[PATCH 27/29] iov_iter: Split dup_iter()

[David Howells]

Split dup_iter() by type.

Signed-off-by: David Howells <dhowe...@redhat.com>
---

 lib/iov_iter.c |   49 +++++++++++++++++++++++++++++--------------------
 1 file changed, 29 insertions(+), 20 deletions(-)

diff --git a/lib/iov_iter.c b/lib/iov_iter.c
index d8ef6c81c55f..ca0e94596eda 100644
--- a/lib/iov_iter.c
+++ b/lib/iov_iter.c
@@ -2078,26 +2078,35 @@ static int discard_npages(const struct iov_iter *i, int 
maxpages)
        return 0;
 }
 
-static const void *xxx_dup_iter(struct iov_iter *new, struct iov_iter *old, 
gfp_t flags)
+static const void *iovec_kvec_dup_iter(struct iov_iter *new, struct iov_iter 
*old, gfp_t flags)
 {
        *new = *old;
-       if (unlikely(iov_iter_is_pipe(new))) {
-               WARN_ON(1);
-               return NULL;
-       }
-       if (unlikely(iov_iter_is_discard(new)))
-               return NULL;
-       if (iov_iter_is_bvec(new))
-               return new->bvec = kmemdup(new->bvec,
-                                   new->nr_segs * sizeof(struct bio_vec),
-                                   flags);
-       else
-               /* iovec and kvec have identical layout */
-               return new->iov = kmemdup(new->iov,
-                                  new->nr_segs * sizeof(struct iovec),
+       /* iovec and kvec have identical layout */
+       return new->iov = kmemdup(new->iov,
+                                 new->nr_segs * sizeof(struct iovec),
+                                 flags);
+}
+
+static const void *bvec_dup_iter(struct iov_iter *new, struct iov_iter *old, 
gfp_t flags)
+{
+       *new = *old;
+       return new->bvec = kmemdup(new->bvec,
+                                  new->nr_segs * sizeof(struct bio_vec),
                                   flags);
 }
 
+static const void *discard_dup_iter(struct iov_iter *new, struct iov_iter 
*old, gfp_t flags)
+{
+       *new = *old;
+       return NULL;
+}
+
+static const void *no_dup_iter(struct iov_iter *new, struct iov_iter *old, 
gfp_t flags)
+{
+       WARN_ON(1);
+       return NULL;
+}
+
 static int copy_compat_iovec_from_user(struct iovec *iov,
                const struct iovec __user *uvec, unsigned long nr_segs)
 {
@@ -2324,7 +2333,7 @@ static const struct iov_iter_ops iovec_iter_ops = {
        .get_pages                      = iovec_get_pages,
        .get_pages_alloc                = iovec_get_pages_alloc,
        .npages                         = iovec_npages,
-       .dup_iter                       = xxx_dup_iter,
+       .dup_iter                       = iovec_kvec_dup_iter,
        .for_each_range                 = xxx_for_each_range,
 };
 
@@ -2358,7 +2367,7 @@ static const struct iov_iter_ops kvec_iter_ops = {
        .get_pages                      = no_get_pages,
        .get_pages_alloc                = no_get_pages_alloc,
        .npages                         = kvec_npages,
-       .dup_iter                       = xxx_dup_iter,
+       .dup_iter                       = iovec_kvec_dup_iter,
        .for_each_range                 = xxx_for_each_range,
 };
 
@@ -2392,7 +2401,7 @@ static const struct iov_iter_ops bvec_iter_ops = {
        .get_pages                      = bvec_get_pages,
        .get_pages_alloc                = bvec_get_pages_alloc,
        .npages                         = bvec_npages,
-       .dup_iter                       = xxx_dup_iter,
+       .dup_iter                       = bvec_dup_iter,
        .for_each_range                 = xxx_for_each_range,
 };
 
@@ -2426,7 +2435,7 @@ static const struct iov_iter_ops pipe_iter_ops = {
        .get_pages                      = pipe_get_pages,
        .get_pages_alloc                = pipe_get_pages_alloc,
        .npages                         = pipe_npages,
-       .dup_iter                       = xxx_dup_iter,
+       .dup_iter                       = no_dup_iter,
        .for_each_range                 = xxx_for_each_range,
 };
 
@@ -2460,6 +2469,6 @@ static const struct iov_iter_ops discard_iter_ops = {
        .get_pages                      = no_get_pages,
        .get_pages_alloc                = no_get_pages_alloc,
        .npages                         = discard_npages,
-       .dup_iter                       = xxx_dup_iter,
+       .dup_iter                       = discard_dup_iter,
        .for_each_range                 = xxx_for_each_range,
 };