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authorOlaf Kirch <okir@lst.de>2008-04-29 13:46:53 -0700
committerRoland Dreier <rolandd@cisco.com>2008-04-29 13:46:53 -0700
commitbbdc2821db041fb07ffa52e4a0e1ebb5410790e9 (patch)
tree1a0757409c89c6236d9c0ffa1eb0f5a63faa2527 /drivers/net/mlx4
parentd227fa7288adebe5ba37fa8e4a589c977d4e4a34 (diff)
downloadlinux-linaro-android-bbdc2821db041fb07ffa52e4a0e1ebb5410790e9.tar.gz
mlx4_core: Avoid recycling old FMR R_Keys too soon
When a FMR is unmapped, mlx4 resets the map count to 0, and clears the upper part of the R_Key which is used as the sequence counter. This poses a problem for RDS, which uses ib_fmr_unmap as a fence operation. RDS assumes that after issuing an unmap, the old R_Keys will be invalid for a "reasonable" period of time. For instance, Oracle processes uses shared memory buffers allocated from a pool of buffers. When a process dies, we want to reclaim these buffers -- but we must make sure there are no pending RDMA operations to/from those buffers. The only way to achieve that is by using unmap and sync the TPT. However, when the sequence count is reset on unmap, there is a high likelihood that a new mapping will be given the same R_Key that was issued a few milliseconds ago. To prevent this, don't reset the sequence count when unmapping a FMR. Signed-off-by: Olaf Kirch <olaf.kirch@oracle.com> Signed-off-by: Roland Dreier <rolandd@cisco.com>
Diffstat (limited to 'drivers/net/mlx4')
-rw-r--r--drivers/net/mlx4/mr.c6
1 files changed, 0 insertions, 6 deletions
diff --git a/drivers/net/mlx4/mr.c b/drivers/net/mlx4/mr.c
index 79b317b88c8..cb46446b269 100644
--- a/drivers/net/mlx4/mr.c
+++ b/drivers/net/mlx4/mr.c
@@ -607,15 +607,9 @@ EXPORT_SYMBOL_GPL(mlx4_fmr_enable);
void mlx4_fmr_unmap(struct mlx4_dev *dev, struct mlx4_fmr *fmr,
u32 *lkey, u32 *rkey)
{
- u32 key;
-
if (!fmr->maps)
return;
- key = key_to_hw_index(fmr->mr.key);
- key &= dev->caps.num_mpts - 1;
- *lkey = *rkey = fmr->mr.key = hw_index_to_key(key);
-
fmr->maps = 0;
*(u8 *) fmr->mpt = MLX4_MPT_STATUS_SW;