significant clean up and optimizations:
- don't call bioq_disksort() on every command, the hardware will do that for
us.
- remove all of the complicated bio deferral code. bio's that can't be
serviced immediately can just wait on the bioq.
- Only reserve one command object for doing control commands to the card.
This simplifies a lot of code and significantly reduces the size of the
command struct.
- Allocate commands out of a slab instead of embedding them into the softc.
- Call the command action method directly instead of having ips_get_free_cmd()
call it indirectly.
MFC After: 1 week
Add two new arguments to bus_dma_tag_create(): lockfunc and lockfuncarg.
Lockfunc allows a driver to provide a function for managing its locking
semantics while using busdma. At the moment, this is used for the
asynchronous busdma_swi and callback mechanism. Two lockfunc implementations
are provided: busdma_lock_mutex() performs standard mutex operations on the
mutex that is specified from lockfuncarg. dftl_lock() is a panic
implementation and is defaulted to when NULL, NULL are passed to
bus_dma_tag_create(). The only time that NULL, NULL should ever be used is
when the driver ensures that bus_dmamap_load() will not be deferred.
Drivers that do not provide their own locking can pass
busdma_lock_mutex,&Giant args in order to preserve the former behaviour.
sparc64 and powerpc do not provide real busdma_swi functions, so this is
largely a noop on those platforms. The busdma_swi on is64 is not properly
locked yet, so warnings will be emitted on this platform when busdma
callback deferrals happen.
If anyone gets panics or warnings from dflt_lock() being called, please
let me know right away.
Reviewed by: tmm, gibbs
series. This driver was generously developed and released by David
Jeffreys and Adaptec. I've updated it to work with 5.x and fixed a
few bugs.
MFC After: 1 week
