pipe: Use self-contained mutex

Update #2843.

4 files changed, 22 insertions, 152 deletions

diff --git a/cpukit/include/rtems/confdefs.h b/cpukit/include/rtems/confdefs.h
index 212b46cd42..0d00726812 100755
--- a/cpukit/include/rtems/confdefs.h
+++ b/cpukit/include/rtems/confdefs.h
@@ -227,17 +227,6 @@ extern rtems_initialization_tasks_table Initialization_tasks[];
   #define _CONFIGURE_BARRIERS_FOR_FIFOS   0
 #endif
 
-/*
- * This specifies the number of semaphores required for the configured
- * number of FIFOs and named pipes.
- */
-#if CONFIGURE_MAXIMUM_FIFOS > 0 || CONFIGURE_MAXIMUM_PIPES > 0
-  #define _CONFIGURE_SEMAPHORES_FOR_FIFOS \
-    (1 + (CONFIGURE_MAXIMUM_FIFOS + CONFIGURE_MAXIMUM_PIPES))
-#else
-  #define _CONFIGURE_SEMAPHORES_FOR_FIFOS 0
-#endif
-
 /**
  *  @defgroup ConfigFilesystems Filesystems and Mount Table Configuration
  *
@@ -445,9 +434,7 @@ extern rtems_initialization_tasks_table Initialization_tasks[];
  * This computes the number of semaphores required for the various
  * file systems including the FIFO plugin to the IMFS.
  */
-#define _CONFIGURE_SEMAPHORES_FOR_FILE_SYSTEMS \
-    (_CONFIGURE_SEMAPHORES_FOR_FIFOS + \
-     _CONFIGURE_SEMAPHORES_FOR_NFS)
+#define _CONFIGURE_SEMAPHORES_FOR_FILE_SYSTEMS _CONFIGURE_SEMAPHORES_FOR_NFS
 
 #ifdef CONFIGURE_INIT
 
diff --git a/cpukit/include/rtems/pipe.h b/cpukit/include/rtems/pipe.h
index 7c6566ad50..a2df29c2c3 100644
--- a/cpukit/include/rtems/pipe.h
+++ b/cpukit/include/rtems/pipe.h
@@ -19,6 +19,7 @@
 #define _RTEMS_PIPE_H
 
 #include <rtems/libio.h>
+#include <rtems/thread.h>
 
 /**
  * @defgroup FIFO_PIPE FIFO/Pipe File System Support
@@ -45,7 +46,7 @@ typedef struct pipe_control {
   unsigned int waitingWriters;
   unsigned int readerCounter;     /* incremental counters */
   unsigned int writerCounter;     /* for differentiation of successive opens */
-  rtems_id Semaphore;
+  rtems_mutex Mutex;
   rtems_id readBarrier;   /* wait queues */
   rtems_id writeBarrier;
 #if 0
diff --git a/cpukit/libfs/src/pipe/fifo.c b/cpukit/libfs/src/pipe/fifo.c
index 4743bd06a1..d664adfba8 100644
--- a/cpukit/libfs/src/pipe/fifo.c
+++ b/cpukit/libfs/src/pipe/fifo.c
@@ -33,7 +33,7 @@
 #define LIBIO_ACCMODE(_iop) (rtems_libio_iop_flags(_iop) & LIBIO_FLAGS_READ_WRITE)
 #define LIBIO_NODELAY(_iop) rtems_libio_iop_is_no_delay(_iop)
 
-static rtems_id pipe_semaphore = RTEMS_ID_NONE;
+static rtems_mutex pipe_mutex = RTEMS_MUTEX_INITIALIZER("Pipes");
 
 
 #define PIPE_EMPTY(_pipe) (_pipe->Length == 0)
@@ -41,11 +41,9 @@ static rtems_id pipe_semaphore = RTEMS_ID_NONE;
 #define PIPE_SPACE(_pipe) (_pipe->Size - _pipe->Length)
 #define PIPE_WSTART(_pipe) ((_pipe->Start + _pipe->Length) % _pipe->Size)
 
