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 From ed656d8deccc5669afa33387568e7ec6f14e3e94 Mon Sep 17 00:00:00 2001 From: Rolf Eike Beer Date: Sat, 26 Dec 2009 17:58:11 +0100 Subject: kfifo: Fix typo in comment It's DECLARE_KFIFO, not DECLARED_KFIFO. Signed-off-by: Rolf Eike Beer Signed-off-by: Linus Torvalds --- include/linux/kfifo.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include/linux/kfifo.h') diff --git a/include/linux/kfifo.h b/include/linux/kfifo.h index 3d44e9c65a8e..7c6b32a1421c 100644 --- a/include/linux/kfifo.h +++ b/include/linux/kfifo.h @@ -81,7 +81,7 @@ union { \ } /** - * INIT_KFIFO - Initialize a kfifo declared by DECLARED_KFIFO + * INIT_KFIFO - Initialize a kfifo declared by DECLARE_KFIFO * @name: name of the declared kfifo datatype */ #define INIT_KFIFO(name) \ -- cgit v1.2.3 From 7e105057a34c83cea542dacc55ff0528bce67afa Mon Sep 17 00:00:00 2001 From: Stefani Seibold Date: Fri, 15 Jan 2010 17:01:02 -0800 Subject: kfifo: fix kfifo_out_locked race bug Fix a wrong optimization in include/linux/kfifo.h which could cause a race in kfifo_out_locked. Signed-off-by: Stefani Seibold Reported-by: Johan Hovold Cc: Pete Zaitcev Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/kfifo.h | 7 ------- 1 file changed, 7 deletions(-) (limited to 'include/linux/kfifo.h') diff --git a/include/linux/kfifo.h b/include/linux/kfifo.h index 7c6b32a1421c..c4ac88b3c302 100644 --- a/include/linux/kfifo.h +++ b/include/linux/kfifo.h @@ -228,13 +228,6 @@ static inline __must_check unsigned int kfifo_out_locked(struct kfifo *fifo, ret = kfifo_out(fifo, to, n); - /* - * optimization: if the FIFO is empty, set the indices to 0 - * so we don't wrap the next time - */ - if (kfifo_is_empty(fifo)) - kfifo_reset(fifo); - spin_unlock_irqrestore(lock, flags); return ret; -- cgit v1.2.3 From 8ecc2951534af10e04ddb5e5ff5c6d217b79f5c2 Mon Sep 17 00:00:00 2001 From: Andi Kleen Date: Fri, 15 Jan 2010 17:01:12 -0800 Subject: kfifo: use void * pointers for user buffers The pointers to user buffers are currently unsigned char *, which requires a lot of casting in the caller for any non-char typed buffers. Use void * instead. Signed-off-by: Andi Kleen Acked-by: Stefani Seibold Cc: Roland Dreier Cc: Dmitry Torokhov Cc: Andy Walls Cc: Vikram Dhillon Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/kfifo.h | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) (limited to 'include/linux/kfifo.h') diff --git a/include/linux/kfifo.h b/include/linux/kfifo.h index c4ac88b3c302..6fb495ea956a 100644 --- a/include/linux/kfifo.h +++ b/include/linux/kfifo.h @@ -104,15 +104,15 @@ union { \ #undef __kfifo_initializer -extern void kfifo_init(struct kfifo *fifo, unsigned char *buffer, +extern void kfifo_init(struct kfifo *fifo, void *buffer, unsigned int size); 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_in(struct kfifo *fifo, - const unsigned char *from, unsigned int len); + const void *from, unsigned int len); extern __must_check unsigned int kfifo_out(struct kfifo *fifo, - unsigned char *to, unsigned int len); + void *to, unsigned int len); /** * kfifo_reset - removes the entire FIFO contents @@ -194,7 +194,7 @@ static inline __must_check unsigned int kfifo_avail(struct kfifo *fifo) * bytes copied. */ static inline unsigned int kfifo_in_locked(struct kfifo *fifo, - const unsigned char *from, unsigned int n, spinlock_t *lock) + const void *from, unsigned int n, spinlock_t *lock) { unsigned long flags; unsigned int ret; @@ -219,7 +219,7 @@ static inline unsigned int kfifo_in_locked(struct kfifo *fifo, * @to buffer and returns the number of copied bytes. */ static inline __must_check unsigned int kfifo_out_locked(struct kfifo *fifo, - unsigned char *to, unsigned int n, spinlock_t *lock) + void *to, unsigned int n, spinlock_t *lock) { unsigned long flags; unsigned int ret; -- cgit v1.2.3 From 64ce1037c5434b1d036cd99ecaee6e00496bc2e9 Mon Sep 17 00:00:00 2001 From: Andi Kleen Date: Fri, 15 Jan 2010 17:01:15 -0800 Subject: kfifo: sanitize *_user error handling Right now for kfifo_*_user it's not easily possible to distingush between a user copy failing and the FIFO not containing enough data. The problem is that both conditions are multiplexed into the same return code. Avoid this by moving the "copy length" into a separate output parameter and only return 0/-EFAULT in the main return value. I didn't fully adapt the weird "record" variants, those seem to be unused anyways and were rather messy (should they be just removed?) I would appreciate some double checking if I did all the conversions correctly. Signed-off-by: Andi Kleen Cc: Stefani Seibold Cc: Roland Dreier Cc: Dmitry Torokhov