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| author | kib <kib@FreeBSD.org> | 2013-10-06 15:59:06 +0000 |
|---|---|---|
| committer | kib <kib@FreeBSD.org> | 2013-10-06 15:59:06 +0000 |
| commit | 71eaa9969e6656920856b321be3430c54dea31fc (patch) | |
| tree | 24687aae118b844902ddf545259d4d32a4bd4f4f | |
| parent | cd8e388205dab0c6cdfbd5884ca0f3127fe71ed5 (diff) | |
| download | FreeBSD-src-71eaa9969e6656920856b321be3430c54dea31fc.zip FreeBSD-src-71eaa9969e6656920856b321be3430c54dea31fc.tar.gz | |
Document LK_TRYUPGRADE.
Sponsored by: The FreeBSD Foundation
MFC after: 3 days
Approved by: re (marius)
| -rw-r--r-- | share/man/man9/lock.9 | 14 |
1 files changed, 11 insertions, 3 deletions
diff --git a/share/man/man9/lock.9 b/share/man/man9/lock.9 index fd608d4..cb77686 100644 --- a/share/man/man9/lock.9 +++ b/share/man/man9/lock.9 @@ -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, the system will .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 |