-#define PIPE_LOCK(_pipe)  \
-  ( rtems_semaphore_obtain(_pipe->Semaphore, RTEMS_WAIT, RTEMS_NO_TIMEOUT)  \
-   == RTEMS_SUCCESSFUL )
+#define PIPE_LOCK(_pipe) rtems_mutex_lock(&(_pipe)->Mutex)
 
-#define PIPE_UNLOCK(_pipe)  rtems_semaphore_release(_pipe->Semaphore)
+#define PIPE_UNLOCK(_pipe) rtems_mutex_unlock(&(_pipe)->Mutex)
 
 #define PIPE_READWAIT(_pipe)  \
   ( rtems_barrier_wait(_pipe->readBarrier, RTEMS_NO_TIMEOUT)  \
@@ -95,18 +93,13 @@ static int pipe_alloc(
         RTEMS_BARRIER_MANUAL_RELEASE, 0,
         &pipe->writeBarrier) != RTEMS_SUCCESSFUL)
     goto err_wbar;
-  if (rtems_semaphore_create(
-        rtems_build_name ('P', 'I', 's', c), 1,
-        RTEMS_BINARY_SEMAPHORE | RTEMS_PRIORITY | RTEMS_INHERIT_PRIORITY,
-        0, &pipe->Semaphore) != RTEMS_SUCCESSFUL)
-    goto err_sem;
+  rtems_mutex_init(&pipe->Mutex, "Pipe");
 
   *pipep = pipe;
   if (c ++ == 'z')
     c = 'a';
   return 0;
 
-err_sem:
   rtems_barrier_delete(pipe->writeBarrier);
 err_wbar:
   rtems_barrier_delete(pipe->readBarrier);
@@ -124,55 +117,19 @@ static inline void pipe_free(
 {
   rtems_barrier_delete(pipe->readBarrier);
   rtems_barrier_delete(pipe->writeBarrier);
-  rtems_semaphore_delete(pipe->Semaphore);
+  rtems_mutex_destroy(&pipe->Mutex);
   free(pipe->Buffer);
   free(pipe);
 }
 
-static int pipe_lock(void)
+static void pipe_lock(void)
 {
-  rtems_status_code sc = RTEMS_SUCCESSFUL;
-
-  if (pipe_semaphore == RTEMS_ID_NONE) {
-    rtems_libio_lock();
-
-    if (pipe_semaphore == RTEMS_ID_NONE) {
-      sc = rtems_semaphore_create(
-        rtems_build_name('P', 'I', 'P', 'E'),
-        1,
-        RTEMS_BINARY_SEMAPHORE | RTEMS_INHERIT_PRIORITY | RTEMS_PRIORITY,
-        RTEMS_NO_PRIORITY,
-        &pipe_semaphore
-      );
-    }
-
-    rtems_libio_unlock();
-  }
-
-  if (sc == RTEMS_SUCCESSFUL) {
-    sc = rtems_semaphore_obtain(pipe_semaphore, RTEMS_WAIT, RTEMS_NO_TIMEOUT);
-  }
-
-  if (sc == RTEMS_SUCCESSFUL) {
-    return 0;
-  } else {
-    return -ENOMEM;
-  }
+  rtems_mutex_lock(&pipe_mutex);
 }
 
 static void pipe_unlock(void)
 {
-#ifdef RTEMS_DEBUG
-  rtems_status_code sc = RTEMS_SUCCESSFUL;
-
-  sc =
-#endif
-   rtems_semaphore_release(pipe_semaphore);
-  #ifdef RTEMS_DEBUG
-    if (sc != RTEMS_SUCCESSFUL) {
-      rtems_fatal_error_occurred(0xdeadbeef);
-    }
-  #endif
+  rtems_mutex_unlock(&pipe_mutex);
 }
 
