From: Sjur Brændeland <[email protected]> This merge reduces code size by unifying the approach for sending scatter-lists and regular buffers. Any type of write operation (splice, write, put_chars) will now allocate a port_buffer and send_buf() and free_buf() can always be used.
Signed-off-by: Sjur Brændeland <[email protected]> cc: Rusty Russell <[email protected]> cc: Michael S. Tsirkin <[email protected]> cc: Amit Shah <[email protected]> cc: Linus Walleij <[email protected]> cc: Masami Hiramatsu <[email protected]> --- drivers/char/virtio_console.c | 141 ++++++++++++++++++----------------------- 1 files changed, 62 insertions(+), 79 deletions(-) diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c index 8ab9c3d..f4f7b04 100644 --- a/drivers/char/virtio_console.c +++ b/drivers/char/virtio_console.c @@ -111,6 +111,11 @@ 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, else sg is used */ + unsigned int sgpages; + + struct scatterlist sg[1]; }; /* @@ -338,23 +343,46 @@ static inline bool use_multiport(struct ports_device *portdev) static void free_buf(struct port_buffer *buf) { + int i; + kfree(buf->buf); + + if (buf->sgpages) + 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 nrbufs) { struct port_buffer *buf; + size_t alloc_size; - buf = kmalloc(sizeof(*buf), GFP_KERNEL); + /* Allocate buffer and the scatter list */ + alloc_size = sizeof(*buf) + sizeof(struct scatterlist) * nrbufs; + buf = kmalloc(alloc_size, GFP_ATOMIC); if (!buf) goto fail; - buf->buf = kzalloc(buf_size, GFP_KERNEL); + + buf->sgpages = nrbufs; + if (nrbufs > 0) + return buf; + + buf->buf = kmalloc(buf_size, GFP_ATOMIC); if (!buf->buf) goto free_buf; buf->len = 0; buf->offset = 0; buf->size = buf_size; + + /* Prepare scatter buffer for sending */ + sg_init_one(buf->sg, buf->buf, buf_size); return buf; free_buf: @@ -476,52 +504,25 @@ 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) +static ssize_t send_buf(struct port *port, struct port_buffer *buf, int nents, + size_t in_count, bool nonblock) { struct virtqueue *out_vq; ssize_t ret; @@ -534,7 +535,7 @@ static ssize_t __send_to_port(struct port *port, struct scatterlist *sg, reclaim_consumed_buffers(port); - ret = virtqueue_add_buf(out_vq, sg, nents, 0, tok, GFP_ATOMIC); + ret = virtqueue_add_buf(out_vq, buf->sg, nents, 0, buf, GFP_ATOMIC); /* Tell Host to go! */ virtqueue_kick(out_vq); @@ -559,8 +560,11 @@ static ssize_t __send_to_port(struct port *port, struct scatterlist *sg, * we need to kmalloc a GFP_ATOMIC buffer each time the * console driver writes something out. */ - while (!virtqueue_get_buf(out_vq, &len)) + for (buf = virtqueue_get_buf(out_vq, &len); !buf; + buf = virtqueue_get_buf(out_vq, &len)) cpu_relax(); + + free_buf(buf); done: spin_unlock_irqrestore(&port->outvq_lock, flags); @@ -572,36 +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 @@ -748,7 +722,7 @@ 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; @@ -766,11 +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; @@ -784,13 +758,13 @@ 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); + ret = send_buf(port, buf, 1, count, nonblock); if (nonblock && ret > 0) goto out; free_buf: - kfree(buf); + free_buf(buf); out: return ret; } @@ -856,6 +830,7 @@ 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, @@ -867,17 +842,17 @@ 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); 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_buf(port, buf, sgl.n, sgl.len, true); + else + free_buf(buf); return ret; } @@ -1031,6 +1006,7 @@ static const struct file_operations port_fops = { static int put_chars(u32 vtermno, const char *buf, int count) { struct port *port; + struct port_buffer *port_buf; if (unlikely(early_put_chars)) return early_put_chars(vtermno, buf, count); @@ -1039,7 +1015,13 @@ static int put_chars(u32 vtermno, const char *buf, int count) if (!port) return -EPIPE; - return send_buf(port, (void *)buf, count, false); + port_buf = alloc_buf(port->out_vq, count, 0); + if (port_buf == NULL) + return -ENOMEM; + + memcpy(port_buf->buf, buf, count); + + return send_buf(port, port_buf, 1, count, false); } /* @@ -1260,10 +1242,11 @@ 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; + memset(buf->buf, 0, PAGE_SIZE); spin_lock_irq(lock); ret = add_inbuf(vq, buf); if (ret < 0) { -- 1.7.5.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
