We can get all the pages in one time instead of calling
gup N times.
Signed-off-by: Asias He <[email protected]>
---
drivers/vhost/tcm_vhost.c | 33 ++++++++++++++++++++-------------
1 file changed, 20 insertions(+), 13 deletions(-)
diff --git a/drivers/vhost/tcm_vhost.c b/drivers/vhost/tcm_vhost.c
index ca35c16..59be442 100644
--- a/drivers/vhost/tcm_vhost.c
+++ b/drivers/vhost/tcm_vhost.c
@@ -430,37 +430,45 @@ static struct tcm_vhost_cmd *vhost_scsi_allocate_cmd(
* Returns the number of scatterlist entries used or -errno on error.
*/
static int vhost_scsi_map_to_sgl(struct scatterlist *sgl,
- unsigned int sgl_count, void __user *ptr, size_t len, int write)
+ unsigned int sgl_count, struct iovec *iov, int write)
{
struct scatterlist *sg = sgl;
unsigned int npages = 0;
+ void __user *ptr = iov->iov_base;
+ size_t len = iov->iov_len;
int ret;
+ unsigned int pages_nr, offset, nbytes;
+ struct page **pages;
+
+ pages_nr = iov_num_pages(iov);
+ pages = kmalloc(pages_nr * sizeof(struct page *), GFP_ATOMIC);
+ if (!pages)
+ return -ENOMEM;
+
+ ret = get_user_pages_fast((unsigned long)ptr, pages_nr, write, pages);
+ if (ret != pages_nr)
+ goto err;
while (len > 0) {
- struct page *page;
- unsigned int offset = (uintptr_t)ptr & ~PAGE_MASK;
- unsigned int nbytes = min_t(unsigned int,
- PAGE_SIZE - offset, len);
+ offset = (uintptr_t)ptr & ~PAGE_MASK;
+ nbytes = min_t(unsigned int, PAGE_SIZE - offset, len);
if (npages == sgl_count) {
ret = -ENOBUFS;
goto err;
}
- ret = get_user_pages_fast((unsigned long)ptr, 1, write, &page);
- BUG_ON(ret == 0); /* we should either get our page or fail */
- if (ret < 0)
- goto err;
-
- sg_set_page(sg, page, nbytes, offset);
+ sg_set_page(sg, pages[npages], nbytes, offset);
ptr += nbytes;
len -= nbytes;
sg++;
npages++;
}
+ kfree(pages);
return npages;
err:
+ kfree(pages);
/* Put pages that we hold */
for (sg = sgl; sg != &sgl[npages]; sg++)
put_page(sg_page(sg));
@@ -498,8 +506,7 @@ static int vhost_scsi_map_iov_to_sgl(struct tcm_vhost_cmd
*tv_cmd,
pr_debug("Mapping %u iovecs for %u pages\n", niov, sgl_count);
for (i = 0; i < niov; i++) {
- ret = vhost_scsi_map_to_sgl(sg, sgl_count, iov[i].iov_base,
- iov[i].iov_len, write);
+ ret = vhost_scsi_map_to_sgl(sg, sgl_count, &iov[i], write);
if (ret < 0) {
for (i = 0; i < tv_cmd->tvc_sgl_count; i++)
put_page(sg_page(&tv_cmd->tvc_sgl[i]));
--
1.8.1
--
To unsubscribe from this list: send the line "unsubscribe kvm" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
