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firewire: ohci: handle receive packets with a data length of zero 

Queueing to receive an ISO packet with a payload length of zero
silently does nothing in dualbuffer mode, and crashes the kernel in
packet-per-buffer mode.  Return an error in dualbuffer mode, because
the DMA controller won't let us do what we want, and work correctly in
packet-per-buffer mode.

Signed-off-by: Jay Fenlason <fenlason@redhat.com>
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Cc: stable@kernel.org
This commit is contained in:
Jay Fenlason 2009-12-11 14:23:58 -05:00 committed by Stefan Richter
parent af0940dac3
commit 8c0c0cc2d9
1 changed files with 10 additions and 2 deletions
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12
drivers/firewire/ohci.c
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@ -2189,6 +2189,13 @@ static int ohci_queue_iso_receive_dualbuffer(struct fw_iso_context *base,
page = payload >> PAGE_SHIFT;
offset = payload & ~PAGE_MASK;
rest = p->payload_length;
/*
* The controllers I've tested have not worked correctly when
* second_req_count is zero. Rather than do something we know won't
* work, return an error
*/
if (rest == 0)
return -EINVAL;
/* FIXME: make packet-per-buffer/dual-buffer a context option */
while (rest > 0) {
@ -2242,7 +2249,7 @@ static int ohci_queue_iso_receive_packet_per_buffer(struct fw_iso_context *base,
unsigned long payload)
{
struct iso_context *ctx = container_of(base, struct iso_context, base);
struct descriptor *d = NULL, *pd = NULL;
struct descriptor *d, *pd;
struct fw_iso_packet *p = packet;
dma_addr_t d_bus, page_bus;
u32 z, header_z, rest;
@ -2280,8 +2287,9 @@ static int ohci_queue_iso_receive_packet_per_buffer(struct fw_iso_context *base,
d->data_address = cpu_to_le32(d_bus + (z * sizeof(*d)));
rest = payload_per_buffer;
pd = d;
for (j = 1; j < z; j++) {
pd = d + j;
pd++;
pd->control = cpu_to_le16(DESCRIPTOR_STATUS |
DESCRIPTOR_INPUT_MORE);