal helper function for updating the out offset + */ +static inline void __kfifo_add_out(struct kfifo *fifo, + unsigned int off) +{ + smp_mb(); + fifo->out += off; +} + +/** + * __kfifo_add_in internal helper function for updating the in offset + */ +static inline void __kfifo_add_in(struct kfifo *fifo, + unsigned int off) +{ + smp_wmb(); + fifo->in += off; +} + +/** + * __kfifo_off internal helper function for calculating the index of a + * given offeset + */ +static inline unsigned int __kfifo_off(struct kfifo *fifo, unsigned int off) +{ + return off & (fifo->size - 1); +} + #endif -- cgit v1.2.3 From 86d4880313603810901f639ccb5c88ff13d4ad3c Mon Sep 17 00:00:00 2001 From: Stefani Seibold Date: Mon, 21 Dec 2009 14:37:32 -0800 Subject: kfifo: add record handling functions Add kfifo_in_rec() - puts some record data into the FIFO Add kfifo_out_rec() - gets some record data from the FIFO Add kfifo_from_user_rec() - puts some data from user space into the FIFO Add kfifo_to_user_rec() - gets data from the FIFO and write it to user space Add kfifo_peek_rec() - gets the size of the next FIFO record field Add kfifo_skip_rec() - skip the next fifo out record Add kfifo_avail_rec() - determinate the number of bytes available in a record FIFO Signed-off-by: Stefani Seibold Acked-by: Greg Kroah-Hartman Acked-by: Mauro Carvalho Chehab Acked-by: Andi Kleen Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/kfifo.h | 330 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 330 insertions(+) (limited to 'include/linux/kfifo.h') diff --git a/include/linux/kfifo.h b/include/linux/kfifo.h index d3230fb08bc7..486e8ad3bb50 100644 --- a/include/linux/kfifo.h +++ b/include/linux/kfifo.h @@ -278,4 +278,334 @@ static inline unsigned int __kfifo_off(struct kfifo *fifo, unsigned int off) return off & (fifo->size - 1); } +/** + * __kfifo_peek_n internal helper function for determinate the length of + * the next record in the fifo + */ +static inline unsigned int __kfifo_peek_n(struct kfifo *fifo, + unsigned int recsize) +{ +#define __KFIFO_GET(fifo, off, shift) \ + ((fifo)->buffer[__kfifo_off((fifo), (fifo)->out+(off))] << (shift)) + + unsigned int l; + + l = __KFIFO_GET(fifo, 0, 0); + + if (--recsize) + l |= __KFIFO_GET(fifo, 1, 8); + + return l; +#undef __KFIFO_GET +} + +/** + * __kfifo_poke_n internal helper function for storing the length of + * the next record into the fifo + */ +static inline void __kfifo_poke_n(struct kfifo *fifo, + unsigned int recsize, unsigned int n) +{ +#define __KFIFO_PUT(fifo, off, val, shift) \ + ( \ + (fifo)->buffer[__kfifo_off((fifo), (fifo)->in+(off))] = \ + (unsigned char)((val) >> (shift)) \ + ) + + __KFIFO_PUT(fifo, 0, n, 0); + + if (--recsize) + __KFIFO_PUT(fifo, 1, n, 8); +#undef __KFIFO_PUT +} + +/** + * __kfifo_in_... internal functions for put date into the fifo + * do not call it directly, use kfifo_in_rec() instead + */ +extern unsigned int __kfifo_in_n(struct kfifo *fifo, + const void *from, unsigned int n, unsigned int recsize); + +extern unsigned int __kfifo_in_generic(struct kfifo *fifo, + const void *from, unsigned int n, unsigned int recsize); + +static inline unsigned int __kfifo_in_rec(struct kfifo *fifo, + const void *from, unsigned int n, unsigned int recsize) +{ + unsigned int ret; + + ret = __kfifo_in_n(fifo, from, n, recsize); + + if (likely(ret == 0)) { + if (recsize) + __kfifo_poke_n(fifo, recsize, n); + __kfifo_add_in(fifo, n + recsize); + } + return ret; +} + +/** + * kfifo_in_rec - puts some record data into the FIFO + * @fifo: the fifo to be used. + * @from: the data to be added. + * @n: the length of the data to be added. + * @recsize: size of record field + * + * This function copies @n bytes from the @from into the FIFO and returns + * the number of bytes which cannot be copied. + * A returned value greater than the @n value means that the record doesn't + * fit into the buffer. + * + * Note that with only one concurrent reader and one concurrent + * writer, you don't need extra locking to use these functions. + */ +static inline __must_check unsigned int kfifo_in_rec(struct kfifo *fifo, + void *from, unsigned int n, unsigned int recsize) +{ + if (!