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    SubjectSource code review around jump label usage
    Date
    Hello,

    I have tried another specific analysis out on the source files
    of "Linux next-20151211" with help of the software "Coccinelle 1.0.4".
    I have taken a more detailed look on the use of the goto statement
    and corresponding jump labels.

    Can statistics like the following support software evolution
    and further constructive considerations?

    ╔═════════════════════════════════════════╤═══════════╗
    ║ target │ incidence ║
    ╠═════════════════════════════════════════╪═══════════╣
    ║ out │ 9782 ║
    ║ done │ 1344 ║
    ║ exit │ 950 ║
    ║ out_unlock │ 538 ║
    ║ unlock │ 509 ║
    ║ bail │ 486 ║
    ║ error │ 418 ║
    ║ retry │ 414 ║
    ║ err │ 400 ║
    ║ end │ 332 ║
    ║ … │ … ║
    ║ abts_pending │ 1 ║
    ║ abts_err │ 1 ║
    ║ absolute_address │ 1 ║
    ║ abort2 │ 1 ║
    ║ abort_fail │ 1 ║
    ║ abort_end │ 1 ║
    ║ abituguru_probe_error │ 1 ║
    ║ abituguru_detect_no_pwms_exit │ 1 ║
    ║ abituguru_detect_bank1_sensor_type_exit │ 1 ║
    ╚═════════════════════════════════════════╧═══════════╝


    How often are different jump targets used within function implementations?
    (Functions without jump labels were not searched for this analysis approach.)

    ╔═════════╤═══════════╗
    ║ counter │ incidence ║
    ╠═════════╪═══════════╣
    ║ 1 │ 18442 ║
    ║ 2 │ 2002 ║
    ║ 3 │ 356 ║
    ║ 4 │ 106 ║
    ║ 5 │ 31 ║
    ║ 6 │ 7 ║
    ║ 7 │ 2 ║
    ║ 8 │ 3 ║
    ╚═════════╧═══════════╝


    How does the text length distribution look like for the used jump targets?

    ╔════════╤═══════════╗
    ║ length │ incidence ║
    ╠════════╪═══════════╣
    ║ 1 │ 2 ║
    ║ 2 │ 29 ║
    ║ 3 │ 10640 ║
    ║ 4 │ 3564 ║
    ║ 5 │ 1714 ║
    ║ 6 │ 1162 ║
    ║ 7 │ 1245 ║
    ║ 8 │ 881 ║
    ║ 9 │ 787 ║
    ║ 10 │ 1252 ║
    ║ … │ … ║
    ║ 35 │ 4 ║
    ║ 36 │ 1 ║
    ║ 37 │ 2 ║
    ║ 38 │ 1 ║
    ║ 39 │ 1 ║
    ╚════════╧═══════════╝


    How often are jump targets called within specific function implementations?

    ╔══════════════════════════╤═════════════════════════════════════════╤══════╤══════════════════════╤═════════╗
    ║ function │ source file │ line │ go to │ counter ║
    ╠══════════════════════════╪═════════════════════════════════════════╪══════╪══════════════════════╪═════════╣
    ║ do_ipv6_setsockopt │ net/ipv6/ipv6_sockglue.c │ 140 │ e_inval │ 52 ║
    ║ dvb_register │ drivers/media/pci/cx88/cx88-dvb.c │ 1005 │ frontend_detach │ 43 ║
    ║ dvb_init │ drivers/media/pci/saa7134/saa7134-dvb.c │ 1210 │ detach_frontend │ 40 ║
    ║ gdbstub_single_step │ arch/mn10300/kernel/gdb-stub.c │ 491 │ fault │ 38 ║
    ║ uinput_ioctl_handler │ drivers/input/misc/uinput.c │ 701 │ out │ 32 ║
    ║ … │ … │ … │ … │ … ║
    ║ kvm_vm_compat_ioctl │ virt/kvm/kvm_main.c │ 2916 │ out │ 1 ║
    ║ kvm_vm_ioctl │ virt/kvm/kvm_main.c │ 2742 │ out_free_irq_routing │ 1 ║
    ║ kvm_vm_ioctl_create_vcpu │ virt/kvm/kvm_main.c │ 2257 │ vcpu_destroy │ 1 ║
    ╚══════════════════════════╧═════════════════════════════════════════╧══════╧══════════════════════╧═════════╝


    Do any of these numbers indicate update candidates which correspond to the
    "one error jump label bug" symptom that is mentioned in the Linux coding
    style documentation?

    Regards,
    Markus


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