Merge tag 'pull-work.iov_iter-base' of git://git.kernel.org/pub/scm/linux/kernel...

[platform/kernel/linux-starfive.git] / lib / iov_iter.c

diff --git a/lib/iov_iter.c b/lib/iov_iter.c
index a4a4406..58648fc 100644 (file)
--- a/lib/iov_iter.c
+++ b/lib/iov_iter.c
@@ -1090,6 +1090,98 @@ void iov_iter_discard(struct iov_iter *i, unsigned int direction, size_t count)
 }
 EXPORT_SYMBOL(iov_iter_discard);
 
+static bool iov_iter_aligned_iovec(const struct iov_iter *i, unsigned addr_mask,
+                                  unsigned len_mask)
+{
+       size_t size = i->count;
+       size_t skip = i->iov_offset;
+       unsigned k;
+
+       for (k = 0; k < i->nr_segs; k++, skip = 0) {
+               size_t len = i->iov[k].iov_len - skip;
+
+               if (len > size)
+                       len = size;
+               if (len & len_mask)
+                       return false;
+               if ((unsigned long)(i->iov[k].iov_base + skip) & addr_mask)
+                       return false;
+
+               size -= len;
+               if (!size)
+                       break;
+       }
+       return true;
+}
+
+static bool iov_iter_aligned_bvec(const struct iov_iter *i, unsigned addr_mask,
+                                 unsigned len_mask)
+{
+       size_t size = i->count;
+       unsigned skip = i->iov_offset;
+       unsigned k;
+
+       for (k = 0; k < i->nr_segs; k++, skip = 0) {
+               size_t len = i->bvec[k].bv_len - skip;
+
+               if (len > size)
+                       len = size;
+               if (len & len_mask)
+                       return false;
+               if ((unsigned long)(i->bvec[k].bv_offset + skip) & addr_mask)
+                       return false;
+
+               size -= len;
+               if (!size)
+                       break;
+       }
+       return true;
+}
+
+/**
+ * iov_iter_is_aligned() - Check if the addresses and lengths of each segments
+ *     are aligned to the parameters.
+ *
+ * @i: &struct iov_iter to restore
+ * @addr_mask: bit mask to check against the iov element's addresses
+ * @len_mask: bit mask to check against the iov element's lengths
+ *
+ * Return: false if any addresses or lengths intersect with the provided masks
+ */
+bool iov_iter_is_aligned(const struct iov_iter *i, unsigned addr_mask,
+                        unsigned len_mask)
+{
+       if (likely(iter_is_iovec(i) || iov_iter_is_kvec(i)))
+               return iov_iter_aligned_iovec(i, addr_mask, len_mask);
+
+       if (iov_iter_is_bvec(i))
+               return iov_iter_aligned_bvec(i, addr_mask, len_mask);
+
+       if (iov_iter_is_pipe(i)) {
+               unsigned int p_mask = i->pipe->ring_size - 1;
+               size_t size = i->count;
+
+               if (size & len_mask)
+                       return false;
+               if (size && allocated(&i->pipe->bufs[i->head & p_mask])) {
+                       if (i->iov_offset & addr_mask)
+                               return false;
+               }
+
+               return true;
+       }
+
+       if (iov_iter_is_xarray(i)) {
+               if (i->count & len_mask)
+                       return false;
+               if ((i->xarray_start + i->iov_offset) & addr_mask)
+                       return false;
+       }
+
+       return true;
+}
+EXPORT_SYMBOL_GPL(iov_iter_is_aligned);
+
 static unsigned long iov_iter_alignment_iovec(const struct iov_iter *i)
 {
        unsigned long res = 0;
@@ -1256,7 +1348,7 @@ static ssize_t iter_xarray_get_pages(struct iov_iter *i,
 {
        unsigned nr, offset;
        pgoff_t index, count;
-       size_t size = maxsize, actual;
+       size_t size = maxsize;
        loff_t pos;
 
        if (!size || !maxpages)
@@ -1283,13 +1375,7 @@ static ssize_t iter_xarray_get_pages(struct iov_iter *i,
        if (nr == 0)
                return 0;
 
-       actual = PAGE_SIZE * nr;
-       actual -= offset;
-       if (nr == count && size > 0) {
-               unsigned last_offset = (nr > 1) ? 0 : offset;
-               actual -= PAGE_SIZE - (last_offset + size);
-       }
-       return actual;
+       return min_t(size_t, nr * PAGE_SIZE - offset, maxsize);
 }
 
 /* must be done on non-empty ITER_IOVEC one */
@@ -1420,7 +1506,7 @@ static ssize_t iter_xarray_get_pages_alloc(struct iov_iter *i,
        struct page **p;
        unsigned nr, offset;
        pgoff_t index, count;
-       size_t size = maxsize, actual;
+       size_t size = maxsize;
        loff_t pos;
 
        if (!size)
@@ -1449,13 +1535,7 @@ static ssize_t iter_xarray_get_pages_alloc(struct iov_iter *i,
        if (nr == 0)
                return 0;
 
-       actual = PAGE_SIZE * nr;
-       actual -= offset;
-       if (nr == count && size > 0) {
-               unsigned last_offset = (nr > 1) ? 0 : offset;
-               actual -= PAGE_SIZE - (last_offset + size);
-       }
-       return actual;
+       return min_t(size_t, nr * PAGE_SIZE - offset, maxsize);
 }
 
 ssize_t iov_iter_get_pages_alloc(struct iov_iter *i,