We use swait instead completion. complete() would only wake up one
waiter, so complete_all() is used. complete_all() wakes max
MAX_UINT/2
waiters which is plenty in all cases. Though withh swait we just wait
until the exptected status shows up and wake any waiter.

Signed-off-by: Daniel Wagner <redacted>
---
 drivers/base/firmware_class.c | 112 +++++++++++++++++++-------------
----------
 include/linux/firmware.h      |  71 ++++++++++++++++++++++++++
 2 files changed, 122 insertions(+), 61 deletions(-)

diff --git a/drivers/base/firmware_class.c

b/drivers/base/firmware_class.c
index 773fc30..bf1ca70 100644

--- a/drivers/base/firmware_class.c
+++ b/drivers/base/firmware_class.c

@@ -30,6 +30,7 @@

 #include <linux/syscore_ops.h>
 #include <linux/reboot.h>
 #include <linux/security.h>
+#include <linux/swait.h>
 
 #include <generated/utsrelease.h>
 

@@ -85,11 +86,36 @@ static inline bool fw_is_builtin_firmware(const

struct firmware *fw)
 }
 #endif
 
-enum {
-	FW_STATUS_LOADING,
-	FW_STATUS_DONE,
-	FW_STATUS_ABORT,
-};
+
+#if defined(CONFIG_FW_LOADER) || (defined(CONFIG_FW_LOADER_MODULE)
&& defined(MODULE))
+
+static inline bool is_fw_sync_done(unsigned long status)
+{
+	return status == FW_STATUS_LOADED || status ==
FW_STATUS_ABORT;
+}
+
+int __firmware_stat_wait(struct firmware_stat *fwst,
+				long timeout)
+{
+	int err;
+	err = swait_event_interruptible_timeout(fwst->wq,
+				is_fw_sync_done(READ_ONCE(fwst-

quoted

status)),

+				timeout);
+	if (err == 0 && fwst->status == FW_STATUS_ABORT)
+		return -ENOENT;
+
+	return err;
+}
+EXPORT_SYMBOL(__firmware_stat_wait);
+
+void __firmware_stat_set(struct firmware_stat *fwst, unsigned long
status)
+{
+	WRITE_ONCE(fwst->status, status);
+	swake_up(&fwst->wq);
+}
+EXPORT_SYMBOL(__firmware_stat_set);
+
+#endif
 
 static int loading_timeout = 60;	/* In seconds */
 

@@ -138,9 +164,8 @@ struct firmware_cache {

 struct firmware_buf {
 	struct kref ref;
 	struct list_head list;
-	struct completion completion;
+	struct firmware_stat fwst;
 	struct firmware_cache *fwc;
-	unsigned long status;
 	void *data;
 	size_t size;
 #ifdef CONFIG_FW_LOADER_USER_HELPER

@@ -194,7 +219,7 @@ static struct firmware_buf

*__allocate_fw_buf(const char *fw_name,
 
 	kref_init(&buf->ref);
 	buf->fwc = fwc;
-	init_completion(&buf->completion);
+	firmware_stat_init(&buf->fwst);
 #ifdef CONFIG_FW_LOADER_USER_HELPER
 	INIT_LIST_HEAD(&buf->pending_list);
 #endif

@@ -292,15 +317,6 @@ static const char * const fw_path[] = {

 module_param_string(path, fw_path_para, sizeof(fw_path_para), 0644);
 MODULE_PARM_DESC(path, "customized firmware image search path with a
higher priority than default path");
 
-static void fw_finish_direct_load(struct device *device,
-				  struct firmware_buf *buf)
-{
-	mutex_lock(&fw_lock);
-	set_bit(FW_STATUS_DONE, &buf->status);
-	complete_all(&buf->completion);
-	mutex_unlock(&fw_lock);
-}
-
 static int fw_get_filesystem_firmware(struct device *device,
 				       struct firmware_buf *buf)
 {

@@ -339,7 +355,7 @@ static int fw_get_filesystem_firmware(struct

device *device,
 		}
 		dev_dbg(device, "direct-loading %s\n", buf->fw_id);
 		buf->size = size;
-		fw_finish_direct_load(device, buf);
+		fw_loading_done(buf->fwst);
 		break;
 	}
 	__putname(path);

@@ -457,12 +473,11 @@ static void __fw_load_abort(struct firmware_buf

*buf)
 	 * There is a small window in which user can write to
'loading'
 	 * between loading done and disappearance of 'loading'
 	 */
-	if (test_bit(FW_STATUS_DONE, &buf->status))
+	if (is_fw_loading_done(buf->fwst))
 		return;
 
 	list_del_init(&buf->pending_list);
-	set_bit(FW_STATUS_ABORT, &buf->status);
-	complete_all(&buf->completion);
+	fw_loading_abort(buf->fwst);
 }
 
 static void fw_load_abort(struct firmware_priv *fw_priv)

