sjur.brandel...@stericsson.com writes: > From: Vikram ARV <vikram....@stericsson.com> > > Add the the Virtio shared memory driver for STE Modems. > caif_virtio is implemented utilizing the virtio framework > for data transport and is managed with the remoteproc frameworks. > > The Virtio queue is used for transmitting data to the modem, and > the new vringh implementation is receiving data over the vring.
OK, let's refine vringh now we can see another user: > + * @head: Last descriptor ID we received from vringh_getdesc_kern. > + * We use this to put descriptor back on the used ring. USHRT_MAX is > + * used to indicate invalid head-id. > + */ > +struct cfv_napi_context { > + struct vringh_kiov riov; > + unsigned short head; > +}; Usually we use an int, and -1. I imagine it'll take no more space, due to padding. > +static inline void ctx_prep_iov(struct cfv_napi_context *ctx) > +{ > + if (ctx->riov.allocated) { > + kfree(ctx->riov.iov); > + ctx->riov.iov = NULL; > + ctx->riov.allocated = false; > + } > + ctx->riov.iov = NULL; > + ctx->riov.i = 0; > + ctx->riov.max = 0; > +} Hmm, we should probably make sure you don't have to do this: that if allocated once, you can simply reuse it by setting i = 0. (This requires some care in the error handling paths, so we don't free it from under you)... And you probably want to free this up in cfv_remove() instead? I'll create and test a patch now. > + if (riov->i == riov->max) { > + if (cfv->ctx.head != USHRT_MAX) { > + vringh_complete_kern(cfv->vr_rx, > + cfv->ctx.head, > + 0); > + cfv->ctx.head = USHRT_MAX; > + } > + > + ctx_prep_iov(&cfv->ctx); > + err = vringh_getdesc_kern( > + cfv->vr_rx, > + riov, > + &wiov, > + &cfv->ctx.head, > + GFP_ATOMIC); > + > + if (err <= 0) > + goto out; > + > + if (wiov.max != 0) { > + /* CAIF does not use write descriptors */ > + err = -EPROTO; > + goto out; > + } This is probably a common case, so we should generate this error inside vringh_getdesc (if wiov is NULL). I'll do that too... > +module_driver(caif_virtio_driver, register_virtio_driver, > + unregister_virtio_driver); > +MODULE_DEVICE_TABLE(virtio, id_table); The comment on module_driver says: * Use this macro to construct bus specific macros for registering * drivers, and do not use it on its own. Want to send me a patch to define module_virtio_driver? Thanks! Rusty. _______________________________________________ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/virtualization