2009-04-29 Sebastian Huber <sebastian.huber@embedded-brains.de>

        * sapi/include/confdefs.h, libblock/include/rtems/bdbuf.h: Changed
        type of rtems_bdbuf_pool_configuration_size to size_t.

        * libblock/include/rtems/bdbuf.h, libblock/include/rtems/blkdev.h,
        libblock/include/rtems/diskdevs.h, libblock/src/bdbuf.c,
        libblock/src/blkdev.c, libblock/src/diskdevs.c: Buffer pool
        allocation is now cache aligned.  The cache functions are
        currently not available on all platforms so the cache line size is
        fixed to 32 bytes for now.  Changed various integer types which
        refer to block sizes, numbers and indexes.  Fixed logical block
        indexes in buffer get and read function.  It is now possible to
        delete logical disks.  Modified documentation

1 files changed, 41 insertions, 238 deletions

diff --git a/cpukit/libblock/src/bdbuf.c b/cpukit/libblock/src/bdbuf.c
index 3d57a3c3b8..6ae6c4dccc 100644
--- a/cpukit/libblock/src/bdbuf.c
+++ b/cpukit/libblock/src/bdbuf.c
@@ -1,3 +1,9 @@
+/**
+ * @file
+ *
+ * Block device buffer management.
+ */
+
 /*
  * Disk I/O buffering
  * Buffer managment
@@ -15,81 +21,6 @@
  */
 
 /**
- * @file
- *
- * The Buffer Descriptor Buffer code implements a cache between the disk
- * devices and file systems. The code provides read ahead and write queuing to
- * the drivers and fast cache look up using an AVL tree.
- *
- * The buffers are held in pools based on size. Each pool has buffers and the
- * buffers follow this state machine:
- *                                  
- *                   read/read ahead
- *          +-------------------------------+
- *          |                               v
- *     +-----------+ read ahead      +------------+
- *     | READY,    |  complete       |            |---------+
- *     |  READ     |<----------------|  TRANSFER  |         |
- *     |   AHEAD   |   +-------------|            |<--+     |
- *     +-----------+   | read/write  +------------+   |     |
- *              | get  v complete                swap |     |
- *              |    +-----------+ modified  +------------+ |
- *              +--->| ACCESSED, |---------->|  MODIFIED, | |
- *                   | ACCESSED  |<----------|  SYNC      | |
- *              +----|  MODIFIED |<--+   get |            | |
- *              |    +-----------+   |       +------------+ |
- *              | release        get |                      |
- *              |    +-----------+   |                      |
- *              +--->|           |---+        read complete |
- *                   |   CACHED  |           write complete |
- *                   |           |<-------------------------+
- *                   +-----------+
- *         
- * Empty buffers are added to the ready list and removed from this queue when a
- * caller requests a buffer. This is referred to as getting a buffer in the
- * code and the event get in the state diagram. The buffer is assigned to a
- * block and inserted to the AVL based on the block/device key. If the block is
- * to be read by the user and not in the cache (ready) it is transfered from
- * the disk into memory. If no ready buffers exist the buffer is taken from the
- * LRU list. If no buffers are on the LRU list the modified list is check. If
- * no buffers are on the modified list the request blocks. If buffers are on
- * the modified list the buffers hold timer is expired and the swap out task
- * woken.
- *
- * A block being accessed is given to the file system layer and not accessable
- * to another requester until released back to the cache. The same goes to a
- * buffer in the transfer state. The transfer state means being read or
- * written. If the file system has modifed the block and releases it as
- * modified it placed on the pool's modified list and a hold timer
- * initialised. The buffer is held for the hold time before being written to
- * disk. Buffers are held for a configurable period of time on the modified
- * list as a write sets the state to transfer and this locks the buffer out
- * from the file system until the write complete. Buffers are often repeatable
- * accessed and modified in a series of small updates so if sent to the disk
- * when released as modified the user would have to block waiting until it had
- * been written. This would be a performance problem.
- *
- * The code performs mulitple block reads and writes. Multiple block reads or
- * read ahead increases performance with hardware that supports it. It also
- * helps with a large cache as the disk head movement is reduced. It how-ever
- * is a speculative operation so excessive use can remove valuable and needed
- * blocks from the cache. The get call knows if a read is a for the file system
- * or if it is a read ahead get. If the get is for a read ahead block and the
- * block is already in the cache or no ready buffers are available the read
- * ahead is stopped. The transfer occurs with the blocks so far. If a buffer is
- * in the read ahead state and release it is placed on the ready list rather
- * than the LRU list. This means these buffers are used before buffers used by
- * the file system.
- *
- * The pool have the following lists of buffers:
- *
- *   ready        - Empty buffers created when the pool is initialised.
- *   modified     - Buffers waiting to be written to disk.
- *   sync         - Buffers to be synced to disk.
- *   lru          - Accessed buffers released in least recently used order.
- */
-
-/**
  * Set to 1 to enable debug tracing.
  */
 #define RTEMS_BDBUF_TRACE 0
@@ -100,6 +31,7 @@
 
