binder: Add support for scatter-gather
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.
Cc: Greg Kroah-Hartman <[email protected]>
Cc: Martijn Coenen <[email protected]>
Cc: Arve Hjønnevåg <[email protected]>
Cc: Amit Pundir <[email protected]>
Cc: Serban Constantinescu <[email protected]>
Cc: Dmitry Shmidt <[email protected]>
Cc: Rom Lemarchand <[email protected]>
Cc: Android Kernel Team <[email protected]>
Signed-off-by: Martijn Coenen <[email protected]>
[jstultz: Fold in small fix from Amit Pundir <[email protected]>]
Signed-off-by: John Stultz <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
2 files changed
