2005-04-16 16:20:36 -06:00
|
|
|
/*
|
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 <stefani@seibold.net>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Acked-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Acked-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-21 15:37:26 -07:00
|
|
|
* A generic kernel FIFO implementation.
|
2005-04-16 16:20:36 -06:00
|
|
|
*
|
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 <stefani@seibold.net>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Acked-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Acked-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-21 15:37:26 -07:00
|
|
|
* Copyright (C) 2009 Stefani Seibold <stefani@seibold.net>
|
2005-04-16 16:20:36 -06:00
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* Copyright (C) 2004 Stelian Pop <stelian@popies.net>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*
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*/
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/slab.h>
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#include <linux/err.h>
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#include <linux/kfifo.h>
|
2007-07-16 00:41:34 -06:00
|
|
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#include <linux/log2.h>
|
2009-12-21 15:37:31 -07:00
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#include <linux/uaccess.h>
|
2005-04-16 16:20:36 -06:00
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|
|
|
2010-01-15 18:01:12 -07:00
|
|
|
static void _kfifo_init(struct kfifo *fifo, void *buffer,
|
2009-12-21 15:37:27 -07:00
|
|
|
unsigned int size)
|
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 <stefani@seibold.net>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Acked-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Acked-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-21 15:37:26 -07:00
|
|
|
{
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|
|
|
fifo->buffer = buffer;
|
|
|
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fifo->size = size;
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|
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|
|
kfifo_reset(fifo);
|
|
|
|
}
|
|
|
|
|
2005-04-16 16:20:36 -06:00
|
|
|
/**
|
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 <stefani@seibold.net>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Acked-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Acked-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-21 15:37:26 -07:00
|
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* kfifo_init - initialize a FIFO using a preallocated buffer
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* @fifo: the fifo to assign the buffer
|
2005-04-16 16:20:36 -06:00
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* @buffer: the preallocated buffer to be used.
|
2010-01-15 18:01:17 -07:00
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* @size: the size of the internal buffer, this has to be a power of 2.
|
2005-04-16 16:20:36 -06:00
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*
|
|
|
|
*/
|
2010-01-15 18:01:12 -07:00
|
|
|
void kfifo_init(struct kfifo *fifo, void *buffer, unsigned int size)
|
2005-04-16 16:20:36 -06:00
|
|
|
{
|
|
|
|
/* size must be a power of 2 */
|
2007-07-16 00:41:34 -06:00
|
|
|
BUG_ON(!is_power_of_2(size));
|
2005-04-16 16:20:36 -06:00
|
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|
|
2009-12-21 15:37:27 -07:00
|
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_kfifo_init(fifo, buffer, size);
|
2005-04-16 16:20:36 -06:00
|
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|
}
|
|
|
|
EXPORT_SYMBOL(kfifo_init);
|
|
|
|
|
|
|
|
/**
|
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 <stefani@seibold.net>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Acked-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Acked-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-21 15:37:26 -07:00
|
|
|
* kfifo_alloc - allocates a new FIFO internal buffer
|
|
|
|
* @fifo: the fifo to assign then new buffer
|
|
|
|
* @size: the size of the buffer to be allocated, this have to be a power of 2.
|
2005-04-16 16:20:36 -06:00
|
|
|
* @gfp_mask: get_free_pages mask, passed to kmalloc()
|
|
|
|
*
|
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 <stefani@seibold.net>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Acked-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Acked-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-21 15:37:26 -07:00
|
|
|
* This function dynamically allocates a new fifo internal buffer
|
|
|
|
*
|
2005-04-16 16:20:36 -06:00
|
|
|
* The size will be rounded-up to a power of 2.
|
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 <stefani@seibold.net>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Acked-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Acked-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-21 15:37:26 -07:00
|
|
|
* The buffer will be release with kfifo_free().
