All of lore.kernel.org
 help / color / mirror / Atom feed
From: John Hubbard <jhubbard@nvidia.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Walls <awalls@md.metrocast.net>,
	Mauro Carvalho Chehab <mchehab@kernel.org>,
	Souptick Joarder <jrdr.linux@gmail.com>,
	<linux-media@vger.kernel.org>,
	LKML <linux-kernel@vger.kernel.org>, <linux-mm@kvack.org>,
	John Hubbard <jhubbard@nvidia.com>
Subject: [PATCH v2 2/2] ivtv: convert get_user_pages() --> pin_user_pages()
Date: Sun, 31 May 2020 15:48:27 -0700	[thread overview]
Message-ID: <20200531224827.769427-3-jhubbard@nvidia.com> (raw)
In-Reply-To: <20200531224827.769427-1-jhubbard@nvidia.com>

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: John Hubbard <jhubbard@nvidia.com>
---
 drivers/media/pci/ivtv/ivtv-udma.c | 19 ++++++-------------
 drivers/media/pci/ivtv/ivtv-yuv.c  | 17 ++++++-----------
 drivers/media/pci/ivtv/ivtvfb.c    |  4 ++--
 3 files changed, 14 insertions(+), 26 deletions(-)

diff --git a/drivers/media/pci/ivtv/ivtv-udma.c b/drivers/media/pci/ivtv/ivtv-udma.c
index 5f8883031c9c..0d8372cc364a 100644
--- a/drivers/media/pci/ivtv/ivtv-udma.c
+++ b/drivers/media/pci/ivtv/ivtv-udma.c
@@ -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;
 }
 
diff --git a/drivers/media/pci/ivtv/ivtv-yuv.c b/drivers/media/pci/ivtv/ivtv-yuv.c
index cd2fe2d444c0..5f7dc9771f8d 100644
--- a/drivers/media/pci/ivtv/ivtv-yuv.c
+++ b/drivers/media/pci/ivtv/ivtv-yuv.c
@@ -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;
 	}
diff --git a/drivers/media/pci/ivtv/ivtvfb.c b/drivers/media/pci/ivtv/ivtvfb.c
index 0c2859844081..e2d56dca5be4 100644
--- a/drivers/media/pci/ivtv/ivtvfb.c
+++ b/drivers/media/pci/ivtv/ivtvfb.c
@@ -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;
 	}
 
-- 
2.26.2


      parent reply	other threads:[~2020-05-31 22:48 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-05-31 22:48 [PATCH v2 0/2] mm/gup, media/ivtv: introduce pin_user_pages_unlocked John Hubbard
2020-05-31 22:48 ` [PATCH v2 1/2] mm/gup: " John Hubbard
2020-05-31 22:48 ` John Hubbard [this message]

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20200531224827.769427-3-jhubbard@nvidia.com \
    --to=jhubbard@nvidia.com \
    --cc=akpm@linux-foundation.org \
    --cc=awalls@md.metrocast.net \
    --cc=jrdr.linux@gmail.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-media@vger.kernel.org \
    --cc=linux-mm@kvack.org \
    --cc=mchehab@kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.