__builtin_constant_p(recsize)) + return __kfifo_in_generic(fifo, from, n, recsize); + return __kfifo_in_rec(fifo, from, n, recsize); +} + +/** + * __kfifo_out_... internal functions for get date from the fifo + * do not call it directly, use kfifo_out_rec() instead + */ +extern unsigned int __kfifo_out_n(struct kfifo *fifo, + void *to, unsigned int reclen, unsigned int recsize); + +extern unsigned int __kfifo_out_generic(struct kfifo *fifo, + void *to, unsigned int n, + unsigned int recsize, unsigned int *total); + +static inline unsigned int __kfifo_out_rec(struct kfifo *fifo, + void *to, unsigned int n, unsigned int recsize, + unsigned int *total) +{ + unsigned int l; + + if (!recsize) { + l = n; + if (total) + *total = l; + } else { + l = __kfifo_peek_n(fifo, recsize); + if (total) + *total = l; + if (n < l) + return l; + } + + return __kfifo_out_n(fifo, to, l, recsize); +} + +/** + * kfifo_out_rec - gets some record data from the FIFO + * @fifo: the fifo to be used. + * @to: where the data must be copied. + * @n: the size of the destination buffer. + * @recsize: size of record field + * @total: pointer where the total number of to copied bytes should stored + * + * This function copies at most @n bytes from the FIFO to @to and returns the + * number of bytes which cannot be copied. + * A returned value greater than the @n value means that the record doesn't + * fit into the @to buffer. + * + * Note that with only one concurrent reader and one concurrent + * writer, you don't need extra locking to use these functions. + */ +static inline __must_check unsigned int kfifo_out_rec(struct kfifo *fifo, + void *to, unsigned int n, unsigned int recsize, + unsigned int *total) + +{ + if (!__builtin_constant_p(recsize)) + return __kfifo_out_generic(fifo, to, n, recsize, total); + return __kfifo_out_rec(fifo, to, n, recsize, total); +} + +/** + * __kfifo_from_user_... internal functions for transfer from user space into + * the fifo. do not call it directly, use kfifo_from_user_rec() instead + */ +extern unsigned int __kfifo_from_user_n(struct kfifo *fifo, + const void __user *from, unsigned int n, unsigned int recsize); + +extern unsigned int __kfifo_from_user_generic(struct kfifo *fifo, + const void __user *from, unsigned int n, unsigned int recsize); + +static inline unsigned int __kfifo_from_user_rec(struct kfifo *fifo, + const void __user *from, unsigned int n, unsigned int recsize) +{ + unsigned int ret; + + ret = __kfifo_from_user_n(fifo, from, n, recsize); + + if (likely(ret == 0)) { + if (recsize) + __kfifo_poke_n(fifo, recsize, n); + __kfifo_add_in(fifo, n + recsize); + } + return ret; +} + +/** + * kfifo_from_user_rec - puts some data from user space into the FIFO + * @fifo: the fifo to be used. + * @from: pointer to the data to be added. + * @n: the length of the data to be added. + * @recsize: size of record field + * + * This function copies @n bytes from the @from into the + * FIFO and returns the number of bytes which cannot be copied. + * + * If the returned value is equal or less the @n value, the copy_from_user() + * functions has failed. Otherwise the record doesn't fit into the buffer. + * + * Note that with only one concurrent reader and one concurrent + * writer, you don't need extra locking to use these functions. + */ +static inline __must_check unsigned int kfifo_from_user_rec(struct kfifo *fifo, + const void __user *from, unsigned int n, unsigned int recsize) +{ + if (!__builtin_constant_p(recsize)) + return __kfifo_from_user_generic(fifo, from, n, recsize); + return __kfifo_from_user_rec(fifo, from, n, recsize); +} + +/** + * __kfifo_to_user_... internal functions for transfer fifo data into user space + * do not call it directly, use kfifo_to_user_rec() instead + */ +extern unsigned int __kfifo_to_user_n(struct kfifo *fifo, + void __user *to, unsigned int n, unsigned int reclen, + unsigned int recsize); + +extern unsigned int __kfifo_to_user_generic(struct kfifo *fifo, + void __user *to, unsigned int n, unsigned int recsize, + unsigned int *total); + +static inline unsigned int __kfifo_to_user_rec(struct kfifo *fifo, + void __user *to, unsigned int n, + unsigned int