|
|
|
|
* Return 0 if no error, otherwise the an error code
|
2005-04-16 16:20:36 -06:00
|
|
|
*/
|
2009-12-21 15:37:27 -07:00
|
|
|
int kfifo_alloc(struct kfifo *fifo, unsigned int size, gfp_t gfp_mask)
|
2005-04-16 16:20:36 -06:00
|
|
|
{
|
|
|
|
unsigned char *buffer;
|
|
|
|
|
|
|
|
/*
|
|
|
|
* round up to the next power of 2, since our 'let the indices
|
2009-06-16 16:33:34 -06:00
|
|
|
* wrap' technique works only in this case.
|
2005-04-16 16:20:36 -06:00
|
|
|
*/
|
2009-06-16 16:33:34 -06:00
|
|
|
if (!is_power_of_2(size)) {
|
2005-04-16 16:20:36 -06:00
|
|
|
BUG_ON(size > 0x80000000);
|
|
|
|
size = roundup_pow_of_two(size);
|
|
|
|
}
|
|
|
|
|
|
|
|
buffer = kmalloc(size, gfp_mask);
|
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 <stefani@seibold.net>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Acked-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Acked-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-21 15:37:26 -07:00
|
|
|
if (!buffer) {
|
2009-12-21 15:37:27 -07:00
|
|
|
_kfifo_init(fifo, 0, 0);
|
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 <stefani@seibold.net>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Acked-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Acked-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-21 15:37:26 -07:00
|
|
|
return -ENOMEM;
|
|
|
|
}
|
2005-04-16 16:20:36 -06:00
|
|
|
|
2009-12-21 15:37:27 -07:00
|
|
|
_kfifo_init(fifo, buffer, size);
|
2005-04-16 16:20:36 -06:00
|
|
|
|
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 <stefani@seibold.net>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Acked-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Acked-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-21 15:37:26 -07:00
|
|
|
return 0;
|
2005-04-16 16:20:36 -06:00
|
|
|
}
|
|
|
|
EXPORT_SYMBOL(kfifo_alloc);
|
|
|
|
|
|
|
|
/**
|
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 <stefani@seibold.net>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Acked-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Acked-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-21 15:37:26 -07:00
|
|
|
* kfifo_free - frees the FIFO internal buffer
|
2005-04-16 16:20:36 -06:00
|
|
|
* @fifo: the fifo to be freed.
|
|
|
|
*/
|
|
|
|
void kfifo_free(struct kfifo *fifo)
|
|
|
|
{
|
|
|
|
kfree(fifo->buffer);
|
2010-01-27 07:09:34 -07:00
|
|
|
_kfifo_init(fifo, NULL, 0);
|
2005-04-16 16:20:36 -06:00
|
|
|
}
|
|
|
|
EXPORT_SYMBOL(kfifo_free);
|
|
|
|
|
2009-12-21 15:37:31 -07:00
|
|
|
/**
|
|
|
|
* kfifo_skip - skip output data
|
|
|
|
* @fifo: the fifo to be used.
|
|
|
|
* @len: number of bytes to skip
|
|
|
|
*/
|
|
|
|
void kfifo_skip(struct kfifo *fifo, unsigned int len)
|
|
|
|
{
|
|
|
|
if (len < kfifo_len(fifo)) {
|
|
|
|
__kfifo_add_out(fifo, len);
|
|
|
|
return;
|
|
|
|
}
|
|
|
|
kfifo_reset_out(fifo);
|
|
|
|
}
|
|
|
|
EXPORT_SYMBOL(kfifo_skip);
|
|
|
|
|
2009-12-21 15:37:32 -07:00
|
|
|
static inline void __kfifo_in_data(struct kfifo *fifo,
|
|
|
|
const void *from, unsigned int len, unsigned int off)
|
2005-04-16 16:20:36 -06:00
|
|
|
{
|
|
|
|
unsigned int l;
|
|
|
|
|
2006-09-29 03:00:11 -06:00
|
|
|
/*
|
|
|
|
* Ensure that we sample the fifo->out index -before- we
|
|
|
|
* start putting bytes into the kfifo.
