_FINI(9E) | Driver Entry Points | _FINI(9E) |
#include <sys/modctl.h> int _fini(void)
int _info(struct modinfo *modinfop);
int _init(void)
_info() returns information about a loadable module. _info() returns the value returned by mod_info(9F).
_fini() prepares a loadable module for unloading. It is called when the system wants to unload a module. If the module determines that it can be unloaded, then _fini() returns the value returned by mod_remove(9F). Upon successful return from _fini() no other routine in the module will be called before _init() is called. If _init() did not successfully complete, _fini() will not be called.
_info() should return the return value from mod_info(9F)
_fini() should return the return value from mod_remove(9F). _fini() is permitted to return EBUSY prior to calling mod_remove(9F) if the driver should not be unloaded. Driver global resources, such as mutexes and calls to ddi_soft_state_fini(9F), should only be destroyed in _fini() after mod_remove() returns successfully.
The following example demonstrates how to initialize and free a mutex(9F).
#include <sys/modctl.h> #include <sys/ddi.h> #include <sys/sunddi.h> static struct dev_ops drv_ops; /* * Module linkage information for the kernel. */ static struct modldrv modldrv = { &mod_driverops, /* Type of module. This one is a driver */ "Sample Driver", &drv_ops /* driver ops */ }; static struct modlinkage modlinkage = { MODREV_1, &modldrv, NULL }; /* * Global driver mutex */ static kmutex_t xx_global_mutex; int _init(void) { int i; /* * Initialize global mutex before mod_install'ing driver. * If mod_install() fails, must clean up mutex initialization */ mutex_init(&xx_global_mutex, NULL, MUTEX_DRIVER, (void *)NULL); if ((i = mod_install(&modlinkage)) != 0) { mutex_destroy(&xx_global_mutex); } return (i); } int _info(struct modinfo *modinfop) { return (mod_info(&modlinkage, modinfop)); } int _fini(void) { int i; /* * If mod_remove() is successful, we destroy our global mutex */ if ((i = mod_remove(&modlinkage)) == 0) { mutex_destroy(&xx_global_mutex); } return (i); }
Writing Device Drivers
May 6, 2020 | OmniOS |