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13 June 2022, 11:31:42 UTC
Revision a39d0d7bdf8c21ac7645c02e9676b5cb2b804c31 authored by Jean Delvare on 28 September 2020, 09:10:37 UTC, committed by Alex Deucher on 29 September 2020, 21:09:22 UTC 
drm/amdgpu: restore proper ref count in amdgpu_display_crtc_set_config
 
A recent attempt to fix a ref count leak in
amdgpu_display_crtc_set_config() turned out to be doing too much and
"fixed" an intended decrease as if it were a leak. Undo that part to
restore the proper balance. This is the very nature of this function
to increase or decrease the power reference count depending on the
situation.

Consequences of this bug is that the power reference would
eventually get down to 0 while the display was still in use,
resulting in that display switching off unexpectedly.

Signed-off-by: Jean Delvare <jdelvare@suse.de>
Fixes: e008fa6fb415 ("drm/amdgpu: fix ref count leak in amdgpu_display_crtc_set_config")
Cc: stable@vger.kernel.org
Cc: Navid Emamdoost <navid.emamdoost@gmail.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
1 parent c73d05e
Raw File
Tip revision: a39d0d7bdf8c21ac7645c02e9676b5cb2b804c31 authored by Jean Delvare on 28 September 2020, 09:10:37 UTC
drm/amdgpu: restore proper ref count in amdgpu_display_crtc_set_config
Tip revision: a39d0d7
scatterwalk.c 
// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Cryptographic API.
 *
 * Cipher operations.
 *
 * Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
 *               2002 Adam J. Richter <adam@yggdrasil.com>
 *               2004 Jean-Luc Cooke <jlcooke@certainkey.com>
 */

#include <crypto/scatterwalk.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/module.h>
#include <linux/scatterlist.h>

static inline void memcpy_dir(void *buf, void *sgdata, size_t nbytes, int out)
{
	void *src = out ? buf : sgdata;
	void *dst = out ? sgdata : buf;

	memcpy(dst, src, nbytes);
}

void scatterwalk_copychunks(void *buf, struct scatter_walk *walk,
			    size_t nbytes, int out)
{
	for (;;) {
		unsigned int len_this_page = scatterwalk_pagelen(walk);
		u8 *vaddr;

		if (len_this_page > nbytes)
			len_this_page = nbytes;

		if (out != 2) {
			vaddr = scatterwalk_map(walk);
			memcpy_dir(buf, vaddr, len_this_page, out);
			scatterwalk_unmap(vaddr);
		}

		scatterwalk_advance(walk, len_this_page);

		if (nbytes == len_this_page)
			break;

		buf += len_this_page;
		nbytes -= len_this_page;

		scatterwalk_pagedone(walk, out & 1, 1);
	}
}
EXPORT_SYMBOL_GPL(scatterwalk_copychunks);

void scatterwalk_map_and_copy(void *buf, struct scatterlist *sg,
			      unsigned int start, unsigned int nbytes, int out)
{
	struct scatter_walk walk;
	struct scatterlist tmp[2];

	if (!nbytes)
		return;

	sg = scatterwalk_ffwd(tmp, sg, start);

	scatterwalk_start(&walk, sg);
	scatterwalk_copychunks(buf, &walk, nbytes, out);
	scatterwalk_done(&walk, out, 0);
}
EXPORT_SYMBOL_GPL(scatterwalk_map_and_copy);

struct scatterlist *scatterwalk_ffwd(struct scatterlist dst[2],
				     struct scatterlist *src,
				     unsigned int len)
{
	for (;;) {
		if (!len)
			return src;

		if (src->length > len)
			break;

		len -= src->length;
		src = sg_next(src);
	}

	sg_init_table(dst, 2);
	sg_set_page(dst, sg_page(src), src->length - len, src->offset + len);
	scatterwalk_crypto_chain(dst, sg_next(src), 2);

	return dst;
}
EXPORT_SYMBOL_GPL(scatterwalk_ffwd);
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