| Message ID | 20231031163104.112469-3-benjamin.gaignard@collabora.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Add DELETE_BUF ioctl | expand |
Hi Benjamin, On Tue, Oct 31, 2023 at 05:30:10PM +0100, Benjamin Gaignard wrote: > Change how offset 'cookie' field value is computed to make possible > to use more buffers. > The maximum number of buffers depends of PAGE_SHIFT value and can > go up to 0x7fff when PAGE_SHIFT = 12. > With this encoding pattern we know the maximum number that a queue > could store so we can check it at queue init time. > It also make easier and faster to find buffer and plane from using > the offset field. > Change __find_plane_by_offset() prototype to return the video buffer > itself rather than it index. > > Signed-off-by: Benjamin Gaignard <benjamin.gaignard@collabora.com> > --- > .../media/common/videobuf2/videobuf2-core.c | 73 +++++++++---------- > 1 file changed, 35 insertions(+), 38 deletions(-) > Thanks a lot for working on this series. Just one comment inline. > diff --git a/drivers/media/common/videobuf2/videobuf2-core.c b/drivers/media/common/videobuf2/videobuf2-core.c > index a5e57affeb30..09be8e026044 100644 > --- a/drivers/media/common/videobuf2/videobuf2-core.c > +++ b/drivers/media/common/videobuf2/videobuf2-core.c > @@ -31,6 +31,11 @@ > > #include <trace/events/vb2.h> > > +#define PLANE_INDEX_SHIFT (PAGE_SHIFT + 3) > +#define PLANE_INDEX_MASK 0x7 Could we somehow ensure that it indeed matches VIDEO_MAX_PLANES? One thing that comes to my mind would be #define PLANE_INDEX_BITS 3 #define PLANE_INDEX_SHIFT (PAGE_SHIFT + PLANE_INDEX_BITS) #define PLANE_INDEX_MASK BIT_MASK(PLANE_INDEX_BITS) BUILD_BUG_ON(BIT(PLANE_INDEX_BITS) != VIDEO_MAX_PLANES); Alternatively we could change the videodev2.h, so that we have #define VIDEO_MAX_PLANES_BITS 3 #define VIDEO_MAX_PLANES (1U < VIDEO_MAX_PLANES_BITS) and then we can just VIDEO_MAX_PLANES_BITS in our definitions in this file and no checks would be necessary. Best regards, Tomasz > +#define MAX_BUFFER_INDEX BIT_MASK(30 - PLANE_INDEX_SHIFT) > +#define BUFFER_INDEX_MASK (MAX_BUFFER_INDEX - 1) > + > static int debug; > module_param(debug, int, 0644); > > @@ -358,21 +363,27 @@ static void __setup_offsets(struct vb2_buffer *vb) > unsigned int plane; > unsigned long offset = 0; > > - if (vb->index) { > - struct vb2_buffer *prev = q->bufs[vb->index - 1]; > - struct vb2_plane *p = &prev->planes[prev->num_planes - 1]; > - > - offset = PAGE_ALIGN(p->m.offset + p->length); > - } > + /* > + * The offset "cookie" value has the following constraints: > + * - a buffer can have up to 8 planes. > + * - v4l2 mem2mem uses bit 30 to distinguish between > + * OUTPUT (aka "source", bit 30 is 0) and > + * CAPTURE (aka "destination", bit 30 is 1) buffers. > + * - must be page aligned > + * That led to this bit mapping when PAGE_SHIFT = 12: > + * |30 |29 15|14 12|11 0| > + * |DST_QUEUE_OFF_BASE|buffer index|plane index| 0 | > + * where there are 15 bits to store the buffer index. > + * Depending on PAGE_SHIFT value we can have fewer bits > + * to store the buffer index. > + */ > + offset = vb->index << PLANE_INDEX_SHIFT; > > for (plane = 0; plane < vb->num_planes; ++plane) { > - vb->planes[plane].m.offset = offset; > + vb->planes[plane].m.offset = offset + (plane << PAGE_SHIFT); > > dprintk(q, 3, "buffer %d, plane %d offset 