 #include <rtems.h>
 #include <rtems/error.h>
+#include <rtems/malloc.h>
 #include <limits.h>
 #include <errno.h>
 #include <assert.h>
@@ -430,7 +362,7 @@ rtems_bdbuf_avl_insert(rtems_bdbuf_buffer** root,
 /**
  * Removes the node from the tree.
  *
- * @param root_addr Pointer to pointer to the root node
+ * @param root Pointer to pointer to the root node
  * @param node Pointer to the node to remove
  * @retval 0 Item removed
  * @retval -1 No such item found
@@ -704,7 +636,7 @@ rtems_bdbuf_avl_remove(rtems_bdbuf_buffer**      root,
 /**
  * Get the pool for the device.
  *
- * @param pdd Physical disk device.
+ * @param pid Physical disk device.
  */
 static rtems_bdbuf_pool*
 rtems_bdbuf_get_pool (const rtems_bdpool_id pid)
@@ -923,11 +855,19 @@ static rtems_status_code
 rtems_bdbuf_initialize_pool (rtems_bdbuf_pool_config* config,
                              rtems_bdpool_id          pid)
 {
+  int                 rv = 0;
   unsigned char*      buffer = config->mem_area;
   rtems_bdbuf_pool*   pool;
   rtems_bdbuf_buffer* bd;
   rtems_status_code   sc;
   uint32_t            b;
+  int                 cache_aligment = 32 /* FIXME rtems_cache_get_data_line_size() */;
+
+  /* For unspecified cache alignments we use the CPU alignment */
+  if (cache_aligment <= 0)
+  {
+    cache_aligment = CPU_ALIGNMENT;
+  }
 
   pool = rtems_bdbuf_get_pool (pid);
   
@@ -961,16 +901,21 @@ rtems_bdbuf_initialize_pool (rtems_bdbuf_pool_config* config,
     return RTEMS_NO_MEMORY;
 
   /*
-   * Allocate memory for buffers if required.
+   * Allocate memory for buffers if required.  The pool memory will be cache
+   * aligned.  It is possible to free the memory allocated by rtems_memalign()
+   * with free().
    */
   if (buffer == NULL)
   {
-    buffer = pool->buffers = malloc (config->num * config->size);
-    if (!pool->buffers)
+    rv = rtems_memalign ((void **) &buffer,
+                         cache_aligment,
+                         config->num * config->size);
+    if (rv != 0)
     {
       free (pool->bds);
       return RTEMS_NO_MEMORY;
     }
+    pool->buffers = buffer;
   }
 
   for (b = 0, bd = pool->bds;
@@ -1079,16 +1024,6 @@ rtems_bdbuf_release_pool (rtems_bdpool_id pid)
   return RTEMS_SUCCESSFUL;
 }
 
-/**
- * Prepare buffering layer to work - initialize buffer descritors and (if it is
- * neccessary) buffers. Buffers will be allocated accoriding to the
- * configuration table, each entry describes the size of block and the size of
- * the pool. After initialization all blocks is placed into the ready state.
- * lists.
- *
- * @return RTEMS status code (RTEMS_SUCCESSFUL if operation completed
- *         successfully or error code if error is occured)
- */
 rtems_status_code
 rtems_bdbuf_init (void)
 {
@@ -1209,7 +1144,7 @@ rtems_bdbuf_init (void)
  * it will make sure the pool is locked when it returns. The pool will be
  * unlocked if the call could block.
  *
- * @param device The physical disk device
+ * @param pdd The physical disk device
  * @param pool The pool reference
  * @param block Absolute media block number
  * @param read_ahead The get is for a read ahead buffer
@@ -1401,30 +1336,6 @@ rtems_bdbuf_get_buffer (rtems_disk_device* pdd,
   return bd;
 }
 
-/**
- * Get block buffer for data to be written into. The buffers is set to the
- * access or modifed access state. If the buffer is in the cache and modified
- * the state is access modified else the state is access. This buffer contents
- * are not initialised if the buffer is not already in the cache. If the block
- * is already resident in memory it is returned how-ever if not in memory the
- * buffer is not read from disk. This call is used when writing the whole block
- * on a disk rather than just changing a part of it. If there is no buffers
- * available this call will block. A buffer obtained with this call will not be
- * involved in a transfer request and will not be returned to another user
- * until released. If the buffer is already with a user when this call is made
- * the call is blocked until the buffer is returned. The highest priority
- * waiter will obtain the buffer first.
- *
- * The block number is the linear block number. This is relative to the start
- * of the partition on the media.
- *
- * @param device Device number (constructed of major and minor device number)
- * @param block  Linear media block number
- * @param bd     Reference to the buffer descriptor pointer.
- *
- * @return       RTEMS status code (RTEMS_SUCCESSFUL if operation completed
- *               successfully or error code if error is occured)
- */
 rtems_status_code
 rtems_bdbuf_get (dev_t                device,
                  rtems_blkdev_bnum    block,
@@ -1447,17 +1358,16 @@ rtems_bdbuf_get (dev_t                device,
     return RTEMS_INVALID_NUMBER;
   }
 