@@ -475,9 +490,6 @@ static void fw_load_abort(struct firmware_priv

*fw_priv)
 	fw_priv->buf = NULL;
 }
 
-#define is_fw_load_aborted(buf)	\
-	test_bit(FW_STATUS_ABORT, &(buf)->status)
-
 static LIST_HEAD(pending_fw_head);
 
 /* reboot notifier for avoid deadlock with usermode_lock */

@@ -577,7 +589,7 @@ static ssize_t firmware_loading_show(struct

device *dev,
 
 	mutex_lock(&fw_lock);
 	if (fw_priv->buf)
-		loading = test_bit(FW_STATUS_LOADING, &fw_priv->buf-

quoted

status);

+		loading = is_fw_loading(fw_priv->buf->fwst);
 	mutex_unlock(&fw_lock);
 
 	return sprintf(buf, "%d\n", loading);

@@ -632,23 +644,20 @@ static ssize_t firmware_loading_store(struct

device *dev,
 	switch (loading) {
 	case 1:
 		/* discarding any previous partial load */
-		if (!test_bit(FW_STATUS_DONE, &fw_buf->status)) {
+		if (!is_fw_loading_done(fw_buf->fwst)) {
 			for (i = 0; i < fw_buf->nr_pages; i++)
 				__free_page(fw_buf->pages[i]);
 			vfree(fw_buf->pages);
 			fw_buf->pages = NULL;
 			fw_buf->page_array_size = 0;
 			fw_buf->nr_pages = 0;
-			set_bit(FW_STATUS_LOADING, &fw_buf->status);
+			fw_loading_start(fw_buf->fwst);
 		}
 		break;
 	case 0:
-		if (test_bit(FW_STATUS_LOADING, &fw_buf->status)) {
+		if (is_fw_loading(fw_buf->fwst)) {
 			int rc;
 
-			set_bit(FW_STATUS_DONE, &fw_buf->status);
-			clear_bit(FW_STATUS_LOADING, &fw_buf-

quoted

status);

-
 			/*
 			 * Several loading requests may be pending
on
 			 * one same firmware buf, so let all
requests

@@ -670,10 +679,11 @@ static ssize_t firmware_loading_store(struct

device *dev,
 			 */
 			list_del_init(&fw_buf->pending_list);
 			if (rc) {
-				set_bit(FW_STATUS_ABORT, &fw_buf-

quoted

status);

+				fw_loading_abort(fw_buf->fwst);
 				written = rc;
+			} else {
+				fw_loading_done(fw_buf->fwst);
 			}
-			complete_all(&fw_buf->completion);
 			break;
 		}
 		/* fallthrough */

@@ -681,7 +691,7 @@ static ssize_t firmware_loading_store(struct

device *dev,
 		dev_err(dev, "%s: unexpected value (%d)\n",
__func__, loading);
 		/* fallthrough */
 	case -1:
-		fw_load_abort(fw_priv);
+		fw_loading_abort(fw_buf->fwst);
 		break;
 	}
 out:

@@ -702,7 +712,7 @@ static ssize_t firmware_data_read(struct file

*filp, struct kobject *kobj,
 
 	mutex_lock(&fw_lock);
 	buf = fw_priv->buf;
-	if (!buf || test_bit(FW_STATUS_DONE, &buf->status)) {
+	if (!buf || is_fw_loading_done(buf->fwst)) {
 		ret_count = -ENODEV;
 		goto out;
 	}

@@ -799,7 +809,7 @@ static ssize_t firmware_data_write(struct file

*filp, struct kobject *kobj,
 
 	mutex_lock(&fw_lock);
 	buf = fw_priv->buf;
-	if (!buf || test_bit(FW_STATUS_DONE, &buf->status)) {
+	if (!buf || is_fw_loading_done(buf->fwst)) {
 		retval = -ENODEV;
 		goto out;
 	}

@@ -917,8 +927,7 @@ static int _request_firmware_load(struct

firmware_priv *fw_priv,
 		timeout = MAX_JIFFY_OFFSET;
 	}
 
-	retval = wait_for_completion_interruptible_timeout(&buf-

quoted

completion,

-			timeout);
+	retval = fw_loading_wait_timeout(buf->fwst, timeout);
 	if (retval == -ERESTARTSYS || !retval) {
 		mutex_lock(&fw_lock);
 		fw_load_abort(fw_priv);

@@ -927,7 +936,7 @@ static int _request_firmware_load(struct

firmware_priv *fw_priv,
 		retval = 0;
 	}
 
-	if (is_fw_load_aborted(buf))
+	if (is_fw_loading_aborted(buf->fwst))
 		retval = -EAGAIN;
 	else if (!buf->data)
 		retval = -ENOMEM;

@@ -986,26 +995,6 @@ static inline void

kill_requests_without_uevent(void) { }
 
 #endif /* CONFIG_FW_LOADER_USER_HELPER */
 
-
-/* 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 (is_fw_load_aborted(buf)) {
-			ret = -ENOENT;
-			break;
-		}
-		mutex_unlock(&fw_lock);
-		ret = wait_for_completion_interruptible(&buf-

quoted

completion);