0x%08lx\n", > vb->index, plane, offset); > - > - offset += vb->planes[plane].length; > - offset = PAGE_ALIGN(offset); > } > } > > @@ -2188,10 +2199,9 @@ EXPORT_SYMBOL_GPL(vb2_core_streamoff); > * __find_plane_by_offset() - find plane associated with the given offset > */ > static int __find_plane_by_offset(struct vb2_queue *q, unsigned long offset, > - unsigned int *_buffer, unsigned int *_plane) > + struct vb2_buffer **vb, unsigned int *plane) > { > - struct vb2_buffer *vb; > - unsigned int buffer, plane; > + unsigned int buffer; > > /* > * Sanity checks to ensure the lock is held, MEMORY_MMAP is > @@ -2209,24 +2219,15 @@ static int __find_plane_by_offset(struct vb2_queue *q, unsigned long offset, > return -EBUSY; > } > > - /* > - * Go over all buffers and their planes, comparing the given offset > - * with an offset assigned to each plane. If a match is found, > - * return its buffer and plane numbers. > - */ > - for (buffer = 0; buffer < q->num_buffers; ++buffer) { > - vb = q->bufs[buffer]; > + /* Get buffer and plane from the offset */ > + buffer = (offset >> PLANE_INDEX_SHIFT) & BUFFER_INDEX_MASK; > + *plane = (offset >> PAGE_SHIFT) & PLANE_INDEX_MASK; > > - for (plane = 0; plane < vb->num_planes; ++plane) { > - if (vb->planes[plane].m.offset == offset) { > - *_buffer = buffer; > - *_plane = plane; > - return 0; > - } > - } > - } > + if (buffer >= q->num_buffers || *plane >= q->bufs[buffer]->num_planes) > + return -EINVAL; > > - return -EINVAL; > + *vb = q->bufs[buffer]; > + return 0; > } > > int vb2_core_expbuf(struct vb2_queue *q, int *fd, unsigned int type, > @@ -2306,7 +2307,7 @@ int vb2_mmap(struct vb2_queue *q, struct vm_area_struct *vma) > { > unsigned long offset = vma->vm_pgoff << PAGE_SHIFT; > struct vb2_buffer *vb; > - unsigned int buffer = 0, plane = 0; > + unsigned int plane = 0; > int ret; > unsigned long length; > > @@ -2335,12 +2336,10 @@ int vb2_mmap(struct vb2_queue *q, struct vm_area_struct *vma) > * Find the plane corresponding to the offset passed by userspace. This > * will return an error if not MEMORY_MMAP or file I/O is in progress. > */ > - ret = __find_plane_by_offset(q, offset, &buffer, &plane); > + ret = __find_plane_by_offset(q, offset, &vb, &plane); > if (ret) > goto unlock; > > - vb = q->bufs[buffer]; > - > /* > * MMAP requires page_aligned buffers. > * The buffer length was page_aligned at __vb2_buf_mem_alloc(), > @@ -2368,7 +2367,7 @@ int vb2_mmap(struct vb2_queue *q, struct vm_area_struct *vma) > if (ret) > return ret; > > - dprintk(q, 3, "buffer %d, plane %d successfully mapped\n", buffer, plane); > + dprintk(q, 3, "buffer %u, plane %d successfully mapped\n", vb->index, plane); > return 0; > } > EXPORT_SYMBOL_GPL(vb2_mmap); > @@ -2382,7 +2381,7 @@ unsigned long vb2_get_unmapped_area(struct vb2_queue *q, > { > unsigned long offset = pgoff << PAGE_SHIFT; > struct vb2_buffer *vb; > - unsigned int buffer, plane; > + unsigned int plane; > void *vaddr; > int ret; > > @@ -2392,12 +2391,10 @@ unsigned long vb2_get_unmapped_area(struct vb2_queue *q, > * Find the plane corresponding to the offset passed by userspace. This > * will return an error if not MEMORY_MMAP or file I/O is in progress. > */ > - ret = __find_plane_by_offset(q, offset, &buffer, &plane); > + ret = __find_plane_by_offset(q, offset, &vb, &plane); > if (ret) > goto unlock; > > - vb = q->bufs[buffer]; > - > vaddr = vb2_plane_vaddr(vb, plane); > mutex_unlock(&q->mmap_lock); > return vaddr ? (unsigned long)vaddr : -EINVAL; > -- > 2.39.2 >
