From 8ca84a50e5b39487ea1de8809d0ee1c8474f6a5c Mon Sep 17 00:00:00 2001 From: Masami Hiramatsu Date: Thu, 9 Aug 2012 21:31:20 +0900 Subject: [PATCH] virtio/console: Allocate scatterlist according to the current pipe size Allocate scatterlist according to the current pipe size. This allows splicing bigger buffer if the pipe size has been changed by fcntl. Changes in v2: - Just a minor fix for avoiding a confliction with previous patch. Signed-off-by: Masami Hiramatsu Acked-by: Amit Shah Signed-off-by: Rusty Russell --- drivers/char/virtio_console.c | 23 ++++++++++++----------- 1 file changed, 12 insertions(+), 11 deletions(-) diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c index b2fc2ab..e88f843 100644 --- a/drivers/char/virtio_console.c +++ b/drivers/char/virtio_console.c @@ -229,7 +229,6 @@ struct port { bool guest_connected; }; -#define MAX_SPLICE_PAGES 32 /* This is the very early arch-specified put chars function. */ static int (*early_put_chars)(u32, const char *, int); @@ -482,15 +481,16 @@ struct buffer_token { void *buf; struct scatterlist *sg; } u; - bool sgpages; + /* If sgpages == 0 then buf is used, else sg is used */ + unsigned int sgpages; }; -static void reclaim_sg_pages(struct scatterlist *sg) +static void reclaim_sg_pages(struct scatterlist *sg, unsigned int nrpages) { int i; struct page *page; - for (i = 0; i < MAX_SPLICE_PAGES; i++) { + for (i = 0; i < nrpages; i++) { page = sg_page(&sg[i]); if (!page) break; @@ -511,7 +511,7 @@ static void reclaim_consumed_buffers(struct port *port) } while ((tok = virtqueue_get_buf(port->out_vq, &len))) { if (tok->sgpages) - reclaim_sg_pages(tok->u.sg); + reclaim_sg_pages(tok->u.sg, tok->sgpages); else kfree(tok->u.buf); kfree(tok); @@ -581,7 +581,7 @@ static ssize_t send_buf(struct port *port, void *in_buf, size_t in_count, tok = kmalloc(sizeof(*tok), GFP_ATOMIC); if (!tok) return -ENOMEM; - tok->sgpages = false; + tok->sgpages = 0; tok->u.buf = in_buf; sg_init_one(sg, in_buf, in_count); @@ -597,7 +597,7 @@ static ssize_t send_pages(struct port *port, struct scatterlist *sg, int nents, tok = kmalloc(sizeof(*tok), GFP_ATOMIC); if (!tok) return -ENOMEM; - tok->sgpages = true; + tok->sgpages = nents; tok->u.sg = sg; return __send_to_port(port, sg, nents, in_count, tok, nonblock); @@ -797,6 +797,7 @@ out: struct sg_list { unsigned int n; + unsigned int size; size_t len; struct scatterlist *sg; }; @@ -807,7 +808,7 @@ static int pipe_to_sg(struct pipe_inode_info *pipe, struct pipe_buffer *buf, struct sg_list *sgl = sd->u.data; unsigned int offset, len; - if (sgl->n == MAX_SPLICE_PAGES) + if (sgl->n == sgl->size) return 0; /* Try lock this page */ @@ -868,12 +869,12 @@ static ssize_t port_fops_splice_write(struct pipe_inode_info *pipe, sgl.n = 0; sgl.len = 0; - sgl.sg = kmalloc(sizeof(struct scatterlist) * MAX_SPLICE_PAGES, - GFP_KERNEL); + sgl.size = pipe->nrbufs; + sgl.sg = kmalloc(sizeof(struct scatterlist) * sgl.size, GFP_KERNEL); if (unlikely(!sgl.sg)) return -ENOMEM; - sg_init_table(sgl.sg, MAX_SPLICE_PAGES); + 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); -- 2.7.4