Provides the means for kernel users to perform direct-access write operations.
#include <sys/device.h> #include <sys/comio.h> #include <sys/tokuser.h> #include <sys/mbuf.h>
int tokfastwrt (devno, m) dev_t devno; struct mbuf *m;
|devno||Specifies major and minor device numbers.|
|m||Pointer to an mbuf structure containing the data to transmit.|
The tokfastwrt entry point is called from a kernel-mode process to pass a write packet to the token-ring device handler for subsequent transmission. The address of this entry point is provided to the kernel user by the CIO_GET_FASTWRT ioctl entry point.
The tokfastwrt entry point provides for only one data packet to be transmitted for a single tokfastwrt call. The tokfastwrt entry point assumes that the calling user is a valid kernel user and that the mbuf structure contains a valid data packet. The device handler frees the mbuf and does not acknowledge transmit completion.
The tokfastwrt entry point can be called from a kernel process or interrupt level. The operation level of the token-ring device handler is TOK_OPLEVEL. This label is defined in the /usr/include/sys/tokuser.h file. The tokfastwrt entry point treats this path as a trusted path and the device handler does not check the parameters.
|ENODEV||Indicates the specified minor number is not valid.|
|EAGAIN||Indicates the transmit queue is full.|
The tokfastwrt entry point functions with a Token-Ring High-Performance Network Adapter that has been correctly configured for use on a qualified network. Consult adapter specifications for more information on configuring the adapter and network qualifications.
The tokmpx entry point, tokopen entry point.
The CIO_GET_FASTWRT tokioctl Token-Ring Device Handler Operation, CIO_START tokioctl Token-Ring Device Handler Operation.
The Memory Buffer (mbuf) Kernel Services in AIX Kernel Extensions and Device Support Programming Concepts.