From: John Hubbard jhubbard@nvidia.com Subject: rapidio: fix an error in get_user_pages_fast() error handling

In the case of get_user_pages_fast() returning fewer pages than requested, rio_dma_transfer() does not quite do the right thing. It attempts to release all the pages that were requested, rather than just the pages that were pinned.

Fix the error handling so that only the pages that were successfully pinned are released.

Link: http://lkml.kernel.org/r/20200517235620.205225-2-jhubbard@nvidia.com Fixes: e8de370188d0 ("rapidio: add mport char device driver") Signed-off-by: John Hubbard jhubbard@nvidia.com Reviewed-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 Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org ---

drivers/rapidio/devices/rio_mport_cdev.c | 5 +++++ 1 file changed, 5 insertions(+)

--- a/drivers/rapidio/devices/rio_mport_cdev.c~rapidio-fix-an-error-in-get_user_pages_fast-error-handling +++ a/drivers/rapidio/devices/rio_mport_cdev.c @@ -877,6 +877,11 @@ rio_dma_transfer(struct file *filp, u32 rmcd_error("pinned %ld out of %ld pages", pinned, nr_pages); ret = -EFAULT; + /* + * Set nr_pages up to mean "how many pages to unpin, in + * the error handler: + */ + nr_pages = pinned; goto err_pg; }

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