Split iov_iter_get_pages() by type.

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

 lib/iov_iter.c |   46 +++++++++++++++++++++++++++++-----------------
 1 file changed, 29 insertions(+), 17 deletions(-)

diff --git a/lib/iov_iter.c b/lib/iov_iter.c
index 5744ddec854f..a2de201b947f 100644
--- a/lib/iov_iter.c
+++ b/lib/iov_iter.c
@@ -1611,6 +1611,8 @@ static ssize_t pipe_get_pages(struct iov_iter *i,
        unsigned int iter_head, npages;
        size_t capacity;
 
+       if (maxsize > i->count)
+               maxsize = i->count;
        if (!maxsize)
                return 0;
 
@@ -1625,19 +1627,14 @@ static ssize_t pipe_get_pages(struct iov_iter *i,
        return __pipe_get_pages(i, min(maxsize, capacity), pages, iter_head, 
start);
 }
 
-static ssize_t xxx_get_pages(struct iov_iter *i,
+static ssize_t iovec_get_pages(struct iov_iter *i,
                   struct page **pages, size_t maxsize, unsigned maxpages,
                   size_t *start)
 {
        if (maxsize > i->count)
                maxsize = i->count;
 
-       if (unlikely(iov_iter_is_pipe(i)))
-               return pipe_get_pages(i, pages, maxsize, maxpages, start);
-       if (unlikely(iov_iter_is_discard(i)))
-               return -EFAULT;
-
-       iterate_all_kinds(i, maxsize, v, ({
+       iterate_over_iovec(i, maxsize, v, ({
                unsigned long addr = (unsigned long)v.iov_base;
                size_t len = v.iov_len + (*start = addr & (PAGE_SIZE - 1));
                int n;
@@ -1653,18 +1650,33 @@ static ssize_t xxx_get_pages(struct iov_iter *i,
                if (unlikely(res < 0))
                        return res;
                return (res == n ? len : res * PAGE_SIZE) - *start;
-       0;}),({
+       0;}));
+       return 0;
+}
+
+static ssize_t bvec_get_pages(struct iov_iter *i,
+                  struct page **pages, size_t maxsize, unsigned maxpages,
+                  size_t *start)
+{
+       if (maxsize > i->count)
+               maxsize = i->count;
+
+       iterate_over_bvec(i, maxsize, v, ({
                /* can't be more than PAGE_SIZE */
                *start = v.bv_offset;
                get_page(*pages = v.bv_page);
                return v.bv_len;
-       }),({
-               return -EFAULT;
-       })
-       )
+       }));
        return 0;
 }
 
+static ssize_t no_get_pages(struct iov_iter *i,
+                  struct page **pages, size_t maxsize, unsigned maxpages,
+                  size_t *start)
+{
+       return -EFAULT;
+}
+
 static struct page **get_pages_array(size_t n)
 {
        return kvmalloc_array(n, sizeof(struct page *), GFP_KERNEL);
@@ -2179,7 +2191,7 @@ static const struct iov_iter_ops iovec_iter_ops = {
        .zero                           = iovec_zero,
        .alignment                      = iovec_alignment,
        .gap_alignment                  = iovec_gap_alignment,
-       .get_pages                      = xxx_get_pages,
+       .get_pages                      = iovec_get_pages,
        .get_pages_alloc                = xxx_get_pages_alloc,
        .npages                         = xxx_npages,
        .dup_iter                       = xxx_dup_iter,
@@ -2213,7 +2225,7 @@ static const struct iov_iter_ops kvec_iter_ops = {
        .zero                           = kvec_zero,
        .alignment                      = kvec_alignment,
        .gap_alignment                  = kvec_gap_alignment,
-       .get_pages                      = xxx_get_pages,
+       .get_pages                      = no_get_pages,
        .get_pages_alloc                = xxx_get_pages_alloc,
        .npages                         = xxx_npages,
        .dup_iter                       = xxx_dup_iter,
@@ -2247,7 +2259,7 @@ static const struct iov_iter_ops bvec_iter_ops = {
        .zero                           = bvec_zero,
        .alignment                      = bvec_alignment,
        .gap_alignment                  = bvec_gap_alignment,
-       .get_pages                      = xxx_get_pages,
+       .get_pages                      = bvec_get_pages,
        .get_pages_alloc                = xxx_get_pages_alloc,
        .npages                         = xxx_npages,
        .dup_iter                       = xxx_dup_iter,
@@ -2281,7 +2293,7 @@ static const struct iov_iter_ops pipe_iter_ops = {
        .zero                           = pipe_zero,
        .alignment                      = pipe_alignment,
        .gap_alignment                  = no_gap_alignment,
-       .get_pages                      = xxx_get_pages,
+       .get_pages                      = pipe_get_pages,
        .get_pages_alloc                = xxx_get_pages_alloc,
        .npages                         = xxx_npages,
        .dup_iter                       = xxx_dup_iter,
@@ -2315,7 +2327,7 @@ static const struct iov_iter_ops discard_iter_ops = {
        .zero                           = discard_zero,
        .alignment                      = no_alignment,
        .gap_alignment                  = no_gap_alignment,
-       .get_pages                      = xxx_get_pages,
+       .get_pages                      = no_get_pages,
        .get_pages_alloc                = xxx_get_pages_alloc,
        .npages                         = xxx_npages,
        .dup_iter                       = xxx_dup_iter,


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