|
|
|
|
*/
|
|
|
|
|
|
|
|
smp_mb();
|
|
|
|
|
2009-12-21 15:37:32 -07:00
|
|
|
off = __kfifo_off(fifo, fifo->in + off);
|
2009-12-21 15:37:31 -07:00
|
|
|
|
2005-04-16 16:20:36 -06:00
|
|
|
/* first put the data starting from fifo->in to buffer end */
|
2009-12-21 15:37:31 -07:00
|
|
|
l = min(len, fifo->size - off);
|
|
|
|
memcpy(fifo->buffer + off, from, l);
|
2005-04-16 16:20:36 -06:00
|
|
|
|
|
|
|
/* then put the rest (if any) at the beginning of the buffer */
|
2009-12-21 15:37:28 -07:00
|
|
|
memcpy(fifo->buffer, from + l, len - l);
|
2005-04-16 16:20:36 -06:00
|
|
|
}
|
|
|
|
|
2009-12-21 15:37:32 -07:00
|
|
|
static inline void __kfifo_out_data(struct kfifo *fifo,
|
|
|
|
void *to, unsigned int len, unsigned int off)
|
2005-04-16 16:20:36 -06:00
|
|
|
{
|
|
|
|
unsigned int l;
|
|
|
|
|
2006-09-29 03:00:11 -06:00
|
|
|
/*
|
|
|
|
* Ensure that we sample the fifo->in index -before- we
|
|
|
|
* start removing bytes from the kfifo.
|
|
|
|
*/
|
|
|
|
|
|
|
|
smp_rmb();
|
|
|
|
|
2009-12-21 15:37:32 -07:00
|
|
|
off = __kfifo_off(fifo, fifo->out + off);
|
2009-12-21 15:37:31 -07:00
|
|
|
|
2005-04-16 16:20:36 -06:00
|
|
|
/* first get the data from fifo->out until the end of the buffer */
|
2009-12-21 15:37:31 -07:00
|
|
|
l = min(len, fifo->size - off);
|
|
|
|
memcpy(to, fifo->buffer + off, l);
|
2005-04-16 16:20:36 -06:00
|
|
|
|
|
|
|
/* then get the rest (if any) from the beginning of the buffer */
|
2009-12-21 15:37:28 -07:00
|
|
|
memcpy(to + l, fifo->buffer, len - l);
|
2009-12-21 15:37:31 -07:00
|
|
|
}
|
|
|
|
|
2010-01-15 18:01:15 -07:00
|
|
|
static inline int __kfifo_from_user_data(struct kfifo *fifo,
|
|
|
|
const void __user *from, unsigned int len, unsigned int off,
|
|
|
|
unsigned *lenout)
|
2009-12-21 15:37:31 -07:00
|
|
|
{
|
|
|
|
unsigned int l;
|
|
|
|
int ret;
|
|
|
|
|
2006-09-29 03:00:11 -06:00
|
|
|
/*
|
2009-12-21 15:37:31 -07:00
|
|
|
* Ensure that we sample the fifo->out index -before- we
|
|
|
|
* start putting bytes into the kfifo.
|
2006-09-29 03:00:11 -06:00
|
|
|
*/
|
|
|
|
|
|
|
|
smp_mb();
|
|
|
|
|
2009-12-21 15:37:32 -07:00
|
|
|
off = __kfifo_off(fifo, fifo->in + off);
|
2009-12-21 15:37:31 -07:00
|
|
|
|
|
|
|
/* first put the data starting from fifo->in to buffer end */
|
|
|
|
l = min(len, fifo->size - off);
|
|
|
|
ret = copy_from_user(fifo->buffer + off, from, l);
|
2010-01-15 18:01:15 -07:00
|
|
|
if (unlikely(ret)) {
|
|
|
|
*lenout = ret;
|
|
|
|
return -EFAULT;
|
|
|
|
}
|
|
|
|
*lenout = l;
|
2009-12-21 15:37:31 -07:00
|
|
|
|
|
|
|
/* then put the rest (if any) at the beginning of the buffer */
|
2010-01-15 18:01:15 -07:00
|
|
|
ret = copy_from_user(fifo->buffer, from + l, len - l);
|
|
|
|
*lenout += ret ? ret : len - l;
|
|
|
|
return ret ? -EFAULT : 0;
|
2009-12-21 15:37:32 -07:00
|
|
|
}
|
|
|
|
|
2010-01-15 18:01:15 -07:00
|
|
|
static inline int __kfifo_to_user_data(struct kfifo *fifo,
|
|
|
|
void __user *to, unsigned int len, unsigned int off, unsigned *lenout)
|
2009-12-21 15:37:32 -07:00
|
|
|
{
|
|
|
|
unsigned int l;
|
|
|
|
int ret;
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Ensure that we sample the fifo->in index -before- we
|
|
|
|
* start removing bytes from the kfifo.
