On 05/17/2017 11:29 AM, Greg Kurz wrote:
First point: is fsdev a Linux-only feature, or can it be compiled on
BSD? If it is Linux-only, then compiling a stub for Windows will still
leave BSD broken, and your #ifdef is wrong. Fixing compilation on mingw
is nice, but not the only platform to worry about.
fsdev compilation currently depends on CONFIG_VIRTFS which is a Linux-only
feature for the moment. There was a tentative to support it on Windows hosts
two years ago but it stayed at the RFC stage.
But even on Linux hosts, the current fsdev implementation also depends on
the target supporting PCI and VIRTIO. We have a fsdev/qemu-fsdev-dummy.c
file to put stubs so that we don't pull all the code for such targets.
Maybe this could be reused for the above stubs as well ?
That helps. The stub should live in qemu-fsdev-dummy.c (where it
shouldn't need any #ifdef, because that file is only compiled when the
condition is false), and...
Second point: if fsdev is indeed a platform-specific feature, then we
don't want to advertise the QMP commands that are useless when running
on a platform that doesn't support it. Anywhere you have to add a stub
for compilation means you ALSO need to patch monitor.c to unregister the
command from being advertised as a valid QMP command. (If you used
#ifdef __LINUX__ to guard the working version, and #ifndef __LINUX__ to
declare the stub, then the monitor.c needs an #ifndef section within
qmp_unregister_commands_hack() to tell QMP to not advertise the stubs.)
monitor.c should wrap the unregister under #ifndef CONFIG_VIRTFS (rather
than a particular platform name).