On 2022-04-22 00:36, Sam Li wrote: > Linux recently added a new io_uring(7) optimization API that QEMU > doesn't take advantage of yet. The liburing library that QEMU uses > has added a corresponding new API calling io_uring_register_ring_fd(). > When this API is called after creating the ring, the io_uring_submit() > library function passes a flag to the io_uring_enter(2) syscall > allowing it to skip the ring file descriptor fdget()/fdput() > operations. This saves some CPU cycles. > > Signed-off-by: Sam Li <faithilike...@gmail.com> > --- > block/io_uring.c | 10 +++++++++- > 1 file changed, 9 insertions(+), 1 deletion(-) > > diff --git a/block/io_uring.c b/block/io_uring.c > index 782afdb433..5247fb79e2 100644 > --- a/block/io_uring.c > +++ b/block/io_uring.c > @@ -435,8 +435,16 @@ LuringState *luring_init(Error **errp) > } > > ioq_init(&s->io_q); > - return s; > + if (io_uring_register_ring_fd(&s->ring) < 0) { > + /* > + * Only warn about this error: we will fallback to the non-optimized > + * io_uring operations. > + */ > + error_reportf_err(*errp, > + "failed to register linux io_uring ring file > descriptor");
IIUC errp can be NULL, so let's not dereference it without checking. So, just use error_report? Fam > + } > > + return s; > } > > void luring_cleanup(LuringState *s) > -- > Use error_reportf_err to avoid memory leak due to not freeing error > object. > -- > 2.35.1 > >