Cc: Andy Walls Cc: Vikram Dhillon Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/kfifo.h | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'include/linux/kfifo.h') diff --git a/include/linux/kfifo.h b/include/linux/kfifo.h index 6fb495ea956a..86ad50a900c8 100644 --- a/include/linux/kfifo.h +++ b/include/linux/kfifo.h @@ -235,11 +235,11 @@ static inline __must_check unsigned int kfifo_out_locked(struct kfifo *fifo, 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 int kfifo_from_user(struct kfifo *fifo, + const void __user *from, unsigned int n, unsigned *lenout); -extern __must_check unsigned int kfifo_to_user(struct kfifo *fifo, - void __user *to, unsigned int n); +extern __must_check int kfifo_to_user(struct kfifo *fifo, + void __user *to, unsigned int n, unsigned *lenout); /* * __kfifo_add_out internal helper function for updating the out offset -- cgit v1.2.3 From a5b9e2c1063046421ce01dcf5ddd7ec12567f3e1 Mon Sep 17 00:00:00 2001 From: Andi Kleen Date: Fri, 15 Jan 2010 17:01:16 -0800 Subject: kfifo: add kfifo_out_peek In some upcoming code it's useful to peek into a FIFO without permanentely removing data. This patch implements a new kfifo_out_peek() to do this. Signed-off-by: Andi Kleen Acked-by: Stefani Seibold Cc: Roland Dreier Cc: Dmitry Torokhov Cc: Andy Walls Cc: Vikram Dhillon Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/kfifo.h | 3 +++ 1 file changed, 3 insertions(+) (limited to 'include/linux/kfifo.h') diff --git a/include/linux/kfifo.h b/include/linux/kfifo.h index 86ad50a900c8..7ad6d32dd673 100644 --- a/include/linux/kfifo.h +++ b/include/linux/kfifo.h @@ -113,6 +113,9 @@ extern unsigned int kfifo_in(struct kfifo *fifo, const void *from, unsigned int len); extern __must_check unsigned int kfifo_out(struct kfifo *fifo, void *to, unsigned int len); +extern __must_check unsigned int kfifo_out_peek(struct kfifo *fifo, + void *to, unsigned int len, unsigned offset); + /** * kfifo_reset - removes the entire FIFO contents -- cgit v1.2.3 From d994ffc247f7c4a48b848f10c4c01c9b06411ada Mon Sep 17 00:00:00 2001 From: Andi Kleen Date: Fri, 15 Jan 2010 17:01:17 -0800 Subject: kfifo: add kfifo_initialized Simple inline that checks if kfifo_init() has been executed on a fifo. This is useful for walking all per CPU fifos, when some of them might not have been brought up yet. Signed-off-by: Andi Kleen Acked-by: Stefani Seibold Cc: Roland Dreier Cc: Dmitry Torokhov Cc: Andy Walls Cc: Vikram Dhillon Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/kfifo.h | 10 ++++++++++ 1 file changed, 10 insertions(+) (limited to 'include/linux/kfifo.h') diff --git a/include/linux/kfifo.h b/include/linux/kfifo.h index 7ad6d32dd673..c8618243ca5a 100644 --- a/include/linux/kfifo.h +++ b/include/linux/kfifo.h @@ -116,6 +116,16 @@ extern __must_check unsigned int kfifo_out(struct kfifo *fifo, extern __must_check unsigned int kfifo_out_peek(struct kfifo *fifo, void *to, unsigned int len, unsigned offset); +/** + * kfifo_initialized - Check if kfifo is initialized. + * @fifo: fifo to check + * Return %true if FIFO is initialized, otherwise %false. + * Assumes the fifo was 0 before. + */ +static inline bool kfifo_initialized(struct kfifo *fifo) +{ + return fifo->buffer != 0; +} /** * kfifo_reset - removes the entire FIFO contents -- cgit v1.2.3 From 5dab600e6a153ceb64832f608069e6c08185411a Mon Sep 17 00:00:00 2001 From: Andi Kleen Date: Fri, 15 Jan 2010 17:01:17 -0800 Subject: kfifo: document everywhere that size has to be power of two On my first try using them I missed that the fifos need to be power of two, resulting in a runtime bug. Document that requirement everywhere (and fix one grammar bug) Signed-off-by: Andi Kleen Acked-by: Stefani Seibold Cc: Roland Dreier Cc: Dmitry Torokhov Cc: Andy Walls Cc: Vikram Dhillon 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 c8618243ca5a..6f6c5f300af6 100644 --- a/include/linux/kfifo.h +++ b/include/linux/kfifo.h @@ -67,7 +67,7 @@ struct kfifo { /** * DECLARE_KFIFO - macro to declare a kfifo and the associated buffer * @name: name of the declared kfifo datatype - * @size: size of the fifo buffer + * @size: size of the fifo buffer. Must be a power of two. * * Note1: the macro can be used inside struct or union declaration * Note2: the macro creates two objects: @@ -91,7 +91,7 @@ union { \ /** * DEFINE_KFIFO - macro to define and initialize a kfifo * @name: name of the declared kfifo datatype - * @size: size of the fifo buffer + * @size: size of the fifo buffer. Must be a power of two. * * Note1: the macro can be used for global and local kfifo data type variables * Note2: the macro creates two objects: -- cgit v1.2.3