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author | Stefan Richter <stefanr@s5r6.in-berlin.de> | 2011-04-22 15:13:54 +0200 |
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committer | Stefan Richter <stefanr@s5r6.in-berlin.de> | 2011-05-10 22:53:44 +0200 |
commit | f30e6d3e419bfb5540fa82ba7eca01d578556e6b (patch) | |
tree | e4d6e7bad161a76b09557bf7513358ae1ce8f7fb /sound/firewire/cmp.c | |
parent | 020abf03cd659388f94cb328e1e1df0656e0d7ff (diff) | |
download | lwn-f30e6d3e419bfb5540fa82ba7eca01d578556e6b.tar.gz lwn-f30e6d3e419bfb5540fa82ba7eca01d578556e6b.zip |
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 <stefanr@s5r6.in-berlin.de>
Acked-by: Clemens Ladisch <clemens@ladisch.de>
Diffstat (limited to 'sound/firewire/cmp.c')
-rw-r--r-- | sound/firewire/cmp.c | 3 |
1 files changed, 1 insertions, 2 deletions
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; |