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Commit 1f2b7959 authored by Ming Lei's avatar Ming Lei Committed by Greg Kroah-Hartman
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firmware loader: always let firmware_buf own the pages buffer 



This patch always let firmware_buf own the pages buffer allocated
inside firmware_data_write, and add all instances of firmware_buf
into the firmware cache global list. Also introduce one private field
in 'struct firmware', so release_firmware will see the instance of
firmware_buf associated with the current firmware instance, then just
'free' the instance of firmware_buf.

The firmware_buf instance represents one pages buffer for one
firmware image, so lots of firmware loading requests can share
the same firmware_buf instance if they request the same firmware
image file.

This patch will make implementation of the following cache_firmware/
uncache_firmware very easy and simple.

In fact, the patch improves request_formware/release_firmware:

        - only request userspace to write firmware image once if
	several devices share one same firmware image and its drivers
	call request_firmware concurrently.

Signed-off-by: default avatarMing Lei <ming.lei@canonical.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 1244691c

drivers/base/firmware_class.c

+171 −69
Original line number Diff line number Diff line
@@ -21,6 +21,7 @@ 
#include <linux/firmware.h>

#include <linux/slab.h>

#include <linux/sched.h>

#include <linux/list.h>



MODULE_AUTHOR("Manuel Estrada Sainz");

MODULE_DESCRIPTION("Multi purpose firmware loading support");
@@ -85,13 +86,17 @@ static inline long firmware_loading_timeout(void) 
	return loading_timeout > 0 ? loading_timeout * HZ : MAX_SCHEDULE_TIMEOUT;

}



/* fw_lock could be moved to 'struct firmware_priv' but since it is just

 * guarding for corner cases a global lock should be OK */

static DEFINE_MUTEX(fw_lock);

struct firmware_cache {

	/* firmware_buf instance will be added into the below list */

	spinlock_t lock;

	struct list_head head;

};



struct firmware_buf {

	struct kref ref;

	struct list_head list;

	struct completion completion;

	struct firmware *fw;

	struct firmware_cache *fwc;

	unsigned long status;

	void *data;

	size_t size;
@@ -106,8 +111,94 @@ struct firmware_priv { 
	bool nowait;

	struct device dev;

	struct firmware_buf *buf;

	struct firmware *fw;

};



#define to_fwbuf(d) container_of(d, struct firmware_buf, ref)



/* fw_lock could be moved to 'struct firmware_priv' but since it is just

 * guarding for corner cases a global lock should be OK */

static DEFINE_MUTEX(fw_lock);



static struct firmware_cache fw_cache;



static struct firmware_buf *__allocate_fw_buf(const char *fw_name,

					      struct firmware_cache *fwc)

{

	struct firmware_buf *buf;



	buf = kzalloc(sizeof(*buf) + strlen(fw_name) + 1 , GFP_ATOMIC);



	if (!buf)

		return buf;



	kref_init(&buf->ref);

	strcpy(buf->fw_id, fw_name);

	buf->fwc = fwc;

	init_completion(&buf->completion);



	pr_debug("%s: fw-%s buf=%p\n", __func__, fw_name, buf);



	return buf;

}



static int fw_lookup_and_allocate_buf(const char *fw_name,

				      struct firmware_cache *fwc,

				      struct firmware_buf **buf)

{

	struct firmware_buf *tmp;



	spin_lock(&fwc->lock);

	list_for_each_entry(tmp, &fwc->head, list)

		if (!strcmp(tmp->fw_id, fw_name)) {

			kref_get(&tmp->ref);

			spin_unlock(&fwc->lock);

			*buf = tmp;

			return 1;

		}



	tmp = __allocate_fw_buf(fw_name, fwc);

	if (tmp)

		list_add(&tmp->list, &fwc->head);

	spin_unlock(&fwc->lock);



	*buf = tmp;



	return tmp ? 0 : -ENOMEM;

