Gitweb: http://git.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=76d7cc0345a037e8eea426f8abc710abd22946dd Commit: 76d7cc0345a037e8eea426f8abc710abd22946dd Parent: dcb3f974da827c964cb8d419fbb4350cdc08a559 Author: Roland Dreier <[EMAIL PROTECTED]> AuthorDate: Tue Oct 9 19:59:17 2007 -0700 Committer: Roland Dreier <[EMAIL PROTECTED]> CommitDate: Tue Oct 9 19:59:17 2007 -0700
IB/mthca: Use mmiowb() to avoid firmware commands getting jumbled up Firmware commands are sent to the HCA by writing multiple words to a command register block. Access to this block of registers is serialized with a mutex. However, on large SGI systems, problems were seen with multiple CPUs issuing FW commands at the same time, because the writes to the register block may be reordered within the system interconnect and reach the HCA in a different order than they were issued (even with the mutex). Fix this by adding an mmiowb() before dropping the mutex. Tested-by: Arthur Kepner <[EMAIL PROTECTED]> Signed-off-by: Roland Dreier <[EMAIL PROTECTED]> --- drivers/infiniband/hw/mthca/mthca_cmd.c | 6 ++++++ 1 files changed, 6 insertions(+), 0 deletions(-) diff --git a/drivers/infiniband/hw/mthca/mthca_cmd.c b/drivers/infiniband/hw/mthca/mthca_cmd.c index acc9589..6966f94 100644 --- a/drivers/infiniband/hw/mthca/mthca_cmd.c +++ b/drivers/infiniband/hw/mthca/mthca_cmd.c @@ -290,6 +290,12 @@ static int mthca_cmd_post(struct mthca_dev *dev, err = mthca_cmd_post_hcr(dev, in_param, out_param, in_modifier, op_modifier, op, token, event); + /* + * Make sure that our HCR writes don't get mixed in with + * writes from another CPU starting a FW command. + */ + mmiowb(); + mutex_unlock(&dev->cmd.hcr_mutex); return err; } - To unsubscribe from this list: send the line "unsubscribe git-commits-head" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html