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vhost/scsi: switch to iov_iter_get_pages() 

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2017-09-24 22:07:59 -04:00
parent 11d49e9d08
commit 2f240c4ae8
1 changed files with 20 additions and 48 deletions
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68
drivers/vhost/scsi.c
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@ -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;
struct scatterlist *sg = sgl;
ssize_t bytes;
size_t offset;
unsigned int npages = 0;
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;
}
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;
int 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;
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;
}