 /*
@@ -188,9 +145,7 @@ static int pipe_new(
   int err = 0;
 
   _Assert( pipep );
-  err = pipe_lock();
-  if (err)
-    return err;
+  pipe_lock();
 
   pipe = *pipep;
   if (pipe == NULL) {
@@ -199,8 +154,7 @@ static int pipe_new(
       goto out;
   }
 
-  if (!PIPE_LOCK(pipe))
-    err = -EINTR;
+  PIPE_LOCK(pipe);
 
   if (*pipep == NULL) {
     if (err)
@@ -222,15 +176,8 @@ void pipe_release(
   pipe_control_t *pipe = *pipep;
   uint32_t mode;
 
-  #if defined(RTEMS_DEBUG)
-    /* WARN pipe not freed and pipep not set to NULL! */
-    if (pipe_lock())
-      rtems_fatal_error_occurred(0xdeadbeef);
-
-    /* WARN pipe not released! */
-    if (!PIPE_LOCK(pipe))
-      rtems_fatal_error_occurred(0xdeadbeef);
-  #endif
+  pipe_lock();
+  PIPE_LOCK(pipe);
 
   mode = LIBIO_ACCMODE(iop);
   if (mode & LIBIO_FLAGS_READ)
@@ -303,8 +250,7 @@ int fifo_open(
           PIPE_UNLOCK(pipe);
           if (! PIPE_READWAIT(pipe))
             goto out_error;
-          if (! PIPE_LOCK(pipe))
-            goto out_error;
+          PIPE_LOCK(pipe);
         } while (prevCounter == pipe->writerCounter);
       }
       break;
@@ -328,8 +274,7 @@ int fifo_open(
           PIPE_UNLOCK(pipe);
           if (! PIPE_WRITEWAIT(pipe))
             goto out_error;
-          if (! PIPE_LOCK(pipe))
-            goto out_error;
+          PIPE_LOCK(pipe);
         } while (prevCounter == pipe->readerCounter);
       }
       break;
@@ -361,8 +306,7 @@ ssize_t pipe_read(
 {
   int chunk, chunk1, read = 0, ret = 0;
 
-  if (! PIPE_LOCK(pipe))
-    return -EINTR;
+  PIPE_LOCK(pipe);
 
   while (PIPE_EMPTY(pipe)) {
     /* Not an error */
@@ -379,11 +323,7 @@ ssize_t pipe_read(
     PIPE_UNLOCK(pipe);
     if (! PIPE_READWAIT(pipe))
       ret = -EINTR;
-    if (! PIPE_LOCK(pipe)) {
-      /* WARN waitingReaders not restored! */
-      ret = -EINTR;
-      goto out_nolock;
-    }
+    PIPE_LOCK(pipe);
     pipe->waitingReaders --;
     if (ret != 0)
       goto out_locked;
@@ -413,7 +353,6 @@ ssize_t pipe_read(
 out_locked:
   PIPE_UNLOCK(pipe);
 
-out_nolock:
   if (read > 0)
     return read;
   return ret;
@@ -432,8 +371,7 @@ ssize_t pipe_write(
   if (count == 0)
     return 0;
 
-  if (! PIPE_LOCK(pipe))
-    return -EINTR;
+  PIPE_LOCK(pipe);
 
   if (pipe->Readers == 0) {
     ret = -EPIPE;
@@ -455,11 +393,7 @@ ssize_t pipe_write(
       PIPE_UNLOCK(pipe);
       if (! PIPE_WRITEWAIT(pipe))
         ret = -EINTR;
-      if (! PIPE_LOCK(pipe)) {
-        /* WARN waitingWriters not restored! */
-        ret = -EINTR;
-        goto out_nolock;
-      }
+      PIPE_LOCK(pipe);
       pipe->waitingWriters --;
       if (ret != 0)
         goto out_locked;
@@ -490,7 +424,6 @@ ssize_t pipe_write(
 out_locked:
   PIPE_UNLOCK(pipe);
 
