1 /***************************************************************************
2  * Copyright (c) 2024 Microsoft Corporation
3  *
4  * This program and the accompanying materials are made available under the
5  * terms of the MIT License which is available at
6  * https://opensource.org/licenses/MIT.
7  *
8  * SPDX-License-Identifier: MIT
9  **************************************************************************/
10 
11 
12 /**************************************************************************/
13 /**************************************************************************/
14 /**                                                                       */
15 /** ThreadX Component                                                     */
16 /**                                                                       */
17 /**   Block Pool                                                          */
18 /**                                                                       */
19 /**************************************************************************/
20 /**************************************************************************/
21 
22 #define TX_SOURCE_CODE
23 
24 
25 /* Include necessary system files.  */
26 
27 #include "tx_api.h"
28 #include "tx_trace.h"
29 #include "tx_thread.h"
30 #include "tx_block_pool.h"
31 
32 
33 /**************************************************************************/
34 /*                                                                        */
35 /*  FUNCTION                                               RELEASE        */
36 /*                                                                        */
37 /*    _tx_block_release                                   PORTABLE C      */
38 /*                                                           6.1          */
39 /*  AUTHOR                                                                */
40 /*                                                                        */
41 /*    William E. Lamie, Microsoft Corporation                             */
42 /*                                                                        */
43 /*  DESCRIPTION                                                           */
44 /*                                                                        */
45 /*    This function returns a previously allocated block to its           */
46 /*    associated memory block pool.                                       */
47 /*                                                                        */
48 /*  INPUT                                                                 */
49 /*                                                                        */
50 /*    block_ptr                         Pointer to memory block           */
51 /*                                                                        */
52 /*  OUTPUT                                                                */
53 /*                                                                        */
54 /*    TX_SUCCESS                        Successful completion status      */
55 /*                                                                        */
56 /*  CALLS                                                                 */
57 /*                                                                        */
58 /*    _tx_thread_system_resume          Resume thread service             */
59 /*    _tx_thread_system_ni_resume       Non-interruptable resume thread   */
60 /*                                                                        */
61 /*  CALLED BY                                                             */
62 /*                                                                        */
63 /*    Application Code                                                    */
64 /*                                                                        */
65 /*  RELEASE HISTORY                                                       */
66 /*                                                                        */
67 /*    DATE              NAME                      DESCRIPTION             */
68 /*                                                                        */
69 /*  05-19-2020     William E. Lamie         Initial Version 6.0           */
70 /*  09-30-2020     Yuxin Zhou               Modified comment(s),          */
71 /*                                            resulting in version 6.1    */
72 /*                                                                        */
73 /**************************************************************************/
_tx_block_release(VOID * block_ptr)74 UINT  _tx_block_release(VOID *block_ptr)
75 {
76 
77 TX_INTERRUPT_SAVE_AREA
78 
79 TX_BLOCK_POOL       *pool_ptr;
80 TX_THREAD           *thread_ptr;
