firmware: Refactoring for splitting user-mode helper code
authorTakashi Iwai <tiwai@suse.de>
Thu, 31 Jan 2013 10:13:54 +0000 (11:13 +0100)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Mon, 4 Feb 2013 01:57:40 +0000 (17:57 -0800)
Since 3.7 kernel, the firmware loader can read the firmware files
directly, and the traditional user-mode helper is invoked only as a
fallback.  This seems working pretty well, and the next step would be
to reduce the redundant user-mode helper stuff in future.

This patch is a preparation for that: refactor the code for splitting
user-mode helper stuff more easily.  No functional change.

Acked-by: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
drivers/base/firmware_class.c

index b392b353be39016818abd096da01fb4a18839450..40ec60affd8f19c23f1f0e35208ddf5b2dd2d9dd 100644 (file)
@@ -319,7 +319,8 @@ static bool fw_read_file_contents(struct file *file, struct firmware_buf *fw_buf
        return true;
 }
 
-static bool fw_get_filesystem_firmware(struct firmware_buf *buf)
+static bool fw_get_filesystem_firmware(struct device *device,
+                                      struct firmware_buf *buf)
 {
        int i;
        bool success = false;
@@ -343,6 +344,16 @@ static bool fw_get_filesystem_firmware(struct firmware_buf *buf)
                        break;
        }
        __putname(path);
+
+       if (success) {
+               dev_dbg(device, "firmware: direct-loading firmware %s\n",
+                       buf->fw_id);
+               mutex_lock(&fw_lock);
+               set_bit(FW_STATUS_DONE, &buf->status);
+               complete_all(&buf->completion);
+               mutex_unlock(&fw_lock);
+       }
+
        return success;
 }
 
@@ -796,99 +807,112 @@ static int fw_add_devm_name(struct device *dev, const char *name)
 }
 #endif
 
-static void _request_firmware_cleanup(const struct firmware **firmware_p)
+/* wait until the shared firmware_buf becomes ready (or error) */
+static int sync_cached_firmware_buf(struct firmware_buf *buf)
 {
-       release_firmware(*firmware_p);
-       *firmware_p = NULL;
+       int ret = 0;
+
+       mutex_lock(&fw_lock);
+       while (!test_bit(FW_STATUS_DONE, &buf->status)) {
+               if (test_bit(FW_STATUS_ABORT, &buf->status)) {
+                       ret = -ENOENT;
+                       break;
+               }
+               mutex_unlock(&fw_lock);
+               wait_for_completion(&buf->completion);
+               mutex_lock(&fw_lock);
+       }
+       mutex_unlock(&fw_lock);
+       return ret;
 }
 
-static struct firmware_priv *
-_request_firmware_prepare(const struct firmware **firmware_p, const char *name,
-                         struct device *device, bool uevent, bool nowait)
+/* prepare firmware and firmware_buf structs;
+ * return 0 if a firmware is already assigned, 1 if need to load one,
+ * or a negative error code
+ */
+static int
+_request_firmware_prepare(struct firmware **firmware_p, const char *name,
+                         struct device *device)
 {
        struct firmware *firmware;
-       struct firmware_priv *fw_priv = NULL;
        struct firmware_buf *buf;
        int ret;
 
-       if (!firmware_p)
-               return ERR_PTR(-EINVAL);
-
        *firmware_p = firmware = kzalloc(sizeof(*firmware), GFP_KERNEL);
        if (!firmware) {
                dev_err(device, "%s: kmalloc(struct firmware) failed\n",
                        __func__);
-               return ERR_PTR(-ENOMEM);
+               return -ENOMEM;
        }
 
        if (fw_get_builtin_firmware(firmware, name)) {
                dev_dbg(device, "firmware: using built-in firmware %s\n", name);
-               return NULL;
+               return 0; /* assigned */
        }
 
        ret = fw_lookup_and_allocate_buf(name, &fw_cache, &buf);
-       if (!ret)
-               fw_priv = fw_create_instance(firmware, name, device,
-                               uevent, nowait);
 
-       if (IS_ERR(fw_priv) || ret < 0) {
-               kfree(firmware);
-               *firmware_p = NULL;
-               return ERR_PTR(-ENOMEM);
-       } else if (fw_priv) {
-               fw_priv->buf = buf;
+       /*
+        * bind with 'buf' now to avoid warning in failure path
+        * of requesting firmware.
+        */
+       firmware->priv = buf;
 
