Techwizz/kernel-fxtec-pro1x
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity

firewire: octlet AT payloads can be stack-allocated

Browse source 
We do not need slab allocations anymore in order to satisfy
streaming DMA mapping constraints, thanks to commit da28947e7e
"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 <stefanr@s5r6.in-berlin.de>
Acked-by: Clemens Ladisch <clemens@ladisch.de>
This commit is contained in:
Stefan Richter 2011-04-22 15:13:54 +02:00
parent 020abf03cd
commit f30e6d3e41
9 changed files with 30 additions and 52 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

16
drivers/firewire/core-card.c
View file

@ -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;
}

4
drivers/firewire/core-cdev.c
View file

@ -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

21
drivers/firewire/core-iso.c
View file

@ -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;
}
}

7
drivers/firewire/core-transaction.c
View file

@ -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,

15
drivers/media/dvb/firewire/firedtv-avc.c
View file

@ -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;
}

3
include/linux/firewire.h
View file

@ -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 */

3
sound/firewire/cmp.c
View file

@ -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;

12
sound/firewire/iso-resources.c
View file

@ -11,7 +11,6 @@
#include <linux/jiffies.h>
#include <linux/mutex.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#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 @@ int fw_iso_resources_allocate(struct fw_iso_resources *r,
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");

1
sound/firewire/iso-resources.h
View file

@ -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,