tee: convert get_user_pages() --> pin_user_pages() (4300cd63) · Commits · 戴 / test

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. Factor out a new, small release_registered_pages() function, in order to consolidate the logic for discerning between TEE_SHM_USER_MAPPED and TEE_SHM_KERNEL_MAPPED pages. This also absorbs the kfree() call that is also required there. 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> Signed-off-by:

Jens Wiklander <jens.wiklander@linaro.org>

drivers/tee/tee_shm.c

+19 −13

Original line number	Diff line number	Diff line
		@@ -12,6 +12,22 @@
		#include <linux/uio.h>
		#include "tee_private.h"

		static void release_registered_pages(struct tee_shm *shm)
		{
		if (shm->pages) {
		if (shm->flags & TEE_SHM_USER_MAPPED) {
		unpin_user_pages(shm->pages, shm->num_pages);
		} else {
		size_t n;

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

		kfree(shm->pages);
		}
		}

		static void tee_shm_release(struct tee_shm *shm)
		{
		struct tee_device *teedev = shm->ctx->teedev;
		@@ -32,17 +48,13 @@ 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]);

		kfree(shm->pages);
		release_registered_pages(shm);
		}

		teedev_ctx_put(shm->ctx);
		@@ -228,7 +240,7 @@ 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;
		@@ -292,18 +304,12 @@ 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]);
		kfree(shm->pages);
		}
		release_registered_pages(shm);
		}
		kfree(shm);
		teedev_ctx_put(ctx);

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