|
|
|
|
*/
|
|
|
|
|
|
|
|
smp_rmb();
|
|
|
|
|
|
|
|
off = __kfifo_off(fifo, fifo->out + off);
|
|
|
|
|
|
|
|
/* first get the data from fifo->out until the end of the buffer */
|
|
|
|
l = min(len, fifo->size - off);
|
|
|
|
ret = copy_to_user(to, fifo->buffer + off, l);
|
2010-01-15 18:01:15 -07:00
|
|
|
*lenout = l;
|
|
|
|
if (unlikely(ret)) {
|
|
|
|
*lenout -= ret;
|
|
|
|
return -EFAULT;
|
|
|
|
}
|
2009-12-21 15:37:31 -07:00
|
|
|
|
2009-12-21 15:37:32 -07:00
|
|
|
/* then get the rest (if any) from the beginning of the buffer */
|
2010-01-15 18:01:15 -07:00
|
|
|
len -= l;
|
|
|
|
ret = copy_to_user(to + l, fifo->buffer, len);
|
|
|
|
if (unlikely(ret)) {
|
|
|
|
*lenout += len - ret;
|
|
|
|
return -EFAULT;
|
|
|
|
}
|
|
|
|
*lenout += len;
|
|
|
|
return 0;
|
2009-12-21 15:37:32 -07:00
|
|
|
}
|
2005-04-16 16:20:36 -06:00
|
|
|
|
2009-12-21 15:37:32 -07:00
|
|
|
unsigned int __kfifo_in_n(struct kfifo *fifo,
|
|
|
|
const void *from, unsigned int len, unsigned int recsize)
|
|
|
|
{
|
|
|
|
if (kfifo_avail(fifo) < len + recsize)
|
|
|
|
return len + 1;
|
|
|
|
|
|
|
|
__kfifo_in_data(fifo, from, len, recsize);
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
EXPORT_SYMBOL(__kfifo_in_n);
|
|
|
|
|
|
|
|
/**
|
|
|
|
* kfifo_in - puts some data into the FIFO
|
|
|
|
* @fifo: the fifo to be used.
|
|
|
|
* @from: the data to be added.
|
|
|
|
* @len: the length of the data to be added.
|
|
|
|
*
|
|
|
|
* 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.
|
|
|
|
*
|
|
|
|
* Note that with only one concurrent reader and one concurrent
|
|
|
|
* writer, you don't need extra locking to use these functions.
