We have to take the block queue's spin lock before invoking the interrupt
routine, otherwise the AVL tree og Genode's block packet stream gets
corrupted.
When finishing a block request in the L4Linux block stub driver,
we#ve to hold the queue lock before using __blk_end_request_all, or
simply use blk_end_request_all instead. Moreover, this commit simplifies
the lock/unlock behaviour when the block queue has to be stopped, or resumed.
Thanks to I. Ismagilov for these suggestions.
Certain symbols from the libgcc_eh library in cxx that is linked with the
L4Linux kernel were resolved by using kernel internal implementations.
This lead to errors because the complete Linux kernel is built regparm=3.
This patch prefixes the appropriate symbols in the Linux Kernel and its
modules. Moreover, it fixes some warnings introduced by the latest update
to gcc 4.7.