crypto: caam - fix uninitialized edesc->dst_dma field

dst_dma not being properly initialized causes ahash_done_ctx_dst
to try to free unallocated DMA memory:

caam_jr ffe301000.jr: DMA-API: device driver tries to free DMA memory it has not allocated [device address=0x0000000006513340] [size=28 bytes]
WARNING: at lib/dma-debug.c:1080
Modules linked in: caamhash(+) [last unloaded: caamhash]
CPU: 0 PID: 1373 Comm: cryptomgr_test Tainted: G        W     3.16.0-rc1 #23
task: ee23e350 ti: effd2000 task.ti: ee1f6000
NIP: c02889fc LR: c02889fc CTR: c02d7020
REGS: effd3d50 TRAP: 0700   Tainted: G        W      (3.16.0-rc1)
MSR: 00029002 <CE,EE,ME>  CR: 44048082  XER: 00000000

GPR00: c02889fc effd3e00 ee23e350 0000008e c1de3478 c1de382c 00000000 00029002
GPR08: 00000007 00000000 01660000 00000000 24048082 00000000 00000018 c07db080
GPR16: 00000006 00000100 0000002c eeb4a7e0 c07e1e10 c0da1180 00029002 c0d9b3c8
GPR24: eeb4a7c0 00000000 effd3e58 00000000 c078ad4c ee130210 00000000 06513340
NIP [c02889fc] check_unmap+0x8ac/0xab0
LR [c02889fc] check_unmap+0x8ac/0xab0
Call Trace:
[effd3e00] [c02889fc] check_unmap+0x8ac/0xab0 (unreliable)
[effd3e50] [c0288c78] debug_dma_unmap_page+0x78/0x90
[effd3ed0] [f94b89ec] ahash_done_ctx_dst+0x11c/0x200 [caamhash]
[effd3f00] [c0429640] caam_jr_dequeue+0x1c0/0x280
[effd3f50] [c002c94c] tasklet_action+0xcc/0x1a0
[effd3f80] [c002cb30] __do_softirq+0x110/0x220
[effd3fe0] [c002cf34] irq_exit+0xa4/0xe0
[effd3ff0] [c000d834] call_do_irq+0x24/0x3c
[ee1f7ae0] [c000489c] do_IRQ+0x8c/0x110
[ee1f7b00] [c000f86c] ret_from_except+0x0/0x18
--- Exception: 501 at _raw_spin_unlock_irq+0x30/0x50
    LR = _raw_spin_unlock_irq+0x2c/0x50
[ee1f7bd0] [c0590158] wait_for_common+0xb8/0x170
[ee1f7c10] [c059024c] wait_for_completion_interruptible+0x1c/0x40
[ee1f7c20] [c022fc78] do_one_async_hash_op.isra.2.part.3+0x18/0x40
[ee1f7c30] [c022ffb8] __test_hash+0x318/0x6c0
[ee1f7de0] [c0230388] test_hash+0x28/0xb0
[ee1f7e00] [c02304a4] alg_test_hash+0x94/0xc0
[ee1f7e20] [c022fa94] alg_test+0x114/0x2e0
[ee1f7ea0] [c022cd1c] cryptomgr_test+0x4c/0x60
[ee1f7eb0] [c00497a4] kthread+0xc4/0xe0
[ee1f7f40] [c000f2fc] ret_from_kernel_thread+0x5c/0x64
Instruction dump:
41de01c8 80a9002c 2f850000 40fe0008 80a90008 80fa0018 3c60c06d 811a001c
3863f4a4 813a0020 815a0024 4830cd01 <0fe00000> 81340048 2f890000 40feff48
Signed-off-by: Horia Geanta <horia.geanta@freescale.com>
Acked-by: Kim Phillips <kim.phillips@freescale.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

drivers/crypto/caam/caamhash.c

@@ -1255,6 +1255,7 @@ static int ahash_update_no_ctx(struct ahash_request *req)
 		edesc->sec4_sg_bytes = sec4_sg_bytes;
 		edesc->sec4_sg = (void *)edesc + sizeof(struct ahash_edesc) +
 				 DESC_JOB_IO_LEN;
+		edesc->dst_dma = 0;
 
 		state->buf_dma = buf_map_to_sec4_sg(jrdev, edesc->sec4_sg,
 						    buf, *buflen);
@@ -1454,6 +1455,7 @@ static int ahash_update_first(struct ahash_request *req)
 		edesc->sec4_sg_bytes = sec4_sg_bytes;
 		edesc->sec4_sg = (void *)edesc + sizeof(struct ahash_edesc) +
 				 DESC_JOB_IO_LEN;
+		edesc->dst_dma = 0;
 
 		if (src_nents) {
 			sg_to_sec4_sg_last(req->src, src_nents,