Re: [PATCH 6.2 073/211] swiotlb: mark swiotlb_memblock_alloc() as __init

[Randy Dunlap <rdunlap@infradead.org>]

Hi,

On 3/14/23 01:54, Alexey Kardashevskiy wrote:
> 
> 
> On 11/3/23 00:37, Greg Kroah-Hartman wrote:
>> From: Randy Dunlap <rdunlap@infradead.org>
>>
>> [ Upstream commit 9b07d27d0fbb7f7441aa986859a0f53ec93a0335 ]
>>
>> swiotlb_memblock_alloc() calls memblock_alloc(), which calls
>> (__init) memblock_alloc_try_nid(). However, swiotlb_membloc_alloc()
>> can be marked as __init since it is only called by swiotlb_init_remap(),
>> which is already marked as __init. This prevents a modpost build
>> warning/error:
>>
>> WARNING: modpost: vmlinux.o: section mismatch in reference: swiotlb_memblock_alloc (section: .text) -> memblock_alloc_try_nid (section: .init.text)
>> WARNING: modpost: vmlinux.o: section mismatch in reference: swiotlb_memblock_alloc (section: .text) -> memblock_alloc_try_nid (section: .init.text)
>>
>> This fixes the build warning/error seen on ARM64, PPC64, S390, i386,
>> and x86_64.
> 
> Did you do something special in your config to get these warnings? Or it is your toolchain? I tested with whatever comes with Ubuntu2210 and Fedora36 and neither printed the warning and I want to see those :-/ Thanks,
> 

I have no idea how I got these build warnings.  I am using gcc-12.2.0.
I don't know what .config file settings that I used.

I just tried about 6 different ARCH builds without this patch applied and I
cannot recreate the build warnings/errors.

Sorry I couldn't help you with this.

> 
>>
>> Fixes: 8d58aa484920 ("swiotlb: reduce the swiotlb buffer size on allocation failure")
>> Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
>> Cc: Alexey Kardashevskiy <aik@amd.com>
>> Cc: Christoph Hellwig <hch@lst.de>
>> Cc: iommu@lists.linux.dev
>> Cc: Mike Rapoport <rppt@kernel.org>
>> Cc: linux-mm@kvack.org
>> Signed-off-by: Christoph Hellwig <hch@lst.de>
>> Signed-off-by: Sasha Levin <sashal@kernel.org>
>> ---
>>   kernel/dma/swiotlb.c | 3 ++-
>>   1 file changed, 2 insertions(+), 1 deletion(-)
>>
>> diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
>> index a34c38bbe28f1..ef3bc3a5bbed3 100644
>> --- a/kernel/dma/swiotlb.c
>> +++ b/kernel/dma/swiotlb.c
>> @@ -300,7 +300,8 @@ static void swiotlb_init_io_tlb_mem(struct io_tlb_mem *mem, phys_addr_t start,
>>       return;
>>   }
>>   -static void *swiotlb_memblock_alloc(unsigned long nslabs, unsigned int flags,
>> +static void __init *swiotlb_memblock_alloc(unsigned long nslabs,
>> +        unsigned int flags,
>>           int (*remap)(void *tlb, unsigned long nslabs))
>>   {
>>       size_t bytes = PAGE_ALIGN(nslabs << IO_TLB_SHIFT);
> 

-- 
~Randy