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authorEugenia Emantayev <eugenia@mellanox.co.il>2012-03-18 04:32:08 +0000
committerDavid S. Miller <davem@davemloft.net>2012-03-19 18:02:05 -0400
commit58a3de0592454c216c68427fa3c31a34823f5115 (patch)
tree0db88951509d01bb815e3357aafd41ba9ef2ee0e
parent1c3ac4289a0e4d60cbd4787b4a91de4a0c785df1 (diff)
mlx4_core: fix race on comm channel
Prevent race condition between commands on comm channel. Happened while unloading the driver when switching from event to polling mode. VF got completion on the last command before switching to polling mode, but toggle was not changed. After the fix - VF will not write the next command before toggle is updated. Signed-off-by: Eugenia Emantayev <eugenia@mellanox.co.il> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--drivers/net/ethernet/mellanox/mlx4/cmd.c9
1 files changed, 9 insertions, 0 deletions
diff --git a/drivers/net/ethernet/mellanox/mlx4/cmd.c b/drivers/net/ethernet/mellanox/mlx4/cmd.c
index 48d5c48d7ce..773c70ea3f6 100644
--- a/drivers/net/ethernet/mellanox/mlx4/cmd.c
+++ b/drivers/net/ethernet/mellanox/mlx4/cmd.c
@@ -239,6 +239,7 @@ static int mlx4_comm_cmd_wait(struct mlx4_dev *dev, u8 op,
{
struct mlx4_cmd *cmd = &mlx4_priv(dev)->cmd;
struct mlx4_cmd_context *context;
+ unsigned long end;
int err = 0;
down(&cmd->event_sem);
@@ -268,6 +269,14 @@ static int mlx4_comm_cmd_wait(struct mlx4_dev *dev, u8 op,
}
out:
+ /* wait for comm channel ready
+ * this is necessary for prevention the race
+ * when switching between event to polling mode
+ */
+ end = msecs_to_jiffies(timeout) + jiffies;
+ while (comm_pending(dev) && time_before(jiffies, end))
+ cond_resched();
+
spin_lock(&cmd->context_lock);
context->next = cmd->free_head;
cmd->free_head = context - cmd->context;