Commit 0c87b672 authored Jul 28, 2016 by Roland Dreier Committed by Doug Ledford Aug 03, 2016

IB/mlx4: Don't use GFP_ATOMIC for CQ resize struct



We allocate a small tracking structure as part of mlx4_ib_resize_cq().
However, we don't need to use GFP_ATOMIC -- immediately after the
allocation, we call mlx4_cq_resize(), which allocates a command
mailbox with GFP_KERNEL and then sleeps on a firmware command, so we
better not be in an atomic context.

This actually has a real impact, because when this GFP_ATOMIC
allocation fails (and GFP_ATOMIC does fail in practice) then a
userspace consumer resizing a CQ will get a spurious failure that we
can easily avoid.

Signed-off-by: Roland Dreier <roland@purestorage.com>
Reviewed-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

parent a154a8cd

drivers/infiniband/hw/mlx4/cq.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -288,7 +288,7 @@ static int mlx4_alloc_resize_buf(struct mlx4_ib_dev dev, struct mlx4_ib_cq cq,
		if (cq->resize_buf)
		return -EBUSY;

		cq->resize_buf = kmalloc(sizeof *cq->resize_buf, GFP_ATOMIC);
		cq->resize_buf = kmalloc(sizeof *cq->resize_buf, GFP_KERNEL);
		if (!cq->resize_buf)
		return -ENOMEM;

		@@ -316,7 +316,7 @@ static int mlx4_alloc_resize_umem(struct mlx4_ib_dev dev, struct mlx4_ib_cq cq
		if (ib_copy_from_udata(&ucmd, udata, sizeof ucmd))
		return -EFAULT;

		cq->resize_buf = kmalloc(sizeof *cq->resize_buf, GFP_ATOMIC);
		cq->resize_buf = kmalloc(sizeof *cq->resize_buf, GFP_KERNEL);
		if (!cq->resize_buf)
		return -ENOMEM;