vhost/scsi: Change vhost_scsi_map_to_sgl to accept iov ptr + len

This patch changes vhost_scsi_map_to_sgl() parameters to accept virtio
iovec ptr + len when determing pages_nr.

This is currently done with iov_num_pages() -> PAGE_ALIGN, so allow
the same parameters as well.

Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

1 files changed, 15 insertions, 22 deletions

diff --git a/drivers/vhost/scsi.c b/drivers/vhost/scsi.c
index 62de820ae2f4..b9800c7a1d5d 100644
--- a/drivers/vhost/scsi.c
+++ b/drivers/vhost/scsi.c
@@ -222,10 +222,10 @@ static struct workqueue_struct *tcm_vhost_workqueue;
 static DEFINE_MUTEX(tcm_vhost_mutex);
 static LIST_HEAD(tcm_vhost_list);
 
-static int iov_num_pages(struct iovec *iov)
+static int iov_num_pages(void __user *iov_base, size_t iov_len)
 {
-        return (PAGE_ALIGN((unsigned long)iov->iov_base + iov->iov_len) -
-               ((unsigned long)iov->iov_base & PAGE_MASK)) >> PAGE_SHIFT;
+        return (PAGE_ALIGN((unsigned long)iov_base + iov_len) -
+               ((unsigned long)iov_base & PAGE_MASK)) >> PAGE_SHIFT;
 }
 
 static void tcm_vhost_done_inflight(struct kref *kref)
@@ -782,25 +782,18 @@ vhost_scsi_get_tag(struct vhost_virtqueue *vq, struct tcm_vhost_tpg *tpg,
  * Returns the number of scatterlist entries used or -errno on error.
  */
 static int
-vhost_scsi_map_to_sgl(struct tcm_vhost_cmd *tv_cmd,
+vhost_scsi_map_to_sgl(struct tcm_vhost_cmd *cmd,
+                      void __user *ptr,
+                      size_t len,
                       struct scatterlist *sgl,
-                      unsigned int sgl_count,
-                      struct iovec *iov,
-                      struct page **pages,
                       bool write)
 {
-        unsigned int npages = 0, pages_nr, offset, nbytes;
+        unsigned int npages = 0, offset, nbytes;
+        unsigned int pages_nr = iov_num_pages(ptr, len);
         struct scatterlist *sg = sgl;
-        void __user *ptr = iov->iov_base;
-        size_t len = iov->iov_len;
+        struct page **pages = cmd->tvc_upages;
         int ret, i;
 
-        pages_nr = iov_num_pages(iov);
-        if (pages_nr > sgl_count) {
-                pr_err("vhost_scsi_map_to_sgl() pages_nr: %u greater than"
-                       " sgl_count: %u\n", pages_nr, sgl_count);
-                return -ENOBUFS;
-        }
         if (pages_nr > TCM_VHOST_PREALLOC_UPAGES) {
                 pr_err("vhost_scsi_map_to_sgl() pages_nr: %u greater than"
                        " preallocated TCM_VHOST_PREALLOC_UPAGES: %u\n",
@@ -845,7 +838,7 @@ vhost_scsi_map_iov_to_sgl(struct tcm_vhost_cmd *cmd,
         int ret, i;
 
         for (i = 0; i < niov; i++)
-                sgl_count += iov_num_pages(&iov[i]);
+                sgl_count += iov_num_pages(iov[i].iov_base, iov[i].iov_len);
 
         if (sgl_count > TCM_VHOST_PREALLOC_SGLS) {
                 pr_err("vhost_scsi_map_iov_to_sgl() sgl_count: %u greater than"
@@ -861,8 +854,8 @@ vhost_scsi_map_iov_to_sgl(struct tcm_vhost_cmd *cmd,
         pr_debug("Mapping iovec %p for %u pages\n", &iov[0], sgl_count);
 
         for (i = 0; i < niov; i++) {
-                ret = vhost_scsi_map_to_sgl(cmd, sg, sgl_count, &iov[i],
-                                            cmd->tvc_upages, write);
+                ret = vhost_scsi_map_to_sgl(cmd, iov[i].iov_base, iov[i].iov_len,
+                                            sg, write);
                 if (ret < 0) {
                         for (i = 0; i < cmd->tvc_sgl_count; i++) {
                                 struct page *page = sg_page(&cmd->tvc_sgl[i]);
@@ -889,7 +882,7 @@ vhost_scsi_map_iov_to_prot(struct tcm_vhost_cmd *cmd,
         int ret, i;
 
         for (i = 0; i < niov; i++)
-                prot_sgl_count += iov_num_pages(&iov[i]);
+                prot_sgl_count += iov_num_pages(iov[i].iov_base, iov[i].iov_len);
 
         if (prot_sgl_count > TCM_VHOST_PREALLOC_PROT_SGLS) {
                 pr_err("vhost_scsi_map_iov_to_prot() sgl_count: %u greater than"
@@ -904,8 +897,8 @@ vhost_scsi_map_iov_to_prot(struct tcm_vhost_cmd *cmd,
         cmd->tvc_prot_sgl_count = prot_sgl_count;
 
         for (i = 0; i < niov; i++) {
-                ret = vhost_scsi_map_to_sgl(cmd, prot_sg, prot_sgl_count, &iov[i],
-                                            cmd->tvc_upages, write);
+                ret = vhost_scsi_map_to_sgl(cmd, iov[i].iov_base, iov[i].iov_len,
+                                            prot_sg, write);
                 if (ret < 0) {
                         for (i = 0; i < cmd->tvc_prot_sgl_count; i++) {
                                 struct page *page = sg_page(&cmd->tvc_prot_sgl[i]);