修改atomic_t的定义

diff --git a/drivers/ide.c b/drivers/ide.c
index dfe96f81812adb9eb1a8b61d2588e5aa815580ca..f7dab9eceffef11a4d2660bb4974e0d29db03d42 100644 (file)
--- a/drivers/ide.c
+++ b/drivers/ide.c
@@ -49,9 +49,9 @@ void ide_pci_init(pci_device_t *pci) {
         semaphore_init(&ide_pci_controller[i].request_queue.sem, 0);
         semaphore_init(&ide_pci_controller[i].disk_intr_sem, 0);
 
-        ide_pci_controller[i].request_cnt = 0;
-        ide_pci_controller[i].irq_cnt = 0;
-        ide_pci_controller[i].consumed_cnt = 0;
+        atomic_set(&ide_pci_controller[i].request_cnt, 0);
+        atomic_set(&ide_pci_controller[i].irq_cnt, 0);
+        atomic_set(&ide_pci_controller[i].consumed_cnt, 0);
 
         iobase += i * 8;  // secondary channel 需要加8
         printd("ide pci Base IO Address Register %08x\n", iobase);
@@ -137,8 +137,8 @@ void ide_irq_bh_handler(void *arg) {
     // printlxy(MPL_IDE, MPO_IDE, "disk irq %u req %u consumed %u ", disk_inter_cnt, disk_request_cnt,
     // disk_handled_cnt);
 
-    printlxy(MPL_IDE0 + channel, MPO_IDE, "IDE%d req %u irq %u consumed %u", channel, ide_ctrl->request_cnt,
-             ide_ctrl->irq_cnt, ide_ctrl->consumed_cnt);
+    printlxy(MPL_IDE0 + channel, MPO_IDE, "IDE%d req %u irq %u consumed %u", channel,
+             atomic_read(&(ide_ctrl->request_cnt)), ide_ctrl->irq_cnt, ide_ctrl->consumed_cnt);
 
     // up里不会立即重新调度进程
     up(&ide_ctrl->disk_intr_sem);

diff --git a/fs/buffer.c b/fs/buffer.c
index fc98755849f8ad0926d115d73205bba7ce63434e..a754b5a2eaae99cbba5259e53724713e5864b822 100644 (file)
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -112,7 +112,8 @@ again:
         assert(NULL != t);
         assert(t->block_size == size);
 
-        if (t->ref_count == 0) {
+        // if (t->ref_count == 0) {
+        if (atomic_read(&t->ref_count) == 0) {
             b = t;
             break;
         }
@@ -139,7 +140,7 @@ again:
     b->block = block;
     b->block_size = size;
     b->dev = dev;
-    b->ref_count = 1;
+    atomic_set(&(b->ref_count), 1);
     b->uptodate = 0;
 
     return b;
@@ -147,7 +148,7 @@ again:
 
 void brelse(bbuffer_t *b) {
     assert(b != NULL);
-    assert(b->ref_count > 0);
+    assert(atomic_read(&(b->ref_count)) > 0);
 
     wait_completion(&b->io_done);
 
@@ -217,7 +218,7 @@ void init_buffer() {
 
             b->block = 0;
             b->block_size = blocksize;
-            b->ref_count = 0;
+            atomic_set(&(b->ref_count), 0);
             b->data = data + j * blocksize;
             b->dev = 0;
             b->page = page;

diff --git a/include/atomic.h b/include/atomic.h
index 4afeb373c36fb7a9fd04b1e4d30d53eeebcd309a..f16af72ccf7d4c72a16b78345789e655df707c6d 100644 (file)
--- a/include/atomic.h
+++ b/include/atomic.h
@@ -11,9 +11,32 @@
 
 #include <types.h>
 
+#if 1
+
+typedef struct atomic {
+    volatile int counter;
+} atomic_t;
+
+static inline void atomic_inc(atomic_t *v) { __sync_add_and_fetch(&(v->counter), 1); }
+static inline void atomic_dec(atomic_t *v) { __sync_sub_and_fetch(&(v->counter), 1); }
+
+static inline int atomic_read(atomic_t *v) { return *((int *)(&(v->counter))); }
+
+static inline void atomic_set(atomic_t *v, int i) { __sync_lock_test_and_set(&(v->counter), i); }
+
+#else
+
+// 以下的定义方式
+// 优点：
+//  1. 简化了类型定义，代码更简洁
+//  2. 可能在某些情况下减少内存开锁
+// 缺点：
+//  1. 会丢失volatile限定符。volatile对于多线程和中断处理等场景中很重要。
+//  2. 限制了扩展性
 typedef uint32_t atomic_t;
 
 #define atomic_inc(x) __sync_add_and_fetch((x), 1)
 #define atomic_dec(x) __sync_sub_and_fetch((x), 1)
 #define atomic_add(x, y) __sync_add_and_fetch((x), (y))
 #define atomic_sub(x, y) __sync_sub_and_fetch((x), (y))
+#endif