On 12.06.2013 20:01, Kenneth D. Merry wrote:
On Wed, Jun 12, 2013 at 09:07:15 +0000, Alexander Motin wrote:
Author: mav
Date: Wed Jun 12 09:07:15 2013
New Revision: 251649
URL: http://svnweb.freebsd.org/changeset/base/251649
Log:
Acquire periph reference when handling d_getattr() method call.
While GEOM in general has provider opened while sending BIO_GETATTR,
GEOM DISK does not really need to open disk to read medium-unrelated
attributes for own use.
Proposed by: ken
I forgot proposing that, but it seems like we probably don't need to
acquire a reference there.
Ah, may be for this point it still was Justin. Sorry, if so.
The primary thing we want to insure is that the
peripheral is valid and doesn't go away. We acquire a reference when we do
the disk_create(), and then release that reference when our GEOM provider
has gone away. (GEOM calls the d_gone() callback, and so we know that it
will not call into the CAM peripheral driver again.)
I assume that once the provider has gone away, there won't be any more
d_getattr() method calls. If so, the existing reference should be enough
to protect it. (If we can get d_getattr() calls after the provider has
gone away, then that needs to be fixed.)
You seems to be right. I've forgot about that d_gone() method. It wasn't
there in original design. Then probably we don't need reference counting
on d_open()/d_close() either any more.
--
Alexander Motin
_______________________________________________
svn-src-head@freebsd.org mailing list
http://lists.freebsd.org/mailman/listinfo/svn-src-head
To unsubscribe, send any mail to "svn-src-head-unsubscr...@freebsd.org"
