From d6cd1fd7cf3ac19f4de69e9522ab910bbe07ef00 Mon Sep 17 00:00:00 2001 From: Mark Johnston Date: Fri, 25 Oct 2024 17:51:16 +0000 Subject: [PATCH] virtio_p9fs: Fix handling of a full request queue If, when submitting a request, the virtqueue is full, we sleep until an interrupt has fired, then restart the request. However, while sleeping the channel lock is dropped, and in the meantime another thread may have reset the per-channel SG list, so upon retrying we'd (re)submit whatever happened to be left over in the previous request. Fix the problem by rebuilding the SG list after sleeping. Sponsored by: Klara, Inc. --- sys/dev/virtio/p9fs/virtio_p9fs.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/sys/dev/virtio/p9fs/virtio_p9fs.c b/sys/dev/virtio/p9fs/virtio_p9fs.c index 43d5c0d9d6b..d359fbbf1a3 100644 --- a/sys/dev/virtio/p9fs/virtio_p9fs.c +++ b/sys/dev/virtio/p9fs/virtio_p9fs.c @@ -152,6 +152,7 @@ vt9p_request(void *handle, struct p9_req_t *req) /* Grab the channel lock*/ VT9P_LOCK(chan); +req_retry: sglist_reset(sg); /* Handle out VirtIO ring buffers */ error = sglist_append(sg, req->tc->sdata, req->tc->size); @@ -170,9 +171,7 @@ vt9p_request(void *handle, struct p9_req_t *req) } writable = sg->sg_nseg - readable; -req_retry: error = virtqueue_enqueue(vq, req, sg, readable, writable); - if (error != 0) { if (error == ENOSPC) { /*