diff options
| author | John Hubbard <jhubbard@nvidia.com> | 2020-06-04 16:51:24 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2020-06-04 19:06:26 -0700 |
| commit | 67446283d89467edae5ad9f632ee31f0fbae35fe (patch) | |
| tree | 278211f545b47db10d20e90aaea19a591054b7f2 | |
| parent | e1c3cdb26ab881b77486dc50370356a349077c74 (diff) | |
| download | lwn-67446283d89467edae5ad9f632ee31f0fbae35fe.tar.gz lwn-67446283d89467edae5ad9f632ee31f0fbae35fe.zip | |
rapidio: convert get_user_pages() --> pin_user_pages()
This code was using get_user_pages_fast(), in a "Case 2" scenario
(DMA/RDMA), using the categorization from [1]. That means that it's time
to convert the get_user_pages_fast() + put_page() calls to
pin_user_pages_fast() + unpin_user_pages() calls.
There is some helpful background in [2]: basically, this is a small
part of fixing a long-standing disconnect between pinning pages, and
file systems' use of those pages.
[1] Documentation/core-api/pin_user_pages.rst
[2] "Explicit pinning of user-space pages":
https://lwn.net/Articles/807108/
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Matt Porter <mporter@kernel.crashing.org>
Cc: Alexandre Bounine <alex.bou9@gmail.com>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Link: http://lkml.kernel.org/r/20200517235620.205225-3-jhubbard@nvidia.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | drivers/rapidio/devices/rio_mport_cdev.c | 13 |
1 files changed, 5 insertions, 8 deletions
diff --git a/drivers/rapidio/devices/rio_mport_cdev.c b/drivers/rapidio/devices/rio_mport_cdev.c index 0b85a80ae7ef..451608e960a1 100644 --- a/drivers/rapidio/devices/rio_mport_cdev.c +++ b/drivers/rapidio/devices/rio_mport_cdev.c @@ -572,14 +572,12 @@ static void dma_req_free(struct kref *ref) struct mport_dma_req *req = container_of(ref, struct mport_dma_req, refcount); struct mport_cdev_priv *priv = req->priv; - unsigned int i; dma_unmap_sg(req->dmach->device->dev, req->sgt.sgl, req->sgt.nents, req->dir); sg_free_table(&req->sgt); if (req->page_list) { - for (i = 0; i < req->nr_pages; i++) - put_page(req->page_list[i]); + unpin_user_pages(req->page_list, req->nr_pages); kfree(req->page_list); } @@ -815,7 +813,7 @@ rio_dma_transfer(struct file *filp, u32 transfer_mode, struct mport_dma_req *req; struct mport_dev *md = priv->md; struct dma_chan *chan; - int i, ret; + int ret; int nents; if (xfer->length == 0) @@ -862,7 +860,7 @@ rio_dma_transfer(struct file *filp, u32 transfer_mode, goto err_req; } - pinned = get_user_pages_fast( + pinned = pin_user_pages_fast( (unsigned long)xfer->loc_addr & PAGE_MASK, nr_pages, dir == DMA_FROM_DEVICE ? FOLL_WRITE : 0, @@ -870,7 +868,7 @@ rio_dma_transfer(struct file *filp, u32 transfer_mode, if (pinned != nr_pages) { if (pinned < 0) { - rmcd_error("get_user_pages_unlocked err=%ld", + rmcd_error("pin_user_pages_fast err=%ld", pinned); nr_pages = 0; } else @@ -951,8 +949,7 @@ rio_dma_transfer(struct file *filp, u32 transfer_mode, err_pg: if (!req->page_list) { - for (i = 0; i < nr_pages; i++) - put_page(page_list[i]); + unpin_user_pages(page_list, nr_pages); kfree(page_list); } err_req: |