Commit 2f240c4a authored by Al Viro's avatar Al Viro
Browse files

vhost/scsi: switch to iov_iter_get_pages() 



Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 11d49e9d

drivers/vhost/scsi.c

+20 −48
Original line number Diff line number Diff line
@@ -210,12 +210,6 @@ static struct workqueue_struct *vhost_scsi_workqueue; 
static DEFINE_MUTEX(vhost_scsi_mutex);

static LIST_HEAD(vhost_scsi_list);



static int iov_num_pages(void __user *iov_base, size_t iov_len)

{

	return (PAGE_ALIGN((unsigned long)iov_base + iov_len) -

	       ((unsigned long)iov_base & PAGE_MASK)) >> PAGE_SHIFT;

}



static void vhost_scsi_done_inflight(struct kref *kref)

{

	struct vhost_scsi_inflight *inflight;
@@ -618,48 +612,31 @@ vhost_scsi_get_tag(struct vhost_virtqueue *vq, struct vhost_scsi_tpg *tpg, 
 */

static int

vhost_scsi_map_to_sgl(struct vhost_scsi_cmd *cmd,

		      void __user *ptr,

		      size_t len,

		      struct iov_iter *iter,

		      struct scatterlist *sgl,

		      bool write)

{

	unsigned int npages = 0, offset, nbytes;

	unsigned int pages_nr = iov_num_pages(ptr, len);

	struct scatterlist *sg = sgl;

	struct page **pages = cmd->tvc_upages;

	int ret, i;



	if (pages_nr > VHOST_SCSI_PREALLOC_UPAGES) {

		pr_err("vhost_scsi_map_to_sgl() pages_nr: %u greater than"

		       " preallocated VHOST_SCSI_PREALLOC_UPAGES: %u\n",

			pages_nr, VHOST_SCSI_PREALLOC_UPAGES);

		return -ENOBUFS;

	}

	struct scatterlist *sg = sgl;

	ssize_t bytes;

	size_t offset;

	unsigned int npages = 0;



	ret = get_user_pages_fast((unsigned long)ptr, pages_nr, write, pages);

	bytes = iov_iter_get_pages(iter, pages, LONG_MAX,

				VHOST_SCSI_PREALLOC_UPAGES, &offset);

	/* No pages were pinned */

	if (ret < 0)

		goto out;

	/* Less pages pinned than wanted */

	if (ret != pages_nr) {

		for (i = 0; i < ret; i++)

			put_page(pages[i]);

		ret = -EFAULT;

		goto out;

	}

	if (bytes <= 0)

		return bytes < 0 ? bytes : -EFAULT;



	while (len > 0) {

		offset = (uintptr_t)ptr & ~PAGE_MASK;

		nbytes = min_t(unsigned int, PAGE_SIZE - offset, len);

		sg_set_page(sg, pages[npages], nbytes, offset);

		ptr += nbytes;

		len -= nbytes;

		sg++;

		npages++;

	}

	iov_iter_advance(iter, bytes);



out:

	return ret;

	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
@@ -687,15 +664,11 @@ vhost_scsi_iov_to_sgl(struct vhost_scsi_cmd *cmd, bool write, 
		      struct iov_iter *iter,

		      struct scatterlist *sg, int sg_count)

{

	size_t off = iter->iov_offset;

	struct scatterlist *p = sg;

	int i, ret;



	for (i = 0; i < iter->nr_segs; i++) {

		void __user *base = iter->iov[i].iov_base + off;

		size_t len = iter->iov[i].iov_len - off;

	int ret;



		ret = vhost_scsi_map_to_sgl(cmd, base, len, sg, write);

	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++);
@@ -705,7 +678,6 @@ vhost_scsi_iov_to_sgl(struct vhost_scsi_cmd *cmd, bool write, 
			return ret;

		}

		sg += ret;

		off = 0;

	}

	return 0;

}