Le 08/11/2023 à 07:23, Tomasz Figa a écrit : > Hi Benjamin, > > On Tue, Oct 31, 2023 at 05:30:10PM +0100, Benjamin Gaignard wrote: >> Change how offset 'cookie' field value is computed to make possible >> to use more buffers. >> The maximum number of buffers depends of PAGE_SHIFT value and can >> go up to 0x7fff when PAGE_SHIFT = 12. >> With this encoding pattern we know the maximum number that a queue >> could store so we can check it at queue init time. >> It also make easier and faster to find buffer and plane from using >> the offset field. >> Change __find_plane_by_offset() prototype to return the video buffer >> itself rather than it index. >> >> Signed-off-by: Benjamin Gaignard <benjamin.gaignard@collabora.com> >> --- >> .../media/common/videobuf2/videobuf2-core.c | 73 +++++++++---------- >> 1 file changed, 35 insertions(+), 38 deletions(-) >> > Thanks a lot for working on this series. Just one comment inline. > >> diff --git a/drivers/media/common/videobuf2/videobuf2-core.c b/drivers/media/common/videobuf2/videobuf2-core.c >> index a5e57affeb30..09be8e026044 100644 >> --- a/drivers/media/common/videobuf2/videobuf2-core.c >> +++ b/drivers/media/common/videobuf2/videobuf2-core.c >> @@ -31,6 +31,11 @@ >> >> #include <trace/events/vb2.h> >> >> +#define PLANE_INDEX_SHIFT (PAGE_SHIFT + 3) >> +#define PLANE_INDEX_MASK 0x7 > Could we somehow ensure that it indeed matches VIDEO_MAX_PLANES? > > One thing that comes to my mind would be > > #define PLANE_INDEX_BITS 3 > #define PLANE_INDEX_SHIFT (PAGE_SHIFT + PLANE_INDEX_BITS) > #define PLANE_INDEX_MASK BIT_MASK(PLANE_INDEX_BITS) > > BUILD_BUG_ON(BIT(PLANE_INDEX_BITS) != VIDEO_MAX_PLANES); > > Alternatively we could change the videodev2.h, so that we have > > #define VIDEO_MAX_PLANES_BITS 3 > #define VIDEO_MAX_PLANES (1U < VIDEO_MAX_PLANES_BITS) > > and then we can just VIDEO_MAX_PLANES_BITS in our definitions in this file > and no checks would be necessary. I would prefer this solution. Hans should I do that in an other patch ? Regards, Benjamin > > Best regards, > Tomasz > >> +#define MAX_BUFFER_INDEX BIT_MASK(30 - PLANE_INDEX_SHIFT) >> +#define BUFFER_INDEX_MASK (MAX_BUFFER_INDEX - 1) >> + >> static int debug; >> module_param(debug, int, 0644); >> >> @@ -358,21 +363,27 @@ static void __setup_offsets(struct vb2_buffer *vb) >> unsigned int plane; >> unsigned long offset = 0; >> >> - if (vb->index) { >> - struct vb2_buffer *prev = q->bufs[vb->index - 1]; >> - struct vb2_plane *p = &prev->planes[prev->num_planes - 1]; >> - >> - offset = PAGE_ALIGN(p->m.offset + p->length); >> - } >> + /* >> + * The offset "cookie" value has the following constraints: >> + * - a buffer can have up to 8 planes. >> + * - v4l2 mem2mem uses bit 30 to distinguish between >> + * OUTPUT (aka "source", bit 30 is 0) and >> + * CAPTURE (aka "destination", bit 30 is 1) buffers. >> + * - must be page aligned >> + * That led to this bit mapping when PAGE_SHIFT = 12: >> + * |30 |29 15|14 12|11 0| >> + * |DST_QUEUE_OFF_BASE|buffer index|plane index| 0 | >> + * where there are 15 bits to store the buffer index. >> + * Depending on PAGE_SHIFT value we can have fewer bits >> + * to store the buffer index. >> + */ >> + offset = vb->index << PLANE_INDEX_SHIFT; >> >> for (plane = 0; plane < vb->num_planes; ++plane) { >> - vb->planes[plane].m.offset = offset; >> + vb->planes[plane].m.offset = offset + (plane << PAGE_SHIFT); >> >> dprintk(q, 3, "buffer %d, plane %d offset 0x%08lx\n", >> vb->index, plane, offset); >> - >> - offset += vb->planes[plane].length; >> - offset = PAGE_ALIGN(offset); >> } >> } >> >> @@ -2188,10 +2199,9 @@ EXPORT_SYMBOL_GPL(vb2_core_streamoff); >> * __find_plane_by_offset() - find plane associated with the given offset >> */ >> static int __find_plane_by_offset(struct vb2_queue *q, unsigned long offset, >> - unsigned int *_buffer, unsigned int *_plane) >> + struct vb2_buffer **vb, unsigned int *plane) >> { >> - struct vb2_buffer *vb; >> - unsigned int buffer, plane; >> + unsigned int buffer; >> >> /* >> * Sanity checks to ensure the lock is held, MEMORY_MMAP is >> @@ -2209,24 +2219,15 @@ static int __find_plane_by_offset(struct vb2_queue *q, unsigned long offset, >> return -EBUSY; >> } >> >> - /* >> - * Go over all buffers and their planes, comparing the given offset >> - * with an offset assigned to each plane. If a match is found, >> - * return its buffer and plane numbers. >> - */ >> - for (buffer = 0; buffer < q->num_buffers; ++buffer) { >> - vb = q->bufs[buffer]; >> + /* Get buffer and plane from the offset */ >> + buffer = (offset >> PLANE_INDEX_SHIFT) & BUFFER_INDEX_MASK; >> + *plane = (offset >> PAGE_SHIFT) & PLANE_INDEX_MASK; >> >> - for (plane = 0; plane < vb->num_planes; ++plane) { >> - if (vb->planes[plane].m.offset == offset) { >> - *_buffer = buffer; >> - *_plane = plane; >> - return 0; >> - } >> - } >> - } >> + if (buffer >= q->num_buffers || *plane >= q->bufs[buffer]->num_planes) >> + return -EINVAL; >> >> - return -EINVAL; >> + *vb = q->bufs[buffer]; >> + return 0; >> } >> >> int vb2_core_expbuf(struct vb2_queue *q, int *fd, unsigned int type, >> @@ -2306,7 +2307,7 @@ int vb2_mmap(struct vb2_queue *q, struct vm_area_struct *vma) >> { >> unsigned long offset = vma->vm_pgoff << PAGE_SHIFT; >> struct vb2_buffer *vb; >> - unsigned int buffer = 0, plane = 0; >> + unsigned int plane = 0; >> int ret; >> unsigned long length; >> >> @@ -2335,12 +2336,10 @@ int vb2_mmap(struct vb2_queue *q, struct vm_area_struct *vma) >> * Find the plane corresponding to the offset passed by userspace. This >> * will return an error if not MEMORY_MMAP or file I/O is in progress. >> */ >> - ret = __find_plane_by_offset(q, offset, &buffer, &plane); >> + ret = __find_plane_by_offset(q, offset, &vb, &plane); >> if (ret) >> goto unlock; >> >> - vb = q->bufs[buffer]; >> - >> /* >> * MMAP requires page_aligned buffers. >> * The buffer length was page_aligned at __vb2_buf_mem_alloc(), >> @@ -2368,7 +2367,7 @@ int vb2_mmap(struct vb2_queue *q, struct vm_area_struct *vma) >> if (ret) >> return ret; >> >> - dprintk(q, 3, "buffer %d, plane %d successfully mapped\n", buffer, plane); >> + dprintk(q, 3, "buffer %u, plane %d successfully mapped\n", vb->index, plane); >> return 0; >> } >> EXPORT_SYMBOL_GPL(vb2_mmap); >> @@ -2382,7 +2381,7 @@ unsigned long vb2_get_unmapped_area(struct vb2_queue *q, >> { >> unsigned long offset = pgoff << PAGE_SHIFT; >> struct vb2_buffer *vb; >> - unsigned int buffer, plane; >> + unsigned int plane; >> void *vaddr; >> int ret; >> >> @@ -2392,12 +2391,10 @@ unsigned long vb2_get_unmapped_area(struct vb2_queue *q, >> * Find the plane corresponding to the offset passed by userspace. This >> * will return an error if not MEMORY_MMAP or file I/O is in progress. >> */ >> - ret = __find_plane_by_offset(q, offset, &buffer, &plane); >> + ret = __find_plane_by_offset(q, offset, &vb, &plane); >> if (ret) >> goto unlock; >> >> - vb = q->bufs[buffer]; >> - >> vaddr = vb2_plane_vaddr(vb, plane); >> mutex_unlock(&q->mmap_lock); >> return vaddr ? (unsigned long)vaddr : -EINVAL; >> -- >> 2.39.2 >>
