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https://github.com/torvalds/linux
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e2fc6edd37
Commit707947247e("media: videobuf2-vmalloc: get_userptr: buffers are always writable") caused problems in a corner case (passing read-only shmem memory as a userptr). So revert this patch. The original problem for which that commit was originally made is something that I could not reproduce after reverting it. So just go back to the way it was for many years, and if problems arise in the future, then another approach should be taken to resolve it. This patch is based on a patch from Hirokazu. Fixes:707947247e("media: videobuf2-vmalloc: get_userptr: buffers are always writable") Signed-off-by: Hirokazu Honda <hiroh@chromium.org> Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl> Acked-by: Tomasz Figa <tfiga@chromium.org> Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>
48 lines
1.4 KiB
C
48 lines
1.4 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#ifndef _MEDIA_FRAME_VECTOR_H
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#define _MEDIA_FRAME_VECTOR_H
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/* Container for pinned pfns / pages in frame_vector.c */
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struct frame_vector {
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unsigned int nr_allocated; /* Number of frames we have space for */
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unsigned int nr_frames; /* Number of frames stored in ptrs array */
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bool got_ref; /* Did we pin pages by getting page ref? */
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bool is_pfns; /* Does array contain pages or pfns? */
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void *ptrs[]; /* Array of pinned pfns / pages. Use
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* pfns_vector_pages() or pfns_vector_pfns()
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* for access */
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};
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struct frame_vector *frame_vector_create(unsigned int nr_frames);
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void frame_vector_destroy(struct frame_vector *vec);
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int get_vaddr_frames(unsigned long start, unsigned int nr_pfns,
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bool write, struct frame_vector *vec);
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void put_vaddr_frames(struct frame_vector *vec);
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int frame_vector_to_pages(struct frame_vector *vec);
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void frame_vector_to_pfns(struct frame_vector *vec);
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static inline unsigned int frame_vector_count(struct frame_vector *vec)
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{
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return vec->nr_frames;
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}
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static inline struct page **frame_vector_pages(struct frame_vector *vec)
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{
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if (vec->is_pfns) {
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int err = frame_vector_to_pages(vec);
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if (err)
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return ERR_PTR(err);
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}
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return (struct page **)(vec->ptrs);
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}
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static inline unsigned long *frame_vector_pfns(struct frame_vector *vec)
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{
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if (!vec->is_pfns)
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frame_vector_to_pfns(vec);
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return (unsigned long *)(vec->ptrs);
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}
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#endif /* _MEDIA_FRAME_VECTOR_H */
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