firewire: core: do not DMA-map stack addresses

The DMA mapping API cannot map on-stack addresses, as explained in
Documentation/DMA-mapping.txt. Convert the two cases of on-stack packet
payload buffers in firewire-core (payload of lock requests in the bus
manager work and in iso resource management) to slab-allocated memory.

There are a number on-stack buffers for quadlet write or quadlet read
requests in firewire-core and firewire-sbp2. These are harmless; they
are copied to/ from card driver internal DMA buffers since quadlet
payloads are inlined with packet headers.

Signed-off-by: Stefan Richter <[e-mail]>

drivers/firewire/core-card.c

···
 {
 	int channel, bandwidth = 0;
 
-	fw_iso_resource_manage(card, generation, 1ULL << 31,
-			       &channel, &bandwidth, true);
+	fw_iso_resource_manage(card, generation, 1ULL << 31, &channel,
+			       &bandwidth, true, card->bm_transaction_data);
 	if (channel == 31) {
 		card->broadcast_channel_allocated = true;
 		device_for_each_child(card->device, (void *)(long)generation,
···
 	bool do_reset = false;
 	bool root_device_is_running;
 	bool root_device_is_cmc;
-	__be32 lock_data[2];
 
 	spin_lock_irqsave(&card->lock, flags);
 
···
 			goto pick_me;
 		}
 
-		lock_data[0] = cpu_to_be32(0x3f);
-		lock_data[1] = cpu_to_be32(local_id);
+		card->bm_transaction_data[0] = cpu_to_be32(0x3f);
+		card->bm_transaction_data[1] = cpu_to_be32(local_id);
 
 		spin_unlock_irqrestore(&card->lock, flags);
 
 		rcode = fw_run_transaction(card, TCODE_LOCK_COMPARE_SWAP,
 				irm_id, generation, SCODE_100,
 				CSR_REGISTER_BASE + CSR_BUS_MANAGER_ID,
-				lock_data, sizeof(lock_data));
+				card->bm_transaction_data,
+				sizeof(card->bm_transaction_data));
 
 		if (rcode == RCODE_GENERATION)
 			/* Another bus reset, BM work has been rescheduled. */
 			goto out;
 
 		if (rcode == RCODE_COMPLETE &&
-		    lock_data[0] != cpu_to_be32(0x3f)) {
+		    card->bm_transaction_data[0] != cpu_to_be32(0x3f)) {
 
 			/* Somebody else is BM.  Only act as IRM. */
 			if (local_id == irm_id)

drivers/firewire/core-cdev.c

···
 	int generation;
 	u64 channels;
 	s32 bandwidth;
+	__be32 transaction_data[2];
 	struct iso_resource_event *e_alloc, *e_dealloc;
 };
 
···
 			r->channels, &channel, &bandwidth,
 			todo == ISO_RES_ALLOC ||
 			todo == ISO_RES_REALLOC ||
-			todo == ISO_RES_ALLOC_ONCE);
+			todo == ISO_RES_ALLOC_ONCE,
+			r->transaction_data);
 	/*
 	 * Is this generation outdated already?  As long as this resource sticks
 	 * in the idr, it will be scheduled again for a newer generation or at

drivers/firewire/core-iso.c

···
  */
 
 static int manage_bandwidth(struct fw_card *card, int irm_id, int generation,
-			    int bandwidth, bool allocate)
+			    int bandwidth, bool allocate, __be32 data[2])
 {
-	__be32 data[2];
 	int try, new, old = allocate ? BANDWIDTH_AVAILABLE_INITIAL : 0;
 
 	/*
···
 }
 
 static int manage_channel(struct fw_card *card, int irm_id, int generation,
-			  u32 channels_mask, u64 offset, bool allocate)
+		u32 channels_mask, u64 offset, bool allocate, __be32 data[2])
 {
-	__be32 data[2], c, all, old;
+	__be32 c, all, old;
 	int i, retry = 5;
 
 	old = all = allocate ? cpu_to_be32(~0) : 0;
···
 }
 
 static void deallocate_channel(struct fw_card *card, int irm_id,
-			       int generation, int channel)
+			       int generation, int channel, __be32 buffer[2])
 {
 	u32 mask;
 	u64 offset;
···
 	offset = channel < 32 ? CSR_REGISTER_BASE + CSR_CHANNELS_AVAILABLE_HI :
 				CSR_REGISTER_BASE + CSR_CHANNELS_AVAILABLE_LO;
 
-	manage_channel(card, irm_id, generation, mask, offset, false);
+	manage_channel(card, irm_id, generation, mask, offset, false, buffer);
 }
 
 /**
···
  */
 void fw_iso_resource_manage(struct fw_card *card, int generation,
 			    u64 channels_mask, int *channel, int *bandwidth,
-			    bool allocate)
+			    bool allocate, __be32 buffer[2])
 {
 	u32 channels_hi = channels_mask;	/* channels 31...0 */
 	u32 channels_lo = channels_mask >> 32;	/* channels 63...32 */
···
 
 	if (channels_hi)
 		c = manage_channel(card, irm_id, generation, channels_hi,
-		    CSR_REGISTER_BASE + CSR_CHANNELS_AVAILABLE_HI, allocate);
+				CSR_REGISTER_BASE + CSR_CHANNELS_AVAILABLE_HI,
+				allocate, buffer);
 	if (channels_lo && c < 0) {
 		c = manage_channel(card, irm_id, generation, channels_lo,
-		    CSR_REGISTER_BASE + CSR_CHANNELS_AVAILABLE_LO, allocate);
+				CSR_REGISTER_BASE + CSR_CHANNELS_AVAILABLE_LO,
+				allocate, buffer);
 		if (c >= 0)
 			c += 32;
 	}
···
 	if (*bandwidth == 0)
 		return;
 
-	ret = manage_bandwidth(card, irm_id, generation, *bandwidth, allocate);
+	ret = manage_bandwidth(card, irm_id, generation, *bandwidth,
+			       allocate, buffer);
 	if (ret < 0)
 		*bandwidth = 0;
 
 	if (allocate && ret < 0 && c >= 0) {
-		deallocate_channel(card, irm_id, generation, c);
+		deallocate_channel(card, irm_id, generation, c, buffer);
 		*channel = ret;
 	}
 }

drivers/firewire/core.h

···
 
 int fw_iso_buffer_map(struct fw_iso_buffer *buffer, struct vm_area_struct *vma);
 void fw_iso_resource_manage(struct fw_card *card, int generation,
-		u64 channels_mask, int *channel, int *bandwidth, bool allocate);
+			    u64 channels_mask, int *channel, int *bandwidth,
+			    bool allocate, __be32 buffer[2]);
 
 
 /* -topology */

include/linux/firewire.h

···
 	struct delayed_work work;
 	int bm_retries;
 	int bm_generation;
+	__be32 bm_transaction_data[2];
 
 	bool broadcast_channel_allocated;
 	u32 broadcast_channel;