On 5/13/25 11:27, wangtao wrote:
Add DMA_BUF_IOCTL_RW_FILE to save/restore data from/to a dma-buf.
Similar approach where rejected before in favor of using udmabuf.
Is there any reason you can't use that approach as well?
Regards, Christian.
Signed-off-by: wangtao tao.wangtao@honor.com
drivers/dma-buf/dma-buf.c | 8 ++++++++ include/linux/dma-buf.h | 3 +++ include/uapi/linux/dma-buf.h | 29 +++++++++++++++++++++++++++++ 3 files changed, 40 insertions(+)
diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c index 5baa83b85515..95d8b0158ffd 100644 --- a/drivers/dma-buf/dma-buf.c +++ b/drivers/dma-buf/dma-buf.c @@ -460,6 +460,7 @@ static long dma_buf_ioctl(struct file *file, struct dma_buf *dmabuf; struct dma_buf_sync sync; enum dma_data_direction direction;
- struct dma_buf_rw_file kfile; int ret;
dmabuf = file->private_data; @@ -504,6 +505,13 @@ static long dma_buf_ioctl(struct file *file, return dma_buf_import_sync_file(dmabuf, (const void __user *)arg); #endif
- case DMA_BUF_IOCTL_RW_FILE:
if (copy_from_user(&kfile, (void __user *) arg, sizeof(kfile)))return -EFAULT;if (!dmabuf->ops->rw_file)return -EINVAL;return dmabuf->ops->rw_file(dmabuf, &kfile);- default: return -ENOTTY; }
diff --git a/include/linux/dma-buf.h b/include/linux/dma-buf.h index 36216d28d8bd..de236ba2094b 100644 --- a/include/linux/dma-buf.h +++ b/include/linux/dma-buf.h @@ -22,6 +22,7 @@ #include <linux/fs.h> #include <linux/dma-fence.h> #include <linux/wait.h> +#include <uapi/linux/dma-buf.h> struct device; struct dma_buf; @@ -285,6 +286,8 @@ struct dma_buf_ops { int (*vmap)(struct dma_buf *dmabuf, struct iosys_map *map); void (*vunmap)(struct dma_buf *dmabuf, struct iosys_map *map);
- int (*rw_file)(struct dma_buf *dmabuf, struct dma_buf_rw_file *file);
}; /** diff --git a/include/uapi/linux/dma-buf.h b/include/uapi/linux/dma-buf.h index 5a6fda66d9ad..ec9164b7b753 100644 --- a/include/uapi/linux/dma-buf.h +++ b/include/uapi/linux/dma-buf.h @@ -167,6 +167,29 @@ struct dma_buf_import_sync_file { __s32 fd; }; +/**
- struct dma_buf_rw_file - read/write file associated with a dma-buf
- Userspace can performs a DMA_BUF_IOCTL_BACK to save data from a dma-buf or
- restore data to a dma-buf.
- */
+struct dma_buf_rw_file {
- /** @flags: Flags indicating read/write for this dma-buf. */
- __u32 flags;
- /** @fd: File descriptor of the file associated with this dma-buf. */
- __s32 fd;
- /** @file_offset: Offset within the file where this dma-buf starts.
** Offset and Length must be page-aligned for direct I/O.*/- __u64 file_offset;
- /** @buf_offset: Offset within this dma-buf where the read/write starts. */
- __u64 buf_offset;
- /** @buf_len: Length of this dma-buf read/write. */
- __u64 buf_len;
+};
#define DMA_BUF_BASE 'b' #define DMA_BUF_IOCTL_SYNC _IOW(DMA_BUF_BASE, 0, struct dma_buf_sync) @@ -179,4 +202,10 @@ struct dma_buf_import_sync_file { #define DMA_BUF_IOCTL_EXPORT_SYNC_FILE _IOWR(DMA_BUF_BASE, 2, struct dma_buf_export_sync_file) #define DMA_BUF_IOCTL_IMPORT_SYNC_FILE _IOW(DMA_BUF_BASE, 3, struct dma_buf_import_sync_file) +#define DMA_BUF_RW_FLAGS_OP_MASK (0xFF << 0) +#define DMA_BUF_RW_FLAGS_READ (1 << 0) /* Restore dma-buf data */ +#define DMA_BUF_RW_FLAGS_WRITE (2 << 0) /* Save dma-buf data */ +#define DMA_BUF_RW_FLAGS_DIRECT (1u << 31) /* Direct read/write file */ +#define DMA_BUF_IOCTL_RW_FILE _IOW(DMA_BUF_BASE, 4, struct dma_buf_rw_file)
#endif
On Tue, May 13, 2025 at 4:31 AM Christian König christian.koenig@amd.com wrote:
On 5/13/25 11:27, wangtao wrote:
Add DMA_BUF_IOCTL_RW_FILE to save/restore data from/to a dma-buf.
