Changeset 19ea61d in mainline

Timestamp:

2017-11-20T20:01:24Z (7 years ago)

Author:

Jiri Svoboda <jiri@…>

Branches:

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

Children:

677cad5

Parents:

c657bd7

Message:

Chardev should allow large data transfers.

Location:

uspace/lib/c/generic/io

Files:

• chardev.c (modified) (2 diffs)
• chardev_srv.c (modified) (3 diffs)

uspace/lib/c/generic/io/chardev.c

@@ -96 +96 @@
 int chardev_read(chardev_t *chardev, void *buf, size_t size, size_t *nread)
 {
-        if (size > 4 * sizeof(sysarg_t))
-                return ELIMIT;
-
         async_exch_t *exch = async_exchange_begin(chardev->sess);
-        sysarg_t message[4] = { 0 };
-        const ssize_t ret = async_req_1_4(exch, CHARDEV_READ, size,
-            &message[0], &message[1], &message[2], &message[3]);
+
+        if (size > DATA_XFER_LIMIT) {
+                /* This should not hurt anything. */
+                size = DATA_XFER_LIMIT;
+        }
+
+        ipc_call_t answer;
+        aid_t req = async_send_0(exch, CHARDEV_READ, &answer);
+        int rc = async_data_read_start(exch, buf, size);
         async_exchange_end(exch);
-        if (ret > 0 && (size_t)ret <= size)
-                memcpy(buf, message, size);
-
-        if (ret < 0) {
+
+        if (rc != EOK) {
+                async_forget(req);
                 *nread = 0;
-                return ret;
-        }
-
-        *nread = ret;
-        return EOK;
-}
-
-/** Write to character device.
- *
- * Write @a size bytes from @a data to character device. On success EOK
- * is returned, all bytes were written and @a *nwritten is set to @a size.
+                return rc;
+        }
+
+        sysarg_t retval;
+        async_wait_for(req, &retval);
+
+        if (retval != EOK) {
+                *nread = 0;
+                return retval;
+        }
+
+        *nread = IPC_GET_ARG2(answer);
+        /* In case of partial success, ARG1 contains the error code */
+        return IPC_GET_ARG1(answer);
+
+}
+
+/** Write up to DATA_XFER_LIMIT bytes to character device.
+ *
+ * Write up to @a size or DATA_XFER_LIMIT bytes from @a data to character
+ * device. On success EOK is returned, bytes were written and @a *nwritten
+ * is set to min(@a size, DATA_XFER_LIMIT)
  *
  * On error a non-zero error code is returned and @a *nwritten is filled with
@@ -131 +144 @@
  * @return EOK on success or non-zero error code
  */
+static int chardev_write_once(chardev_t *chardev, const void *data,
+    size_t size, size_t *nwritten)
+{
+        async_exch_t *exch = async_exchange_begin(chardev->sess);
+        ipc_call_t answer;
+        aid_t req;
+        int rc;
+
+        /* Break down large transfers */
+        if (size > DATA_XFER_LIMIT)
+                size = DATA_XFER_LIMIT;
+
+        req = async_send_0(exch, CHARDEV_WRITE, &answer);
+        rc = async_data_write_start(exch, data, size);
+        async_exchange_end(exch);
+
+        if (rc != EOK) {
+                async_forget(req);
+                *nwritten = 0;
+                return rc;
+        }
+
+        sysarg_t retval;
+        async_wait_for(req, &retval);
+        if (retval != EOK) {
+                *nwritten = 0;
+                return retval;
+        }
+
+        *nwritten = IPC_GET_ARG2(answer);
+        /* In case of partial success, ARG1 contains the error code */
+        return IPC_GET_ARG1(answer);
+}
+
+/** Write to character device.
+ *
+ * Write @a size bytes from @a data to character device. On success EOK
+ * is returned, all bytes were written and @a *nwritten is set to @a size.
+ *
+ * On error a non-zero error code is returned and @a *nwritten is filled with
+ * the number of bytes that were successfully transferred.
+ *
+ * @param chardev Character device
+ * @param buf Destination buffer
+ * @param size Maximum number of bytes to read
+ * @param nwritten Place to store actual number of bytes written
+ *
+ * @return EOK on success or non-zero error code
+ */
 int chardev_write(chardev_t *chardev, const void *data, size_t size,
     size_t *nwritten)
 {
-        int ret;
-
-        if (size > 3 * sizeof(sysarg_t))
-                return ELIMIT;
-
-        async_exch_t *exch = async_exchange_begin(chardev->sess);
-        sysarg_t message[3] = { 0 };
-        memcpy(message, data, size);
-        ret = async_req_4_0(exch, CHARDEV_WRITE, size,
-            message[0], message[1], message[2]);
-        async_exchange_end(exch);
-
-        if (ret < 0) {
-                *nwritten = 0;
-                return ret;
-        }
-
-        *nwritten = ret;
+        size_t nw;
+        size_t p;
+        int rc;
+
+        p = 0;
+        while (p < size) {
+                rc = chardev_write_once(chardev, data + p, size - p, &nw);
+                /* nw is always valid, we can have partial success */
+                p += nw;
+
+                if (rc != EOK) {
+                        /* We can return partial success */
+                        *nwritten = p;
+                        return rc;
+                }
+        }
+
+        *nwritten = p;
         return EOK;
 }

