This code was using get_user_pages*(), in a "Case 2" scenario (DMA/RDMA), using the categorization from [1]. That means that it's time to convert the get_user_pages*() + put_page() calls to pin_user_pages*() + 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/

Cc: Jens Wiklander jens.wiklander@linaro.org Cc: Sumit Semwal sumit.semwal@linaro.org Cc: tee-dev@lists.linaro.org Cc: linux-media@vger.kernel.org Cc: dri-devel@lists.freedesktop.org Cc: linaro-mm-sig@lists.linaro.org Signed-off-by: John Hubbard jhubbard@nvidia.com ---

OK, this should be indentical to v1 [1], but now rebased against Linux 5.9-rc2.

As before, I've compile-tested it again with a cross compiler, but that's the only testing I'm set up for with CONFIG_TEE.

[1] https://lore.kernel.org/r/20200519051850.2845561-1-jhubbard@nvidia.com

thanks, John Hubbard NVIDIA

drivers/tee/tee_shm.c | 12 +++--------- 1 file changed, 3 insertions(+), 9 deletions(-)

diff --git a/drivers/tee/tee_shm.c b/drivers/tee/tee_shm.c index 827ac3d0fea9..3c29e6c3ebe8 100644 --- a/drivers/tee/tee_shm.c +++ b/drivers/tee/tee_shm.c @@ -32,16 +32,13 @@ static void tee_shm_release(struct tee_shm *shm)

poolm->ops->free(poolm, shm); } else if (shm->flags & TEE_SHM_REGISTER) { - size_t n; int rc = teedev->desc->ops->shm_unregister(shm->ctx, shm);

if (rc) dev_err(teedev->dev.parent, "unregister shm %p failed: %d", shm, rc);

- for (n = 0; n < shm->num_pages; n++) - put_page(shm->pages[n]); - + unpin_user_pages(shm->pages, shm->num_pages); kfree(shm->pages); }

@@ -228,7 +225,7 @@ struct tee_shm *tee_shm_register(struct tee_context *ctx, unsigned long addr, }

if (flags & TEE_SHM_USER_MAPPED) { - rc = get_user_pages_fast(start, num_pages, FOLL_WRITE, + rc = pin_user_pages_fast(start, num_pages, FOLL_WRITE, shm->pages); } else { struct kvec *kiov; @@ -292,16 +289,13 @@ struct tee_shm *tee_shm_register(struct tee_context *ctx, unsigned long addr, return shm; err: if (shm) { - size_t n; - if (shm->id >= 0) { mutex_lock(&teedev->mutex); idr_remove(&teedev->idr, shm->id); mutex_unlock(&teedev->mutex); } if (shm->pages) { - for (n = 0; n < shm->num_pages; n++) - put_page(shm->pages[n]); + unpin_user_pages(shm->pages, shm->num_pages); kfree(shm->pages); } }