Commit e7920310 authored by John Hubbard's avatar John Hubbard Committed by Linus Torvalds
Browse files

ivtv: convert get_user_pages() --> pin_user_pages() 

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/



Signed-off-by: default avatarJohn Hubbard <jhubbard@nvidia.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Cc: Andy Walls <awalls@md.metrocast.net>
Cc: Mauro Carvalho Chehab <mchehab@kernel.org>
Link: http://lkml.kernel.org/r/20200518012157.1178336-3-jhubbard@nvidia.com


Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 91429023

drivers/media/pci/ivtv/ivtv-udma.c

+6 −13
Original line number Diff line number Diff line
@@ -92,7 +92,7 @@ int ivtv_udma_setup(struct ivtv *itv, unsigned long ivtv_dest_addr, 
{

	struct ivtv_dma_page_info user_dma;

	struct ivtv_user_dma *dma = &itv->udma;

	int i, err;

	int err;



	IVTV_DEBUG_DMA("ivtv_udma_setup, dst: 0x%08x\n", (unsigned int)ivtv_dest_addr);
@@ -111,16 +111,15 @@ int ivtv_udma_setup(struct ivtv *itv, unsigned long ivtv_dest_addr, 
		return -EINVAL;

	}



	/* Get user pages for DMA Xfer */

	err = get_user_pages_unlocked(user_dma.uaddr, user_dma.page_count,

	/* Pin user pages for DMA Xfer */

	err = pin_user_pages_unlocked(user_dma.uaddr, user_dma.page_count,

			dma->map, FOLL_FORCE);



	if (user_dma.page_count != err) {

		IVTV_DEBUG_WARN("failed to map user pages, returned %d instead of %d\n",

			   err, user_dma.page_count);

		if (err >= 0) {

			for (i = 0; i < err; i++)

				put_page(dma->map[i]);

			unpin_user_pages(dma->map, err);

			return -EINVAL;

		}

		return err;
@@ -130,9 +129,7 @@ int ivtv_udma_setup(struct ivtv *itv, unsigned long ivtv_dest_addr, 


	/* Fill SG List with new values */

	if (ivtv_udma_fill_sg_list(dma, &user_dma, 0) < 0) {

		for (i = 0; i < dma->page_count; i++) {

			put_page(dma->map[i]);

		}

		unpin_user_pages(dma->map, dma->page_count);

		dma->page_count = 0;

		return -ENOMEM;

	}
@@ -153,7 +150,6 @@ int ivtv_udma_setup(struct ivtv *itv, unsigned long ivtv_dest_addr, 
void ivtv_udma_unmap(struct ivtv *itv)

{

	struct ivtv_user_dma *dma = &itv->udma;

	int i;



	IVTV_DEBUG_INFO("ivtv_unmap_user_dma\n");
@@ -169,10 +165,7 @@ void ivtv_udma_unmap(struct ivtv *itv) 
	/* sync DMA */

	ivtv_udma_sync_for_cpu(itv);



	/* Release User Pages */

	for (i = 0; i < dma->page_count; i++) {

		put_page(dma->map[i]);

	}

	unpin_user_pages(dma->map, dma->page_count);

	dma->page_count = 0;

}

drivers/media/pci/ivtv/ivtv-yuv.c

+6 −11
Original line number Diff line number Diff line
@@ -30,7 +30,6 @@ static int ivtv_yuv_prep_user_dma(struct ivtv *itv, struct ivtv_user_dma *dma, 
	struct yuv_playback_info *yi = &itv->yuv_info;

	u8 frame = yi->draw_frame;

	struct yuv_frame_info *f = &yi->new_frame_info[frame];

	int i;

	int y_pages, uv_pages;

	unsigned long y_buffer_offset, uv_buffer_offset;

	int y_decode_height, uv_decode_height, y_size;
@@ -62,12 +61,12 @@ static int ivtv_yuv_prep_user_dma(struct ivtv *itv, struct ivtv_user_dma *dma, 
	ivtv_udma_get_page_info (&y_dma, (unsigned long)args->y_source, 720 * y_decode_height);

	ivtv_udma_get_page_info (&uv_dma, (unsigned long)args->uv_source, 360 * uv_decode_height);



	/* Get user pages for DMA Xfer */

	y_pages = get_user_pages_unlocked(y_dma.uaddr,

	/* Pin user pages for DMA Xfer */

	y_pages = pin_user_pages_unlocked(y_dma.uaddr,

			y_dma.page_count, &dma->map[0], FOLL_FORCE);

	uv_pages = 0; /* silence gcc. value is set and consumed only if: */

	if (y_pages == y_dma.page_count) {

		uv_pages = get_user_pages_unlocked(uv_dma.uaddr,

		uv_pages = pin_user_pages_unlocked(uv_dma.uaddr,

				uv_dma.page_count, &dma->map[y_pages],

				FOLL_FORCE);

	}
@@ -81,8 +80,7 @@ static int ivtv_yuv_prep_user_dma(struct ivtv *itv, struct ivtv_user_dma *dma, 
				 uv_pages, uv_dma.page_count);



			if (uv_pages >= 0) {

				for (i = 0; i < uv_pages; i++)

					put_page(dma->map[y_pages + i]);

				unpin_user_pages(&dma->map[y_pages], uv_pages);

				rc = -EFAULT;

			} else {

				rc = uv_pages;
@@ -93,8 +91,7 @@ static int ivtv_yuv_prep_user_dma(struct ivtv *itv, struct ivtv_user_dma *dma, 
				 y_pages, y_dma.page_count);

		}

		if (y_pages >= 0) {

			for (i = 0; i < y_pages; i++)

				put_page(dma->map[i]);

			unpin_user_pages(dma->map, y_pages);

			/*

			 * Inherit the -EFAULT from rc's

			 * initialization, but allow it to be
@@ -112,9 +109,7 @@ static int ivtv_yuv_prep_user_dma(struct ivtv *itv, struct ivtv_user_dma *dma, 
	/* Fill & map SG List */

	if (ivtv_udma_fill_sg_list (dma, &uv_dma, ivtv_udma_fill_sg_list (dma, &y_dma, 0)) < 0) {

		IVTV_DEBUG_WARN("could not allocate bounce buffers for highmem userspace buffers\n");

		for (i = 0; i < dma->page_count; i++) {

			put_page(dma->map[i]);

		}

		unpin_user_pages(dma->map, dma->page_count);

		dma->page_count = 0;

		return -ENOMEM;

	}

drivers/media/pci/ivtv/ivtvfb.c

+2 −2
Original line number Diff line number Diff line
@@ -281,10 +281,10 @@ static int ivtvfb_prep_dec_dma_to_device(struct ivtv *itv, 
	/* Map User DMA */

	if (ivtv_udma_setup(itv, ivtv_dest_addr, userbuf, size_in_bytes) <= 0) {

		mutex_unlock(&itv->udma.lock);

		IVTVFB_WARN("ivtvfb_prep_dec_dma_to_device, Error with get_user_pages: %d bytes, %d pages returned\n",

		IVTVFB_WARN("ivtvfb_prep_dec_dma_to_device, Error with pin_user_pages: %d bytes, %d pages returned\n",

			       size_in_bytes, itv->udma.page_count);



		/* get_user_pages must have failed completely */

		/* pin_user_pages must have failed completely */

		return -EIO;

	}