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[PATCH v2 11/13] udmabuf: drop WARN_ON() check.

by Gerd Hoffmann

Reported-by: Laurent Pinchart <laurent.pinchart(a)ideasonboard.com> Signed-off-by: Gerd Hoffmann <kraxel(a)redhat.com> --- drivers/dma-buf/udmabuf.c | 3 --- 1 file changed, 3 deletions(-) diff --git a/drivers/dma-buf/udmabuf.c b/drivers/dma-buf/udmabuf.c index b637a8be6d..7a4fd2194d 100644 --- a/drivers/dma-buf/udmabuf.c +++ b/drivers/dma-buf/udmabuf.c @@ -25,9 +25,6 @@ static int udmabuf_vm_fault(struct vm_fault *vmf) struct vm_area_struct *vma = vmf->vma; struct udmabuf *ubuf = vma->vm_private_data; - if (WARN_ON(vmf->pgoff >= ubuf->pagecount)) - return VM_FAULT_SIGBUS; - vmf->page = ubuf->pages[vmf->pgoff]; get_page(vmf->page); return 0; -- 2.9.3

7 years

[PATCH v2 13/13] udmabuf: add documentation

by Gerd Hoffmann

Signed-off-by: Gerd Hoffmann <kraxel(a)redhat.com> --- include/uapi/linux/udmabuf.h | 50 +++++++++++++++++++++++++++++++++--- Documentation/driver-api/dma-buf.rst | 8 ++++++ 2 files changed, 55 insertions(+), 3 deletions(-) diff --git a/include/uapi/linux/udmabuf.h b/include/uapi/linux/udmabuf.h index 46b6532ed8..f30b37cb5c 100644 --- a/include/uapi/linux/udmabuf.h +++ b/include/uapi/linux/udmabuf.h @@ -5,8 +5,38 @@ #include <linux/types.h> #include <linux/ioctl.h> +/** + * DOC: udmabuf + * + * udmabuf is a device driver which allows userspace create dmabufs. + * The memory used for these dmabufs must be backed by memfd. The + * memfd must have F_SEAL_SHRINK and it must not have F_SEAL_WRITE. + * + * The driver has two ioctls, one to create a dmabuf from a single + * memory block and one to create a dmabuf from a list of memory + * blocks. + * + * UDMABUF_CREATE - _IOW('u', 0x42, udmabuf_create) + * + * UDMABUF_CREATE_LIST - _IOW('u', 0x43, udmabuf_create_list) + */ + +#define UDMABUF_CREATE _IOW('u', 0x42, struct udmabuf_create) +#define UDMABUF_CREATE_LIST _IOW('u', 0x43, struct udmabuf_create_list) + #define UDMABUF_FLAGS_CLOEXEC 0x01 +/** + * struct udmabuf_create - create a dmabuf from a single memory block. + * + * @memfd: The file handle. + * @offset: Start of the buffer (from memfd start). + * Must be page aligned. + * @size: Size of the buffer. Must be rounded to page size. + * + * flags: + * UDMABUF_FLAGS_CLOEXEC: set CLOEXEC flag for the dmabuf. + */ struct udmabuf_create { __u32 memfd; __u32 flags; @@ -14,6 +44,14 @@ struct udmabuf_create { __u64 size; }; +/** + * struct udmabuf_create_item - one memory block list item. + * + * @memfd: The file handle. + * @offset: Start of the buffer (from memfd start). + * Must be page aligned. + * @size: Size of the buffer. Must be rounded to page size. + */ struct udmabuf_create_item { __u32 memfd; __u32 __pad; @@ -21,13 +59,19 @@ struct udmabuf_create_item { __u64 size; }; +/** + * struct udmabuf_create_list - create a dmabuf from a memory block list. + * + * @count: The number of list elements. + * @list: The memory block list + * + * flags: + * UDMABUF_FLAGS_CLOEXEC: set CLOEXEC flag for the dmabuf. + */ struct udmabuf_create_list { __u32 flags; __u32 count; struct udmabuf_create_item list[]; }; -#define UDMABUF_CREATE _IOW('u', 0x42, struct udmabuf_create) -#define UDMABUF_CREATE_LIST _IOW('u', 0x43, struct udmabuf_create_list) - #endif /* _UAPI_LINUX_UDMABUF_H */ diff --git a/Documentation/driver-api/dma-buf.rst b/Documentation/driver-api/dma-buf.rst index b541e97c7a..1f62c30a14 100644 --- a/Documentation/driver-api/dma-buf.rst +++ b/Documentation/driver-api/dma-buf.rst @@ -166,3 +166,11 @@ DMA Fence uABI/Sync File .. kernel-doc:: include/linux/sync_file.h :internal: +Userspace DMA Buffer driver +~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +.. kernel-doc:: include/uapi/linux/udmabuf.h + :doc: udmabuf + +.. kernel-doc:: include/uapi/linux/udmabuf.h + :internal: -- 2.9.3

