[intel-tdx:guest 129/144] kernel/dma/swiotlb.c:389:15-33: WARNING: casting value returned by memory allocation function to (struct io_tlb_area *) is useless.

[intel-tdx:guest 129/144] kernel/dma/swiotlb.c:389:15-33: WARNING: casting value returned by memory allocation function to (struct io_tlb_area *) is useless.

[kernel test robot]

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tree:   https://github.com/intel/tdx.git guest
head:   41fe88a1b3c28543f49fa6ed9e0e9b6650ed7614
commit: 4529b5784c141782c72ec9bd9a92df2b68cb7d45 [129/144] swiotlb: Split up single swiotlb lock
config: x86_64-randconfig-c002-20211118 (attached as .config)
compiler: gcc-9 (Debian 9.3.0-22) 9.3.0

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>


cocci warnings: (new ones prefixed by >>)
>> kernel/dma/swiotlb.c:389:15-33: WARNING: casting value returned by memory allocation function to (struct io_tlb_area *) is useless.

Please review and possibly fold the followup patch.

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org

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[PATCH] swiotlb: fix alloc_cast.cocci warnings

[kernel test robot]

From: kernel test robot <lkp@intel.com>

kernel/dma/swiotlb.c:389:15-33: WARNING: casting value returned by memory allocation function to (struct io_tlb_area *) is useless.

 Remove casting the values returned by memory allocation functions
 like kmalloc, kzalloc, kmem_cache_alloc, kmem_cache_zalloc etc.

Semantic patch information:
 This makes an effort to find cases of casting of values returned by
 kmalloc, kzalloc, kcalloc, kmem_cache_alloc, kmem_cache_zalloc,
 kmem_cache_alloc_node, kmalloc_node and kzalloc_node and removes
 the casting as it is not required. The result in the patch case may
 need some reformatting.

Generated by: scripts/coccinelle/api/alloc/alloc_cast.cocci

Fixes: 4529b5784c14 ("swiotlb: Split up single swiotlb lock")
CC: Andi Kleen <ak@linux.intel.com>
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: kernel test robot <lkp@intel.com>
---

tree:   https://github.com/intel/tdx.git guest
head:   41fe88a1b3c28543f49fa6ed9e0e9b6650ed7614
commit: 4529b5784c141782c72ec9bd9a92df2b68cb7d45 [129/144] swiotlb: Split up single swiotlb lock
:::::: branch date: 9 days ago
:::::: commit date: 9 days ago

 swiotlb.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/kernel/dma/swiotlb.c
+++ b/kernel/dma/swiotlb.c
@@ -386,7 +386,7 @@ swiotlb_late_init_with_tbl(char *tlb, un
 		return -ENOMEM;
 	}
 
-	mem->areas = (struct io_tlb_area *)kcalloc(num_areas,
+	mem->areas = kcalloc(num_areas,
 						   sizeof(struct io_tlb_area),
 						   GFP_KERNEL);
 	if (!mem->areas) {