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 <masami.hiramatsu.pt@hitachi.com>
Acked-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
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 @@
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 @@
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 @@
}
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 @@
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 @@
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 @@
struct sg_list {
unsigned int n;
+ unsigned int size;
size_t len;
struct scatterlist *sg;
};
@@ -807,7 +808,7 @@
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 @@
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);