mlx4_en: don't try to split and vmap dma coherent allocations

From: Christoph Hellwig
Date: Tue Apr 19 2016 - 14:12:14 EST

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The memory returned by dma_alloc_coherent is not suitable for calling
virt_to_page on it, as it might for example come from vmap allocator.

Remove the code that calls virt_to_page and vmap on dma coherent
allocations from the mlx4 drivers, and replace them with a single
high-order dma_alloc_coherent call.

Signed-off-by: Christoph Hellwig <hch@xxxxxx>
Reported-by: Sinan Kaya <okaya@xxxxxxxxxxxxxx>
---
drivers/net/ethernet/mellanox/mlx4/alloc.c | 89 ++++-------------------
drivers/net/ethernet/mellanox/mlx4/en_cq.c | 7 --
drivers/net/ethernet/mellanox/mlx4/en_resources.c | 31 --------
drivers/net/ethernet/mellanox/mlx4/en_rx.c | 8 --
drivers/net/ethernet/mellanox/mlx4/en_tx.c | 9 ---
drivers/net/ethernet/mellanox/mlx4/mlx4_en.h | 2 -
drivers/net/ethernet/mellanox/mlx4/mr.c | 5 +-
include/linux/mlx4/device.h | 8 +-
8 files changed, 16 insertions(+), 143 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlx4/alloc.c b/drivers/net/ethernet/mellanox/mlx4/alloc.c
index 0c51c69..8d15b35 100644
--- a/drivers/net/ethernet/mellanox/mlx4/alloc.c
+++ b/drivers/net/ethernet/mellanox/mlx4/alloc.c
@@ -588,91 +588,30 @@ int mlx4_buf_alloc(struct mlx4_dev *dev, int size, int max_direct,
{
dma_addr_t t;

- if (size <= max_direct) {
- buf->nbufs = 1;
- buf->npages = 1;
- buf->page_shift = get_order(size) + PAGE_SHIFT;
- buf->direct.buf = dma_alloc_coherent(&dev->persist->pdev->dev,
- size, &t, gfp);
- if (!buf->direct.buf)
- return -ENOMEM;
-
- buf->direct.map = t;
-
- while (t & ((1 << buf->page_shift) - 1)) {
- --buf->page_shift;
- buf->npages *= 2;
- }
+ buf->npages = 1;
+ buf->page_shift = get_order(size) + PAGE_SHIFT;
+ buf->direct.buf = dma_alloc_coherent(&dev->persist->pdev->dev,
+ size, &t, gfp);
+ if (!buf->direct.buf)
+ return -ENOMEM;

- memset(buf->direct.buf, 0, size);
- } else {
- int i;
-
- buf->direct.buf = NULL;
- buf->nbufs = (size + PAGE_SIZE - 1) / PAGE_SIZE;
- buf->npages = buf->nbufs;
- buf->page_shift = PAGE_SHIFT;
- buf->page_list = kcalloc(buf->nbufs, sizeof(*buf->page_list),
- gfp);
- if (!buf->page_list)
- return -ENOMEM;
-
- for (i = 0; i < buf->nbufs; ++i) {
- buf->page_list[i].buf =
- dma_alloc_coherent(&dev->persist->pdev->dev,
- PAGE_SIZE,
- &t, gfp);
- if (!buf->page_list[i].buf)
- goto err_free;
-
- buf->page_list[i].map = t;
-
- memset(buf->page_list[i].buf, 0, PAGE_SIZE);
- }
+ buf->direct.map = t;

- if (BITS_PER_LONG == 64) {
- struct page **pages;
- pages = kmalloc(sizeof *pages * buf->nbufs, gfp);
- if (!pages)
- goto err_free;
- for (i = 0; i < buf->nbufs; ++i)
- pages[i] = virt_to_page(buf->page_list[i].buf);
- buf->direct.buf = vmap(pages, buf->nbufs, VM_MAP, PAGE_KERNEL);
- kfree(pages);
- if (!buf->direct.buf)
- goto err_free;
- }
+ while (t & ((1 << buf->page_shift) - 1)) {
+ --buf->page_shift;
+ buf->npages *= 2;
}

+ memset(buf->direct.buf, 0, size);
return 0;
-
-err_free:
- mlx4_buf_free(dev, size, buf);
-
- return -ENOMEM;
}
EXPORT_SYMBOL_GPL(mlx4_buf_alloc);

void mlx4_buf_free(struct mlx4_dev *dev, int size, struct mlx4_buf *buf)
{
- int i;
-
- if (buf->nbufs == 1)
- dma_free_coherent(&dev->persist->pdev->dev, size,
- buf->direct.buf,
- buf->direct.map);
- else {
- if (BITS_PER_LONG == 64)
- vunmap(buf->direct.buf);
-
- for (i = 0; i < buf->nbufs; ++i)
- if (buf->page_list[i].buf)
- dma_free_coherent(&dev->persist->pdev->dev,
- PAGE_SIZE,
- buf->page_list[i].buf,
- buf->page_list[i].map);
- kfree(buf->page_list);
- }
+ dma_free_coherent(&dev->persist->pdev->dev, size,
+ buf->direct.buf,
+ buf->direct.map);
}
EXPORT_SYMBOL_GPL(mlx4_buf_free);

