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firmware loader: always let firmware_buf own the pages buffer
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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: Ming Lei <ming.lei@canonical.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Ming Lei authored and Greg Kroah-Hartman committed Aug 16, 2012
1 parent 1244691 commit 1f2b795
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Showing 2 changed files with 174 additions and 69 deletions.
240 changes: 171 additions & 69 deletions drivers/base/firmware_class.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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");
Expand Down Expand Up @@ -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;
Expand All @@ -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);
Expand All @@ -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,
Expand Down Expand Up @@ -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);
Expand Down Expand Up @@ -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 */
Expand Down Expand Up @@ -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 */
Expand Down Expand Up @@ -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);
Expand All @@ -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;

Expand All @@ -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);
Expand All @@ -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;
}
return fw_priv;
}

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

/* 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);
/* 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;

return 0;
exit:
mutex_unlock(&fw_lock);
return fw_priv;
}

static int _request_firmware_load(struct firmware_priv *fw_priv, bool uevent,
Expand Down Expand Up @@ -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);

Expand Down Expand Up @@ -753,6 +854,7 @@ request_firmware_nowait(

static int __init firmware_class_init(void)
{
fw_cache_init();
return class_register(&firmware_class);
}

Expand Down
3 changes: 3 additions & 0 deletions include/linux/firmware.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -12,6 +12,9 @@ struct firmware {
size_t size;
const u8 *data;
struct page **pages;

/* firmware loader private fields */
void *priv;
};

struct module;
Expand Down

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