7 years

[PATCH v2 12/13] udmabuf: use sizeof(variable) instead of sizeof(type)

by Gerd Hoffmann

Reported-by: Laurent Pinchart <laurent.pinchart(a)ideasonboard.com> Signed-off-by: Gerd Hoffmann <kraxel(a)redhat.com> --- drivers/dma-buf/udmabuf.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/dma-buf/udmabuf.c b/drivers/dma-buf/udmabuf.c index 7a4fd2194d..92af9b5300 100644 --- a/drivers/dma-buf/udmabuf.c +++ b/drivers/dma-buf/udmabuf.c @@ -128,7 +128,7 @@ static long udmabuf_create(const struct udmabuf_create_list *head, int seals, ret = -EINVAL; u32 i, flags; - ubuf = kzalloc(sizeof(struct udmabuf), GFP_KERNEL); + ubuf = kzalloc(sizeof(*ubuf), GFP_KERNEL); if (!ubuf) return -ENOMEM; @@ -142,7 +142,7 @@ static long udmabuf_create(const struct udmabuf_create_list *head, if (ubuf->pagecount > pglimit) goto err; } - ubuf->pages = kmalloc_array(ubuf->pagecount, sizeof(struct page *), + ubuf->pages = kmalloc_array(ubuf->pagecount, sizeof(*ubuf->pages), GFP_KERNEL); if (!ubuf->pages) { ret = -ENOMEM; @@ -211,7 +211,7 @@ static long udmabuf_ioctl_create(struct file *filp, unsigned long arg) struct udmabuf_create_item list; if (copy_from_user(&create, (void __user *)arg, - sizeof(struct udmabuf_create))) + sizeof(create))) return -EFAULT; head.flags = create.flags; -- 2.9.3

7 years

[PATCH v2 05/13] udmabuf: constify udmabuf_create args

by Gerd Hoffmann

7 years

[PATCH v2 10/13] udmabuf: use ENOTTY for invalid ioctls

by Gerd Hoffmann

7 years

[PATCH v2 09/13] udmabuf: use EBADFD in case we didn't got a memfd

by Gerd Hoffmann

Reported-by: Laurent Pinchart <laurent.pinchart(a)ideasonboard.com> Signed-off-by: Gerd Hoffmann <kraxel(a)redhat.com> Acked-by: Daniel Vetter <daniel.vetter(a)ffwll.ch> --- drivers/dma-buf/udmabuf.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/drivers/dma-buf/udmabuf.c b/drivers/dma-buf/udmabuf.c index e821361566..652707f993 100644 --- a/drivers/dma-buf/udmabuf.c +++ b/drivers/dma-buf/udmabuf.c @@ -154,14 +154,17 @@ static long udmabuf_create(const struct udmabuf_create_list *head, pgbuf = 0; for (i = 0; i < head->count; i++) { + ret = -EBADFD; memfd = fget(list[i].memfd); if (!memfd) goto err; if (!shmem_mapping(file_inode(memfd)->i_mapping)) goto err; seals = memfd_fcntl(memfd, F_GET_SEALS, 0); - if (seals == -EINVAL || - (seals & SEALS_WANTED) != SEALS_WANTED || + if (seals == -EINVAL) + goto err; + ret = -EINVAL; + if ((seals & SEALS_WANTED) != SEALS_WANTED || (seals & SEALS_DENIED) != 0) goto err; pgoff = list[i].offset >> PAGE_SHIFT; -- 2.9.3

