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>

diff --git a/drivers/vhost/scsi.c b/drivers/vhost/scsi.c
index 62de820ae2f4fc72244ad85b04fbd5ce99fbba75..b9800c7a1d5db25764b0871af204ab914d749801 100644 (file)
--- 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]);