}



static void __fw_free_buf(struct kref *ref)

{

	struct firmware_buf *buf = to_fwbuf(ref);

	struct firmware_cache *fwc = buf->fwc;

	int i;



	pr_debug("%s: fw-%s buf=%p data=%p size=%u\n",

		 __func__, buf->fw_id, buf, buf->data,

		 (unsigned int)buf->size);



	spin_lock(&fwc->lock);

	list_del(&buf->list);

	spin_unlock(&fwc->lock);



	vunmap(buf->data);

	for (i = 0; i < buf->nr_pages; i++)

		__free_page(buf->pages[i]);

	kfree(buf->pages);

	kfree(buf);

}



static void fw_free_buf(struct firmware_buf *buf)

{

	kref_put(&buf->ref, __fw_free_buf);

}



static void __init fw_cache_init(void)

{

	spin_lock_init(&fw_cache.lock);

	INIT_LIST_HEAD(&fw_cache.head);

}



static struct firmware_priv *to_firmware_priv(struct device *dev)

{

	return container_of(dev, struct firmware_priv, dev);
@@ -118,7 +209,7 @@ static void fw_load_abort(struct firmware_priv *fw_priv) 
	struct firmware_buf *buf = fw_priv->buf;



	set_bit(FW_STATUS_ABORT, &buf->status);

	complete(&buf->completion);

	complete_all(&buf->completion);

}



static ssize_t firmware_timeout_show(struct class *class,
@@ -158,18 +249,6 @@ static struct class_attribute firmware_class_attrs[] = { 
	__ATTR_NULL

};



static void fw_free_buf(struct firmware_buf *buf)

{

	int i;



	if (!buf)

		return;



	for (i = 0; i < buf->nr_pages; i++)

		__free_page(buf->pages[i]);

	kfree(buf->pages);

}



static void fw_dev_release(struct device *dev)

{

	struct firmware_priv *fw_priv = to_firmware_priv(dev);
@@ -212,13 +291,8 @@ static ssize_t firmware_loading_show(struct device *dev, 
/* firmware holds the ownership of pages */

static void firmware_free_data(const struct firmware *fw)

{

	int i;

	vunmap(fw->data);

	if (fw->pages) {

		for (i = 0; i < PFN_UP(fw->size); i++)

			__free_page(fw->pages[i]);

		kfree(fw->pages);

	}

	WARN_ON(!fw->priv);

	fw_free_buf(fw->priv);

}



/* Some architectures don't have PAGE_KERNEL_RO */
@@ -269,7 +343,7 @@ static ssize_t firmware_loading_store(struct device *dev, 
		if (test_bit(FW_STATUS_LOADING, &fw_buf->status)) {

			set_bit(FW_STATUS_DONE, &fw_buf->status);

			clear_bit(FW_STATUS_LOADING, &fw_buf->status);

			complete(&fw_buf->completion);

			complete_all(&fw_buf->completion);

			break;

		}

		/* fallthrough */
@@ -448,7 +522,6 @@ fw_create_instance(struct firmware *firmware, const char *fw_name, 
		   struct device *device, bool uevent, bool nowait)

{

	struct firmware_priv *fw_priv;

	struct firmware_buf *buf;

	struct device *f_dev;



	fw_priv = kzalloc(sizeof(*fw_priv), GFP_KERNEL);
@@ -458,21 +531,10 @@ fw_create_instance(struct firmware *firmware, const char *fw_name, 
		goto exit;

	}



	buf = kzalloc(sizeof(*buf) + strlen(fw_name) + 1, GFP_KERNEL);

	if (!buf) {

		dev_err(device, "%s: kmalloc failed\n", __func__);

		kfree(fw_priv);

		fw_priv = ERR_PTR(-ENOMEM);

		goto exit;