diff --git a/drivers/net/ethernet/mellanox/mlx4/en_cq.c b/drivers/net/ethernet/mellanox/mlx4/en_cq.c
index af975a2..16ef8cf 100644
--- a/drivers/net/ethernet/mellanox/mlx4/en_cq.c
+++ b/drivers/net/ethernet/mellanox/mlx4/en_cq.c
@@ -78,17 +78,11 @@ int mlx4_en_create_cq(struct mlx4_en_priv *priv,
if (err)
goto err_cq;

- err = mlx4_en_map_buffer(&cq->wqres.buf);
- if (err)
- goto err_res;
-
cq->buf = (struct mlx4_cqe *)cq->wqres.buf.direct.buf;
*pcq = cq;

return 0;

-err_res:
- mlx4_free_hwq_res(mdev->dev, &cq->wqres, cq->buf_size);
err_cq:
kfree(cq);
*pcq = NULL;
@@ -177,7 +171,6 @@ void mlx4_en_destroy_cq(struct mlx4_en_priv *priv, struct mlx4_en_cq **pcq)
struct mlx4_en_dev *mdev = priv->mdev;
struct mlx4_en_cq *cq = *pcq;

- mlx4_en_unmap_buffer(&cq->wqres.buf);
mlx4_free_hwq_res(mdev->dev, &cq->wqres, cq->buf_size);
if (mlx4_is_eq_vector_valid(mdev->dev, priv->port, cq->vector) &&
cq->is_tx == RX)
diff --git a/drivers/net/ethernet/mellanox/mlx4/en_resources.c b/drivers/net/ethernet/mellanox/mlx4/en_resources.c
index 02e925d..a6b0db0 100644
--- a/drivers/net/ethernet/mellanox/mlx4/en_resources.c
+++ b/drivers/net/ethernet/mellanox/mlx4/en_resources.c
@@ -107,37 +107,6 @@ int mlx4_en_change_mcast_lb(struct mlx4_en_priv *priv, struct mlx4_qp *qp,
return ret;
}

-int mlx4_en_map_buffer(struct mlx4_buf *buf)
-{
- struct page **pages;
- int i;
-
- if (BITS_PER_LONG == 64 || buf->nbufs == 1)
- return 0;
-
- pages = kmalloc(sizeof *pages * buf->nbufs, GFP_KERNEL);
- if (!pages)
- return -ENOMEM;
-
- for (i = 0; i < buf->nbufs; ++i)
- pages[i] = virt_to_page(buf->page_list[i].buf);
-
- buf->direct.buf = vmap(pages, buf->nbufs, VM_MAP, PAGE_KERNEL);
- kfree(pages);
- if (!buf->direct.buf)
- return -ENOMEM;
-
- return 0;
-}
-
-void mlx4_en_unmap_buffer(struct mlx4_buf *buf)
-{
- if (BITS_PER_LONG == 64 || buf->nbufs == 1)
- return;
-
- vunmap(buf->direct.buf);
-}
-
void mlx4_en_sqp_event(struct mlx4_qp *qp, enum mlx4_event event)
{
return;
diff --git a/drivers/net/ethernet/mellanox/mlx4/en_rx.c b/drivers/net/ethernet/mellanox/mlx4/en_rx.c
index 86bcfe5..bc6c14a 100644
--- a/drivers/net/ethernet/mellanox/mlx4/en_rx.c
+++ b/drivers/net/ethernet/mellanox/mlx4/en_rx.c
@@ -396,11 +396,6 @@ int mlx4_en_create_rx_ring(struct mlx4_en_priv *priv,
if (err)
goto err_info;

- err = mlx4_en_map_buffer(&ring->wqres.buf);
- if (err) {
- en_err(priv, "Failed to map RX buffer\n");
- goto err_hwq;
- }
ring->buf = ring->wqres.buf.direct.buf;

ring->hwtstamp_rx_filter = priv->hwtstamp_config.rx_filter;
@@ -408,8 +403,6 @@ int mlx4_en_create_rx_ring(struct mlx4_en_priv *priv,
*pring = ring;
return 0;

-err_hwq:
- mlx4_free_hwq_res(mdev->dev, &ring->wqres, ring->buf_size);
err_info:
vfree(ring->rx_info);
ring->rx_info = NULL;
@@ -513,7 +506,6 @@ void mlx4_en_destroy_rx_ring(struct mlx4_en_priv *priv,
struct mlx4_en_dev *mdev = priv->mdev;
struct mlx4_en_rx_ring *ring = *pring;

