On Tue, 2013-11-12 at 18:09 -0800, David Decotigny wrote:
> I was considering the following scenario wherein the "if
> (scsi_device_created(sdev))" test at the end would test garbage at
> best (or unmapped data):
Well, no, the counting isn't right:
> if (!(sdev = scsi_device_lookup_by_target(starget, 0))) { // not found
> sdev = scsi_alloc_sdev(starget, 0, NULL); // -> ref cnt = 2
1
> if (scsi_device_get(sdev)) { // -> ref cnt = 3
2
> }
> ...
> }
> ...
> res = scsi_probe_and_add_lun(starget, // ->
> ref cnt = 1
No idea what you think here, where were the other puts? If starget,lun
is sdev, then the count goes to 3 here otherwise it stays at 2 if it
isn't reported in the scan.
...
> scsi_device_put(sdev); // -> reclaimed
No, it goes to either 2 or 1 here. If it goes to 1 it's because the
sdev was never probed and thus it remains in the created state.
> if (scsi_device_created(sdev)) // test on garbage or unmapped data (#PF)
Which means this test passes and it gets garbage collected by
__scsi_remove_device(). Otherwise we exit with refcount 2.
James
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