mirror of
https://mirrors.bfsu.edu.cn/git/linux.git
synced 2024-11-26 13:44:15 +08:00
f30e6d3e41
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>
39 lines
1.2 KiB
C
39 lines
1.2 KiB
C
#ifndef SOUND_FIREWIRE_ISO_RESOURCES_H_INCLUDED
|
|
#define SOUND_FIREWIRE_ISO_RESOURCES_H_INCLUDED
|
|
|
|
#include <linux/mutex.h>
|
|
#include <linux/types.h>
|
|
|
|
struct fw_unit;
|
|
|
|
/**
|
|
* struct fw_iso_resources - manages channel/bandwidth allocation
|
|
* @channels_mask: if the device does not support all channel numbers, set this
|
|
* bit mask to something else than the default (all ones)
|
|
*
|
|
* This structure manages (de)allocation of isochronous resources (channel and
|
|
* bandwidth) for one isochronous stream.
|
|
*/
|
|
struct fw_iso_resources {
|
|
u64 channels_mask;
|
|
/* private: */
|
|
struct fw_unit *unit;
|
|
struct mutex mutex;
|
|
unsigned int channel;
|
|
unsigned int bandwidth; /* in bandwidth units, without overhead */
|
|
unsigned int bandwidth_overhead;
|
|
int generation; /* in which allocation is valid */
|
|
bool allocated;
|
|
};
|
|
|
|
int fw_iso_resources_init(struct fw_iso_resources *r,
|
|
struct fw_unit *unit);
|
|
void fw_iso_resources_destroy(struct fw_iso_resources *r);
|
|
|
|
int fw_iso_resources_allocate(struct fw_iso_resources *r,
|
|
unsigned int max_payload_bytes, int speed);
|
|
int fw_iso_resources_update(struct fw_iso_resources *r);
|
|
void fw_iso_resources_free(struct fw_iso_resources *r);
|
|
|
|
#endif
|