-out_nolock:
 #ifdef RTEMS_POSIX_API
   /* Signal SIGPIPE */
   if (ret == -EPIPE)
@@ -513,8 +446,7 @@ int pipe_ioctl(
     if (buffer == NULL)
       return -EFAULT;
 
-    if (! PIPE_LOCK(pipe))
-      return -EINTR;
+    PIPE_LOCK(pipe);
 
     /* Return length of pipe */
     *(unsigned int *)buffer = pipe->Length;
diff --git a/testsuites/sptests/spfifo02/init.c b/testsuites/sptests/spfifo02/init.c
index a1cb2a3a55..4fca304d92 100644
--- a/testsuites/sptests/spfifo02/init.c
+++ b/testsuites/sptests/spfifo02/init.c
@@ -26,9 +26,7 @@ const char rtems_test_name[] = "SPFIFO 2";
 /* forward declarations to avoid warnings */
 rtems_task Init(rtems_task_argument argument);
 void create_all_barriers(void);
-void create_all_semaphores(void);
 void delete_barrier(void);
-void delete_semaphore(void);
 void create_fifo(void);
 void open_fifo(int expected, int flags);
 
@@ -66,31 +64,6 @@ void create_all_barriers(void)
   }
 }
 
-void create_all_semaphores(void)
-{
-  rtems_status_code status;
-  int               i;
-
-  SemaphoreCount = 0;
-
-  for ( i=0 ; i<MAXIMUM ; i++ ) {
-    status = rtems_semaphore_create(
-      rtems_build_name( 'S', 'E', 'M', 0x30+i ),
-      0,
-      RTEMS_DEFAULT_ATTRIBUTES,
-      0,
-      &Semaphores[i]
-    );
-    if ( status == RTEMS_TOO_MANY ) {
-      printf( "%d Semaphores created\n", SemaphoreCount+1 );
-      return;
-    } 
-
-    directive_failed( status, "semaphore create" );
-    SemaphoreCount++;
-  }
-}
-
 void delete_barrier(void)
 {
   rtems_status_code status;
@@ -102,17 +75,6 @@ void delete_barrier(void)
   directive_failed( status, "barrier delete" );
 }
 
-void delete_semaphore(void)
-{
-  rtems_status_code status;
-  
-  SemaphoreCount--;
-  printf( "Deleting semaphore id=0x%08x\n",
-    (unsigned int) Semaphores[SemaphoreCount] );
-  status = rtems_semaphore_delete( Semaphores[SemaphoreCount] );
-  directive_failed( status, "semaphore delete" );
-}
-
 void create_fifo(void)
 {
   int status;
@@ -149,17 +111,9 @@ rtems_task Init(
   puts( "Creating all barriers" );
   create_all_barriers();
 
-  puts( "Creating all semaphores" );
-  create_all_semaphores();
-
   puts( "Creating FIFO" );
   create_fifo();
 
-  puts( "Opening FIFO.. expect ENOMEM (semaphore for pipe could not be created)" );
-  open_fifo(ENOMEM, O_RDWR);
-
-  delete_semaphore();
-
   alloc_ptr = malloc( malloc_free_space() - 4 );
   puts("Opening FIFO.. expect ENOMEM since no memory is available");
   open_fifo(ENOMEM, O_RDWR);
@@ -173,10 +127,6 @@ rtems_task Init(
   open_fifo(ENOMEM, O_RDWR);
 
   delete_barrier();
-  puts( "Opening FIFO.. expect ENOMEM (semaphore-1 for pipe could not be created" );
-  open_fifo(ENOMEM, O_RDWR);
-
-  delete_semaphore();
   puts( "Opening FIFO in RDWR mode. Expect OK" );
   open_fifo(0, O_RDWR);
   ++num_opens;