-               /*
-                * bind with 'buf' now to avoid warning in failure path
-                * of requesting firmware.
-                */
-               firmware->priv = buf;
-               return fw_priv;
+       if (ret > 0) {
+               ret = sync_cached_firmware_buf(buf);
+               if (!ret) {
+                       fw_set_page_data(buf, firmware);
+                       return 0; /* assigned */
+               }
        }
 
-       /* share the cached buf, which is inprogessing or completed */
- check_status:
+       if (ret < 0)
+               return ret;
+       return 1; /* need to load */
+}
+
+static int assign_firmware_buf(struct firmware *fw, struct device *device)
+{
+       struct firmware_buf *buf = fw->priv;
+
        mutex_lock(&fw_lock);
-       if (test_bit(FW_STATUS_ABORT, &buf->status)) {
-               fw_priv = ERR_PTR(-ENOENT);
-               firmware->priv = buf;
-               _request_firmware_cleanup(firmware_p);
-               goto exit;
-       } else if (test_bit(FW_STATUS_DONE, &buf->status)) {
-               fw_priv = NULL;
-               fw_set_page_data(buf, firmware);
-               goto exit;
+       if (!buf->size || test_bit(FW_STATUS_ABORT, &buf->status)) {
+               mutex_unlock(&fw_lock);
+               return -ENOENT;
        }
-       mutex_unlock(&fw_lock);
-       wait_for_completion(&buf->completion);
-       goto check_status;
 
-exit:
+       /*
+        * add firmware name into devres list so that we can auto cache
+        * and uncache firmware for device.
+        *
+        * device may has been deleted already, but the problem
+        * should be fixed in devres or driver core.
+        */
+       if (device)
+               fw_add_devm_name(device, buf->fw_id);
+
+       /*
+        * After caching firmware image is started, let it piggyback
+        * on request firmware.
+        */
+       if (buf->fwc->state == FW_LOADER_START_CACHE) {
+               if (fw_cache_piggyback_on_request(buf->fw_id))
+                       kref_get(&buf->ref);
+       }
+
+       /* pass the pages buffer to driver at the last minute */
+       fw_set_page_data(buf, fw);
        mutex_unlock(&fw_lock);
-       return fw_priv;
+       return 0;
 }
 
+/* load a firmware via user helper */
 static int _request_firmware_load(struct firmware_priv *fw_priv, bool uevent,
                                  long timeout)
 {
        int retval = 0;
        struct device *f_dev = &fw_priv->dev;
        struct firmware_buf *buf = fw_priv->buf;
-       struct firmware_cache *fwc = &fw_cache;
-       int direct_load = 0;
-
-       /* try direct loading from fs first */
-       if (fw_get_filesystem_firmware(buf)) {
-               dev_dbg(f_dev->parent, "firmware: direct-loading"
-                       " firmware %s\n", buf->fw_id);
-
-               mutex_lock(&fw_lock);
-               set_bit(FW_STATUS_DONE, &buf->status);
-               mutex_unlock(&fw_lock);
-               complete_all(&buf->completion);
-               direct_load = 1;
-               goto handle_fw;
-       }
 
        /* fall back on userspace loading */
        buf->fmt = PAGE_BUF;
@@ -929,38 +953,7 @@ static int _request_firmware_load(struct firmware_priv *fw_priv, bool uevent,
 
        cancel_delayed_work_sync(&fw_priv->timeout_work);
 
-handle_fw:
-       mutex_lock(&fw_lock);
-       if (!buf->size || test_bit(FW_STATUS_ABORT, &buf->status))
-               retval = -ENOENT;
-
-       /*
-        * add firmware name into devres list so that we can auto cache
-        * and uncache firmware for device.
-        *
-        * f_dev->parent may has been deleted already, but the problem
-        * should be fixed in devres or driver core.
-        */
-       if (!retval && f_dev->parent)
-               fw_add_devm_name(f_dev->parent, buf->fw_id);
-
-       /*
-        * After caching firmware image is started, let it piggyback
-        * on request firmware.
-        */
-       if (!retval && fwc->state == FW_LOADER_START_CACHE) {
-               if (fw_cache_piggyback_on_request(buf->fw_id))
-                       kref_get(&buf->ref);
-       }
-
-       /* pass the pages buffer to driver at the last minute */
-       fw_set_page_data(buf, fw_priv->fw);
-
        fw_priv->buf = NULL;
-       mutex_unlock(&fw_lock);
-
-       if (direct_load)
-               goto err_put_dev;
 
        device_remove_file(f_dev, &dev_attr_loading);
 err_del_bin_attr:
@@ -972,6 +965,73 @@ err_put_dev:
        return retval;
 }
 
