kfifo_to_user(9) [suse man page]

KFIFO_TO_USER(9)						    FIFO Buffer 						  KFIFO_TO_USER(9)

NAME

       kfifo_to_user - gets data from the FIFO and write it to user space

SYNOPSIS

       int kfifo_to_user(struct kfifo * fifo, void __user * to, unsigned int len, unsigned * lenout);

ARGUMENTS

       fifo
	   the fifo to be used.

       to
	   where the data must be copied.

       len
	   the size of the destination buffer.

       lenout
	   pointer to output variable with copied data

DESCRIPTION

       This function copies at most len bytes from the FIFO into the to buffer and 0 or -EFAULT.

       Note that with only one concurrent reader and one concurrent writer, you don't need extra locking to use these functions.

COPYRIGHT

Kernel Hackers Manual 2.6.					     July 2010							  KFIFO_TO_USER(9)

COPY(9) 						   BSD Kernel Developer's Manual						   COPY(9)

NAME

     copy, copyin, copyin_nofault, copyout, copyout_nofault, copystr, copyinstr -- kernel copy functions

SYNOPSIS

     #include <sys/types.h>
     #include <sys/systm.h>

     int
     copyin(const void *uaddr, void *kaddr, size_t len);

     int
     copyin_nofault(const void *uaddr, void *kaddr, size_t len);

     int
     copyout(const void *kaddr, void *uaddr, size_t len);

     int
     copyout_nofault(const void *kaddr, void *uaddr, size_t len);

     int
     copystr(const void *kfaddr, void *kdaddr, size_t len, size_t *done);

     int
     copyinstr(const void *uaddr, void *kaddr, size_t len, size_t *done);

DESCRIPTION

     The copy functions are designed to copy contiguous data from one address to another.  All but copystr() copy data from user-space to kernel-
     space or vice-versa.

     The copyin() and copyin_nofault() functions copy len bytes of data from the user-space address uaddr to the kernel-space address kaddr.

     The copyout() and copyout_nofault() functions copy len bytes of data from the kernel-space address kaddr to the user-space address uaddr.

     The copyin_nofault() and copyout_nofault() functions require that the kernel-space and user-space data be accessible without incurring a page
     fault.  The source and destination addresses must be physically mapped for read and write access, respectively, and neither the source nor
     destination addresses may be pageable.

     The copystr() function copies a NUL-terminated string, at most len bytes long, from kernel-space address kfaddr to kernel-space address
     kdaddr.  The number of bytes actually copied, including the terminating NUL, is returned in *done (if done is non-NULL).

     The copyinstr() function copies a NUL-terminated string, at most len bytes long, from user-space address uaddr to kernel-space address kaddr.
     The number of bytes actually copied, including the terminating NUL, is returned in *done (if done is non-NULL).

RETURN VALUES

     The copy functions return 0 on success or EFAULT if a bad address is encountered.	In addition, the copyin_nofault() and copyout_nofault()
     functions return EFAULT if a page fault occurs, and the copystr() and copyinstr() functions return ENAMETOOLONG if the string is longer than
     len bytes.

SEE ALSO

     fetch(9), store(9)

BSD
								   July 9, 2011 							       BSD