|
|
|
|
*/
|
2010-01-15 18:01:12 -07:00
|
|
|
unsigned int kfifo_in(struct kfifo *fifo, const void *from,
|
2009-12-21 15:37:32 -07:00
|
|
|
unsigned int len)
|
|
|
|
{
|
|
|
|
len = min(kfifo_avail(fifo), len);
|
|
|
|
|
|
|
|
__kfifo_in_data(fifo, from, len, 0);
|
|
|
|
__kfifo_add_in(fifo, len);
|
2005-04-16 16:20:36 -06:00
|
|
|
return len;
|
|
|
|
}
|
2009-12-21 15:37:32 -07:00
|
|
|
EXPORT_SYMBOL(kfifo_in);
|
|
|
|
|
|
|
|
unsigned int __kfifo_in_generic(struct kfifo *fifo,
|
|
|
|
const void *from, unsigned int len, unsigned int recsize)
|
|
|
|
{
|
|
|
|
return __kfifo_in_rec(fifo, from, len, recsize);
|
|
|
|
}
|
|
|
|
EXPORT_SYMBOL(__kfifo_in_generic);
|
|
|
|
|
|
|
|
unsigned int __kfifo_out_n(struct kfifo *fifo,
|
|
|
|
void *to, unsigned int len, unsigned int recsize)
|
|
|
|
{
|
|
|
|
if (kfifo_len(fifo) < len + recsize)
|
|
|
|
return len;
|
|
|
|
|
|
|
|
__kfifo_out_data(fifo, to, len, recsize);
|
|
|
|
__kfifo_add_out(fifo, len + recsize);
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
EXPORT_SYMBOL(__kfifo_out_n);
|
2009-12-21 15:37:31 -07:00
|
|
|
|
|
|
|
/**
|
2009-12-21 15:37:32 -07:00
|
|
|
* kfifo_out - gets some data from the FIFO
|
2009-12-21 15:37:31 -07:00
|
|
|
* @fifo: the fifo to be used.
|
|
|
|
* @to: where the data must be copied.
|
|
|
|
* @len: the size of the destination buffer.
|
|
|
|
*
|
|
|
|
* This function copies at most @len bytes from the FIFO into the
|
|
|
|
* @to buffer and returns the number of copied bytes.
|
|
|
|
*
|
|
|
|
* Note that with only one concurrent reader and one concurrent
|
|
|
|
* writer, you don't need extra locking to use these functions.
|
|
|
|
*/
|
2010-01-15 18:01:12 -07:00
|
|
|
unsigned int kfifo_out(struct kfifo *fifo, void *to, unsigned int len)
|
2009-12-21 15:37:31 -07:00
|
|
|
{
|
2009-12-21 15:37:32 -07:00
|
|
|
len = min(kfifo_len(fifo), len);
|
2009-12-21 15:37:31 -07:00
|
|
|
|
2009-12-21 15:37:32 -07:00
|
|
|
__kfifo_out_data(fifo, to, len, 0);
|
|
|
|
__kfifo_add_out(fifo, len);
|
2009-12-21 15:37:31 -07:00
|
|
|
|
2009-12-21 15:37:32 -07:00
|
|
|
return len;
|
|
|
|
}
|
|
|
|
EXPORT_SYMBOL(kfifo_out);
|
2009-12-21 15:37:31 -07:00
|
|
|
|
2010-01-15 18:01:16 -07:00
|
|
|
/**
|
|
|
|
* kfifo_out_peek - copy some data from the FIFO, but do not remove it
|
|
|
|
* @fifo: the fifo to be used.
|
|
|
|
* @to: where the data must be copied.
|
|
|
|
* @len: the size of the destination buffer.
|
|
|
|
* @offset: offset into the fifo
|
|
|
|
*
|
|
|
|
* This function copies at most @len bytes at @offset from the FIFO
|
|
|
|
* into the @to buffer and returns the number of copied bytes.
|
|
|
|
* The data is not removed from the FIFO.