On 08/11/2023 11:14, Benjamin Gaignard wrote: > > Le 08/11/2023 à 07:23, Tomasz Figa a écrit : >> Hi Benjamin, >> >> On Tue, Oct 31, 2023 at 05:30:10PM +0100, Benjamin Gaignard wrote: >>> Change how offset 'cookie' field value is computed to make possible >>> to use more buffers. >>> The maximum number of buffers depends of PAGE_SHIFT value and can >>> go up to 0x7fff when PAGE_SHIFT = 12. >>> With this encoding pattern we know the maximum number that a queue >>> could store so we can check it at queue init time. >>> It also make easier and faster to find buffer and plane from using >>> the offset field. >>> Change __find_plane_by_offset() prototype to return the video buffer >>> itself rather than it index. >>> >>> Signed-off-by: Benjamin Gaignard <benjamin.gaignard@collabora.com> >>> --- >>> .../media/common/videobuf2/videobuf2-core.c | 73 +++++++++---------- >>> 1 file changed, 35 insertions(+), 38 deletions(-) >>> >> Thanks a lot for working on this series. Just one comment inline. >> >>> diff --git a/drivers/media/common/videobuf2/videobuf2-core.c b/drivers/media/common/videobuf2/videobuf2-core.c >>> index a5e57affeb30..09be8e026044 100644 >>> --- a/drivers/media/common/videobuf2/videobuf2-core.c >>> +++ b/drivers/media/common/videobuf2/videobuf2-core.c >>> @@ -31,6 +31,11 @@ >>> #include <trace/events/vb2.h> >>> +#define PLANE_INDEX_SHIFT (PAGE_SHIFT + 3) >>> +#define PLANE_INDEX_MASK 0x7 >> Could we somehow ensure that it indeed matches VIDEO_MAX_PLANES? >> >> One thing that comes to my mind would be >> >> #define PLANE_INDEX_BITS 3 >> #define PLANE_INDEX_SHIFT (PAGE_SHIFT + PLANE_INDEX_BITS) >> #define PLANE_INDEX_MASK BIT_MASK(PLANE_INDEX_BITS) >> >> BUILD_BUG_ON(BIT(PLANE_INDEX_BITS) != VIDEO_MAX_PLANES); >> >> Alternatively we could change the videodev2.h, so that we have >> >> #define VIDEO_MAX_PLANES_BITS 3 >> #define VIDEO_MAX_PLANES (1U < VIDEO_MAX_PLANES_BITS) >> >> and then we can just VIDEO_MAX_PLANES_BITS in our definitions in this file >> and no checks would be necessary. > > I would prefer this solution. > Hans should I do that in an other patch ? I prefer to not make changes in videodev2.h, to be honest. I think it is fine to just add a check in videobuf2-core.c. Regards, Hans > > Regards, > Benjamin > >> >> Best regards, >> Tomasz >> >>> +#define MAX_BUFFER_INDEX BIT_MASK(30 - PLANE_INDEX_SHIFT) >>> +#define BUFFER_INDEX_MASK (MAX_BUFFER_INDEX - 1) >>> + >>> static int debug; >>> module_param(debug, int, 0644); >>> @@ -358,21 +363,27 @@ static void __setup_offsets(struct vb2_buffer *vb) >>> unsigned int plane; >>> unsigned long offset = 0; >>> - if (vb->index) { >>> - struct vb2_buffer *prev = q->bufs[vb->index - 1]; >>> - struct vb2_plane *p = &prev->planes[prev->num_planes - 1]; >>> - >>> - offset = PAGE_ALIGN(p->m.offset + p->length); >>> - } >>> + /* >>> + * The offset "cookie" value has the following constraints: >>> + * - a