ioremap: Delay sanity check until after a successful mapping (c7a7b814) · Commits · 戴 / test

While tracking down the reason for an ioremap() failure I was distracted by the WARN_ONCE() in __ioremap_caller(). Performing a WARN_ONCE() sanity check before the mapping is successful seems pointless if the caller sends bad values. A case in point is when the BIOS provides erroneous screen_info values causing vesafb_probe() to request an outrageuous size. The WARN_ONCE is then wasted on bogosity. Move the warning to a point where the mapping has been successfully allocated. Addresses: http://bugs.launchpad.net/bugs/772042 Reviewed-by:

Suresh Siddha <suresh.b.siddha@intel.com> Signed-off-by:

Tim Gardner <tim.gardner@canonical.com> Link: http://lkml.kernel.org/r/4DB99D2E.9080106@canonical.com Signed-off-by:

Ingo Molnar <mingo@elte.hu>

arch/x86/mm/ioremap.c

+7 −7

Original line number	Diff line number	Diff line
		@@ -90,13 +90,6 @@ static void __iomem *__ioremap_caller(resource_size_t phys_addr,
		if (is_ISA_range(phys_addr, last_addr))
		return (__force void __iomem *)phys_to_virt(phys_addr);

		/*
		* Check if the request spans more than any BAR in the iomem resource
		* tree.
		*/
		WARN_ONCE(iomem_map_sanity_check(phys_addr, size),
		KERN_INFO "Info: mapping multiple BARs. Your kernel is fine.");

		/*
		* Don't allow anybody to remap normal RAM that we're using..
		*/
		@@ -170,6 +163,13 @@ static void __iomem *__ioremap_caller(resource_size_t phys_addr,
		ret_addr = (void __iomem *) (vaddr + offset);
		mmiotrace_ioremap(unaligned_phys_addr, unaligned_size, ret_addr);

		/*
		* Check if the request spans more than any BAR in the iomem resource
		* tree.
		*/
		WARN_ONCE(iomem_map_sanity_check(unaligned_phys_addr, unaligned_size),
		KERN_INFO "Info: mapping multiple BARs. Your kernel is fine.");

		return ret_addr;
		err_free_area:
		free_vm_area(area);

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