[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-Id: <f31e80bc67774d08f8d3bfb7ca0a970eeb369ca5.1632156835.git.linux_oss@crudebyte.com>
Date: Mon, 20 Sep 2021 18:44:13 +0200
From: Christian Schoenebeck <linux_oss@...debyte.com>
To: v9fs-developer@...ts.sourceforge.net
Cc: netdev@...r.kernel.org,
Dominique Martinet <asmadeus@...ewreck.org>,
Eric Van Hensbergen <ericvh@...il.com>,
Latchesar Ionkov <lucho@...kov.net>,
Greg Kurz <groug@...d.org>, Vivek Goyal <vgoyal@...hat.com>
Subject: [PATCH v2 6/7] 9p/trans_virtio: support larger msize values
The virtio transport supports by default a 9p 'msize' of up to
approximately 500 kB. This patch adds support for larger 'msize'
values by resizing the amount of scatter/gather lists if required.
Signed-off-by: Christian Schoenebeck <linux_oss@...debyte.com>
---
net/9p/trans_virtio.c | 57 +++++++++++++++++++++++++++++++++++++++++++
1 file changed, 57 insertions(+)
diff --git a/net/9p/trans_virtio.c b/net/9p/trans_virtio.c
index 0db8de84bd51..4cb75f45aa15 100644
--- a/net/9p/trans_virtio.c
+++ b/net/9p/trans_virtio.c
@@ -200,6 +200,31 @@ static struct virtqueue_sg *vq_sg_alloc(unsigned int nsgl)
return vq_sg;
}
+/**
+ * vq_sg_resize - resize passed virtqueue scatter/gather lists to the passed
+ * amount of lists
+ * @_vq_sg: scatter/gather lists to be resized
+ * @nsgl: new amount of scatter/gather lists
+ */
+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;
+
+ kfree(*_vq_sg);
+ *_vq_sg = vq_sg;
+ return 0;
+}
+
/**
* p9_virtio_close - reclaim resources of a channel
* @client: client instance
@@ -771,6 +796,10 @@ 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;
@@ -793,6 +822,34 @@ 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) {
+#ifdef CONFIG_ARCH_NO_SG_CHAIN
+ pr_info("limiting 'msize' to %d because architecture does not "
+ "support chained scatter gather lists\n",
+ client->trans_maxsize);
+#else
+ 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 /* CONFIG_ARCH_NO_SG_CHAIN */
+ }
+
client->trans = (void *)chan;
client->status = Connected;
chan->client = client;
--
2.20.1
Powered by blists - more mailing lists