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authorSean Hefty <sean.hefty@intel.com>2012-01-10 23:53:41 +0000
committerRoland Dreier <roland@purestorage.com>2012-01-27 10:07:48 -0800
commit9ced69ca5296567033804950d8d2161f454c5012 (patch)
tree6db2856c3ba7e3c018ac039c4c664be0179c1ff3 /drivers/infiniband
parentdcd6c92267155e70a94b3927bce681ce74b80d1f (diff)
downloadlinux-9ced69ca5296567033804950d8d2161f454c5012.tar.bz2
RDMA/ucma: Discard all events for new connections until accepted
After reporting a new connection request to user space, the rdma_ucm will discard subsequent events until the user has associated a user space idenfier with the kernel cm_id. This is needed to avoid reporting a reject/disconnect event to the user for a request that they may not have processed. The user space identifier is set once the user tries to accept the connection request. However, the following race exists in ucma_accept(): ctx->uid = cmd.uid; <events may be reported now> ret = rdma_accept(ctx->cm_id, ...); Once ctx->uid has been set, new events may be reported to the user. While the above mentioned race is avoided, there is an issue that the user _may_ receive a reject/disconnect event if rdma_accept() fails, depending on when the event is processed. To simplify the use of rdma_accept(), discard all events unless rdma_accept() succeeds. This problem was discovered based on questions from Roland Dreier <roland@purestorage.com>. Signed-off-by: Sean Hefty <sean.hefty@intel.com> Signed-off-by: Roland Dreier <roland@purestorage.com>
Diffstat (limited to 'drivers/infiniband')
-rw-r--r--drivers/infiniband/core/ucma.c5
1 files changed, 4 insertions, 1 deletions
diff --git a/drivers/infiniband/core/ucma.c b/drivers/infiniband/core/ucma.c
index b37b0c02a7b9..5034a87cc72d 100644
--- a/drivers/infiniband/core/ucma.c
+++ b/drivers/infiniband/core/ucma.c
@@ -808,9 +808,12 @@ static ssize_t ucma_accept(struct ucma_file *file, const char __user *inbuf,
return PTR_ERR(ctx);
if (cmd.conn_param.valid) {
- ctx->uid = cmd.uid;
ucma_copy_conn_param(&conn_param, &cmd.conn_param);
+ mutex_lock(&file->mut);
ret = rdma_accept(ctx->cm_id, &conn_param);
+ if (!ret)
+ ctx->uid = cmd.uid;
+ mutex_unlock(&file->mut);
} else
ret = rdma_accept(ctx->cm_id, NULL);