Changeset 3ede440 in mainline for uspace/lib/c/include/fibril_synch.h

Timestamp:

2019-02-01T22:30:53Z (6 years ago)

Author:

Jiří Zárevúcky <zarevucky.jiri@…>

Parents:

1a37496

git-author:

Jiří Zárevúcky <zarevucky.jiri@…> (2019-02-01 22:12:04)

git-committer:

Jiří Zárevúcky <zarevucky.jiri@…> (2019-02-01 22:30:53)

Message:

Change the meaning of counter in fibril mutex

Previously analogous to semaphore tokens, initially 1 and
counting downward into negative numbers.

Now the number of fibrils currently accessing or waiting for access
to the critical sections. Initially 0 (unlocked mutex), and counting
up. Never negative when used correctly. Also consistent with
readers/writers counts in rwlock.

This way is IMO easier to understand.

File:

• uspace/lib/c/include/fibril_synch.h (modified) (2 diffs)

uspace/lib/c/include/fibril_synch.h

@@ -44 +44 @@
 typedef struct {
         fibril_owner_info_t oi;  /**< Keep this the first thing. */
-        int counter;
+        int counter;  /**< # of fibrils currently waiting for or running in the critical section. */
         list_t waiters;
 } fibril_mutex_t;
@@ -53 +53 @@
                         .owned_by = NULL \
                 }, \
-                .counter = 1, \
+                .counter = 0, \
                 .waiters = LIST_INITIALIZER((name).waiters), \
         }