tree 971c2671b8fa18543ae97d9aeef1b3115271d728
parent 67403dbba76fb294fb3a2317227f4b77037145cc
author Kevin Wolf <kwolf@redhat.com> 1319794093 -0400
committer Kevin Wolf <kwolf@redhat.com> 1320413038 +0100

dma: Avoid reentrancy in DMA transfer handlers

With the conversion of the block layer to coroutines, bdrv_read/write
have changed to run a nested event loop that calls qemu_bh_poll.
Consequently a scheduled BH can be called while a DMA transfer handler
runs and this means that DMA_run becomes reentrant.

Devices haven't been designed to cope with that, so instead of running a
nested transfer handler just wait for the next invocation of the BH from the
main loop.

This fixes some problems with the floppy device.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>