swiotlb: add checks for the return value of memblock_alloc*()

Add panic() calls if memblock_alloc() returns NULL.

The panic() format duplicates the one used by memblock itself and in
order to avoid explosion with long parameters list replace open coded
allocation size calculations with a local variable.

Link: http://lkml.kernel.org/r/[e-mail]
Signed-off-by: Mike Rapoport <[e-mail]>
Cc: Catalin Marinas <[e-mail]>
Cc: Christophe Leroy <[e-mail]>
Cc: Christoph Hellwig <[e-mail]>
Cc: "David S. Miller" <[e-mail]>
Cc: Dennis Zhou <[e-mail]>
Cc: Geert Uytterhoeven <[e-mail]>
Cc: Greentime Hu <[e-mail]>
Cc: Greg Kroah-Hartman <[e-mail]>
Cc: Guan Xuetao <[e-mail]>
Cc: Guo Ren <[e-mail]>
Cc: Guo Ren <[e-mail]> [c-sky]
Cc: Heiko Carstens <[e-mail]>
Cc: Juergen Gross <[e-mail]> [Xen]
Cc: Mark Salter <[e-mail]>
Cc: Matt Turner <[e-mail]>
Cc: Max Filippov <[e-mail]>
Cc: Michael Ellerman <[e-mail]>
Cc: Michal Simek <[e-mail]>
Cc: Paul Burton <[e-mail]>
Cc: Petr Mladek <[e-mail]>
Cc: Richard Weinberger <[e-mail]>
Cc: Rich Felker <[e-mail]>
Cc: Rob Herring <[e-mail]>
Cc: Rob Herring <[e-mail]>
Cc: Russell King <[e-mail]>
Cc: Stafford Horne <[e-mail]>
Cc: Tony Luck <[e-mail]>
Cc: Vineet Gupta <[e-mail]>
Cc: Yoshinori Sato <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

kernel/dma/swiotlb.c

···
 int __init swiotlb_init_with_tbl(char *tlb, unsigned long nslabs, int verbose)
 {
 	unsigned long i, bytes;
+	size_t alloc_size;
 
 	bytes = nslabs << IO_TLB_SHIFT;
 
···
 	 * to find contiguous free memory regions of size up to IO_TLB_SEGSIZE
 	 * between io_tlb_start and io_tlb_end.
 	 */
-	io_tlb_list = memblock_alloc(
-				PAGE_ALIGN(io_tlb_nslabs * sizeof(int)),
-				PAGE_SIZE);
-	io_tlb_orig_addr = memblock_alloc(
-				PAGE_ALIGN(io_tlb_nslabs * sizeof(phys_addr_t)),
-				PAGE_SIZE);
+	alloc_size = PAGE_ALIGN(io_tlb_nslabs * sizeof(int));
+	io_tlb_list = memblock_alloc(alloc_size, PAGE_SIZE);
+	if (!io_tlb_list)
+		panic("%s: Failed to allocate %lu bytes align=0x%lx\n",
+		      __func__, alloc_size, PAGE_SIZE);
+
+	alloc_size = PAGE_ALIGN(io_tlb_nslabs * sizeof(phys_addr_t));
+	io_tlb_orig_addr = memblock_alloc(alloc_size, PAGE_SIZE);
+	if (!io_tlb_orig_addr)
+		panic("%s: Failed to allocate %lu bytes align=0x%lx\n",
+		      __func__, alloc_size, PAGE_SIZE);
+
 	for (i = 0; i < io_tlb_nslabs; i++) {
 		io_tlb_list[i] = IO_TLB_SEGSIZE - OFFSET(i, IO_TLB_SEGSIZE);
 		io_tlb_orig_addr[i] = INVALID_PHYS_ADDR;