recsize, unsigned int *total) +{ + unsigned int l; + + if (!recsize) { + l = n; + if (total) + *total = l; + } else { + l = __kfifo_peek_n(fifo, recsize); + if (total) + *total = l; + if (n < l) + return l; + } + + return __kfifo_to_user_n(fifo, to, n, l, recsize); +} + +/** + * kfifo_to_user_rec - gets data from the FIFO and write it to user space + * @fifo: the fifo to be used. + * @to: where the data must be copied. + * @n: the size of the destination buffer. + * @recsize: size of record field + * @total: pointer where the total number of to copied bytes should stored + * + * This function copies at most @n bytes from the FIFO to the @to. + * In case of an error, the function returns the number of bytes which cannot + * be copied. + * If the returned value is equal or less the @n value, the copy_to_user() + * functions has failed. Otherwise the record doesn't fit into the @to buffer. + * + * Note that with only one concurrent reader and one concurrent + * writer, you don't need extra locking to use these functions. + */ +static inline __must_check unsigned int kfifo_to_user_rec(struct kfifo *fifo, + void __user *to, unsigned int n, unsigned int recsize, + unsigned int *total) +{ + if (!__builtin_constant_p(recsize)) + return __kfifo_to_user_generic(fifo, to, n, recsize, total); + return __kfifo_to_user_rec(fifo, to, n, recsize, total); +} + +/** + * __kfifo_peek_... internal functions for peek into the next fifo record + * do not call it directly, use kfifo_peek_rec() instead + */ +extern unsigned int __kfifo_peek_generic(struct kfifo *fifo, + unsigned int recsize); + +/** + * kfifo_peek_rec - gets the size of the next FIFO record data + * @fifo: the fifo to be used. + * @recsize: size of record field + * + * This function returns the size of the next FIFO record in number of bytes + */ +static inline __must_check unsigned int kfifo_peek_rec(struct kfifo *fifo, + unsigned int recsize) +{ + if (!__builtin_constant_p(recsize)) + return __kfifo_peek_generic(fifo, recsize); + if (!recsize) + return kfifo_len(fifo); + return __kfifo_peek_n(fifo, recsize); +} + +/** + * __kfifo_skip_... internal functions for skip the next fifo record + * do not call it directly, use kfifo_skip_rec() instead + */ +extern void __kfifo_skip_generic(struct kfifo *fifo, unsigned int recsize); + +static inline void __kfifo_skip_rec(struct kfifo *fifo, + unsigned int recsize) +{ + unsigned int l; + + if (recsize) { + l = __kfifo_peek_n(fifo, recsize); + + if (l + recsize <= kfifo_len(fifo)) { + __kfifo_add_out(fifo, l + recsize); + return; + } + } + kfifo_reset_out(fifo); +} + +/** + * kfifo_skip_rec - skip the next fifo out record + * @fifo: the fifo to be used. + * @recsize: size of record field + * + * This function skips the next FIFO record + */ +static inline void kfifo_skip_rec(struct kfifo *fifo, + unsigned int recsize) +{ + if (!__builtin_constant_p(recsize)) + __kfifo_skip_generic(fifo, recsize); + else + __kfifo_skip_rec(fifo, recsize); +} + +/** + * kfifo_avail_rec - returns the number of bytes available in a record FIFO + * @fifo: the fifo to be used. + * @recsize: size of record field + */ +static inline __must_check unsigned int kfifo_avail_rec(struct kfifo *fifo, + unsigned int recsize) +{ + unsigned int l = kfifo_size(fifo) - kfifo_len(fifo); + + return (l > recsize) ? l - recsize : 0; +} + #endif -- cgit v1.2.3 From 9c717de946ed7f5782e6dffacf2d05859073058c Mon Sep 17 00:00:00 2001 From: Randy Dunlap Date: Wed, 23 Dec 2009 09:23:33 -0800 Subject: kfifo: fix Error/broken kernel-doc notation Fix kernel-doc errors and warnings in new header file kfifo.h. Don't use kernel-doc "/**" for internal functions whose comments are not in kernel-doc format. kernel-doc section header names (like "Note:") must be unique per function. Looks like I need to document that. Error(include/linux/kfifo.h:76): duplicate section name 'Note' Warning(include/linux/kfifo.h:88): Excess function parameter 'size' description in 'INIT_KFIFO' Error(include/linux/kfifo.h:101): duplicate section name 'Note' Warning(include/linux/kfifo.h:257): No description found for parameter 'fifo' (many of this last type, from internal