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authorDavid Gibson <dwg@au1.ibm.com>2006-10-21 10:24:13 -0700
committerLinus Torvalds <torvalds@g5.osdl.org>2006-10-21 13:35:06 -0700
commit047a66d4bb24aaf19f41d620f8f0534c2153cd0b (patch)
tree448062113a3fe5083354da6181310d76f1d52af6 /drivers/net/ibmveth.c
parentd42552c3ace1fa1f16ae02ce642f4c733cec40ca (diff)
[PATCH] ibmveth: Fix index increment calculation
The recent commit 751ae21c6cd1493e3d0a4935b08fb298b9d89773 introduced a bug in the producer/consumer index calculation in the ibmveth driver - incautious use of the post-increment ++ operator resulted in an increment being immediately reverted. This patch corrects the logic. Without this patch, the driver oopses almost immediately after activation on at least some machines. Signed-off-by: David Gibson <dwg@au1.ibm.com> Acked-by: Santiago Leon <santil@us.ibm.com> Cc: Jeff Garzik <jeff@garzik.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Andy Whitcroft <apw@shadowen.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'drivers/net/ibmveth.c')
-rw-r--r--drivers/net/ibmveth.c10
1 files changed, 6 insertions, 4 deletions
diff --git a/drivers/net/ibmveth.c b/drivers/net/ibmveth.c
index 2802db23d3c..44c9f993dcc 100644
--- a/drivers/net/ibmveth.c
+++ b/drivers/net/ibmveth.c
@@ -212,8 +212,8 @@ static void ibmveth_replenish_buffer_pool(struct ibmveth_adapter *adapter, struc
break;
}
- free_index = pool->consumer_index++ % pool->size;
- pool->consumer_index = free_index;
+ free_index = pool->consumer_index;
+ pool->consumer_index = (pool->consumer_index + 1) % pool->size;
index = pool->free_map[free_index];
ibmveth_assert(index != IBM_VETH_INVALID_MAP);
@@ -329,8 +329,10 @@ static void ibmveth_remove_buffer_from_pool(struct ibmveth_adapter *adapter, u64
adapter->rx_buff_pool[pool].buff_size,
DMA_FROM_DEVICE);
- free_index = adapter->rx_buff_pool[pool].producer_index++ % adapter->rx_buff_pool[pool].size;
- adapter->rx_buff_pool[pool].producer_index = free_index;
+ free_index = adapter->rx_buff_pool[pool].producer_index;
+ adapter->rx_buff_pool[pool].producer_index
+ = (adapter->rx_buff_pool[pool].producer_index + 1)
+ % adapter->rx_buff_pool[pool].size;
adapter->rx_buff_pool[pool].free_map[free_index] = index;
mb();