Use extract_iter_to_sg() to build a scatterlist from an iterator.
Signed-off-by: David Howells <dhowells@xxxxxxxxxx>
cc: James E.J. Bottomley <jejb@xxxxxxxxxxxxx>
cc: Martin K. Petersen <martin.petersen@xxxxxxxxxx>
cc: Christoph Hellwig <hch@xxxxxx>
cc: linux-scsi@xxxxxxxxxxxxxxx
---
drivers/vhost/scsi.c | 79 +++++++++++++-------------------------------
1 file changed, 23 insertions(+), 56 deletions(-)
diff --git a/drivers/vhost/scsi.c b/drivers/vhost/scsi.c
index bb10fa4bb4f6..7bb41e2a0d64 100644
--- a/drivers/vhost/scsi.c
+++ b/drivers/vhost/scsi.c
@@ -75,6 +75,9 @@ struct vhost_scsi_cmd {
u32 tvc_prot_sgl_count;
/* Saved unpacked SCSI LUN for vhost_scsi_target_queue_cmd() */
u32 tvc_lun;
+ /* Cleanup modes for scatterlists */
+ unsigned int tvc_need_unpin;
+ unsigned int tvc_prot_need_unpin;
/* Pointer to the SGL formatted memory from virtio-scsi */
struct scatterlist *tvc_sgl;
struct scatterlist *tvc_prot_sgl;
@@ -327,14 +330,13 @@ static void vhost_scsi_release_cmd_res(struct se_cmd *se_cmd)
struct vhost_scsi_inflight *inflight = tv_cmd->inflight;
int i;
- if (tv_cmd->tvc_sgl_count) {
+ if (tv_cmd->tvc_need_unpin && tv_cmd->tvc_sgl_count)
for (i = 0; i < tv_cmd->tvc_sgl_count; i++)
- put_page(sg_page(&tv_cmd->tvc_sgl[i]));
- }
- if (tv_cmd->tvc_prot_sgl_count) {
+ unpin_user_page(sg_page(&tv_cmd->tvc_sgl[i]));
+
+ if (tv_cmd->tvc_prot_need_unpin && tv_cmd->tvc_prot_sgl_count)
for (i = 0; i < tv_cmd->tvc_prot_sgl_count; i++)
- put_page(sg_page(&tv_cmd->tvc_prot_sgl[i]));
- }
+ unpin_user_page(sg_page(&tv_cmd->tvc_prot_sgl[i]));
sbitmap_clear_bit(&svq->scsi_tags, se_cmd->map_tag);
vhost_scsi_put_inflight(inflight);
@@ -606,38 +608,6 @@ vhost_scsi_get_cmd(struct vhost_virtqueue *vq, struct vhost_scsi_tpg *tpg,
return cmd;
}
-/*
- * Map a user memory range into a scatterlist
- *
- * Returns the number of scatterlist entries used or -errno on error.
- */
-static int
-vhost_scsi_map_to_sgl(struct vhost_scsi_cmd *cmd,
- struct iov_iter *iter,
- struct scatterlist *sgl,
- bool write)
-{
- struct page **pages = cmd->tvc_upages;
- struct scatterlist *sg = sgl;
- ssize_t bytes;
- size_t offset;
- unsigned int npages = 0;
-
- bytes = iov_iter_get_pages2(iter, pages, LONG_MAX,
- VHOST_SCSI_PREALLOC_UPAGES, &offset);
- /* No pages were pinned */
- if (bytes <= 0)
- return bytes < 0 ? bytes : -EFAULT;
-
- while (bytes) {
- unsigned n = min_t(unsigned, PAGE_SIZE - offset, bytes);
- sg_set_page(sg++, pages[npages++], n, offset);
- bytes -= n;
- offset = 0;
- }
- return npages;
-}
-
static int
vhost_scsi_calc_sgls(struct iov_iter *iter, size_t bytes, int max_sgls)
{
@@ -661,24 +631,19 @@ vhost_scsi_calc_sgls(struct iov_iter *iter, size_t bytes, int max_sgls)
static int
vhost_scsi_iov_to_sgl(struct vhost_scsi_cmd *cmd, bool write,
struct iov_iter *iter,
- struct scatterlist *sg, int sg_count)
+ struct scatterlist *sg, int sg_count,
+ unsigned int *need_unpin)
{
- struct scatterlist *p = sg;
- int ret;
+ struct sg_table sgt = { .sgl = sg };
+ ssize_t ret;
- while (iov_iter_count(iter)) {
- ret = vhost_scsi_map_to_sgl(cmd, iter, sg, write);
- if (ret < 0) {
- while (p < sg) {
- struct page *page = sg_page(p++);
- if (page)
- put_page(page);
- }
- return ret;
- }
- sg += ret;
- }
- return 0;
+ ret = extract_iter_to_sg(iter, LONG_MAX, &sgt, sg_count,
+ write ? WRITE_FROM_ITER : READ_INTO_ITER);
+ if (ret > 0)
+ sg_mark_end(sg + sgt.nents - 1);
+
+ *need_unpin = iov_iter_extract_will_pin(iter);
+ return ret;
}
static int
@@ -702,7 +667,8 @@ vhost_scsi_mapal(struct vhost_scsi_cmd *cmd,
ret = vhost_scsi_iov_to_sgl(cmd, write, prot_iter,
cmd->tvc_prot_sgl,
- cmd->tvc_prot_sgl_count);
+ cmd->tvc_prot_sgl_count,
+ &cmd->tvc_prot_need_unpin);
if (ret < 0) {
cmd->tvc_prot_sgl_count = 0;
return ret;
@@ -719,7 +685,8 @@ vhost_scsi_mapal(struct vhost_scsi_cmd *cmd,
cmd->tvc_sgl, cmd->tvc_sgl_count);
ret = vhost_scsi_iov_to_sgl(cmd, write, data_iter,
- cmd->tvc_sgl, cmd->tvc_sgl_count);
+ cmd->tvc_sgl, cmd->tvc_sgl_count,
+ &cmd->tvc_need_unpin);
if (ret < 0) {
cmd->tvc_sgl_count = 0;
return ret;