|
|
|
|
*/
|
|
|
|
unsigned int kfifo_out_peek(struct kfifo *fifo, void *to, unsigned int len,
|
|
|
|
unsigned offset)
|
|
|
|
{
|
|
|
|
len = min(kfifo_len(fifo), len + offset);
|
|
|
|
|
|
|
|
__kfifo_out_data(fifo, to, len, offset);
|
|
|
|
return len;
|
|
|
|
}
|
|
|
|
EXPORT_SYMBOL(kfifo_out_peek);
|
|
|
|
|
2009-12-21 15:37:32 -07:00
|
|
|
unsigned int __kfifo_out_generic(struct kfifo *fifo,
|
|
|
|
void *to, unsigned int len, unsigned int recsize,
|
|
|
|
unsigned int *total)
|
|
|
|
{
|
|
|
|
return __kfifo_out_rec(fifo, to, len, recsize, total);
|
|
|
|
}
|
|
|
|
EXPORT_SYMBOL(__kfifo_out_generic);
|
2009-12-21 15:37:31 -07:00
|
|
|
|
2009-12-21 15:37:32 -07:00
|
|
|
unsigned int __kfifo_from_user_n(struct kfifo *fifo,
|
|
|
|
const void __user *from, unsigned int len, unsigned int recsize)
|
|
|
|
{
|
2010-01-15 18:01:15 -07:00
|
|
|
unsigned total;
|
|
|
|
|
2009-12-21 15:37:32 -07:00
|
|
|
if (kfifo_avail(fifo) < len + recsize)
|
|
|
|
return len + 1;
|
2009-12-21 15:37:31 -07:00
|
|
|
|
2010-01-15 18:01:15 -07:00
|
|
|
__kfifo_from_user_data(fifo, from, len, recsize, &total);
|
|
|
|
return total;
|
2009-12-21 15:37:32 -07:00
|
|
|
}
|
|
|
|
EXPORT_SYMBOL(__kfifo_from_user_n);
|
2009-12-21 15:37:31 -07:00
|
|
|
|
2009-12-21 15:37:32 -07:00
|
|
|
/**
|
|
|
|
* kfifo_from_user - puts some data from user space into the FIFO
|
|
|
|
* @fifo: the fifo to be used.
|
|
|
|
* @from: pointer to the data to be added.
|
|
|
|
* @len: the length of the data to be added.
|
2010-02-02 14:44:01 -07:00
|
|
|
* @total: the actual returned data length.
|
2009-12-21 15:37:32 -07:00
|
|
|
*
|
|
|
|
* This function copies at most @len bytes from the @from into the
|
2010-01-15 18:01:15 -07:00
|
|
|
* FIFO depending and returns -EFAULT/0.
|
2009-12-21 15:37:32 -07:00
|
|
|
*
|
|
|
|
* Note that with only one concurrent reader and one concurrent
|
|
|
|
* writer, you don't need extra locking to use these functions.
|
|
|
|
*/
|
2010-01-15 18:01:15 -07:00
|
|
|
int kfifo_from_user(struct kfifo *fifo,
|
|
|
|
const void __user *from, unsigned int len, unsigned *total)
|
2009-12-21 15:37:32 -07:00
|
|
|
{
|
2010-01-15 18:01:15 -07:00
|
|
|
int ret;
|
2009-12-21 15:37:32 -07:00
|
|
|
len = min(kfifo_avail(fifo), len);
|
2010-01-15 18:01:15 -07:00
|
|
|
ret = __kfifo_from_user_data(fifo, from, len, 0, total);
|
|
|
|
if (ret)
|
|
|
|
return ret;
|
2009-12-21 15:37:32 -07:00
|
|
|
__kfifo_add_in(fifo, len);
|
2010-01-15 18:01:15 -07:00
|
|
|
return 0;
|
2009-12-21 15:37:32 -07:00
|
|
|
}
|
|
|
|
EXPORT_SYMBOL(kfifo_from_user);
|
2009-12-21 15:37:31 -07:00
|
|
|
|
2009-12-21 15:37:32 -07:00
|
|
|
unsigned int __kfifo_from_user_generic(struct kfifo *fifo,
|
|
|
|
const void __user *from, unsigned int len, unsigned int recsize)
|
|
|
|
{
|
|
|
|
return __kfifo_from_user_rec(fifo, from, len, recsize);
|
|
|
|
}
|
|
|
|
EXPORT_SYMBOL(__kfifo_from_user_generic);
|
2009-12-21 15:37:31 -07:00
|
|
|
|
2009-12-21 15:37:32 -07:00
|
|
|
unsigned int __kfifo_to_user_n(struct kfifo *fifo,
|
|
|
|
void __user *to, unsigned int len, unsigned int reclen,
|
|
|
|
unsigned int recsize)
|
|
|
|
{
|
2010-01-15 18:01:15 -07:00
|
|
|
unsigned int ret, total;
|
2009-12-21 15:37:31 -07:00
|
|
|
|
2009-12-21 15:37:32 -07:00
|
|
|
if (kfifo_len(fifo) < reclen + recsize)
|
|
|
|
return len;
|
2009-12-21 15:37:31 -07:00
|
|
|
|
2010-01-15 18:01:15 -07:00
|
|
|
ret = __kfifo_to_user_data(fifo, to, reclen, recsize, &total);
|
2009-12-21 15:37:32 -07:00
|
|
|
|
|
|
|
if (likely(ret == 0))
|
|
|
|
__kfifo_add_out(fifo, reclen + recsize);
|
|
|
|
|
2010-01-15 18:01:15 -07:00
|
|
|
return total;
|
2009-12-21 15:37:32 -07:00
|
|
|
}
|
|
|
|
EXPORT_SYMBOL(__kfifo_to_user_n);
|
|
|
|
|
|
|
|
/**
|
|
|
|
* kfifo_to_user - gets data from the FIFO and write it to user space
|
|
|
|
* @fifo: the fifo to be used.
