From: Dean Luick <dean.luick@xxxxxxxxxxxxxxxxxxxx>
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@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro@xxxxxxxxxxxxxxxxxxxx>
---
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 3c609b11e71c..d7487555d109 100644
--- a/drivers/infiniband/hw/hfi1/user_exp_rcv.c
+++ b/drivers/infiniband/hw/hfi1/user_exp_rcv.c
@@ -282,16 +282,13 @@ 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)
@@ -400,10 +397,11 @@ 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;
