diff options
| author | Dakshaja Uppalapati <dakshaja@chelsio.com> | 2021-08-05 18:13:32 +0530 |
|---|---|---|
| committer | Jason Gunthorpe <jgg@nvidia.com> | 2021-08-05 22:33:00 -0300 |
| commit | 2638a32348bbb1c384dbbd515fd2b12c155f0188 (patch) | |
| tree | 9fb7afbc32e8c6172a2cac36a79c88e51b5aefb1 /drivers/infiniband/hw/cxgb4/cq.c | |
| parent | 8b436a99cd708bd158231a0630ffa49b1d6175e4 (diff) | |
RDMA/iw_cxgb4: Fix refcount underflow while destroying cqs.
Previous atomic increment/decrement logic expects the atomic count to be
'0' after the final decrement.
Replacing atomic count with refcount does not allow that, as
refcount_dec() considers count of 1 as underflow and triggers a kernel
splat.
Fix the current refcount logic by using the usual pattern of decrementing
the refcount and test if it is '0' on the final deref in
c4iw_destroy_cq(). Use wait_for_completion() instead of wait_event().
Fixes: 7183451f846d ("RDMA/cxgb4: Use refcount_t instead of atomic_t for reference counting")
Link: https://lore.kernel.org/r/1628167412-12114-1-git-send-email-dakshaja@chelsio.com
Signed-off-by: Dakshaja Uppalapati <dakshaja@chelsio.com>
Reviewed-by: Potnuri Bharat Teja <bharat@chelsio.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Diffstat (limited to 'drivers/infiniband/hw/cxgb4/cq.c')
| -rw-r--r-- | drivers/infiniband/hw/cxgb4/cq.c | 12 |
1 files changed, 9 insertions, 3 deletions
diff --git a/drivers/infiniband/hw/cxgb4/cq.c b/drivers/infiniband/hw/cxgb4/cq.c index 6c8c910f4e86..c7e8d7b3baa1 100644 --- a/drivers/infiniband/hw/cxgb4/cq.c +++ b/drivers/infiniband/hw/cxgb4/cq.c @@ -967,6 +967,12 @@ int c4iw_poll_cq(struct ib_cq *ibcq, int num_entries, struct ib_wc *wc) return !err || err == -ENODATA ? npolled : err; } +void c4iw_cq_rem_ref(struct c4iw_cq *chp) +{ + if (refcount_dec_and_test(&chp->refcnt)) + complete(&chp->cq_rel_comp); +} + int c4iw_destroy_cq(struct ib_cq *ib_cq, struct ib_udata *udata) { struct c4iw_cq *chp; @@ -976,8 +982,8 @@ int c4iw_destroy_cq(struct ib_cq *ib_cq, struct ib_udata *udata) chp = to_c4iw_cq(ib_cq); xa_erase_irq(&chp->rhp->cqs, chp->cq.cqid); - refcount_dec(&chp->refcnt); - wait_event(chp->wait, !refcount_read(&chp->refcnt)); + c4iw_cq_rem_ref(chp); + wait_for_completion(&chp->cq_rel_comp); ucontext = rdma_udata_to_drv_context(udata, struct c4iw_ucontext, ibucontext); @@ -1081,7 +1087,7 @@ int c4iw_create_cq(struct ib_cq *ibcq, const struct ib_cq_init_attr *attr, spin_lock_init(&chp->lock); spin_lock_init(&chp->comp_handler_lock); refcount_set(&chp->refcnt, 1); - init_waitqueue_head(&chp->wait); + init_completion(&chp->cq_rel_comp); ret = xa_insert_irq(&rhp->cqs, chp->cq.cqid, chp, GFP_KERNEL); if (ret) goto err_destroy_cq; |