Function firmware_get_flags

freebsd/kern/subr_firmware.c:287–339

* Lookup and potentially load the specified firmware image. * If the firmware is not found in the registry, try to load a kernel * module named as the image name. * If the firmware is located, a reference is returned. The caller must * release this reference for the image to be eligible for removal/unload. */

 * release this reference for the image to be eligible for removal/unload.
 */
const struct firmware *
firmware_get_flags(const char *imagename, uint32_t flags)
{
	struct task fwload_task;
	struct thread *td;
	struct priv_fw *fp;

	mtx_lock(&firmware_mtx);
	fp = lookup(imagename);
	if (fp != NULL)
		goto found;
	/*
	 * Image not present, try to load the module holding it.
	 */
	td = curthread;
	if (priv_check(td, PRIV_FIRMWARE_LOAD) != 0 ||
	    securelevel_gt(td->td_ucred, 0) != 0) {
		mtx_unlock(&firmware_mtx);
		printf("%s: insufficient privileges to "
		    "load firmware image %s\n", __func__, imagename);
		return NULL;
	}
	/*
	 * Defer load to a thread with known context.  linker_reference_module
	 * may do filesystem i/o which requires root & current dirs, etc.
	 * Also we must not hold any mtx's over this call which is problematic.
	 */
	if (!cold) {
		struct fw_loadimage fwli;

		fwli.imagename = imagename;
		fwli.flags = flags;
		TASK_INIT(&fwload_task, 0, loadimage, (void *)&fwli);
		taskqueue_enqueue(firmware_tq, &fwload_task);
		PHOLD(curproc);
		msleep((void *)&fwli, &firmware_mtx, 0, "fwload", 0);
		PRELE(curproc);
	}
	/*
	 * After attempting to load the module, see if the image is registered.
	 */
	fp = lookup(imagename);
	if (fp == NULL) {
		mtx_unlock(&firmware_mtx);
		return NULL;
	}
found:				/* common exit point on success */
	if (fp->refcnt == 0 && fp->parent != NULL)
		fp->parent->refcnt++;
	fp->refcnt++;
	mtx_unlock(&firmware_mtx);
	return &fp->fw;
}

const struct firmware *
firmware_get(const char *imagename)