Direct IO support

[mirror_zfs.git] / module / zfs / zpl_file.c

diff --git a/module/zfs/zpl_file.c b/module/zfs/zpl_file.c
index 91251f9e6e0fd986cf5a1d33e620d89972eded93..8d9c44b37294531d73e51f36bf2aae7f90d6055b 100644 (file)
--- a/module/zfs/zpl_file.c
+++ b/module/zfs/zpl_file.c
@@ -438,6 +438,57 @@ zpl_aio_write(struct kiocb *kiocb, const struct iovec *iovp,
 }
 #endif /* HAVE_VFS_RW_ITERATE */
 
+#if defined(HAVE_VFS_RW_ITERATE)
+static ssize_t
+zpl_direct_IO_impl(int rw, struct kiocb *kiocb, struct iov_iter *iter)
+{
+       if (rw == WRITE)
+               return (zpl_iter_write(kiocb, iter));
+       else
+               return (zpl_iter_read(kiocb, iter));
+}
+#if defined(HAVE_VFS_DIRECT_IO_ITER)
+static ssize_t
+zpl_direct_IO(struct kiocb *kiocb, struct iov_iter *iter)
+{
+       return (zpl_direct_IO_impl(iov_iter_rw(iter), kiocb, iter));
+}
+#elif defined(HAVE_VFS_DIRECT_IO_ITER_OFFSET)
+static ssize_t
+zpl_direct_IO(struct kiocb *kiocb, struct iov_iter *iter, loff_t pos)
+{
+       ASSERT3S(pos, ==, kiocb->ki_pos);
+       return (zpl_direct_IO_impl(iov_iter_rw(iter), kiocb, iter));
+}
+#elif defined(HAVE_VFS_DIRECT_IO_ITER_RW_OFFSET)
+static ssize_t
+zpl_direct_IO(int rw, struct kiocb *kiocb, struct iov_iter *iter, loff_t pos)
+{
+       ASSERT3S(pos, ==, kiocb->ki_pos);
+       return (zpl_direct_IO_impl(rw, kiocb, iter));
+}
+#else
+#error "Unknown direct IO interface"
+#endif
+
+#else
+
+#if defined(HAVE_VFS_DIRECT_IO_IOVEC)
+static ssize_t
+zpl_direct_IO(int rw, struct kiocb *kiocb, const struct iovec *iovp,
+    loff_t pos, unsigned long nr_segs)
+{
+       if (rw == WRITE)
+               return (zpl_aio_write(kiocb, iovp, nr_segs, pos));
+       else
+               return (zpl_aio_read(kiocb, iovp, nr_segs, pos));
+}
+#else
+#error "Unknown direct IO interface"
+#endif
+
+#endif /* HAVE_VFS_RW_ITERATE */
+
 static loff_t
 zpl_llseek(struct file *filp, loff_t offset, int whence)
 {
@@ -929,6 +980,7 @@ const struct address_space_operations zpl_address_space_operations = {
        .readpage       = zpl_readpage,
        .writepage      = zpl_writepage,
        .writepages     = zpl_writepages,
+       .direct_IO      = zpl_direct_IO,
 };
 
 const struct file_operations zpl_file_operations = {