uspace/lib/c/generic/io/chardev_srv.c

@@ -46 +46 @@
     ipc_call_t *call)
 {
-        size_t size = IPC_GET_ARG1(*call);
+        void *buf;
+        size_t size;
         int rc;
+        ipc_callid_t rcallid;
 
-        if (srv->srvs->ops->read == NULL) {
-                async_answer_0(callid, ENOTSUP);
+        if (!async_data_read_receive(&rcallid, &size)) {
+                async_answer_0(callid, EINVAL);
                 return;
         }
 
-        if (size <= 4 * sizeof(sysarg_t)) {
-                sysarg_t message[4] = {};
+        buf = malloc(size);
+        if (buf == NULL) {
+                async_answer_0(rcallid, ENOMEM);
+                async_answer_0(callid, ENOMEM);
+                return;
+        }
 
-                rc = srv->srvs->ops->read(srv, (char *)message, size);
-                async_answer_4(callid, rc, message[0], message[1],
-                    message[2], message[3]);
-        } else {
-                async_answer_0(callid, ELIMIT);
+        if (srv->srvs->ops->read == NULL) {
+                async_answer_0(rcallid, ENOTSUP);
+                async_answer_0(callid, ENOTSUP);
+                free(buf);
+                return;
         }
+
+        rc = srv->srvs->ops->read(srv, buf, size);
+        if (rc < 0) {
+                async_answer_0(rcallid, rc);
+                async_answer_0(callid, rc);
+                free(buf);
+                return;
+        }
+
+        async_data_read_finalize(rcallid, buf, size);
+
+        free(buf);
+        async_answer_2(callid, EOK, EOK, rc /* nread */);
 }
 
@@ -68 +87 @@
     ipc_call_t *call)
 {
-        size_t size = IPC_GET_ARG1(*call);
+        void *data;
+        size_t size;
         int rc;
+
+        rc = async_data_write_accept(&data, false, 0, 0, 0, &size);
+        if (rc != EOK) {
+                async_answer_0(callid, rc);
+                return;
+        }
 
         if (srv->srvs->ops->write == NULL) {
@@ -76 +102 @@
         }
 
-        if (size <= 3 * sizeof(sysarg_t)) {
-                const sysarg_t message[3] = {
-                        IPC_GET_ARG2(*call),
-                        IPC_GET_ARG3(*call),
-                        IPC_GET_ARG4(*call)
-                };
+        rc = srv->srvs->ops->write(srv, data, size);
+        free(data);
+        if (rc < 0)
+                async_answer_0(callid, rc);
 
-                rc = srv->srvs->ops->write(srv, (char *)message, size);
-                async_answer_0(callid, rc);
-        } else {
-                async_answer_0(callid, ELIMIT);
-        }
+        async_answer_2(callid, EOK, EOK, rc /* nwritten */);
 }