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| author | Stefan Richter <stefanr@s5r6.in-berlin.de> | 2010-07-27 13:20:33 +0200 |
|---|---|---|
| committer | Stefan Richter <stefanr@s5r6.in-berlin.de> | 2010-07-29 23:06:25 +0200 |
| commit | 071595ebdc66d70219e2d1ce746016f64b2b19e7 (patch) | |
| tree | 3083b0de17a6d0633420ffda1dfa04a0b4b880b2 | |
| parent | 8e2b2b46ea4ca5ef790dddf78b360ed736a62d7c (diff) | |
firewire: ohci: use memory barriers to order descriptor updates
When we append to a DMA program, we need to ensure that the order in
which initialization of the new descriptors and update of the
branch_address of the old tail descriptor, as seen by the PCI device,
happen as intended.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
| -rw-r--r-- | drivers/firewire/ohci.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/drivers/firewire/ohci.c b/drivers/firewire/ohci.c index 5f6bb2c5380..3f59d1df650 100644 --- a/drivers/firewire/ohci.c +++ b/drivers/firewire/ohci.c @@ -595,6 +595,7 @@ static int ar_context_add_page(struct ar_context *ctx) ab->descriptor.res_count = cpu_to_le16(PAGE_SIZE - offset); ab->descriptor.branch_address = 0; + wmb(); /* finish init of new descriptors before branch_address update */ ctx->last_buffer->descriptor.branch_address = cpu_to_le32(ab_bus | 1); ctx->last_buffer->next = ab; ctx->last_buffer = ab; @@ -982,6 +983,8 @@ static void context_append(struct context *ctx, d_bus = desc->buffer_bus + (d - desc->buffer) * sizeof(*d); desc->used += (z + extra) * sizeof(*d); + + wmb(); /* finish init of new descriptors before branch_address update */ ctx->prev->branch_address = cpu_to_le32(d_bus | z); ctx->prev = find_branch_descriptor(d, z); |