netmap: Use device_t in preference to struct device *
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Authored by markj on Apr 9 2021, 3:50 PM.

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rGe93766bcd4e1: netmap: don't use linux type struct device *
rG89a4cc5c8a3d: netmap: don't use linux type struct device *
rG70275a6735df: netmap: don't use linux type struct device *

Summary

In preparation for renaming struct device to something that doesn't
collide with the LinuxKPI's struct device.

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rS FreeBSD src repository - subversion

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Buildable 38458
Build 35347: arc lint + arc unit

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markj created this revision.Apr 9 2021, 3:50 PM

Herald added a subscriber: imp. · View Herald TranscriptApr 9 2021, 3:50 PM

markj requested review of this revision.Apr 9 2021, 3:50 PM

Harbormaster completed remote builds in B38458: Diff 87121.Apr 9 2021, 3:50 PM

Usage of "struct device *" was just wrong. Thanks spotting the issue.
Commit 70275a6735df8a514f48be77418491f2f8dba817 should have the same effect.

In D29677#666334, @vmaffione wrote:

Usage of "struct device *" was just wrong. Thanks spotting the issue.
Commit 70275a6735df8a514f48be77418491f2f8dba817 should have the same effect.

Thanks, but the commit looks a bit strange: we are treating the pdev as a bus_dma_tag_t when it's really a pointer to a netmap adapter. It is not used at all on FreeBSD so it doesn't really matter, but maybe I'm missing something.

BTW, the problem here isn't that netmap is using a Linux struct device, it's just that we generally have problems caused by the LinuxKPI struct device and FreeBSD struct device colliding with each other. Almost all of the kernel uses device_t to refer to a FreeBSD device structure, so I was just changing netmap to follow this convention.

This revision was not accepted when it landed; it landed in state Needs Review.Apr 12 2021, 3:49 AM

Closed by commit rG70275a6735df: netmap: don't use linux type struct device * (authored by vmaffione). · Explain Why

This revision was automatically updated to reflect the committed changes.

vmaffione added a commit: rG70275a6735df: netmap: don't use linux type struct device *.

Thanks, but the commit looks a bit strange: we are treating the pdev as a bus_dma_tag_t when it's really a pointer to a netmap adapter. It is not used at all on FreeBSD so it doesn't really matter, but maybe I'm missing something.

And it is strange, indeed. But at least it is fixing an inconsistency, where "struct device" (meaning the Linux) type is used in code that is supposed to be common to both FreeBSD and the Linux netmap module. The argument is actually a pointer to the device object associated to the netmap adapter, which is always NULL in FreeBSD (because it's not used).
In any case, the situation can be improved and I'll do it asap.

BTW, the problem here isn't that netmap is using a Linux struct device, it's just that we generally have problems caused by the LinuxKPI struct device and FreeBSD struct device colliding with each other. Almost all of the kernel uses device_t to refer to a FreeBSD device structure, so I was just changing netmap to follow this convention.

Sure, but in this case na->pdev is not pointing to a device_t, so that would have been more confusing IMHO.
Thanks for the help!

markj added a commit: rG89a4cc5c8a3d: netmap: don't use linux type struct device *.Apr 19 2021, 6:18 PM

vmaffione added a commit: rGe93766bcd4e1: netmap: don't use linux type struct device *.Dec 31 2022, 12:40 PM