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Commit 86695e1d authored by Puranam V G Tejaswi's avatar Puranam V G Tejaswi
Browse files

msm: kgsl: Use dma_buf_get() to get dma_buf structure 



Currently we don't ensure if vma->vm_file is associated with dma_buf. This
can cause issues later when private_data from a non dma_buf file is used as
dma_buf structure. Hence get the fd that is associated with vma->vm_file
and use dma_buf_get() to get pointer to dma_buf structure. dma_buf_get()
ensures that the file from the input fd is associated with dma_buf.

Change-Id: Ib78aef8b16bedca5ca86d3a132278ff9f07dce73
Signed-off-by: default avatarPuranam V G Tejaswi <quic_pvgtejas@quicinc.com>
parent 114c9c6c

drivers/gpu/msm/kgsl.c

+33 −8
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0-only

/*

 * Copyright (c) 2008-2021, The Linux Foundation. All rights reserved.

 * Copyright (c) 2022 Qualcomm Innovation Center, Inc. All rights reserved.

 * Copyright (c) 2022-2023, Qualcomm Innovation Center, Inc. All rights reserved.

 */



#include <uapi/linux/sched/types.h>
@@ -2677,6 +2677,15 @@ static int kgsl_setup_anon_useraddr(struct kgsl_pagetable *pagetable, 
}



#ifdef CONFIG_DMA_SHARED_BUFFER

static int match_file(const void *p, struct file *file, unsigned int fd)

{

	/*

	 * We must return fd + 1 because iterate_fd stops searching on

	 * non-zero return, but 0 is a valid fd.

	 */

	return (p == file) ? (fd + 1) : 0;

}



static void _setup_cache_mode(struct kgsl_mem_entry *entry,

		struct vm_area_struct *vma)

{
@@ -2714,6 +2723,8 @@ static int kgsl_setup_dmabuf_useraddr(struct kgsl_device *device, 
	vma = find_vma(current->mm, hostptr);



	if (vma && vma->vm_file) {

		int fd;



		ret = check_vma_flags(vma, entry->memdesc.flags);

		if (ret) {

			up_read(&current->mm->mmap_sem);
@@ -2729,13 +2740,27 @@ static int kgsl_setup_dmabuf_useraddr(struct kgsl_device *device, 
			return -EFAULT;

		}



		/* Look for the fd that matches this vma file */

		fd = iterate_fd(current->files, 0, match_file, vma->vm_file);

		if (fd) {

			dmabuf = dma_buf_get(fd - 1);

			if (IS_ERR(dmabuf)) {

				up_read(&current->mm->mmap_sem);

				return PTR_ERR(dmabuf);

			}

			/*

		 * Take a refcount because dma_buf_put() decrements the

		 * refcount

			 * It is possible that the fd obtained from iterate_fd

			 * was closed before passing the fd to dma_buf_get().

			 * Hence dmabuf returned by dma_buf_get() could be

			 * different from vma->vm_file->private_data. Return

			 * failure if this happens.

			 */

		get_file(vma->vm_file);



		dmabuf = vma->vm_file->private_data;

			if (dmabuf != vma->vm_file->private_data) {

				dma_buf_put(dmabuf);

				up_read(&current->mm->mmap_sem);

				return -EBADF;

			}

		}

	}



	if (IS_ERR_OR_NULL(dmabuf)) {