What is config KERNEL INTERRUPT PRIORITY?

Dear Gaurav,

FreeRTOS critical sections disable interrupts up to configKERNEL_INTERRUPT_PRIORITY
I thought if only configKERNEL_INTERRUPT_PRIORITY is used, then in critical section, all interrupts are disabled? And when configMAX_SYSCALL_INTERRUPT_PRIORITY is used, then critical sections disable interrupts up to configMAX_SYSCALL_INTERRUPT_PRIORITY itself?

Critical sections are the sections of code which manipulate FreeRTOS internal data structures…
I thought in taskEnterCritical(), the only thing happening in there is that the interrupts got disabled? I cannot find anywhere in taskEnterCritical() that manipulates FreeRTOS internal data structure

Please correct me if I am wrong: I think it should be like below:

                                         ^ +------------+
                                         | |  IRQ1      |
                                         | |            |
                                         | +------------+
        Blocked during critical section  | |  IRQ2      |
                                         | |            |
                                         | +------------+
                                         | |  IRQ3      |<------- **configMAX_SYSCALL_INTERRUPT_PRIORITY**
                                         v |            |
                                        ---+------------+
                                         ^ |  IRQ4      |
                                         | |            |
    Not blocked during critical section  | +------------+
                                         | |  IRQ5      |
                                         | |            |
                                         v +------------+