-  block += dd->start;
-
   pool = rtems_bdbuf_get_pool (dd->phys_dev->pool);
   
   rtems_bdbuf_lock_pool (pool);
 
 #if RTEMS_BDBUF_TRACE
-  rtems_bdbuf_printf ("get: %d (dev = %08x)\n", block, device);
+  /* Print the block index relative to the physical disk */
+  rtems_bdbuf_printf ("get: %d (dev = %08x)\n", block + dd->start, device);
 #endif
 
-  bd = rtems_bdbuf_get_buffer (dd->phys_dev, pool, block, false);
+  bd = rtems_bdbuf_get_buffer (dd->phys_dev, pool, block + dd->start, false);
 
   if (bd->state == RTEMS_BDBUF_STATE_MODIFIED)
     bd->state = RTEMS_BDBUF_STATE_ACCESS_MODIFIED;
@@ -1494,31 +1404,6 @@ rtems_bdbuf_read_done (void* arg, rtems_status_code status, int error)
   rtems_event_send (req->io_task, RTEMS_BDBUF_TRANSFER_SYNC);
 }
 
-/**
- * Get the block buffer and if not already in the cache read from the disk. If
- * specified block already cached return. The buffer is set to the access or
- * modifed access state. If the buffer is in the cache and modified the state
- * is access modified else the state is access. If block is already being read
- * from disk for being written to disk this call blocks. If the buffer is
- * waiting to be written it is removed from modified queue and returned to the
- * user. If the buffer is not in the cache a new buffer is obtained and the
- * data read from disk. The call may block until these operations complete. A
- * buffer obtained with this call will not be involved in a transfer request
- * and will not be returned to another user until released. If the buffer is
- * already with a user when this call is made the call is blocked until the
- * buffer is returned. The highest priority waiter will obtain the buffer
- * first.
- *
- * @note Read ahead always reads buffers in sequence. All multi-block reads
- *       read consecutive blocks.
- *
- * @param device Device number (constructed of major and minor device number)
- * @param block  Linear media block number
- * @param bd     Reference to the buffer descriptor pointer.
- *
- * @return       RTEMS status code (RTEMS_SUCCESSFUL if operation completed
- *               successfully or error code if error is occured)
- */
 rtems_status_code
 rtems_bdbuf_read (dev_t                device,
                   rtems_blkdev_bnum    block,
@@ -1545,18 +1430,16 @@ rtems_bdbuf_read (dev_t                device,
   dd = rtems_disk_obtain (device);
   if (dd == NULL)
     return RTEMS_INVALID_ID;
-
-  block += dd->start;
-  
-#if RTEMS_BDBUF_TRACE
-  rtems_bdbuf_printf ("read: %d (dev = %08x)\n", block, device);
-#endif
   
-  if (block >= dd->size)
-  {
+  if (block >= dd->size) {
     rtems_disk_release(dd);
     return RTEMS_INVALID_NUMBER;
   }
+  
+#if RTEMS_BDBUF_TRACE
+  /* Print the block index relative to the physical disk */
+  rtems_bdbuf_printf ("read: %d (dev = %08x)\n", block + dd->start, device);
+#endif
 
   req->bufnum = 0;
 
@@ -1587,7 +1470,7 @@ rtems_bdbuf_read (dev_t                device,
      * caller.
      */
     bd = rtems_bdbuf_get_buffer (dd->phys_dev, pool,
-                                 block + req->bufnum,
+                                 block + dd->start + req->bufnum,
                                  req->bufnum == 0 ? false : true);
 
     /*
@@ -1711,19 +1594,6 @@ rtems_bdbuf_read (dev_t                device,
   return RTEMS_SUCCESSFUL;
 }
 
