Changeset d5ac90f in mainline

Timestamp:

2011-04-09T08:27:57Z (13 years ago)

Author:

Vojtech Horky <vojtechhorky@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

a546687

Parents:

61727bf

Message:

Serialization of IPC requests over pipe phone

The pipe phone is now guarded by a fibril mutex.

Location:

uspace/lib/usb

Files:

• include/usb/pipes.h (modified) (2 diffs)
• src/pipesinit.c (modified) (1 diff)
• src/pipesio.c (modified) (14 diffs)

uspace/lib/usb/include/usb/pipes.h

@@ -42 +42 @@
 #include <ipc/devman.h>
 #include <ddf/driver.h>
+#include <fibril_synch.h>
 
 /** Abstraction of a physical connection to the device.
@@ -80 +81 @@
          */
         int hc_phone;
+
+        /** Guard for serialization of requests over the phone. */
+        fibril_mutex_t hc_phone_mutex;
 } usb_pipe_t;
 

uspace/lib/usb/src/pipesinit.c

@@ -358 +358 @@
         pipe->wire = connection;
         pipe->hc_phone = -1;
+        fibril_mutex_initialize(&pipe->hc_phone_mutex);
         pipe->endpoint_no = endpoint_no;
         pipe->transfer_type = transfer_type;

uspace/lib/usb/src/pipesio.c

@@ -50 +50 @@
 #include <usbhc_iface.h>
 
+/** Ensure exclusive access to the IPC phone of given pipe.
+ *
+ * @param pipe Pipe to be exclusively accessed.
+ */
+static void pipe_acquire(usb_pipe_t *pipe)
+{
+        fibril_mutex_lock(&pipe->hc_phone_mutex);
+}
+
+/** Terminate exclusive access to the IPC phone of given pipe.
+ *
+ * @param pipe Pipe to be released from exclusive usage.
+ */
+static void pipe_release(usb_pipe_t *pipe)
+{
+        fibril_mutex_unlock(&pipe->hc_phone_mutex);
+}
+
+
+
 /** Request an in transfer, no checking of input parameters.
  *
@@ -78 +98 @@
         }
 
+        /* Ensure serialization over the phone. */
+        pipe_acquire(pipe);
+
         /*
          * Make call identifying target USB device and type of transfer.
@@ -87 +110 @@
             NULL);
         if (opening_request == 0) {
+                pipe_release(pipe);
                 return ENOMEM;
         }
@@ -96 +120 @@
         aid_t data_request = async_data_read(pipe->hc_phone, buffer, size,
             &data_request_call);
+
+        /*
+         * Since now on, someone else might access the backing phone
+         * without breaking the transfer IPC protocol.
+         */
+        pipe_release(pipe);
 
         if (data_request == 0) {
@@ -210 +240 @@
         }
 
+        /* Ensure serialization over the phone. */
+        pipe_acquire(pipe);
+
         /*
          * Make call identifying target USB device and type of transfer.
@@ -219 +252 @@
             NULL);
         if (opening_request == 0) {
+                pipe_release(pipe);
                 return ENOMEM;
         }
@@ -226 +260 @@
          */
         int rc = async_data_write_start(pipe->hc_phone, buffer, size);
+
+        /*
+         * Since now on, someone else might access the backing phone
+         * without breaking the transfer IPC protocol.
+         */
+        pipe_release(pipe);
+
         if (rc != EOK) {
                 async_wait_for(opening_request, NULL);
@@ -293 +334 @@
     void *data_buffer, size_t data_buffer_size, size_t *data_transfered_size)
 {
+        /* Ensure serialization over the phone. */
+        pipe_acquire(pipe);
+
         /*
          * Make call identifying target USB device and control transfer type.
@@ -311 +355 @@
             setup_buffer, setup_buffer_size);
         if (rc != EOK) {
+                pipe_release(pipe);
                 async_wait_for(opening_request, NULL);
                 return rc;
@@ -322 +367 @@
             data_buffer, data_buffer_size,
             &data_request_call);
+
+        /*
+         * Since now on, someone else might access the backing phone
+         * without breaking the transfer IPC protocol.
+         */
+        pipe_release(pipe);
+
+
         if (data_request == 0) {
                 async_wait_for(opening_request, NULL);
@@ -418 +471 @@
     void *data_buffer, size_t data_buffer_size)
 {
+        /* Ensure serialization over the phone. */
+        pipe_acquire(pipe);
+
         /*
          * Make call identifying target USB device and control transfer type.
@@ -428 +484 @@
             NULL);
         if (opening_request == 0) {
+                pipe_release(pipe);
                 return ENOMEM;
         }
@@ -437 +494 @@
             setup_buffer, setup_buffer_size);
         if (rc != EOK) {
+                pipe_release(pipe);
                 async_wait_for(opening_request, NULL);
                 return rc;
@@ -447 +505 @@
                 rc = async_data_write_start(pipe->hc_phone,
                     data_buffer, data_buffer_size);
+
+                /* All data sent, pipe can be released. */
+                pipe_release(pipe);
+
                 if (rc != EOK) {
                         async_wait_for(opening_request, NULL);
                         return rc;
                 }
+        } else {
+                /* No data to send, we can release the pipe for others. */
+                pipe_release(pipe);
         }