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author | Stefani Seibold <stefani@seibold.net> | 2009-12-21 14:37:31 -0800 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2009-12-22 14:17:56 -0800 |
commit | a121f24accac1600bf5b6fb1e12eeabdfed7cb1a (patch) | |
tree | 24a3bb527e50304677785dbb390dd5ff838c94e8 /include/linux/kfifo.h | |
parent | 37bdfbbfaab47811fcec84dff23c4e8da1a09f9e (diff) | |
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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 <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>
Diffstat (limited to 'include/linux/kfifo.h')
-rw-r--r-- | include/linux/kfifo.h | 47 |
1 files changed, 47 insertions, 0 deletions
diff --git a/include/linux/kfifo.h b/include/linux/kfifo.h index dd53eed..d3230fb 100644 --- a/include/linux/kfifo.h +++ b/include/linux/kfifo.h @@ -125,6 +125,16 @@ static inline void kfifo_reset(struct kfifo *fifo) } /** + * 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 |