81 UCHAR               *work_ptr;
82 UCHAR               **return_block_ptr;
83 UCHAR               **next_block_ptr;
84 UINT                suspended_count;
85 TX_THREAD           *next_thread;
86 TX_THREAD           *previous_thread;
87 
88 
89     /* Disable interrupts to put this block back in the pool.  */
90     TX_DISABLE
91 
92     /* Pickup the pool pointer which is just previous to the starting
93        address of the block that the caller sees.  */
94     work_ptr =        TX_VOID_TO_UCHAR_POINTER_CONVERT(block_ptr);
95     work_ptr =        TX_UCHAR_POINTER_SUB(work_ptr, (sizeof(UCHAR *)));
96     next_block_ptr =  TX_UCHAR_TO_INDIRECT_UCHAR_POINTER_CONVERT(work_ptr);
97     pool_ptr =        TX_UCHAR_TO_BLOCK_POOL_POINTER_CONVERT((*next_block_ptr));
98 
99 #ifdef TX_BLOCK_POOL_ENABLE_PERFORMANCE_INFO
100 
101     /* Increment the total releases counter.  */
102     _tx_block_pool_performance_release_count++;
103 
104     /* Increment the number of releases on this pool.  */
105     pool_ptr -> tx_block_pool_performance_release_count++;
106 #endif
107 
108     /* If trace is enabled, insert this event into the trace buffer.  */
109     TX_TRACE_IN_LINE_INSERT(TX_TRACE_BLOCK_RELEASE, pool_ptr, TX_POINTER_TO_ULONG_CONVERT(block_ptr), pool_ptr -> tx_block_pool_suspended_count, TX_POINTER_TO_ULONG_CONVERT(&work_ptr), TX_TRACE_BLOCK_POOL_EVENTS)
110 
111     /* Log this kernel call.  */
112     TX_EL_BLOCK_RELEASE_INSERT
113 
114     /* Determine if there are any threads suspended on the block pool.  */
115     thread_ptr =  pool_ptr -> tx_block_pool_suspension_list;
116     if (thread_ptr != TX_NULL)
117     {
118 
119         /* Remove the suspended thread from the list.  */
120 
121         /* Decrement the number of threads suspended.  */
122         (pool_ptr -> tx_block_pool_suspended_count)--;
123 
124         /* Pickup the suspended count.  */
125         suspended_count =  (pool_ptr -> tx_block_pool_suspended_count);
126 
127         /* See if this is the only suspended thread on the list.  */
128         if (suspended_count == TX_NO_SUSPENSIONS)
129         {
130 
131             /* Yes, the only suspended thread.  */
132 
133             /* Update the head pointer.  */
134             pool_ptr -> tx_block_pool_suspension_list =  TX_NULL;
135         }
136         else
137         {
138 
139             /* At least one more thread is on the same expiration list.  */
140 
141             /* Update the list head pointer.  */
142             next_thread =                                thread_ptr -> tx_thread_suspended_next;
143             pool_ptr -> tx_block_pool_suspension_list =  next_thread;
144 
145             /* Update the links of the adjacent threads.  */
146             previous_thread =                              thread_ptr -> tx_thread_suspended_previous;
147             next_thread -> tx_thread_suspended_previous =  previous_thread;
148             previous_thread -> tx_thread_suspended_next =  next_thread;
149         }
150 
151         /* Prepare for resumption of the first thread.  */
152 
153         /* Clear cleanup routine to avoid timeout.  */
154         thread_ptr -> tx_thread_suspend_cleanup =  TX_NULL;
155 
156         /* Return this block pointer to the suspended thread waiting for
157            a block.  */
158         return_block_ptr =  TX_VOID_TO_INDIRECT_UCHAR_POINTER_CONVERT(thread_ptr -> tx_thread_additional_suspend_info);
159         work_ptr =          TX_VOID_TO_UCHAR_POINTER_CONVERT(block_ptr);
160         *return_block_ptr =  work_ptr;
161 
162         /* Put return status into the thread control block.  */
163         thread_ptr -> tx_thread_suspend_status =  TX_SUCCESS;
164 
165 #ifdef TX_NOT_INTERRUPTABLE
166 
167         /* Resume the thread!  */
168         _tx_thread_system_ni_resume(thread_ptr);
169 
170         /* Restore interrupts.  */
171         TX_RESTORE
172 #else
173 
174         /* Temporarily disable preemption.  */
175         _tx_thread_preempt_disable++;
176 
177         /* Restore interrupts.  */
178         TX_RESTORE
179 
180         /* Resume thread.  */
181         _tx_thread_system_resume(thread_ptr);
182 #endif
183     }
184     else
185     {
186 
187         /* No thread is suspended for a memory block.  */
188 
189         /* Put the block back in the available list.  */
190         *next_block_ptr =  pool_ptr -> tx_block_pool_available_list;
191 
192         /* Adjust the head pointer.  */
193         pool_ptr -> tx_block_pool_available_list =  work_ptr;
194 
195         /* Increment the count of available blocks.  */
196         pool_ptr -> tx_block_pool_available++;
197 
198         /* Restore interrupts.  */
199         TX_RESTORE
200     }
201 
202     /* Return successful completion status.  */
203     return(TX_SUCCESS);
204 }
205 
206