| Message ID | 810050b76b9b04f045e3d21b0082358ea3f21391.1631816768.git.linux_oss@crudebyte.com |
|---|---|
| State | New |
| Headers | show |
| Series | None | expand |
On Donnerstag, 16. September 2021 20:25:16 CEST Christian Schoenebeck wrote: > The virtio transport supports by default a 9p 'msize' of up to > approximately 500 kB. This patches adds support for larger 'msize' > values by resizing the amount of scatter/gather lists if required. > > Signed-off-by: Christian Schoenebeck <linux_oss@crudebyte.com> > --- s/patches/patch/ > net/9p/trans_virtio.c | 52 +++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 52 insertions(+) > > diff --git a/net/9p/trans_virtio.c b/net/9p/trans_virtio.c > index 1a45e0df2336..1f9a0283d7b8 100644 > --- a/net/9p/trans_virtio.c > +++ b/net/9p/trans_virtio.c > @@ -195,6 +195,30 @@ static struct virtqueue_sg *vq_sg_alloc(unsigned int > nsgl) return vq_sg; > } > > +/** > + * Resize passed virtqueue scatter/gather lists to the passed amount of > + * list blocks. > + * @_vq_sg: scatter/gather lists to be resized > + * @nsgl: new amount of scatter/gather list blocks > + */ > +static int vq_sg_resize(struct virtqueue_sg **_vq_sg, unsigned int nsgl) > +{ > + struct virtqueue_sg *vq_sg; > + > + BUG_ON(!_vq_sg || !nsgl); > + vq_sg = *_vq_sg; > + if (vq_sg->nsgl == nsgl) > + return 0; > + > + /* lazy resize implementation for now */ > + vq_sg = vq_sg_alloc(nsgl); > + if (!vq_sg) > + return -ENOMEM; > + Missing kfree(*_vq_sg); here, and probably also a prior memcpy() as in patch 7, i.e.: /* copy over old scatter gather lists */ sz = sizeof(struct virtqueue_sg) + (*_vq_sg)->nsgl * sizeof(struct scatterlist *); memcpy(vq_sg, *_vq_sg, sz); > + *_vq_sg = vq_sg; > + return 0; > +} > + > /** > * p9_virtio_close - reclaim resources of a channel > * @client: client instance > @@ -766,6 +790,10 @@ p9_virtio_create(struct p9_client *client, const char > *devname, char *args) struct virtio_chan *chan; > int ret = -ENOENT; > int found = 0; > +#if !defined(CONFIG_ARCH_NO_SG_CHAIN) > + size_t npages; > + size_t nsgl; > +#endif > > if (devname == NULL) > return -EINVAL; > @@ -788,6 +816,30 @@ p9_virtio_create(struct p9_client *client, const char > *devname, char *args) return ret; > } > > + /* > + * if user supplied an 'msize' option that's larger than what this > + * transport supports by default, then try to allocate more sg lists > + */ > + if (client->msize > client->trans_maxsize) { > +#if !defined(CONFIG_ARCH_NO_SG_CHAIN) > + npages = DIV_ROUND_UP(client->msize, PAGE_SIZE); > + if (npages > chan->p9_max_pages) > + npages = chan->p9_max_pages; > + nsgl = DIV_ROUND_UP(npages, SG_USER_PAGES_PER_LIST); > + if (nsgl > chan->vq_sg->nsgl) { > + /* > + * if resize fails, no big deal, then just > + * continue with default msize instead > + */ > + if (!vq_sg_resize(&chan->vq_sg, nsgl)) { > + client->trans_maxsize = > + PAGE_SIZE * > + ((nsgl * SG_USER_PAGES_PER_LIST) - 3); > + } > + } > +#endif /* !defined(CONFIG_ARCH_NO_SG_CHAIN) */ > + } Probably an error/info message for architectures not supporting SG chains would be useful here, to let users on those system know why they cannot get beyond 500k msize. > + > client->trans = (void *)chan; > client->status = Connected; > chan->client = client;
diff --git a/net/9p/trans_virtio.c b/net/9p/trans_virtio.c index 1a45e0df2336..1f9a0283d7b8 100644 --- a/net/9p/trans_virtio.c +++ b/net/9p/trans_virtio.c @@ -195,6 +195,30 @@ static struct virtqueue_sg *vq_sg_alloc(unsigned int nsgl) return vq_sg; } +/** + * Resize passed virtqueue scatter/gather lists to the passed amount of + * list blocks. + * @_vq_sg: scatter/gather lists to be resized + * @nsgl: new amount of scatter/gather list blocks + */ +static int vq_sg_resize(struct virtqueue_sg **_vq_sg, unsigned int nsgl) +{ + struct virtqueue_sg *vq_sg; + + BUG_ON(!_vq_sg || !nsgl); + vq_sg = *_vq_sg; + if (vq_sg->nsgl == nsgl) + return 0; + + /* lazy resize implementation for now */ + vq_sg = vq_sg_alloc(nsgl); + if (!vq_sg) + return -ENOMEM; + + *_vq_sg = vq_sg; + return 0; +} + /** * p9_virtio_close - reclaim resources of a channel * @client: client instance @@ -766,6 +790,10 @@ p9_virtio_create(struct p9_client *client, const char *devname, char *args) struct virtio_chan *chan; int ret = -ENOENT; int found = 0; +#if !defined(CONFIG_ARCH_NO_SG_CHAIN) + size_t npages; + size_t nsgl; +#endif if (devname == NULL) return -EINVAL; @@ -788,6 +816,30 @@ p9_virtio_create(struct p9_client *client, const char *devname, char *args) return ret; } + /* + * if user supplied an 'msize' option that's larger than what this + * transport supports by default, then try to allocate more sg lists + */ + if (client->msize > client->trans_maxsize) { +#if !defined(CONFIG_ARCH_NO_SG_CHAIN) + npages = DIV_ROUND_UP(client->msize, PAGE_SIZE); + if (npages > chan->p9_max_pages) + npages = chan->p9_max_pages; + nsgl = DIV_ROUND_UP(npages, SG_USER_PAGES_PER_LIST); + if (nsgl > chan->vq_sg->nsgl) { + /* + * if resize fails, no big deal, then just + * continue with default msize instead + */ + if (!vq_sg_resize(&chan->vq_sg, nsgl)) { + client->trans_maxsize = + PAGE_SIZE * + ((nsgl * SG_USER_PAGES_PER_LIST) - 3); + } + } +#endif /* !defined(CONFIG_ARCH_NO_SG_CHAIN) */ + } + client->trans = (void *)chan; client->status = Connected; chan->client = client;
The virtio transport supports by default a 9p 'msize' of up to approximately 500 kB. This patches adds support for larger 'msize' values by resizing the amount of scatter/gather lists if required. Signed-off-by: Christian Schoenebeck <linux_oss@crudebyte.com> --- net/9p/trans_virtio.c | 52 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 52 insertions(+)