This patch introduces enhanced message support that allows the device-mapper core to recognise messages that are common to all devices, and for messages to return data to userspace. Core messages are processed by the function "message_for_md". If the device mapper doesn't support the message, it is passed to the target driver. If the message returns data, the kernel sets the flag DM_MESSAGE_OUT_FLAG.
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| @@ -336,4 +336,9 @@ enum { · 335 unmodified lines | |||
| 336 | */ | 336 | */ |
| 337 | #define DM_SECURE_DATA_FLAG (1 << 15) /* In */ | 337 | #define DM_SECURE_DATA_FLAG (1 << 15) /* In */ |
| 338 | 338 | ||
| 339 | /* | ||
| 340 | * If set, a message generated output data. | ||
| 341 | */ | ||
| 342 | #define DM_DATA_OUT_FLAG (1 << 16) /* Out */ | ||
| 343 | |||
| 339 | #endif /* _LINUX_DM_IOCTL_H */ | 344 | #endif /* _LINUX_DM_IOCTL_H */ |