-/**
- * Release the buffer obtained by a read call back to the cache. If the buffer
- * was obtained by a get call and was not already in the cache the release
- * modified call should be used. A buffer released with this call obtained by a
- * get call may not be in sync with the contents on disk. If the buffer was in
- * the cache and modified before this call it will be returned to the modified
- * queue. The buffers is returned to the end of the LRU list.
- *
- * @param bd Reference to the buffer descriptor.
- *
- * @return RTEMS status code (RTEMS_SUCCESSFUL if operation completed
- *         successfully or error code if error is occured)
- */
 rtems_status_code
 rtems_bdbuf_release (rtems_bdbuf_buffer* bd)
 {
@@ -1785,21 +1655,6 @@ rtems_bdbuf_release (rtems_bdbuf_buffer* bd)
   return RTEMS_SUCCESSFUL;
 }
 
-/**
- * Release the buffer allocated with a get or read call placing it on the
- * modidied list.  If the buffer was not released modified before the hold
- * timer is set to the configuration value. If the buffer had been released
- * modified before but not written to disk the hold timer is not updated. The
- * buffer will be written to disk when the hold timer has expired, there are
- * not more buffers available in the cache and a get or read buffer needs one
- * or a sync call has been made. If the buffer is obtained with a get or read
- * before the hold timer has expired the buffer will be returned to the user.
- *
- * @param bd Reference to the buffer descriptor.
- *
- * @return RTEMS status code (RTEMS_SUCCESSFUL if operation completed
- *         successfully or error code if error is occured)
- */
 rtems_status_code
 rtems_bdbuf_release_modified (rtems_bdbuf_buffer* bd)
 {
@@ -1828,20 +1683,6 @@ rtems_bdbuf_release_modified (rtems_bdbuf_buffer* bd)
   return RTEMS_SUCCESSFUL;
 }
 
-/**
- * Release the buffer as modified and wait until it has been synchronized with
- * the disk by writing it. This buffer will be the first to be transfer to disk
- * and other buffers may also be written if the maximum number of blocks in a
- * requests allows it.
- *
- * @note This code does not lock the sync mutex and stop additions to the
- *       modified queue.
- *
- * @param bd Reference to the buffer descriptor.
- *
- * @return RTEMS status code (RTEMS_SUCCESSFUL if operation completed
- *         successfully or error code if error is occured)
- */
 rtems_status_code
 rtems_bdbuf_sync (rtems_bdbuf_buffer* bd)
 {
@@ -1895,17 +1736,6 @@ rtems_bdbuf_sync (rtems_bdbuf_buffer* bd)
   return RTEMS_SUCCESSFUL;
 }
 
-/**
- * Synchronize all modified buffers for this device with the disk and wait
- * until the transfers have completed. The sync mutex for the pool is locked
- * stopping the addition of any further modifed buffers. It is only the
- * currently modified buffers that are written.
- *
- * @param dev Block device number
- *
- * @return RTEMS status code (RTEMS_SUCCESSFUL if operation completed
- *         successfully or error code if error is occured)
- */
 rtems_status_code
 rtems_bdbuf_syncdev (dev_t dev)
 {
@@ -2427,21 +2257,6 @@ rtems_bdbuf_swapout_task (rtems_task_argument arg)
   rtems_task_delete (RTEMS_SELF);
 }
 
-/**
- * Find first appropriate buffer pool. This primitive returns the index of
- * first buffer pool which block size is greater than or equal to specified
- * size.
- *
- * @param block_size Requested block size
- * @param pool The pool to use for the requested pool size.
- *
- * @return RTEMS status code (RTEMS_SUCCESSFUL if operation completed
- *         successfully or error code if error is occured)
- * @retval RTEMS_INVALID_SIZE The specified block size is invalid (not a power
- *         of 2)
- * @retval RTEMS_NOT_DEFINED The buffer pool for this or greater block size
- *         is not configured.
- */
 rtems_status_code
 rtems_bdbuf_find_pool (uint32_t block_size, rtems_bdpool_id *pool)
 {
@@ -2480,23 +2295,11 @@ rtems_bdbuf_find_pool (uint32_t block_size, rtems_bdpool_id *pool)
   }
 }
 
-/**
- * Obtain characteristics of buffer pool with specified number.
- *
- * @param pool Buffer pool number
- * @param block_size Block size for which buffer pool is configured returned
- *                   there
- * @param blocks Number of buffers in buffer pool.
- *
- * RETURNS:
- * @return RTEMS status code (RTEMS_SUCCESSFUL if operation completed
- *         successfully or error code if error is occured)
- * @retval RTEMS_INVALID_SIZE The appropriate buffer pool is not configured.
- *
- * @note Buffer pools enumerated continuously starting from 0.
- */
-rtems_status_code
-rtems_bdbuf_get_pool_info (rtems_bdpool_id pool, int* block_size, int* blocks)
+rtems_status_code rtems_bdbuf_get_pool_info(
+  rtems_bdpool_id pool,
+  uint32_t *block_size,
+  uint32_t *blocks
+)
 {
   if (pool >= rtems_bdbuf_ctx.npools)
     return RTEMS_INVALID_NUMBER;