7 years

[PATCH v2 08/13] udmabuf: improve udmabuf_create error handling

by Gerd Hoffmann

Reported-by: Laurent Pinchart <laurent.pinchart(a)ideasonboard.com> Signed-off-by: Gerd Hoffmann <kraxel(a)redhat.com> Reviewed-by: Laurent Pinchart <laurent.pinchart(a)ideasonboard.com> Acked-by: Daniel Vetter <daniel.vetter(a)ffwll.ch> --- drivers/dma-buf/udmabuf.c | 25 ++++++++++++------------- 1 file changed, 12 insertions(+), 13 deletions(-) diff --git a/drivers/dma-buf/udmabuf.c b/drivers/dma-buf/udmabuf.c index a01fcf6a66..e821361566 100644 --- a/drivers/dma-buf/udmabuf.c +++ b/drivers/dma-buf/udmabuf.c @@ -126,7 +126,7 @@ static long udmabuf_create(const struct udmabuf_create_list *head, struct file *memfd = NULL; struct udmabuf *ubuf; struct dma_buf *buf; - pgoff_t pgoff, pgcnt, pgidx, pgbuf, pglimit; + pgoff_t pgoff, pgcnt, pgidx, pgbuf = 0, pglimit; struct page *page; int seals, ret = -EINVAL; u32 i, flags; @@ -138,32 +138,32 @@ static long udmabuf_create(const struct udmabuf_create_list *head, pglimit = (size_limit_mb * 1024 * 1024) >> PAGE_SHIFT; for (i = 0; i < head->count; i++) { if (!IS_ALIGNED(list[i].offset, PAGE_SIZE)) - goto err_free_ubuf; + goto err; if (!IS_ALIGNED(list[i].size, PAGE_SIZE)) - goto err_free_ubuf; + goto err; ubuf->pagecount += list[i].size >> PAGE_SHIFT; if (ubuf->pagecount > pglimit) - goto err_free_ubuf; + goto err; } ubuf->pages = kmalloc_array(ubuf->pagecount, sizeof(struct page *), GFP_KERNEL); if (!ubuf->pages) { ret = -ENOMEM; - goto err_free_ubuf; + goto err; } pgbuf = 0; for (i = 0; i < head->count; i++) { memfd = fget(list[i].memfd); if (!memfd) - goto err_put_pages; + goto err; if (!shmem_mapping(file_inode(memfd)->i_mapping)) - goto err_put_pages; + goto err; seals = memfd_fcntl(memfd, F_GET_SEALS, 0); if (seals == -EINVAL || (seals & SEALS_WANTED) != SEALS_WANTED || (seals & SEALS_DENIED) != 0) - goto err_put_pages; + goto err; pgoff = list[i].offset >> PAGE_SHIFT; pgcnt = list[i].size >> PAGE_SHIFT; for (pgidx = 0; pgidx < pgcnt; pgidx++) { @@ -171,13 +171,13 @@ static long udmabuf_create(const struct udmabuf_create_list *head, file_inode(memfd)->i_mapping, pgoff + pgidx); if (IS_ERR(page)) { ret = PTR_ERR(page); - goto err_put_pages; + goto err; } ubuf->pages[pgbuf++] = page; } fput(memfd); + memfd = NULL; } - memfd = NULL; exp_info.ops = &udmabuf_ops; exp_info.size = ubuf->pagecount << PAGE_SHIFT; @@ -186,7 +186,7 @@ static long udmabuf_create(const struct udmabuf_create_list *head, buf = dma_buf_export(&exp_info); if (IS_ERR(buf)) { ret = PTR_ERR(buf); - goto err_put_pages; + goto err; } flags = 0; @@ -194,10 +194,9 @@ static long udmabuf_create(const struct udmabuf_create_list *head, flags |= O_CLOEXEC; return dma_buf_fd(buf, flags); -err_put_pages: +err: while (pgbuf > 0) put_page(ubuf->pages[--pgbuf]); -err_free_ubuf: if (memfd) fput(memfd); kfree(ubuf->pages); -- 2.9.3