Similar approach where rejected before in favor of using udmabuf.
Is there any reason you can't use that approach as well?
I also recently verified that udmabuf + O_DIRECT works with sendfile(), and you can even MADV_COLLAPSE the underlying shmem if you want.
Regards, Christian.
Signed-off-by: wangtao tao.wangtao@honor.com
drivers/dma-buf/dma-buf.c | 8 ++++++++ include/linux/dma-buf.h | 3 +++ include/uapi/linux/dma-buf.h | 29 +++++++++++++++++++++++++++++ 3 files changed, 40 insertions(+)
diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c index 5baa83b85515..95d8b0158ffd 100644 --- a/drivers/dma-buf/dma-buf.c +++ b/drivers/dma-buf/dma-buf.c @@ -460,6 +460,7 @@ static long dma_buf_ioctl(struct file *file, struct dma_buf *dmabuf; struct dma_buf_sync sync; enum dma_data_direction direction;
struct dma_buf_rw_file kfile; int ret; dmabuf = file->private_data;@@ -504,6 +505,13 @@ static long dma_buf_ioctl(struct file *file, return dma_buf_import_sync_file(dmabuf, (const void __user *)arg); #endif
case DMA_BUF_IOCTL_RW_FILE:if (copy_from_user(&kfile, (void __user *) arg, sizeof(kfile)))return -EFAULT;if (!dmabuf->ops->rw_file)return -EINVAL;return dmabuf->ops->rw_file(dmabuf, &kfile);default: return -ENOTTY; }diff --git a/include/linux/dma-buf.h b/include/linux/dma-buf.h index 36216d28d8bd..de236ba2094b 100644 --- a/include/linux/dma-buf.h +++ b/include/linux/dma-buf.h @@ -22,6 +22,7 @@ #include <linux/fs.h> #include <linux/dma-fence.h> #include <linux/wait.h> +#include <uapi/linux/dma-buf.h>
struct device; struct dma_buf; @@ -285,6 +286,8 @@ struct dma_buf_ops {
int (*vmap)(struct dma_buf *dmabuf, struct iosys_map *map); void (*vunmap)(struct dma_buf *dmabuf, struct iosys_map *map);
int (*rw_file)(struct dma_buf *dmabuf, struct dma_buf_rw_file *file);};
/** diff --git a/include/uapi/linux/dma-buf.h b/include/uapi/linux/dma-buf.h index 5a6fda66d9ad..ec9164b7b753 100644 --- a/include/uapi/linux/dma-buf.h +++ b/include/uapi/linux/dma-buf.h @@ -167,6 +167,29 @@ struct dma_buf_import_sync_file { __s32 fd; };
+/**
- struct dma_buf_rw_file - read/write file associated with a dma-buf
- Userspace can performs a DMA_BUF_IOCTL_BACK to save data from a dma-buf or
- restore data to a dma-buf.
- */
+struct dma_buf_rw_file {
/** @flags: Flags indicating read/write for this dma-buf. */__u32 flags;/** @fd: File descriptor of the file associated with this dma-buf. */__s32 fd;/** @file_offset: Offset within the file where this dma-buf starts.** Offset and Length must be page-aligned for direct I/O.*/__u64 file_offset;/** @buf_offset: Offset within this dma-buf where the read/write starts. */__u64 buf_offset;/** @buf_len: Length of this dma-buf read/write. */__u64 buf_len;+};
#define DMA_BUF_BASE 'b' #define DMA_BUF_IOCTL_SYNC _IOW(DMA_BUF_BASE, 0, struct dma_buf_sync)
@@ -179,4 +202,10 @@ struct dma_buf_import_sync_file { #define DMA_BUF_IOCTL_EXPORT_SYNC_FILE _IOWR(DMA_BUF_BASE, 2, struct dma_buf_export_sync_file) #define DMA_BUF_IOCTL_IMPORT_SYNC_FILE _IOW(DMA_BUF_BASE, 3, struct dma_buf_import_sync_file)
+#define DMA_BUF_RW_FLAGS_OP_MASK (0xFF << 0) +#define DMA_BUF_RW_FLAGS_READ (1 << 0) /* Restore dma-buf data */ +#define DMA_BUF_RW_FLAGS_WRITE (2 << 0) /* Save dma-buf data */ +#define DMA_BUF_RW_FLAGS_DIRECT (1u << 31) /* Direct read/write file */ +#define DMA_BUF_IOCTL_RW_FILE _IOW(DMA_BUF_BASE, 4, struct dma_buf_rw_file)
#endif
On 5/13/25 17:55, T.J. Mercier wrote:
On Tue, May 13, 2025 at 4:31 AM Christian König christian.koenig@amd.com wrote:
On 5/13/25 11:27, wangtao wrote:
Add DMA_BUF_IOCTL_RW_FILE to save/restore data from/to a dma-buf.
