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firmware loader: fix one reqeust_firmware race

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Several loading requests may be pending on one same
firmware buf, and this patch moves fw_map_pages_buf()
before complete_all(&fw_buf->completion) and let all
requests see the mapped 'buf->data' once the loading
is completed.

Signed-off-by: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Ming Lei 2012-10-09 12:01:02 +08:00 committed by Greg Kroah-Hartman
parent 373304fe10
commit 253c9240ee
1 changed files with 20 additions and 12 deletions
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32
drivers/base/firmware_class.c
View file

@ -423,6 +423,18 @@ static void firmware_free_data(const struct firmware *fw)
#ifndef PAGE_KERNEL_RO
#define PAGE_KERNEL_RO PAGE_KERNEL
#endif
/* one pages buffer should be mapped/unmapped only once */
static int fw_map_pages_buf(struct firmware_buf *buf)
{
if (buf->data)
vunmap(buf->data);
buf->data = vmap(buf->pages, buf->nr_pages, 0, PAGE_KERNEL_RO);
if (!buf->data)
return -ENOMEM;
return 0;
}
/**
* firmware_loading_store - set value in the 'loading' control file
* @dev: device pointer
@ -467,6 +479,14 @@ 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);
/*
* Several loading requests may be pending on
* one same firmware buf, so let all requests
* see the mapped 'buf->data' once the loading
* is completed.
* */
fw_map_pages_buf(fw_buf);
complete_all(&fw_buf->completion);
break;
}
@ -670,15 +690,6 @@ exit:
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)
{
@ -884,9 +895,6 @@ static int _request_firmware_load(struct firmware_priv *fw_priv, bool uevent,
if (!retval && f_dev->parent)
fw_add_devm_name(f_dev->parent, buf->fw_id);
if (!retval)
retval = fw_map_pages_buf(buf);
/*
* After caching firmware image is started, let it piggyback
* on request firmware.