+static int fw_load_from_user_helper(struct firmware *firmware,
+                                   const char *name, struct device *device,
+                                   bool uevent, bool nowait, long timeout)
+{
+       struct firmware_priv *fw_priv;
+
+       fw_priv = fw_create_instance(firmware, name, device, uevent, nowait);
+       if (IS_ERR(fw_priv))
+               return PTR_ERR(fw_priv);
+
+       fw_priv->buf = firmware->priv;
+       return _request_firmware_load(fw_priv, uevent, timeout);
+}
+
+/* called from request_firmware() and request_firmware_work_func() */
+static int
+_request_firmware(const struct firmware **firmware_p, const char *name,
+                 struct device *device, bool uevent, bool nowait)
+{
+       struct firmware *fw;
+       long timeout;
+       int ret;
+
+       if (!firmware_p)
+               return -EINVAL;
+
+       ret = _request_firmware_prepare(&fw, name, device);
+       if (ret <= 0) /* error or already assigned */
+               goto out;
+
+       ret = 0;
+       timeout = firmware_loading_timeout();
+       if (nowait) {
+               timeout = usermodehelper_read_lock_wait(timeout);
+               if (!timeout) {
+                       dev_dbg(device, "firmware: %s loading timed out\n",
+                               name);
+                       ret = -EBUSY;
+                       goto out;
+               }
+       } else {
+               ret = usermodehelper_read_trylock();
+               if (WARN_ON(ret)) {
+                       dev_err(device, "firmware: %s will not be loaded\n",
+                               name);
+                       goto out;
+               }
+       }
+
+       if (!fw_get_filesystem_firmware(device, fw->priv))
+               ret = fw_load_from_user_helper(fw, name, device,
+                                              uevent, nowait, timeout);
+       if (!ret)
+               ret = assign_firmware_buf(fw, device);
+
+       usermodehelper_read_unlock();
+
+ out:
+       if (ret < 0) {
+               release_firmware(fw);
+               fw = NULL;
+       }
+
+       *firmware_p = fw;
+       return ret;
+}
+
 /**
  * request_firmware: - send firmware request and wait for it
  * @firmware_p: pointer to firmware image
@@ -996,26 +1056,7 @@ int
 request_firmware(const struct firmware **firmware_p, const char *name,
                  struct device *device)
 {
-       struct firmware_priv *fw_priv;
-       int ret;
-
-       fw_priv = _request_firmware_prepare(firmware_p, name, device, true,
-                                           false);
-       if (IS_ERR_OR_NULL(fw_priv))
-               return PTR_RET(fw_priv);
-
-       ret = usermodehelper_read_trylock();
-       if (WARN_ON(ret)) {
-               dev_err(device, "firmware: %s will not be loaded\n", name);
-       } else {
-               ret = _request_firmware_load(fw_priv, true,
-                                       firmware_loading_timeout());
-               usermodehelper_read_unlock();
-       }
-       if (ret)
-               _request_firmware_cleanup(firmware_p);
-
-       return ret;
+       return _request_firmware(firmware_p, name, device, true, false);
 }
 
 /**
@@ -1046,33 +1087,13 @@ static void request_firmware_work_func(struct work_struct *work)
 {
        struct firmware_work *fw_work;
        const struct firmware *fw;
-       struct firmware_priv *fw_priv;
-       long timeout;
-       int ret;
 
        fw_work = container_of(work, struct firmware_work, work);
-       fw_priv = _request_firmware_prepare(&fw, fw_work->name, fw_work->device,
-                       fw_work->uevent, true);
-       if (IS_ERR_OR_NULL(fw_priv)) {
-               ret = PTR_RET(fw_priv);
-               goto out;
-       }
 
-       timeout = usermodehelper_read_lock_wait(firmware_loading_timeout());
-       if (timeout) {
-               ret = _request_firmware_load(fw_priv, fw_work->uevent, timeout);
-               usermodehelper_read_unlock();
-       } else {
-               dev_dbg(fw_work->device, "firmware: %s loading timed out\n",
-                       fw_work->name);
-               ret = -EAGAIN;
-       }
-       if (ret)
-               _request_firmware_cleanup(&fw);
-
- out:
+       _request_firmware(&fw, fw_work->name, fw_work->device,
+                         fw_work->uevent, true);
        fw_work->cont(fw, fw_work->context);
-       put_device(fw_work->device);
+       put_device(fw_work->device); /* taken in request_firmware_nowait() */
 
        module_put(fw_work->module);
        kfree(fw_work);
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