diff options
| -rw-r--r-- | drivers/char/virtio_console.c | 129 |
1 files changed, 53 insertions, 76 deletions
diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c index db244b5b6c8a..548224686963 100644 --- a/drivers/char/virtio_console.c +++ b/drivers/char/virtio_console.c @@ -111,6 +111,12 @@ struct port_buffer { size_t len; /* offset in the buf from which to consume data */ size_t offset; + + /* If sgpages == 0 then buf is used */ + unsigned int sgpages; + + /* sg is used if spages > 0. sg must be the last in is struct */ + struct scatterlist sg[0]; }; /* @@ -338,17 +344,39 @@ static inline bool use_multiport(struct ports_device *portdev) static void free_buf(struct port_buffer *buf) { + unsigned int i; + kfree(buf->buf); + for (i = 0; i < buf->sgpages; i++) { + struct page *page = sg_page(&buf->sg[i]); + if (!page) + break; + put_page(page); + } + kfree(buf); } -static struct port_buffer *alloc_buf(size_t buf_size) +static struct port_buffer *alloc_buf(struct virtqueue *vq, size_t buf_size, + int pages) { struct port_buffer *buf; - buf = kmalloc(sizeof(*buf), GFP_KERNEL); + /* + * Allocate buffer and the sg list. The sg list array is allocated + * directly after the port_buffer struct. + */ + buf = kmalloc(sizeof(*buf) + sizeof(struct scatterlist) * pages, + GFP_KERNEL); if (!buf) goto fail; + + buf->sgpages = pages; + if (pages > 0) { + buf->buf = NULL; + return buf; + } + buf->buf = kmalloc(buf_size, GFP_KERNEL); if (!buf->buf) goto free_buf; @@ -478,52 +506,26 @@ static ssize_t send_control_msg(struct port *port, unsigned int event, return 0; } -struct buffer_token { - union { - void *buf; - struct scatterlist *sg; - } u; - /* If sgpages == 0 then buf is used, else sg is used */ - unsigned int sgpages; -}; - -static void reclaim_sg_pages(struct scatterlist *sg, unsigned int nrpages) -{ - int i; - struct page *page; - - for (i = 0; i < nrpages; i++) { - page = sg_page(&sg[i]); - if (!page) - break; - put_page(page); - } - kfree(sg); -} /* Callers must take the port->outvq_lock */ static void reclaim_consumed_buffers(struct port *port) { - struct buffer_token *tok; + struct port_buffer *buf; unsigned int len; if (!port->portdev) { /* Device has been unplugged. vqs are already gone. */ return; } - while ((tok = virtqueue_get_buf(port->out_vq, &len))) { - if (tok->sgpages) - reclaim_sg_pages(tok->u.sg, tok->sgpages); - else - kfree(tok->u.buf); - kfree(tok); + while ((buf = virtqueue_get_buf(port->out_vq, &len))) { + free_buf(buf); port->outvq_full = false; } } static ssize_t __send_to_port(struct port *port, struct scatterlist *sg, int nents, size_t in_count, - struct buffer_token *tok, bool nonblock) + void *data, bool nonblock) { struct virtqueue *out_vq; int err; @@ -536,7 +538,7 @@ static ssize_t __send_to_port(struct port *port, struct scatterlist *sg, reclaim_consumed_buffers(port); - err = virtqueue_add_buf(out_vq, sg, nents, 0, tok, GFP_ATOMIC); + err = virtqueue_add_buf(out_vq, sg, nents, 0, data, GFP_ATOMIC); /* Tell Host to go! */ virtqueue_kick(out_vq); @@ -574,37 +576,6 @@ done: return in_count; } -static ssize_t send_buf(struct port *port, void *in_buf, size_t in_count, - bool nonblock) -{ - struct scatterlist sg[1]; - struct buffer_token *tok; - - tok = kmalloc(sizeof(*tok), GFP_ATOMIC); - if (!tok) - return -ENOMEM; - tok->sgpages = 0; - tok->u.buf = in_buf; - - sg_init_one(sg, in_buf, in_count); - - return __send_to_port(port, sg, 1, in_count, tok, nonblock); -} - -static ssize_t send_pages(struct port *port, struct scatterlist *sg, int nents, - size_t in_count, bool nonblock) -{ - struct buffer_token *tok; - - tok = kmalloc(sizeof(*tok), GFP_ATOMIC); - if (!tok) - return -ENOMEM; - tok->sgpages = nents; - tok->u.sg = sg; - - return __send_to_port(port, sg, nents, in_count, tok, nonblock); -} - /* * Give out the data that's requested from the buffer that we have * queued up. @@ -750,9 +721,10 @@ static ssize_t port_fops_write(struct file *filp, const char __user *ubuf, size_t count, loff_t *offp) { struct port *port; - char *buf; + struct port_buffer *buf; ssize_t ret; bool nonblock; + struct scatterlist sg[1]; /* Userspace could be out to fool us */ if (!count) @@ -768,11 +740,11 @@ static ssize_t port_fops_write(struct file *filp, const char __user *ubuf, count = min((size_t)(32 * 1024), count); - buf = kmalloc(count, GFP_KERNEL); + buf = alloc_buf(port->out_vq, count, 0); if (!buf) return -ENOMEM; - ret = copy_from_user(buf, ubuf, count); + ret = copy_from_user(buf->buf, ubuf, count); if (ret) { ret = -EFAULT; goto free_buf; @@ -786,13 +758,14 @@ static ssize_t port_fops_write(struct file *filp, const char __user *ubuf, * through to the host. */ nonblock = true; - ret = send_buf(port, buf, count, nonblock); + sg_init_one(sg, buf->buf, count); + ret = __send_to_port(port, sg, 1, count, buf, nonblock); if (nonblock && ret > 0) goto out; free_buf: - kfree(buf); + free_buf(buf); out: return ret; } @@ -858,6 +831,7 @@ static ssize_t port_fops_splice_write(struct pipe_inode_info *pipe, struct port *port = filp->private_data; struct sg_list sgl; ssize_t ret; + struct port_buffer *buf; struct splice_desc sd = { .total_len = len, .flags = flags, @@ -869,17 +843,18 @@ static ssize_t port_fops_splice_write(struct pipe_inode_info *pipe, if (ret < 0) return ret; + buf = alloc_buf(port->out_vq, 0, pipe->nrbufs); + if (!buf) + return -ENOMEM; + sgl.n = 0; sgl.len = 0; sgl.size = pipe->nrbufs; - sgl.sg = kmalloc(sizeof(struct scatterlist) * sgl.size, GFP_KERNEL); - if (unlikely(!sgl.sg)) - return -ENOMEM; - + sgl.sg = buf->sg; sg_init_table(sgl.sg, sgl.size); ret = __splice_from_pipe(pipe, &sd, pipe_to_sg); if (likely(ret > 0)) - ret = send_pages(port, sgl.sg, sgl.n, sgl.len, true); + ret = __send_to_port(port, buf->sg, sgl.n, sgl.len, buf, true); if (unlikely(ret <= 0)) kfree(sgl.sg); @@ -1035,6 +1010,7 @@ static const struct file_operations port_fops = { static int put_chars(u32 vtermno, const char *buf, int count) { struct port *port; + struct scatterlist sg[1]; if (unlikely(early_put_chars)) return early_put_chars(vtermno, buf, count); @@ -1043,7 +1019,8 @@ static int put_chars(u32 vtermno, const char *buf, int count) if (!port) return -EPIPE; - return send_buf(port, (void *)buf, count, false); + sg_init_one(sg, buf, count); + return __send_to_port(port, sg, 1, count, (void *)buf, false); } /* @@ -1264,7 +1241,7 @@ static unsigned int fill_queue(struct virtqueue *vq, spinlock_t *lock) nr_added_bufs = 0; do { - buf = alloc_buf(PAGE_SIZE); + buf = alloc_buf(vq, PAGE_SIZE, 0); if (!buf) break; |