	}



	buf->fw = firmware;

	fw_priv->buf = buf;

	fw_priv->nowait = nowait;

	fw_priv->fw = firmware;

	setup_timer(&fw_priv->timeout,

		    firmware_class_timeout, (u_long) fw_priv);

	strcpy(buf->fw_id, fw_name);

	init_completion(&buf->completion);



	f_dev = &fw_priv->dev;
@@ -484,12 +546,42 @@ fw_create_instance(struct firmware *firmware, const char *fw_name, 
	return fw_priv;

}



/* one pages buffer is mapped/unmapped only once */

static int fw_map_pages_buf(struct firmware_buf *buf)

{

	buf->data = vmap(buf->pages, buf->nr_pages, 0, PAGE_KERNEL_RO);

	if (!buf->data)

		return -ENOMEM;

	return 0;

}



/* store the pages buffer info firmware from buf */

static void fw_set_page_data(struct firmware_buf *buf, struct firmware *fw)

{

	fw->priv = buf;

	fw->pages = buf->pages;

	fw->size = buf->size;

	fw->data = buf->data;



	pr_debug("%s: fw-%s buf=%p data=%p size=%u\n",

		 __func__, buf->fw_id, buf, buf->data,

		 (unsigned int)buf->size);

}



static void _request_firmware_cleanup(const 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)

{

	struct firmware *firmware;

	struct firmware_priv *fw_priv;

	struct firmware_priv *fw_priv = NULL;

	struct firmware_buf *buf;

	int ret;



	if (!firmware_p)

		return ERR_PTR(-EINVAL);
@@ -506,35 +598,45 @@ _request_firmware_prepare(const struct firmware **firmware_p, const char *name, 
		return NULL;

	}



	fw_priv = fw_create_instance(firmware, name, device, uevent, nowait);

	if (IS_ERR(fw_priv)) {

		release_firmware(firmware);

	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;

		return fw_priv;

	}



static void _request_firmware_cleanup(const struct firmware **firmware_p)

{

	release_firmware(*firmware_p);

	*firmware_p = NULL;

	/* 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);

		_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;

	}

	mutex_unlock(&fw_lock);

	wait_for_completion(&buf->completion);

	goto check_status;



/* transfer the ownership of pages to firmware */

static int fw_set_page_data(struct firmware_buf *buf)

{

	struct firmware *fw = buf->fw;



	buf->data = vmap(buf->pages, buf->nr_pages, 0, PAGE_KERNEL_RO);

	if (!buf->data)

		return -ENOMEM;



	fw->data = buf->data;

	fw->pages = buf->pages;

	fw->size = buf->size;

	WARN_ON(PFN_UP(fw->size) != buf->nr_pages);



	return 0;

exit:

	mutex_unlock(&fw_lock);

	return fw_priv;

}



static int _request_firmware_load(struct firmware_priv *fw_priv, bool uevent,
@@ -585,13 +687,12 @@ static int _request_firmware_load(struct firmware_priv *fw_priv, bool uevent, 
	if (!buf->size || test_bit(FW_STATUS_ABORT, &buf->status))

		retval = -ENOENT;



	/* transfer pages ownership at the last minute */

	if (!retval)

		retval = fw_set_page_data(buf);

	if (retval)

		fw_free_buf(buf); /* free untransfered pages buffer */

		retval = fw_map_pages_buf(buf);



	/* pass the pages buffer to driver at the last minute */

	fw_set_page_data(buf, fw_priv->fw);



	kfree(buf);

	fw_priv->buf = NULL;

	mutex_unlock(&fw_lock);
@@ -753,6 +854,7 @@ request_firmware_nowait( 


static int __init firmware_class_init(void)

{

	fw_cache_init();

	return class_register(&firmware_class);

}

include/linux/firmware.h

+3 −0
Original line number Diff line number Diff line
@@ -12,6 +12,9 @@ struct firmware { 
	size_t size;

	const u8 *data;

	struct page **pages;



	/* firmware loader private fields */

	void *priv;

};



struct module;