Similar approach where rejected before in favor of using udmabuf.
Is there any reason you can't use that approach as well?
I also recently verified that udmabuf + O_DIRECT works with sendfile(), and you can even MADV_COLLAPSE the underlying shmem if you want.
Oh, nice :)
Going to keep that in mind if somebody ask for that feature again.
Regards, Christian.
Regards, Christian.
Signed-off-by: wangtao tao.wangtao@honor.com
drivers/dma-buf/dma-buf.c | 8 ++++++++ include/linux/dma-buf.h | 3 +++ include/uapi/linux/dma-buf.h | 29 +++++++++++++++++++++++++++++ 3 files changed, 40 insertions(+)
diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c index 5baa83b85515..95d8b0158ffd 100644 --- a/drivers/dma-buf/dma-buf.c +++ b/drivers/dma-buf/dma-buf.c @@ -460,6 +460,7 @@ static long dma_buf_ioctl(struct file *file, struct dma_buf *dmabuf; struct dma_buf_sync sync; enum dma_data_direction direction;
struct dma_buf_rw_file kfile; int ret; dmabuf = file->private_data;@@ -504,6 +505,13 @@ static long dma_buf_ioctl(struct file *file, return dma_buf_import_sync_file(dmabuf, (const void __user *)arg); #endif
case DMA_BUF_IOCTL_RW_FILE:if (copy_from_user(&kfile, (void __user *) arg, sizeof(kfile)))return -EFAULT;if (!dmabuf->ops->rw_file)return -EINVAL;return dmabuf->ops->rw_file(dmabuf, &kfile);default: return -ENOTTY; }diff --git a/include/linux/dma-buf.h b/include/linux/dma-buf.h index 36216d28d8bd..de236ba2094b 100644 --- a/include/linux/dma-buf.h +++ b/include/linux/dma-buf.h @@ -22,6 +22,7 @@ #include <linux/fs.h> #include <linux/dma-fence.h> #include <linux/wait.h> +#include <uapi/linux/dma-buf.h>
struct device; struct dma_buf; @@ -285,6 +286,8 @@ struct dma_buf_ops {
int (*vmap)(struct dma_buf *dmabuf, struct iosys_map *map); void (*vunmap)(struct dma_buf *dmabuf, struct iosys_map *map);
int (*rw_file)(struct dma_buf *dmabuf, struct dma_buf_rw_file *file);};
/** diff --git a/include/uapi/linux/dma-buf.h b/include/uapi/linux/dma-buf.h index 5a6fda66d9ad..ec9164b7b753 100644 --- a/include/uapi/linux/dma-buf.h +++ b/include/uapi/linux/dma-buf.h @@ -167,6 +167,29 @@ struct dma_buf_import_sync_file { __s32 fd; };
+/**
- struct dma_buf_rw_file - read/write file associated with a dma-buf
- Userspace can performs a DMA_BUF_IOCTL_BACK to save data from a dma-buf or
- restore data to a dma-buf.
- */
+struct dma_buf_rw_file {
/** @flags: Flags indicating read/write for this dma-buf. */__u32 flags;/** @fd: File descriptor of the file associated with this dma-buf. */__s32 fd;/** @file_offset: Offset within the file where this dma-buf starts.** Offset and Length must be page-aligned for direct I/O.*/__u64 file_offset;/** @buf_offset: Offset within this dma-buf where the read/write starts. */__u64 buf_offset;/** @buf_len: Length of this dma-buf read/write. */__u64 buf_len;+};
#define DMA_BUF_BASE 'b' #define DMA_BUF_IOCTL_SYNC _IOW(DMA_BUF_BASE, 0, struct dma_buf_sync)
@@ -179,4 +202,10 @@ struct dma_buf_import_sync_file { #define DMA_BUF_IOCTL_EXPORT_SYNC_FILE _IOWR(DMA_BUF_BASE, 2, struct dma_buf_export_sync_file) #define DMA_BUF_IOCTL_IMPORT_SYNC_FILE _IOW(DMA_BUF_BASE, 3, struct dma_buf_import_sync_file)
+#define DMA_BUF_RW_FLAGS_OP_MASK (0xFF << 0) +#define DMA_BUF_RW_FLAGS_READ (1 << 0) /* Restore dma-buf data */ +#define DMA_BUF_RW_FLAGS_WRITE (2 << 0) /* Save dma-buf data */ +#define DMA_BUF_RW_FLAGS_DIRECT (1u << 31) /* Direct read/write file */ +#define DMA_BUF_IOCTL_RW_FILE _IOW(DMA_BUF_BASE, 4, struct dma_buf_rw_file)
#endif
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