9pnet: allow making incomplete read requests
net/9p: remove unused p9_req_t aux field
9p: document short read behaviour with O_NONBLOCK
9p/xen: increase XEN_9PFS_RING_ORDER
v9fs_dir_readdir: fix double-free on p9stat_read error
9p: clear dangling pointers in p9stat_free
9p: Use a slab for allocating requests
9p: Remove p9_idpool