|
|
|
|
* @to: where the data must be copied.
|
|
|
|
* @len: the size of the destination buffer.
|
2010-02-02 14:44:01 -07:00
|
|
|
* @lenout: pointer to output variable with copied data
|
2009-12-21 15:37:32 -07:00
|
|
|
*
|
|
|
|
* This function copies at most @len bytes from the FIFO into the
|
2010-01-15 18:01:15 -07:00
|
|
|
* @to buffer and 0 or -EFAULT.
|
2009-12-21 15:37:32 -07:00
|
|
|
*
|
|
|
|
* Note that with only one concurrent reader and one concurrent
|
|
|
|
* writer, you don't need extra locking to use these functions.
|
|
|
|
*/
|
2010-01-15 18:01:15 -07:00
|
|
|
int kfifo_to_user(struct kfifo *fifo,
|
|
|
|
void __user *to, unsigned int len, unsigned *lenout)
|
2009-12-21 15:37:32 -07:00
|
|
|
{
|
2010-01-15 18:01:15 -07:00
|
|
|
int ret;
|
2009-12-21 15:37:32 -07:00
|
|
|
len = min(kfifo_len(fifo), len);
|
2010-01-15 18:01:15 -07:00
|
|
|
ret = __kfifo_to_user_data(fifo, to, len, 0, lenout);
|
|
|
|
__kfifo_add_out(fifo, *lenout);
|
|
|
|
return ret;
|
2009-12-21 15:37:31 -07:00
|
|
|
}
|
|
|
|
EXPORT_SYMBOL(kfifo_to_user);
|
|
|
|
|
2009-12-21 15:37:32 -07:00
|
|
|
unsigned int __kfifo_to_user_generic(struct kfifo *fifo,
|
|
|
|
void __user *to, unsigned int len, unsigned int recsize,
|
|
|
|
unsigned int *total)
|
|
|
|
{
|
|
|
|
return __kfifo_to_user_rec(fifo, to, len, recsize, total);
|
|
|
|
}
|
|
|
|
EXPORT_SYMBOL(__kfifo_to_user_generic);
|
|
|
|
|
|
|
|
unsigned int __kfifo_peek_generic(struct kfifo *fifo, unsigned int recsize)
|
|
|
|
{
|
|
|
|
if (recsize == 0)
|
|
|
|
return kfifo_avail(fifo);
|
|
|
|
|
|
|
|
return __kfifo_peek_n(fifo, recsize);
|
|
|
|
}
|
|
|
|
EXPORT_SYMBOL(__kfifo_peek_generic);
|
|
|
|
|
|
|
|
void __kfifo_skip_generic(struct kfifo *fifo, unsigned int recsize)
|
|
|
|
{
|
|
|
|
__kfifo_skip_rec(fifo, recsize);
|
|
|
|
}
|
|
|
|
EXPORT_SYMBOL(__kfifo_skip_generic);
|
|
|
|
|