From f30e6d3e419bfb5540fa82ba7eca01d578556e6b Mon Sep 17 00:00:00 2001 From: Stefan Richter Date: Fri, 22 Apr 2011 15:13:54 +0200 Subject: [PATCH] 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 ++++++++-------- drivers/firewire/core-cdev.c | 4 +--- drivers/firewire/core-iso.c | 21 +++++++++++---------- drivers/firewire/core-transaction.c | 7 ++++--- drivers/media/dvb/firewire/firedtv-avc.c | 15 +-------------- include/linux/firewire.h | 3 +-- sound/firewire/cmp.c | 3 +-- sound/firewire/iso-resources.c | 12 +++--------- sound/firewire/iso-resources.h | 1 - 9 files changed, 30 insertions(+), 52 deletions(-) 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; } diff --git a/drivers/firewire/core-cdev.c b/drivers/firewire/core-cdev.c index 62ac111af243..2a3f1c4d6906 100644 --- a/drivers/firewire/core-cdev.c +++ b/drivers/firewire/core-cdev.c @@ -141,7 +141,6 @@ struct iso_resource { int generation; u64 channels; s32 bandwidth; - __be32 transaction_data[2]; struct iso_resource_event *e_alloc, *e_dealloc; }; @@ -1229,8 +1228,7 @@ static void iso_resource_work(struct work_struct *work) r->channels, &channel, &bandwidth, todo == ISO_RES_ALLOC || todo == ISO_RES_REALLOC || - todo == ISO_RES_ALLOC_ONCE, - r->transaction_data); + todo == ISO_RES_ALLOC_ONCE); /* * 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 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; } } diff --git a/drivers/firewire/core-transaction.c b/drivers/firewire/core-transaction.c index d00f8ce902cc..77275fdf6c1f 100644 --- a/drivers/firewire/core-transaction.c +++ b/drivers/firewire/core-transaction.c @@ -326,8 +326,8 @@ static int allocate_tlabel(struct fw_card *card) * It will contain tag, channel, and sy data instead of a node ID then. * * The payload buffer at @data is going to be DMA-mapped except in case of - * quadlet-sized payload or of local (loopback) requests. Hence make sure that - * the buffer complies with the restrictions for DMA-mapped memory. The + * @length <= 8 or of local (loopback) requests. Hence make sure that the + * buffer complies with the restrictions of the streaming DMA mapping API. * @payload must not be freed before the @callback is called. * * In case of request types without payload, @data is NULL and @length is 0. @@ -411,7 +411,8 @@ static void transaction_callback(struct fw_card *card, int rcode, * * Returns the RCODE. See fw_send_request() for parameter documentation. * Unlike fw_send_request(), @data points to the payload of the request or/and - * to the payload of the response. + * to the payload of the response. DMA mapping restrictions apply to outbound + * request payloads of >= 8 bytes but not to inbound response payloads. */ int fw_run_transaction(struct fw_card *card, int tcode, int destination_id, int generation, int speed, unsigned long long offset, diff --git a/drivers/media/dvb/firewire/firedtv-avc.c b/drivers/media/dvb/firewire/firedtv-avc.c index fc5ccd8c923a..21c52e3b522e 100644 --- a/drivers/media/dvb/firewire/firedtv-avc.c +++ b/drivers/media/dvb/firewire/firedtv-avc.c @@ -1320,14 +1320,10 @@ static int cmp_read(struct firedtv *fdtv, u64 addr, __be32 *data) { int ret; - mutex_lock(&fdtv->avc_mutex); - ret = fdtv_read(fdtv, addr, data); if (ret < 0) dev_err(fdtv->device, "CMP: read I/O error\n"); - mutex_unlock(&fdtv->avc_mutex); - return ret; } @@ -1335,18 +1331,9 @@ static int cmp_lock(struct firedtv *fdtv, u64 addr, __be32 data[]) { int ret; - mutex_lock(&fdtv->avc_mutex); - - /* data[] is stack-allocated and should not be DMA-mapped. */ - memcpy(fdtv->avc_data, data, 8); - - ret = fdtv_lock(fdtv, addr, fdtv->avc_data); + ret = fdtv_lock(fdtv, addr, data); if (ret < 0) dev_err(fdtv->device, "CMP: lock I/O error\n"); - else - memcpy(data, fdtv->avc_data, 8); - - mutex_unlock(&fdtv->avc_mutex); return ret; } diff --git a/include/linux/firewire.h b/include/linux/firewire.h index c64f3680d4f1..de90e1ff8488 100644 --- a/include/linux/firewire.h +++ b/include/linux/firewire.h @@ -125,7 +125,6 @@ struct fw_card { struct delayed_work bm_work; /* bus manager job */ int bm_retries; int bm_generation; - __be32 bm_transaction_data[2]; int bm_node_id; bool bm_abdicate; @@ -447,6 +446,6 @@ int fw_iso_context_stop(struct fw_iso_context *ctx); void fw_iso_context_destroy(struct fw_iso_context *ctx); 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); #endif /* _LINUX_FIREWIRE_H */ diff --git a/sound/firewire/cmp.c b/sound/firewire/cmp.c index 4a37f3a6fab9..14cacbc655dd 100644 --- a/sound/firewire/cmp.c +++ b/sound/firewire/cmp.c @@ -49,10 +49,9 @@ static int pcr_modify(struct cmp_connection *c, enum bus_reset_handling bus_reset_handling) { struct fw_device *device = fw_parent_device(c->resources.unit); - __be32 *buffer = c->resources.buffer; int generation = c->resources.generation; int rcode, errors = 0; - __be32 old_arg; + __be32 old_arg, buffer[2]; int err; buffer[0] = c->last_pcr_value; diff --git a/sound/firewire/iso-resources.c b/sound/firewire/iso-resources.c index 775dbd5f3445..bb9c0c1fb529 100644 --- a/sound/firewire/iso-resources.c +++ b/sound/firewire/iso-resources.c @@ -11,7 +11,6 @@ #include #include #include -#include #include #include "iso-resources.h" @@ -25,10 +24,6 @@ */ int fw_iso_resources_init(struct fw_iso_resources *r, struct fw_unit *unit) { - r->buffer = kmalloc(2 * 4, GFP_KERNEL); - if (!r->buffer) - return -ENOMEM; - r->channels_mask = ~0uLL; r->unit = fw_unit_get(unit); mutex_init(&r->mutex); @@ -44,7 +39,6 @@ int fw_iso_resources_init(struct fw_iso_resources *r, struct fw_unit *unit) void fw_iso_resources_destroy(struct fw_iso_resources *r) { WARN_ON(r->allocated); - kfree(r->buffer); mutex_destroy(&r->mutex); fw_unit_put(r->unit); } @@ -131,7 +125,7 @@ retry_after_bus_reset: bandwidth = r->bandwidth + r->bandwidth_overhead; fw_iso_resource_manage(card, r->generation, r->channels_mask, - &channel, &bandwidth, true, r->buffer); + &channel, &bandwidth, true); if (channel == -EAGAIN) { mutex_unlock(&r->mutex); goto retry_after_bus_reset; @@ -184,7 +178,7 @@ int fw_iso_resources_update(struct fw_iso_resources *r) bandwidth = r->bandwidth + r->bandwidth_overhead; fw_iso_resource_manage(card, r->generation, 1uLL << r->channel, - &channel, &bandwidth, true, r->buffer); + &channel, &bandwidth, true); /* * When another bus reset happens, pretend that the allocation * succeeded; we will try again for the new generation later. @@ -220,7 +214,7 @@ void fw_iso_resources_free(struct fw_iso_resources *r) if (r->allocated) { bandwidth = r->bandwidth + r->bandwidth_overhead; fw_iso_resource_manage(card, r->generation, 1uLL << r->channel, - &channel, &bandwidth, false, r->buffer); + &channel, &bandwidth, false); if (channel < 0) dev_err(&r->unit->device, "isochronous resource deallocation failed\n"); diff --git a/sound/firewire/iso-resources.h b/sound/firewire/iso-resources.h index 3f0730e4d841..5a9af7c61657 100644 --- a/sound/firewire/iso-resources.h +++ b/sound/firewire/iso-resources.h @@ -24,7 +24,6 @@ struct fw_iso_resources { unsigned int bandwidth_overhead; int generation; /* in which allocation is valid */ bool allocated; - __be32 *buffer; }; int fw_iso_resources_init(struct fw_iso_resources *r, -- 2.20.1