buffer can have up to 8 planes. >>> + * - v4l2 mem2mem uses bit 30 to distinguish between >>> + * OUTPUT (aka "source", bit 30 is 0) and >>> + * CAPTURE (aka "destination", bit 30 is 1) buffers. >>> + * - must be page aligned >>> + * That led to this bit mapping when PAGE_SHIFT = 12: >>> + * |30 |29 15|14 12|11 0| >>> + * |DST_QUEUE_OFF_BASE|buffer index|plane index| 0 | >>> + * where there are 15 bits to store the buffer index. >>> + * Depending on PAGE_SHIFT value we can have fewer bits >>> + * to store the buffer index. >>> + */ >>> + offset = vb->index << PLANE_INDEX_SHIFT; >>> for (plane = 0; plane < vb->num_planes; ++plane) { >>> - vb->planes[plane].m.offset = offset; >>> + vb->planes[plane].m.offset = offset + (plane << PAGE_SHIFT); >>> dprintk(q, 3, "buffer %d, plane %d offset 0x%08lx\n", >>> vb->index, plane, offset); >>> - >>> - offset += vb->planes[plane].length; >>> - offset = PAGE_ALIGN(offset); >>> } >>> } >>> @@ -2188,10 +2199,9 @@ EXPORT_SYMBOL_GPL(vb2_core_streamoff); >>> * __find_plane_by_offset() - find plane associated with the given offset >>> */ >>> static int __find_plane_by_offset(struct vb2_queue *q, unsigned long offset, >>> - unsigned int *_buffer, unsigned int *_plane) >>> + struct vb2_buffer **vb, unsigned int *plane) >>> { >>> - struct vb2_buffer *vb; >>> - unsigned int buffer, plane; >>> + unsigned int buffer; >>> /* >>> * Sanity checks to ensure the lock is held, MEMORY_MMAP is >>> @@ -2209,24 +2219,15 @@ static int __find_plane_by_offset(struct vb2_queue *q, unsigned long offset, >>> return -EBUSY; >>> } >>> - /* >>> - * Go over all buffers and their planes, comparing the given offset >>> - * with an offset assigned to each plane. If a match is found, >>> - * return its buffer and plane numbers. >>> - */ >>> - for (buffer = 0; buffer < q->num_buffers; ++buffer) { >>> - vb = q->bufs[buffer]; >>> + /* Get buffer and plane from the offset */ >>> + buffer = (offset >> PLANE_INDEX_SHIFT) & BUFFER_INDEX_MASK; >>> + *plane = (offset >> PAGE_SHIFT) & PLANE_INDEX_MASK; >>> - for (plane = 0; plane < vb->num_planes; ++plane) { >>> - if (vb->planes[plane].m.offset == offset) { >>> - *_buffer = buffer; >>> - *_plane = plane; >>> - return 0; >>> - } >>> - } >>> - } >>> + if (buffer >= q->num_buffers || *plane >= q->bufs[buffer]->num_planes) >>> + return -EINVAL; >>> - return -EINVAL; >>> + *vb = q->bufs[buffer]; >>> + return 0; >>> } >>> int vb2_core_expbuf(struct vb2_queue *q, int *fd, unsigned int type, >>> @@ -2306,7 +2307,7 @@ int vb2_mmap(struct vb2_queue *q, struct vm_area_struct *vma) >>> { >>> unsigned long offset = vma->vm_pgoff << PAGE_SHIFT; >>> struct vb2_buffer *vb; >>> - unsigned int buffer = 0, plane = 0; >>> + unsigned int plane = 0; >>> int ret; >>> unsigned long length; >>> @@ -2335,12 +2336,10 @@ int vb2_mmap(struct vb2_queue *q, struct vm_area_struct *vma) >>> * Find the plane corresponding to the offset passed by userspace. This >>> * will return an error if not MEMORY_MMAP or file I/O is in progress. >>> */ >>> - ret = __find_plane_by_offset(q, offset, &buffer, &plane); >>> + ret = __find_plane_by_offset(q, offset, &vb, &plane); >>> if (ret) >>> goto unlock; >>> - vb = q->bufs[buffer]; >>> - >>> /* >>> * MMAP requires page_aligned buffers. >>> * The buffer length was page_aligned at __vb2_buf_mem_alloc(), >>> @@ -2368,7 +2367,7 @@ int vb2_mmap(struct vb2_queue *q, struct vm_area_struct *vma) >>> if (ret) >>> return ret; >>> - dprintk(q, 3, "buffer %d, plane %d successfully mapped\n", buffer, plane); >>> + dprintk(q, 3, "buffer %u, plane %d successfully mapped\n", vb->index, plane); >>> return 0; >>> } >>> EXPORT_SYMBOL_GPL(vb2_mmap); >>> @@ -2382,7 +2381,7 @@ unsigned long vb2_get_unmapped_area(struct vb2_queue *q, >>> { >>> unsigned long offset = pgoff << PAGE_SHIFT; >>> struct vb2_buffer *vb; >>> - unsigned int buffer, plane; >>> + unsigned int plane; >>> void *vaddr; >>> int ret; >>> @@ -2392,12 +2391,10 @@ unsigned long vb2_get_unmapped_area(struct vb2_queue *q, >>> * Find the plane corresponding to the offset passed by userspace. This >>> * will return an error if not MEMORY_MMAP or file I/O is in progress. >>> */ >>> - ret = __find_plane_by_offset(q, offset, &buffer, &plane); >>> + ret = __find_plane_by_offset(q, offset, &vb, &plane); >>> if (ret) >>> goto unlock; >>> - vb = q->bufs[buffer]; >>> - >>> vaddr = vb2_plane_vaddr(vb, plane); >>> mutex_unlock(&q->mmap_lock); >>> return vaddr ? (unsigned long)vaddr : -EINVAL; >>> -- >>> 2.39.2 >>>
diff --git a/drivers/media/common/videobuf2/videobuf2-core.c b/drivers/media/common/videobuf2/videobuf2-core.c index a5e57affeb30..09be8e026044 100644 --- a/drivers/media/common/videobuf2/videobuf2-core.c +++ b/drivers/media/common/videobuf2/videobuf2-core.c @@ -31,6 +31,11 @@ #include <trace/events/vb2.h> +#define PLANE_INDEX_SHIFT (PAGE_SHIFT + 3) +#define PLANE_INDEX_MASK 0x7 +#define MAX_BUFFER_INDEX BIT_MASK(30 - PLANE_INDEX_SHIFT) +#define BUFFER_INDEX_MASK (MAX_BUFFER_INDEX - 1) + static int debug; module_param(debug, int, 0644); @@ -358,21 +363,27 @@ static void __setup_offsets(struct vb2_buffer *vb) unsigned int plane; unsigned long offset = 0; - if (vb->index) { - struct vb2_buffer *prev = q->bufs[vb->index - 1]; - struct vb2_plane *p = &prev->planes[prev->num_planes - 1]; - - offset = PAGE_ALIGN(p->m.offset + p->length); - } + /* + * The offset "cookie" value has the following constraints: + * - a buffer can have up to 8 planes. + * - v4l2 mem2mem uses bit 30 to distinguish between + * OUTPUT (aka "source", bit 30 is 0) and + * CAPTURE (aka "destination", bit 30 is 1) buffers. + * - must be page aligned + * That led to this bit mapping when PAGE_SHIFT = 12: + * |30 |29 15|14 12|11 0| + * |DST_QUEUE_OFF_BASE|buffer index|plane index| 0 | + * where there are 15 bits to store the buffer index. + * Depending on PAGE_SHIFT value we can have fewer bits + * to store the buffer index. + */ + offset = vb->index << PLANE_INDEX_SHIFT; for (plane = 0; plane < vb->num_planes; ++plane) { - vb->planes[plane].m.offset = offset; + vb->planes[plane].m.offset = offset + (plane << PAGE_SHIFT); dprintk(q, 3, "buffer %d, plane %d offset 0x%08lx\n", vb->index, plane, offset); - - offset += vb->planes[plane].length; - offset = PAGE_ALIGN(offset); } } @@ -2188,10 +2199,9 @@ EXPORT_SYMBOL_GPL(vb2_core_streamoff); * __find_plane_by_offset() - find plane associated with the given offset */ static int __find_plane_by_offset(struct vb2_queue *q, unsigned long offset, - unsigned int *_buffer, unsigned int *_plane) + struct vb2_buffer **vb, unsigned int *plane) { - struct vb2_buffer *vb; - unsigned int buffer, plane; + unsigned int buffer; /* * Sanity checks to ensure the lock is held, MEMORY_MMAP is @@ -2209,24 +2219,15 @@ static