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Subject[PATCH 1/4] firmware: Refactoring for splitting user-mode helper code
Date
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.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
---
drivers/base/firmware_class.c | 286 +++++++++++++++++++++++-------------------
1 file changed, 159 insertions(+), 127 deletions(-)

diff --git a/drivers/base/firmware_class.c b/drivers/base/firmware_class.c
index b392b35..7da18e3 100644
--- a/drivers/base/firmware_class.c
+++ b/drivers/base/firmware_class.c
@@ -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 +807,122 @@ static int fw_add_devm_name(struct device *dev, const char *name)
}
#endif

-static void _request_firmware_cleanup(const struct firmware **firmware_p)
+static void _request_firmware_cleanup(struct firmware **firmware_p)
{
release_firmware(*firmware_p);
*firmware_p = NULL;
}

-static struct firmware_priv *
-_request_firmware_prepare(const struct firmware **firmware_p, const char *name,
- struct device *device, bool uevent, bool nowait)
+/* wait until the shared firmware_buf becomes ready (or error) */
+static int sync_cached_firmware_buf(struct firmware_buf *buf)
+{
+ 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;
+}
+
+/* prepare firmware and firmware_buf structs;
+ * return 1 if a firmware is already assigned, 0 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);
+ return -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 1; /* 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 1; /* assigned */
+ }
}

- /* share the cached buf, which is inprogessing or completed */
- check_status:
- mutex_lock(&fw_lock);
- if (test_bit(FW_STATUS_ABORT, &buf->status)) {
- fw_priv = ERR_PTR(-ENOENT);
- firmware->priv = buf;
+ if (ret < 0)
_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;
+
+ return ret;
+}
+
+static int assign_firmware_buf(struct firmware *fw, struct device *device)
+{
+ struct firmware_buf *buf = fw->priv;
+
+ mutex_lock(&fw_lock);
+ 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 +963,10 @@ 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);
+ if (!retval)
+ retval = assign_firmware_buf(fw_priv->fw, f_dev->parent);

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 +978,71 @@ 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)
+{
+ struct firmware_priv *fw_priv;
+ long timeout;
+ int ret;
+
+ 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;
+
+ timeout = firmware_loading_timeout();
+ if (nowait) {
+ timeout = usermodehelper_read_lock_wait(timeout);
+ if (!timeout) {
+ dev_dbg(device, "firmware: %s loading timed out\n",
+ name);
+ kfree(fw_priv);
+ return -EAGAIN;
+ }
+ } else {
+ ret = usermodehelper_read_trylock();
+ if (WARN_ON(ret)) {
+ dev_err(device, "firmware: %s will not be loaded\n",
+ name);
+ kfree(fw_priv);
+ return ret;
+ }
+ }
+
+ ret = _request_firmware_load(fw_priv, uevent, timeout);
+ usermodehelper_read_unlock();
+ return ret;
+}
+
+/* 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;
+ int ret;
+
+ ret = _request_firmware_prepare(&fw, name, device);
+ if (ret < 0)
+ return ret;
+ else if (ret) { /* assigned from either built-in or cache */
+ *firmware_p = fw;
+ return 0;
+ }
+
+ if (fw_get_filesystem_firmware(device, fw->priv))
+ ret = assign_firmware_buf(fw, device);
+ else
+ ret = fw_load_from_user_helper(fw, name, device,
+ uevent, nowait);
+ if (ret)
+ _request_firmware_cleanup(&fw);
+ *firmware_p = fw;
+ return ret;
+}
+
/**
* request_firmware: - send firmware request and wait for it
* @firmware_p: pointer to firmware image
@@ -996,26 +1067,7 @@ 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);
}

/**
@@ -1046,31 +1098,11 @@ 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);

--
1.8.1.1


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