7 years

[PATCH v2 07/13] udmabuf: rework limits

by Gerd Hoffmann

Create variable for the list length limit. Serves as documentation, also allows to make it a module parameter if needed. Also add a total size limit. Signed-off-by: Gerd Hoffmann <kraxel(a)redhat.com> Acked-by: Daniel Vetter <daniel.vetter(a)ffwll.ch> --- drivers/dma-buf/udmabuf.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/drivers/dma-buf/udmabuf.c b/drivers/dma-buf/udmabuf.c index 4167da8141..a01fcf6a66 100644 --- a/drivers/dma-buf/udmabuf.c +++ b/drivers/dma-buf/udmabuf.c @@ -12,6 +12,9 @@ #include <linux/slab.h> #include <linux/udmabuf.h> +static const u32 list_limit = 1024; /* udmabuf_create_list->count limit */ +static const size_t size_limit_mb = 64; /* total dmabuf size, in megabytes */ + struct udmabuf { pgoff_t pagecount; struct page **pages; @@ -123,7 +126,7 @@ static long udmabuf_create(const struct udmabuf_create_list *head, struct file *memfd = NULL; struct udmabuf *ubuf; struct dma_buf *buf; - pgoff_t pgoff, pgcnt, pgidx, pgbuf; + pgoff_t pgoff, pgcnt, pgidx, pgbuf, pglimit; struct page *page; int seals, ret = -EINVAL; u32 i, flags; @@ -132,12 +135,15 @@ static long udmabuf_create(const struct udmabuf_create_list *head, if (!ubuf) return -ENOMEM; + pglimit = (size_limit_mb * 1024 * 1024) >> PAGE_SHIFT; for (i = 0; i < head->count; i++) { if (!IS_ALIGNED(list[i].offset, PAGE_SIZE)) goto err_free_ubuf; if (!IS_ALIGNED(list[i].size, PAGE_SIZE)) goto err_free_ubuf; ubuf->pagecount += list[i].size >> PAGE_SHIFT; + if (ubuf->pagecount > pglimit) + goto err_free_ubuf; } ubuf->pages = kmalloc_array(ubuf->pagecount, sizeof(struct page *), GFP_KERNEL); @@ -227,7 +233,7 @@ static long udmabuf_ioctl_create_list(struct file *filp, unsigned long arg) if (copy_from_user(&head, (void __user *)arg, sizeof(head))) return -EFAULT; - if (head.count > 1024) + if (head.count > list_limit) return -EINVAL; lsize = sizeof(struct udmabuf_create_item) * head.count; list = memdup_user((void __user *)(arg + sizeof(head)), lsize); -- 2.9.3

7 years

[PATCH v2 06/13] udmabuf: add MEMFD_CREATE dependency

by Gerd Hoffmann

udmabuf builds without it, but if userspace can not create memfd handles in the first place it is rather pointless to include it, except for test builds. Signed-off-by: Gerd Hoffmann <kraxel(a)redhat.com> Acked-by: Daniel Vetter <daniel.vetter(a)ffwll.ch> --- drivers/dma-buf/Kconfig | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/dma-buf/Kconfig b/drivers/dma-buf/Kconfig index 338129eb12..2e5a0faa2c 100644 --- a/drivers/dma-buf/Kconfig +++ b/drivers/dma-buf/Kconfig @@ -34,6 +34,7 @@ config UDMABUF bool "userspace dmabuf misc driver" default n depends on DMA_SHARED_BUFFER + depends on MEMFD_CREATE || COMPILE_TEST help A driver to let userspace turn memfd regions into dma-bufs. Qemu can use this to create host dmabufs for guest framebuffers. -- 2.9.3

7 years

[PATCH v2 04/13] udmabuf: constify udmabuf_ops

by Gerd Hoffmann

7 years

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