int __find_plane_by_offset(struct vb2_queue *q, unsigned long offset, return -EBUSY; } - /* - * Go over all buffers and their planes, comparing the given offset - * with an offset assigned to each plane. If a match is found, - * return its buffer and plane numbers. - */ - for (buffer = 0; buffer < q->num_buffers; ++buffer) { - vb = q->bufs[buffer]; + /* Get buffer and plane from the offset */ + buffer = (offset >> PLANE_INDEX_SHIFT) & BUFFER_INDEX_MASK; + *plane = (offset >> PAGE_SHIFT) & PLANE_INDEX_MASK; - for (plane = 0; plane < vb->num_planes; ++plane) { - if (vb->planes[plane].m.offset == offset) { - *_buffer = buffer; - *_plane = plane; - return 0; - } - } - } + if (buffer >= q->num_buffers || *plane >= q->bufs[buffer]->num_planes) + return -EINVAL; - return -EINVAL; + *vb = q->bufs[buffer]; + return 0; } int vb2_core_expbuf(struct vb2_queue *q, int *fd, unsigned int type, @@ -2306,7 +2307,7 @@ int vb2_mmap(struct vb2_queue *q, struct vm_area_struct *vma) { unsigned long offset = vma->vm_pgoff << PAGE_SHIFT; struct vb2_buffer *vb; - unsigned int buffer = 0, plane = 0; + unsigned int plane = 0; int ret; unsigned long length; @@ -2335,12 +2336,10 @@ int vb2_mmap(struct vb2_queue *q, struct vm_area_struct *vma) * Find the plane corresponding to the offset passed by userspace. This * will return an error if not MEMORY_MMAP or file I/O is in progress. */ - ret = __find_plane_by_offset(q, offset, &buffer, &plane); + ret = __find_plane_by_offset(q, offset, &vb, &plane); if (ret) goto unlock; - vb = q->bufs[buffer]; - /* * MMAP requires page_aligned buffers. * The buffer length was page_aligned at __vb2_buf_mem_alloc(), @@ -2368,7 +2367,7 @@ int vb2_mmap(struct vb2_queue *q, struct vm_area_struct *vma) if (ret) return ret; - dprintk(q, 3, "buffer %d, plane %d successfully mapped\n", buffer, plane); + dprintk(q, 3, "buffer %u, plane %d successfully mapped\n", vb->index, plane); return 0; } EXPORT_SYMBOL_GPL(vb2_mmap); @@ -2382,7 +2381,7 @@ unsigned long vb2_get_unmapped_area(struct vb2_queue *q, { unsigned long offset = pgoff << PAGE_SHIFT; struct vb2_buffer *vb; - unsigned int buffer, plane; + unsigned int plane; void *vaddr; int ret; @@ -2392,12 +2391,10 @@ unsigned long vb2_get_unmapped_area(struct vb2_queue *q, * Find the plane corresponding to the offset passed by userspace. This * will return an error if not MEMORY_MMAP or file I/O is in progress. */ - ret = __find_plane_by_offset(q, offset, &buffer, &plane); + ret = __find_plane_by_offset(q, offset, &vb, &plane); if (ret) goto unlock; - vb = q->bufs[buffer]; - vaddr = vb2_plane_vaddr(vb, plane); mutex_unlock(&q->mmap_lock); return vaddr ? (unsigned long)vaddr : -EINVAL;
Change how offset 'cookie' field value is computed to make possible to use more buffers. The maximum number of buffers depends of PAGE_SHIFT value and can go up to 0x7fff when PAGE_SHIFT = 12. With this encoding pattern we know the maximum number that a queue could store so we can check it at queue init time. It also make easier and faster to find buffer and plane from using the offset field. Change __find_plane_by_offset() prototype to return the video buffer itself rather than it index. Signed-off-by: Benjamin Gaignard <benjamin.gaignard@collabora.com> --- .../media/common/videobuf2/videobuf2-core.c | 73 +++++++++---------- 1 file changed, 35 insertions(+), 38 deletions(-)