functions) Signed-off-by: Randy Dunlap Cc: Stefani Seibold Signed-off-by: Linus Torvalds --- include/linux/kfifo.h | 31 +++++++++++++++---------------- 1 file changed, 15 insertions(+), 16 deletions(-) (limited to 'include/linux/kfifo.h') diff --git a/include/linux/kfifo.h b/include/linux/kfifo.h index 486e8ad3bb50..3d44e9c65a8e 100644 --- a/include/linux/kfifo.h +++ b/include/linux/kfifo.h @@ -69,8 +69,8 @@ struct kfifo { * @name: name of the declared kfifo datatype * @size: size of the fifo buffer * - * Note: the macro can be used inside struct or union declaration - * Note: the macro creates two objects: + * Note1: the macro can be used inside struct or union declaration + * Note2: the macro creates two objects: * A kfifo object with the given name and a buffer for the kfifo * object named name##kfifo_buffer */ @@ -83,7 +83,6 @@ union { \ /** * 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) - \ @@ -94,8 +93,8 @@ union { \ * @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 - * Note: the macro creates two objects: + * Note1: the macro can be used for global and local kfifo data type variables + * Note2: the macro creates two objects: * A kfifo object with the given name and a buffer for the kfifo * object named name##kfifo_buffer */ @@ -249,7 +248,7 @@ extern __must_check unsigned int kfifo_from_user(struct kfifo *fifo, extern __must_check unsigned int kfifo_to_user(struct kfifo *fifo, void __user *to, unsigned int n); -/** +/* * __kfifo_add_out internal helper function for updating the out offset */ static inline void __kfifo_add_out(struct kfifo *fifo, @@ -259,7 +258,7 @@ static inline void __kfifo_add_out(struct kfifo *fifo, fifo->out += off; } -/** +/* * __kfifo_add_in internal helper function for updating the in offset */ static inline void __kfifo_add_in(struct kfifo *fifo, @@ -269,7 +268,7 @@ static inline void __kfifo_add_in(struct kfifo *fifo, fifo->in += off; } -/** +/* * __kfifo_off internal helper function for calculating the index of a * given offeset */ @@ -278,7 +277,7 @@ static inline unsigned int __kfifo_off(struct kfifo *fifo, unsigned int off) return off & (fifo->size - 1); } -/** +/* * __kfifo_peek_n internal helper function for determinate the length of * the next record in the fifo */ @@ -299,7 +298,7 @@ static inline unsigned int __kfifo_peek_n(struct kfifo *fifo, #undef __KFIFO_GET } -/** +/* * __kfifo_poke_n internal helper function for storing the length of * the next record into the fifo */ @@ -319,7 +318,7 @@ static inline void __kfifo_poke_n(struct kfifo *fifo, #undef __KFIFO_PUT } -/** +/* * __kfifo_in_... internal functions for put date into the fifo * do not call it directly, use kfifo_in_rec() instead */ @@ -367,7 +366,7 @@ static inline __must_check unsigned int kfifo_in_rec(struct kfifo *fifo, return __kfifo_in_rec(fifo, from, n, recsize); } -/** +/* * __kfifo_out_... internal functions for get date from the fifo * do not call it directly, use kfifo_out_rec() instead */ @@ -425,7 +424,7 @@ static inline __must_check unsigned int kfifo_out_rec(struct kfifo *fifo, return __kfifo_out_rec(fifo, to, n, recsize, total); } -/** +/* * __kfifo_from_user_... internal functions for transfer from user space into * the fifo. do not call it directly, use kfifo_from_user_rec() instead */ @@ -474,7 +473,7 @@ static inline __must_check unsigned int kfifo_from_user_rec(struct kfifo *fifo, return __kfifo_from_user_rec(fifo, from, n, recsize); } -/** +/* * __kfifo_to_user_... internal functions for transfer fifo data into user space * do not call it directly, use kfifo_to_user_rec() instead */ @@ -533,7 +532,7 @@ static inline __must_check unsigned int kfifo_to_user_rec(struct kfifo *fifo, return __kfifo_to_user_rec(fifo, to, n, recsize, total); } -/** +/* * __kfifo_peek_... internal functions for peek into the next fifo record * do not call it directly, use kfifo_peek_rec() instead */ @@ -557,7 +556,7 @@ static inline __must_check unsigned int kfifo_peek_rec(struct kfifo *fifo, return __kfifo_peek_n(fifo, recsize); } -/** +/* * __kfifo_skip_... internal functions for skip the next fifo record * do not call it directly, use kfifo_skip_rec() instead */ -- cgit v1.2.3