On Monday, November 28, 2022 11:18:48 AM CET Markus Armbruster wrote: > Greg Kurz <gr...@kaod.org> writes: > > > On Mon, 28 Nov 2022 08:35:22 +0100 > > Markus Armbruster <arm...@redhat.com> wrote: > > > >> Greg Kurz <gr...@kaod.org> writes: > >> > >> > The qemu_v9fs_synth_mkdir() and qemu_v9fs_synth_add_file() functions > >> > currently return a positive errno value on failure. This causes > >> > checkpatch.pl to spit several errors like the one below: > >> > > >> > ERROR: return of an errno should typically be -ve (return -EAGAIN) > >> > #79: FILE: hw/9pfs/9p-synth.c:79: > >> > + return EAGAIN; > >> > > >> > Simply change the sign. This has no consequence since callers > >> > assert() the returned value to be equal to 0. > >> > >> Out of curiosity: why is assert() appropriate? > >> > > > > Most of the code base comes from the original synth backend which > > was designed to expose QEMU internals to the guest using 9p. The > > hope of the virtio-9p authors was that each QEMU subsystem would > > create its own tree using these two functions (note that they > > are declared extern). Of course these never happened and the synth > > backend remained nearly dead code for years, until finally it got > > re-used to implement 9p qtest. In this context, failure to create a > > synthetic directory or file means the related test has a bug (e.g. > > messing with the paths used by some other test). This code likely > > needs improvements but we never got to it. > > I was about to suggest putting this in a file comment, but then I saw > > /* > * Not so fast! You might want to read the 9p developer docs first: > * https://wiki.qemu.org/Documentation/9p > */ > > and behind the link, there's a paragraph "3. synth fs driver". > > Perhaps a brief note on the use of assert() in synth_init() would still > make sense. Up to you.
Like what comment would you expect there? The synth driver is a simplified hack fs driver with hard coded directories & files, only used for 9p protocol conformance test cases. Best regards, Christian Schoenebeck
