Remove stale comment from rw_tryupgrade()

Commit f58040c0fc8bc6490fcc75db7fc3e709dfc3c656 should have removed
this comment which is no longer relevant.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Clemens Fruhwirth <clemens@endorphin.org>
Issue #589

diff --git a/include/sys/rwlock.h b/include/sys/rwlock.h
index 4197785db126fb4f1d019ac4e5566370ef2bfe60..ffb7b90b6f2863563ba983a812ff1cdbfb031660 100644 (file)
--- a/include/sys/rwlock.h
+++ b/include/sys/rwlock.h
@@ -213,14 +213,6 @@ RW_LOCK_HELD(krwlock_t *rwp)
        spl_rw_lockdep_on_maybe(rwp);                                   \
 })
 
-/*
- * This implementation of rw_tryupgrade() behaves slightly differently
- * from its counterparts on other platforms.  It drops the RW_READER lock
- * and then acquires the RW_WRITER lock leaving a small window where no
- * lock is held.  On other platforms the lock is never released during
- * the upgrade process.  This is necessary under Linux because the kernel
- * does not provide an upgrade function.
- */
 #define rw_tryupgrade(rwp)                                             \
 ({                                                                     \
        int _rc_ = 0;                                                   \