- mlx4_en_unmap_buffer(&ring->wqres.buf);
mlx4_free_hwq_res(mdev->dev, &ring->wqres, size * stride + TXBB_SIZE);
vfree(ring->rx_info);
ring->rx_info = NULL;
diff --git a/drivers/net/ethernet/mellanox/mlx4/en_tx.c b/drivers/net/ethernet/mellanox/mlx4/en_tx.c
index c0d7b72..3c6b59c 100644
--- a/drivers/net/ethernet/mellanox/mlx4/en_tx.c
+++ b/drivers/net/ethernet/mellanox/mlx4/en_tx.c
@@ -101,12 +101,6 @@ int mlx4_en_create_tx_ring(struct mlx4_en_priv *priv,
goto err_bounce;
}

- err = mlx4_en_map_buffer(&ring->wqres.buf);
- if (err) {
- en_err(priv, "Failed to map TX buffer\n");
- goto err_hwq_res;
- }
-
ring->buf = ring->wqres.buf.direct.buf;

en_dbg(DRV, priv, "Allocated TX ring (addr:%p) - buf:%p size:%d buf_size:%d dma:%llx\n",
@@ -155,8 +149,6 @@ int mlx4_en_create_tx_ring(struct mlx4_en_priv *priv,
err_reserve:
mlx4_qp_release_range(mdev->dev, ring->qpn, 1);
err_map:
- mlx4_en_unmap_buffer(&ring->wqres.buf);
-err_hwq_res:
mlx4_free_hwq_res(mdev->dev, &ring->wqres, ring->buf_size);
err_bounce:
kfree(ring->bounce_buf);
@@ -182,7 +174,6 @@ void mlx4_en_destroy_tx_ring(struct mlx4_en_priv *priv,
mlx4_qp_remove(mdev->dev, &ring->qp);
mlx4_qp_free(mdev->dev, &ring->qp);
mlx4_qp_release_range(priv->mdev->dev, ring->qpn, 1);
- mlx4_en_unmap_buffer(&ring->wqres.buf);
mlx4_free_hwq_res(mdev->dev, &ring->wqres, ring->buf_size);
kfree(ring->bounce_buf);
ring->bounce_buf = NULL;
diff --git a/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h b/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h
index d12ab6a..a70e2d0 100644
--- a/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h
+++ b/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h
@@ -671,8 +671,6 @@ void mlx4_en_fill_qp_context(struct mlx4_en_priv *priv, int size, int stride,
int is_tx, int rss, int qpn, int cqn, int user_prio,
struct mlx4_qp_context *context);
void mlx4_en_sqp_event(struct mlx4_qp *qp, enum mlx4_event event);
-int mlx4_en_map_buffer(struct mlx4_buf *buf);
-void mlx4_en_unmap_buffer(struct mlx4_buf *buf);
int mlx4_en_change_mcast_lb(struct mlx4_en_priv *priv, struct mlx4_qp *qp,
int loopback);
void mlx4_en_calc_rx_buf(struct net_device *dev);
diff --git a/drivers/net/ethernet/mellanox/mlx4/mr.c b/drivers/net/ethernet/mellanox/mlx4/mr.c
index 9319519..b61052f 100644
--- a/drivers/net/ethernet/mellanox/mlx4/mr.c
+++ b/drivers/net/ethernet/mellanox/mlx4/mr.c
@@ -802,10 +802,7 @@ int mlx4_buf_write_mtt(struct mlx4_dev *dev, struct mlx4_mtt *mtt,
return -ENOMEM;

for (i = 0; i < buf->npages; ++i)
- if (buf->nbufs == 1)
- page_list[i] = buf->direct.map + (i << buf->page_shift);
- else
- page_list[i] = buf->page_list[i].map;
+ page_list[i] = buf->direct.map + (i << buf->page_shift);

err = mlx4_write_mtt(dev, mtt, 0, buf->npages, page_list);

diff --git a/include/linux/mlx4/device.h b/include/linux/mlx4/device.h
index 8541a91..536b547 100644
--- a/include/linux/mlx4/device.h
+++ b/include/linux/mlx4/device.h
@@ -618,8 +618,6 @@ struct mlx4_buf_list {

struct mlx4_buf {
struct mlx4_buf_list direct;
- struct mlx4_buf_list *page_list;
- int nbufs;
int npages;
int page_shift;
};
@@ -1051,11 +1049,7 @@ int mlx4_buf_alloc(struct mlx4_dev *dev, int size, int max_direct,
void mlx4_buf_free(struct mlx4_dev *dev, int size, struct mlx4_buf *buf);
static inline void *mlx4_buf_offset(struct mlx4_buf *buf, int offset)
{
- if (BITS_PER_LONG == 64 || buf->nbufs == 1)
- return buf->direct.buf + offset;
- else
- return buf->page_list[offset >> PAGE_SHIFT].buf +
- (offset & (PAGE_SIZE - 1));
+ return buf->direct.buf + offset;
}

int mlx4_pd_alloc(struct mlx4_dev *dev, u32 *pdn);
--
2.1.4

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