Date: Sun, 6 Oct 2013 15:59:06 +0000 (UTC) From: Konstantin Belousov <kib@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r256089 - head/share/man/man9 Message-ID: <201310061559.r96Fx6jD039797@svn.freebsd.org>
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Author: kib Date: Sun Oct 6 15:59:06 2013 New Revision: 256089 URL: http://svnweb.freebsd.org/changeset/base/256089 Log: Document LK_TRYUPGRADE. Sponsored by: The FreeBSD Foundation MFC after: 3 days Approved by: re (marius) Modified: head/share/man/man9/lock.9 Modified: head/share/man/man9/lock.9 ============================================================================== --- head/share/man/man9/lock.9 Sun Oct 6 13:01:42 2013 (r256088) +++ head/share/man/man9/lock.9 Sun Oct 6 15:59:06 2013 (r256089) @@ -26,7 +26,7 @@ .\" .\" $FreeBSD$ .\" -.Dd November 16, 2011 +.Dd October 6, 2013 .Dt LOCK 9 .Os .Sh NAME @@ -164,11 +164,17 @@ If an exclusive lock has been recursed, .Xr panic 9 . .It Dv LK_UPGRADE Upgrade a shared lock to an exclusive lock. -If this call fails, the shared lock is lost. +If this call fails, the shared lock is lost, even if the +.Dv LK_NOWAIT +flag is specified. During the upgrade, the shared lock could be temporarily dropped. Attempts to upgrade an exclusive lock will cause a .Xr panic 9 . +.It Dv LK_TRYUPGRADE +Try to upgrade a shared lock to an exclusive lock. +The failure to upgrade does not result in the dropping +of the shared lock ownership. .It Dv LK_RELEASE Release the lock. Releasing a lock that is not held can cause a @@ -333,7 +339,9 @@ fail if: was requested and another thread had already requested a lock upgrade. .It Bq Er EBUSY .Dv LK_NOWAIT -was set, and a sleep would have been required. +was set, and a sleep would have been required, or +.Dv LK_TRYUPGRADE +operation was not able to upgrade the lock. .It Bq Er ENOLCK .Dv LK_SLEEPFAIL was set and
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