> drivers/infiniband/core/ucma.c | 3 +--
> 1 files changed, 1 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/infiniband/core/ucma.c b/drivers/infiniband/core/ucma.c
> index 8002ae6..6cc40de 100644
> --- a/drivers/infiniband/core/ucma.c
> +++ b/drivers/infiniband/core/ucma.c
> @@ -803,9 +803,8 @@ static ssize_t ucma_accept(struct ucma_file *file, const
> char __user *inbuf,
> if (cmd.conn_param.valid) {
> ucma_copy_conn_param(&conn_param, &cmd.conn_param);
> mutex_lock(&file->mut);
> + ctx->uid = cmd.uid;
> ret = rdma_accept(ctx->cm_id, &conn_param);
> - if (!ret)
> - ctx->uid = cmd.uid;
This is actually trying to revert a previous commit:
commit 9ced69ca5296567033804950d8d2161f454c5012
Author: Sean Hefty <sean.he...@intel.com>
Date: Tue Jan 10 23:53:41 2012 +0000
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
<rol...@purestorage.com>.
Signed-off-by: Sean Hefty <sean.he...@intel.com>
Signed-off-by: Roland Dreier <rol...@purestorage.com>
The file->mut should protect against an event being reported to user space with
the uid set to 0.
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