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-iso.c | 21 +++++++++++---------- 1 file changed, 11 insertions(+), 10 deletions(-) (limited to 'drivers/firewire/core-iso.c') diff --git a/drivers/firewire/core-iso.c b/drivers/firewire/core-iso.c index 481056df9268..f872ede5af37 100644 --- a/drivers/firewire/core-iso.c +++ b/drivers/firewire/core-iso.c @@ -196,9 +196,10 @@ EXPORT_SYMBOL(fw_iso_context_stop); */ static int manage_bandwidth(struct fw_card *card, int irm_id, int generation, - int bandwidth, bool allocate, __be32 data[2]) + int bandwidth, bool allocate) { int try, new, old = allocate ? BANDWIDTH_AVAILABLE_INITIAL : 0; + __be32 data[2]; /* * On a 1394a IRM with low contention, try < 1 is enough. @@ -233,9 +234,10 @@ static int manage_bandwidth(struct fw_card *card, int irm_id, int generation, } static int manage_channel(struct fw_card *card, int irm_id, int generation, - u32 channels_mask, u64 offset, bool allocate, __be32 data[2]) + u32 channels_mask, u64 offset, bool allocate) { __be32 bit, all, old; + __be32 data[2]; int channel, ret = -EIO, retry = 5; old = all = allocate ? cpu_to_be32(~0) : 0; @@ -284,7 +286,7 @@ static int manage_channel(struct fw_card *card, int irm_id, int generation, } static void deallocate_channel(struct fw_card *card, int irm_id, - int generation, int channel, __be32 buffer[2]) + int generation, int channel) { u32 mask; u64 offset; @@ -293,7 +295,7 @@ static void deallocate_channel(struct fw_card *card, int irm_id, 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, buffer); + manage_channel(card, irm_id, generation, mask, offset, false); } /** @@ -322,7 +324,7 @@ static void deallocate_channel(struct fw_card *card, int irm_id, */ void fw_iso_resource_manage(struct fw_card *card, int generation, u64 channels_mask, int *channel, int *bandwidth, - bool allocate, __be32 buffer[2]) + bool allocate) { u32 channels_hi = channels_mask; /* channels 31...0 */ u32 channels_lo = channels_mask >> 32; /* channels 63...32 */ @@ -335,11 +337,11 @@ void fw_iso_resource_manage(struct fw_card *card, int generation, if (channels_hi) c = manage_channel(card, irm_id, generation, channels_hi, CSR_REGISTER_BASE + CSR_CHANNELS_AVAILABLE_HI, - allocate, buffer); + allocate); if (channels_lo && c < 0) { c = manage_channel(card, irm_id, generation, channels_lo, CSR_REGISTER_BASE + CSR_CHANNELS_AVAILABLE_LO, - allocate, buffer); + allocate); if (c >= 0) c += 32; } @@ -351,14 +353,13 @@ void fw_iso_resource_manage(struct fw_card *card, int generation, if (*bandwidth == 0) return; - ret = manage_bandwidth(card, irm_id, generation, *bandwidth, - allocate, buffer); + ret = manage_bandwidth(card, irm_id, generation, *bandwidth, allocate); if (ret < 0) *bandwidth = 0; if (allocate && ret < 0) { if (c >= 0) - deallocate_channel(card, irm_id, generation, c, buffer); + deallocate_channel(card, irm_id, generation, c); *channel = ret; } } -- cgit v1.2.3