-		mutex_lock(&fw_lock);
-	}
-	mutex_unlock(&fw_lock);
-	return ret;
-}
-
 /* 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

@@ -1039,7 +1028,8 @@ _request_firmware_prepare(struct firmware

**firmware_p, const char *name,
 	firmware->priv = buf;
 
 	if (ret > 0) {
-		ret = sync_cached_firmware_buf(buf);
+		ret = fw_loading_wait_timeout(buf->fwst,
+					      firmware_loading_timeo
ut());
 		if (!ret) {
 			fw_set_page_data(buf, firmware);
 			return 0; /* assigned */

@@ -1057,7 +1047,7 @@ static int assign_firmware_buf(struct firmware

*fw, struct device *device,
 	struct firmware_buf *buf = fw->priv;
 
 	mutex_lock(&fw_lock);
-	if (!buf->size || is_fw_load_aborted(buf)) {
+	if (!buf->size || is_fw_loading_aborted(buf->fwst)) {
 		mutex_unlock(&fw_lock);
 		return -ENOENT;
 	}

diff --git a/include/linux/firmware.h b/include/linux/firmware.h
index 5c41c5e..f584160 100644
--- a/include/linux/firmware.h
+++ b/include/linux/firmware.h

@@ -4,10 +4,17 @@

 #include <linux/types.h>
 #include <linux/compiler.h>
 #include <linux/gfp.h>
+#include <linux/swait.h>
 
 #define FW_ACTION_NOHOTPLUG 0
 #define FW_ACTION_HOTPLUG 1
 
+enum {
+	FW_STATUS_LOADING,
+	FW_STATUS_LOADED,
+	FW_STATUS_ABORT,
+};
+
 struct firmware {
 	size_t size;
 	const u8 *data;

@@ -17,6 +24,11 @@ struct firmware {

 	void *priv;
 };
 
+struct firmware_stat {
+	unsigned long status;
+	struct swait_queue_head wq;
+};
+
 struct module;
 struct device;
 

@@ -49,6 +61,36 @@ int request_firmware_direct(const struct firmware

**fw, const char *name,
 			    struct device *device);
 
 void release_firmware(const struct firmware *fw);
+
+static inline void firmware_stat_init(struct firmware_stat *fwst)
+{
+	init_swait_queue_head(&fwst->wq);
+}
+
+static inline unsigned long __firmware_stat_get(struct firmware_stat
*fwst)
+{
+	return READ_ONCE(fwst->status);
+}
+void __firmware_stat_set(struct firmware_stat *fwst, unsigned long
status);
+int __firmware_stat_wait(struct firmware_stat *fwst, long timeout);
+
+#define fw_loading_start(fwst)					
\
+	__firmware_stat_set(&fwst, FW_STATUS_LOADING)
+#define fw_loading_done(fwst)					
\
+	__firmware_stat_set(&fwst, FW_STATUS_LOADED)
+#define fw_loading_abort(fwst)					
\
+	__firmware_stat_set(&fwst, FW_STATUS_ABORT)
+#define fw_loading_wait(fwst)					
\
+	__firmware_stat_wait(&fwst, 0)
+#define fw_loading_wait_timeout(fwst, timeout)			
\
+	__firmware_stat_wait(&fwst, timeout)
+#define is_fw_loading(fwst)					\
+	(__firmware_stat_get(&fwst) == FW_STATUS_LOADING)
+#define is_fw_loading_done(fwst)				\
+	(__firmware_stat_get(&fwst) == FW_STATUS_LOADED)
+#define is_fw_loading_aborted(fwst)				\
+	(__firmware_stat_get(&fwst) == FW_STATUS_ABORT)
+
 #else
 static inline int request_firmware(const struct firmware **fw,
 				   const char *name,

@@ -75,5 +117,34 @@ static inline int request_firmware_direct(const

struct firmware **fw,
 	return -EINVAL;
 }
 
+static inline void firmware_stat_init(struct firmware_stat *fwst)
+{
+}
+
+static inline unsigned long __firmware_stat_get(struct firmware_stat
*fwst)
+{
+	return -EINVAL;
+}
+
+static inline void __firmware_stat_set(struct firmware_stat *fwst,
+				       unsigned long status)
+{
+}
+
+static inline int __firmware_stat_wait(struct firmware_stat *fwst,
+				       long timeout)
+{
+	return -EINVAL;
+}
+
+#define fw_loading_start(fwst)
+#define fw_loading_done(fwst)
+#define fw_loading_abort(fwst)
+#define fw_loading_wait(fwst)
+#define fw_loading_wait_timeout(fwst, timeout)
+#define is_fw_loading(fwst)		0
+#define is_fw_loading_done(fwst)	0
+#define is_fw_loading_aborted(fwst)	0
+
 #endif
 #endif