Previously all data passed over binder needed to be serialized, with the exception of Binder objects and file descriptors. This patchs adds support for scatter-gathering raw memory buffers into a binder transaction, avoiding the need to first serialize them into a Parcel. To remain backwards compatibile with existing binder clients, it introduces two new command ioctls for this purpose - BC_TRANSACTION_SG and BC_REPLY_SG. These commands may only be used with the new binder_transaction_data_sg structure, which adds a field for the total size of the buffers we are scatter-gathering. Because memory buffers may contain pointers to other buffers, we allow callers to specify a parent buffer and an offset into it, to indicate this is a location pointing to the buffer that we are fixing up. The kernel will then take care of fixing up the pointer to that buffer as well.
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| @@ -33,6 +33,7 @@ enum { · 32 unmodified lines | ||
| 33 | 33 | BINDER_TYPE_HANDLE = B_PACK_CHARS('s', 'h', '*', B_TYPE_LARGE), |
| 34 | 34 | BINDER_TYPE_WEAK_HANDLE = B_PACK_CHARS('w', 'h', '*', B_TYPE_LARGE), |
| 35 | 35 | BINDER_TYPE_FD = B_PACK_CHARS('f', 'd', '*', B_TYPE_LARGE), |
| 36 | + BINDER_TYPE_PTR = B_PACK_CHARS('p', 't', '*', B_TYPE_LARGE), | |
| 36 | 37 | }; |
| 37 | 38 | |
| 38 | 39 | enum { |
| @@ -95,6 +96,39 @@ struct binder_fd_object { · 56 unmodified lines | ||
| 95 | 96 | |
| 96 | 97 | binder_uintptr_t cookie; |
| 97 | 98 | }; |
| 99 | + | |
| 100 | +/* struct binder_buffer_object - object describing a userspace buffer | |
| 101 | + * @hdr: common header structure | |
| 102 | + * @flags: one or more BINDER_BUFFER_* flags | |
| 103 | + * @buffer: address of the buffer | |
| 104 | + * @length: length of the buffer | |
| 105 | + * @parent: index in offset array pointing to parent buffer | |
| 106 | + * @parent_offset: offset in @parent pointing to this buffer | |
| 107 | + * | |
| 108 | + * A binder_buffer object represents an object that the | |
| 109 | + * binder kernel driver can copy verbatim to the target | |
| 110 | + * address space. A buffer itself may be pointed to from | |
| 111 | + * within another buffer, meaning that the pointer inside | |
| 112 | + * that other buffer needs to be fixed up as well. This | |
| 113 | + * can be done by setting the BINDER_BUFFER_FLAG_HAS_PARENT | |
| 114 | + * flag in @flags, by setting @parent buffer to the index | |
| 115 | + * in the offset array pointing to the parent binder_buffer_object, | |
| 116 | + * and by setting @parent_offset to the offset in the parent buffer | |
| 117 | + * at which the pointer to this buffer is located. | |
| 118 | + */ | |
| 119 | +struct binder_buffer_object { | |
| 120 | + struct binder_object_header hdr; | |
| 121 | + __u32 flags; | |
| 122 | + binder_uintptr_t buffer; | |
| 123 | + binder_size_t length; | |
| 124 | + binder_size_t parent; | |
| 125 | + binder_size_t parent_offset; | |
| 126 | +}; | |
| 127 | + | |
| 128 | +enum { | |
| 129 | + BINDER_BUFFER_FLAG_HAS_PARENT = 0x01, | |
| 130 | +}; | |
| 131 | + | |
| 98 | 132 | /* |
| 99 | 133 | * On 64-bit platforms where user code may run in 32-bits the driver must |
| 100 | 134 | * translate the buffer (and local binder) addresses appropriately. |
| @@ -187,6 +221,11 @@ struct binder_transaction_data { · 86 unmodified lines | ||
| 187 | 221 | } data; |
| 188 | 222 | }; |
| 189 | 223 | |
| 224 | +struct binder_transaction_data_sg { | |
| 225 | + struct binder_transaction_data transaction_data; | |
| 226 | + binder_size_t buffers_size; | |
| 227 | +}; | |
| 228 | + | |
| 190 | 229 | struct binder_ptr_cookie { |
| 191 | 230 | binder_uintptr_t ptr; |
| 192 | 231 | binder_uintptr_t cookie; |
| @@ -371,6 +410,12 @@ enum binder_driver_command_protocol { · 178 unmodified lines | ||
| 371 | 410 | /* |
| 372 | 411 | * void *: cookie |
| 373 | 412 | */ |
| 413 | + | |
| 414 | + BC_TRANSACTION_SG = _IOW('c', 17, struct binder_transaction_data_sg), | |
| 415 | + BC_REPLY_SG = _IOW('c', 18, struct binder_transaction_data_sg), | |
| 416 | + /* | |
| 417 | + * binder_transaction_data_sg: the sent command. | |
| 418 | + */ | |
| 374 | 419 | }; |
| 375 | 420 | |
| 376 | 421 | #endif /* _UAPI_LINUX_BINDER_H */ |