Date: Wed, 16 May 2001 14:48:23 -0700 (PDT) From: Matt Dillon <dillon@earth.backplane.com> To: freebsd-arch@FreeBSD.ORG Subject: Upgrading u_short cr_ref to u_int cr_ref in ucred on -stable Message-ID: <200105162148.f4GLmNm79465@earth.backplane.com> References: <14721.48065.766815.376959@grasshopper.cs.duke.edu>
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As per conversations on this list 5-10 April (see
'Eliminate crget() from...') I intend to MFC the change
Alfred made in -current to -stable for the ucred reference count.
This will occur tonight.
The change will turn cr_ref from a u_short to a u_int. Due to
alignment issues, the other fields in the structure will not
change their location and a quick run through the driver code
seems to show that device drivers do not access cr_ref.
That is, only crhold() seems to really reference the cr_ref
field directly and devices do not appear to call crhold(), so I
think we are plenty safe enough in regards to binary compatibility.
This being between releases, if this change creates a serious issue
somewhere along the line we can always rip it out and throw in
Terry's stop-gap fix (that allocates a new copy when the ref count
would otherwise overflow). I do not think that will be necessary
though.
-Matt
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