lkml.org 
[lkml]   [2012]   [Jul]   [24]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[RFC PATCH 01/13] driver core: firmware loader: simplify pages ownership transfer
Date
This patch doesn't transfer ownership of pages' buffer to the
instance of firmware until the firmware loading is completed,
which will simplify firmware_loading_store a lot, so help
to introduce the following cache_firmware and uncache_firmware
mechanism during system suspend-resume cycle.

In fact, this patch fixes one bug: if writing data into
firmware loader device is bypassed between writting 1 and 0 to
'loading', OOPS will be triggered without the patch.

Also add some comments to make code more readable.

Signed-off-by: Ming Lei <ming.lei@canonical.com>
---
drivers/base/firmware_class.c | 57 ++++++++++++++++++++++++-----------------
1 file changed, 34 insertions(+), 23 deletions(-)

diff --git a/drivers/base/firmware_class.c b/drivers/base/firmware_class.c
index 803cfc1..f789bbd 100644
--- a/drivers/base/firmware_class.c
+++ b/drivers/base/firmware_class.c
@@ -93,6 +93,8 @@ struct firmware_priv {
struct completion completion;
struct firmware *fw;
unsigned long status;
+ void *data;
+ size_t size;
struct page **pages;
int nr_pages;
int page_array_size;
@@ -156,9 +158,11 @@ static void fw_dev_release(struct device *dev)
struct firmware_priv *fw_priv = to_firmware_priv(dev);
int i;

+ /* free untransfered pages buffer */
for (i = 0; i < fw_priv->nr_pages; i++)
__free_page(fw_priv->pages[i]);
kfree(fw_priv->pages);
+
kfree(fw_priv);

module_put(THIS_MODULE);
@@ -194,6 +198,7 @@ static ssize_t firmware_loading_show(struct device *dev,
return sprintf(buf, "%d\n", loading);
}

+/* firmware holds the ownership of pages */
static void firmware_free_data(const struct firmware *fw)
{
int i;
@@ -237,9 +242,7 @@ static ssize_t firmware_loading_store(struct device *dev,

switch (loading) {
case 1:
- firmware_free_data(fw_priv->fw);
- memset(fw_priv->fw, 0, sizeof(struct firmware));
- /* If the pages are not owned by 'struct firmware' */
+ /* discarding any previous partial load */
for (i = 0; i < fw_priv->nr_pages; i++)
__free_page(fw_priv->pages[i]);
kfree(fw_priv->pages);
@@ -250,20 +253,6 @@ static ssize_t firmware_loading_store(struct device *dev,
break;
case 0:
if (test_bit(FW_STATUS_LOADING, &fw_priv->status)) {
- vunmap(fw_priv->fw->data);
- fw_priv->fw->data = vmap(fw_priv->pages,
- fw_priv->nr_pages,
- 0, PAGE_KERNEL_RO);
- if (!fw_priv->fw->data) {
- dev_err(dev, "%s: vmap() failed\n", __func__);
- goto err;
- }
- /* Pages are now owned by 'struct firmware' */
- fw_priv->fw->pages = fw_priv->pages;
- fw_priv->pages = NULL;
-
- fw_priv->page_array_size = 0;
- fw_priv->nr_pages = 0;
complete(&fw_priv->completion);
clear_bit(FW_STATUS_LOADING, &fw_priv->status);
break;
@@ -273,7 +262,6 @@ static ssize_t firmware_loading_store(struct device *dev,
dev_err(dev, "%s: unexpected value (%d)\n", __func__, loading);
/* fallthrough */
case -1:
- err:
fw_load_abort(fw_priv);
break;
}
@@ -299,12 +287,12 @@ static ssize_t firmware_data_read(struct file *filp, struct kobject *kobj,
ret_count = -ENODEV;
goto out;
}
- if (offset > fw->size) {
+ if (offset > fw_priv->size) {
ret_count = 0;
goto out;
}
- if (count > fw->size - offset)
- count = fw->size - offset;
+ if (count > fw_priv->size - offset)
+ count = fw_priv->size - offset;

ret_count = count;

@@ -396,6 +384,7 @@ static ssize_t firmware_data_write(struct file *filp, struct kobject *kobj,
retval = -ENODEV;
goto out;
}
+
retval = fw_realloc_buffer(fw_priv, offset + count);
if (retval)
goto out;
@@ -418,7 +407,7 @@ static ssize_t firmware_data_write(struct file *filp, struct kobject *kobj,
count -= page_cnt;
}

- fw->size = max_t(size_t, offset, fw->size);
+ fw_priv->size = max_t(size_t, offset, fw_priv->size);
out:
mutex_unlock(&fw_lock);
return retval;
@@ -504,6 +493,24 @@ static void _request_firmware_cleanup(const struct firmware **firmware_p)
*firmware_p = NULL;
}

+/* transfer the ownership of pages to firmware */
+static void fw_set_page_data(struct firmware_priv *fw_priv)
+{
+ struct firmware *fw = fw_priv->fw;
+
+ fw_priv->data = vmap(fw_priv->pages, fw_priv->nr_pages,
+ 0, PAGE_KERNEL_RO);
+ fw->data = fw_priv->data;
+ fw->pages = fw_priv->pages;
+ fw->size = fw_priv->size;
+
+ WARN_ON(PFN_UP(fw->size) != fw_priv->nr_pages);
+
+ fw_priv->nr_pages = 0;
+ fw_priv->pages = NULL;
+ fw_priv->data = NULL;
+}
+
static int _request_firmware_load(struct firmware_priv *fw_priv, bool uevent,
long timeout)
{
@@ -549,8 +556,12 @@ static int _request_firmware_load(struct firmware_priv *fw_priv, bool uevent,
del_timer_sync(&fw_priv->timeout);

mutex_lock(&fw_lock);
- if (!fw_priv->fw->size || test_bit(FW_STATUS_ABORT, &fw_priv->status))
+ if (!fw_priv->size || test_bit(FW_STATUS_ABORT, &fw_priv->status))
retval = -ENOENT;
+
+ /* transfer pages ownership at the last minute */
+ if (!retval)
+ fw_set_page_data(fw_priv);
fw_priv->fw = NULL;
mutex_unlock(&fw_lock);

--
1.7.9.5


\
 
 \ /
  Last update: 2012-07-24 19:41    [W:0.113 / U:7.220 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site