From f30e6d3e419bfb5540fa82ba7eca01d578556e6b Mon Sep 17 00:00:00 2001 From: Stefan Richter Date: Fri, 22 Apr 2011 15:13:54 +0200 Subject: firewire: octlet AT payloads can be stack-allocated We do not need slab allocations anymore in order to satisfy streaming DMA mapping constraints, thanks to commit da28947e7e36 "firewire: ohci: avoid separate DMA mapping for small AT payloads". (Besides, the slab-allocated buffers that firewire-core, firewire-sbp2, and firedtv used to provide for 8-byte write and lock requests were still not fully portable since they crossed cacheline boundaries or shared a cacheline with unrelated CPU-accessed data. snd-firewire-lib got this aspect right by using an extra kmalloc/ kfree just for the 8-byte transaction buffer.) This change replaces kmalloc'ed lock transaction scratch buffers in firewire-core, firedtv, and snd-firewire-lib by local stack allocations. Perhaps the most notable result of the change is simpler locking because there is no need to serialize usages of preallocated per-device buffers anymore. Also, allocations and deallocations are simpler. Signed-off-by: Stefan Richter Acked-by: Clemens Ladisch --- drivers/firewire/core-card.c | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-) (limited to 'drivers/firewire/core-card.c') diff --git a/drivers/firewire/core-card.c b/drivers/firewire/core-card.c index 3c44fbc81acb..e119f1e6ba47 100644 --- a/drivers/firewire/core-card.c +++ b/drivers/firewire/core-card.c @@ -258,8 +258,7 @@ static void allocate_broadcast_channel(struct fw_card *card, int generation) if (!card->broadcast_channel_allocated) { fw_iso_resource_manage(card, generation, 1ULL << 31, - &channel, &bandwidth, true, - card->bm_transaction_data); + &channel, &bandwidth, true); if (channel != 31) { fw_notify("failed to allocate broadcast channel\n"); return; @@ -294,6 +293,7 @@ static void bm_work(struct work_struct *work) bool root_device_is_cmc; bool irm_is_1394_1995_only; bool keep_this_irm; + __be32 transaction_data[2]; spin_lock_irq(&card->lock); @@ -355,21 +355,21 @@ static void bm_work(struct work_struct *work) goto pick_me; } - card->bm_transaction_data[0] = cpu_to_be32(0x3f); - card->bm_transaction_data[1] = cpu_to_be32(local_id); + transaction_data[0] = cpu_to_be32(0x3f); + transaction_data[1] = cpu_to_be32(local_id); spin_unlock_irq(&card->lock); rcode = fw_run_transaction(card, TCODE_LOCK_COMPARE_SWAP, irm_id, generation, SCODE_100, CSR_REGISTER_BASE + CSR_BUS_MANAGER_ID, - card->bm_transaction_data, 8); + transaction_data, 8); if (rcode == RCODE_GENERATION) /* Another bus reset, BM work has been rescheduled. */ goto out; - bm_id = be32_to_cpu(card->bm_transaction_data[0]); + bm_id = be32_to_cpu(transaction_data[0]); spin_lock_irq(&card->lock); if (rcode == RCODE_COMPLETE && generation == card->generation) @@ -490,11 +490,11 @@ static void bm_work(struct work_struct *work) /* * Make sure that the cycle master sends cycle start packets. */ - card->bm_transaction_data[0] = cpu_to_be32(CSR_STATE_BIT_CMSTR); + transaction_data[0] = cpu_to_be32(CSR_STATE_BIT_CMSTR); rcode = fw_run_transaction(card, TCODE_WRITE_QUADLET_REQUEST, root_id, generation, SCODE_100, CSR_REGISTER_BASE + CSR_STATE_SET, - card->bm_transaction_data, 4); + transaction_data, 4); if (rcode == RCODE_GENERATION) goto out; } -- cgit