From: Dean Luick dean.luick@cornelisnetworks.com
[ Upstream commit ecf91551cdd2925ed6d9a9d99074fa5f67b90596 ]
To avoid a race, reserve the number of user expected TIDs before setup.
Fixes: 7e7a436ecb6e ("staging/hfi1: Add TID entry program function body") Signed-off-by: Dean Luick dean.luick@cornelisnetworks.com Signed-off-by: Dennis Dalessandro dennis.dalessandro@cornelisnetworks.com Link: https://lore.kernel.org/r/167328547636.1472310.7419712824785353905.stgit@awf... Signed-off-by: Leon Romanovsky leon@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/infiniband/hw/hfi1/user_exp_rcv.c | 14 ++++++-------- 1 file changed, 6 insertions(+), 8 deletions(-)
diff --git a/drivers/infiniband/hw/hfi1/user_exp_rcv.c b/drivers/infiniband/hw/hfi1/user_exp_rcv.c index 056ffab86a06..b17c1fc59f7e 100644 --- a/drivers/infiniband/hw/hfi1/user_exp_rcv.c +++ b/drivers/infiniband/hw/hfi1/user_exp_rcv.c @@ -349,16 +349,13 @@ int hfi1_user_exp_rcv_setup(struct hfi1_filedata *fd, /* Find sets of physically contiguous pages */ tidbuf->n_psets = find_phys_blocks(tidbuf, pinned);
- /* - * We don't need to access this under a lock since tid_used is per - * process and the same process cannot be in hfi1_user_exp_rcv_clear() - * and hfi1_user_exp_rcv_setup() at the same time. - */ + /* Reserve the number of expected tids to be used. */ spin_lock(&fd->tid_lock); if (fd->tid_used + tidbuf->n_psets > fd->tid_limit) pageset_count = fd->tid_limit - fd->tid_used; else pageset_count = tidbuf->n_psets; + fd->tid_used += pageset_count; spin_unlock(&fd->tid_lock);
if (!pageset_count) @@ -468,10 +465,11 @@ int hfi1_user_exp_rcv_setup(struct hfi1_filedata *fd, nomem: hfi1_cdbg(TID, "total mapped: tidpairs:%u pages:%u (%d)", tididx, mapped_pages, ret); + /* adjust reserved tid_used to actual count */ + spin_lock(&fd->tid_lock); + fd->tid_used -= pageset_count - tididx; + spin_unlock(&fd->tid_lock); if (tididx) { - spin_lock(&fd->tid_lock); - fd->tid_used += tididx; - spin_unlock(&fd->tid_lock); tinfo->tidcnt = tididx; tinfo->length = mapped_pages * PAGE_SIZE;