On 01/22/2017 04:58 AM, zhongjiang wrote:
From: zhong jiang <zhongjiang@xxxxxxxxxx>
Recently, I find the ioremap_page_range had been abusing. The improper
address mapping is a issue. it will result in the crash. so, remove
the symbol. It can be replaced by the ioremap_cache or others symbol.
Hi Zhong,
After thinking about this for a bit, and looking through our own (out-of-tree) kernel modules, I
think you have a good point. I just can't see any reason for a driver to call ioremap_page_range
directly. So the code change looks good to me.
For the commit description, here is a proposed re-wording, optional, that perhaps may be a little
clearer. See if you like it?
-------
Recently, I've found cases in which ioremap_page_range was used incorrectly, in external modules,
leading to crashes. This can be partly attributed to the fact that ioremap_page_range is
lower-level, with fewer protections, as compared to the other functions that an external module
would typically call. Those include:
ioremap_cache
ioremap_nocache
ioremap_prot
ioremap_uc
ioremap_wc
ioremap_wt
...each of which wraps __ioremap_caller, which in turn provides a safer way to achieve the mapping.
Therefore, stop EXPORT-ing ioremap_page_range.
-------
I may get some heat for this if another out-of-tree driver needs that symbol, but if no one else
pops up and shrieks, you can add:
Reviewed-by: John Hubbard <jhubbard@xxxxxxxxxx>
thanks,
john h
Signed-off-by: zhong jiang <zhongjiang@xxxxxxxxxx>
---
lib/ioremap.c | 1 -
1 file changed, 1 deletion(-)
diff --git a/lib/ioremap.c b/lib/ioremap.c
index 86c8911..a3e14ce 100644
--- a/lib/ioremap.c
+++ b/lib/ioremap.c
@@ -144,4 +144,3 @@ int ioremap_page_range(unsigned long addr,
return err;
}
-EXPORT_SYMBOL_GPL(ioremap_page_range);
--
1.8.3.1
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