write_iter variants of {__,}generic_file_aio_write()

[mirror_ubuntu-zesty-kernel.git] / mm / filemap.c

diff --git a/mm/filemap.c b/mm/filemap.c
index c0404b763a17fb48832b58ac0137589148da915c..d2d9eeec8bf0559ec717a5843210a60116690410 100644 (file)
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -2542,10 +2542,9 @@ again:
 EXPORT_SYMBOL(generic_perform_write);
 
 /**
- * __generic_file_aio_write - write data to a file
+ * __generic_file_write_iter - write data to a file
  * @iocb:      IO state structure (file, offset, etc.)
- * @iov:       vector with data to write
- * @nr_segs:   number of segments in the vector
+ * @from:      iov_iter with data to write
  *
  * This function does all the work needed for actually writing data to a
  * file. It does all basic checks, removes SUID from the file, updates
@@ -2559,21 +2558,16 @@ EXPORT_SYMBOL(generic_perform_write);
  * A caller has to handle it. This is mainly due to the fact that we want to
  * avoid syncing under i_mutex.
  */
-ssize_t __generic_file_aio_write(struct kiocb *iocb, const struct iovec *iov,
-                                unsigned long nr_segs)
+ssize_t __generic_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
 {
        struct file *file = iocb->ki_filp;
        struct address_space * mapping = file->f_mapping;
-       size_t count;           /* after file limit checks */
        struct inode    *inode = mapping->host;
        loff_t          pos = iocb->ki_pos;
        ssize_t         written = 0;
        ssize_t         err;
        ssize_t         status;
-       struct iov_iter from;
-
-       count = iov_length(iov, nr_segs);
-       iov_iter_init(&from, WRITE, iov, nr_segs, count);
+       size_t          count = iov_iter_count(from);
 
        /* We can write back this queue in page reclaim */
        current->backing_dev_info = mapping->backing_dev_info;
@@ -2584,7 +2578,7 @@ ssize_t __generic_file_aio_write(struct kiocb *iocb, const struct iovec *iov,
        if (count == 0)
                goto out;
 
-       iov_iter_truncate(&from, count);
+       iov_iter_truncate(from, count);
 
        err = file_remove_suid(file);
        if (err)
@@ -2598,7 +2592,7 @@ ssize_t __generic_file_aio_write(struct kiocb *iocb, const struct iovec *iov,
        if (unlikely(file->f_flags & O_DIRECT)) {
                loff_t endbyte;
 
-               written = generic_file_direct_write(iocb, &from, pos);
+               written = generic_file_direct_write(iocb, from, pos);
                if (written < 0 || written == count)
                        goto out;
 
@@ -2609,7 +2603,7 @@ ssize_t __generic_file_aio_write(struct kiocb *iocb, const struct iovec *iov,
                pos += written;
                count -= written;
 
-               status = generic_perform_write(file, &from, pos);
+               status = generic_perform_write(file, from, pos);
                /*
                 * If generic_perform_write() returned a synchronous error
                 * then we want to return the number of bytes which were
@@ -2641,7 +2635,7 @@ ssize_t __generic_file_aio_write(struct kiocb *iocb, const struct iovec *iov,
                         */
                }
        } else {
-               written = generic_perform_write(file, &from, pos);
+               written = generic_perform_write(file, from, pos);
                if (likely(written >= 0))
                        iocb->ki_pos = pos + written;
        }
@@ -2649,30 +2643,36 @@ out:
        current->backing_dev_info = NULL;
        return written ? written : err;
 }
+EXPORT_SYMBOL(__generic_file_write_iter);
+
+ssize_t __generic_file_aio_write(struct kiocb *iocb, const struct iovec *iov,
+                                unsigned long nr_segs)
+{
+       size_t count = iov_length(iov, nr_segs);
+       struct iov_iter from;
+
+       iov_iter_init(&from, WRITE, iov, nr_segs, count);
+       return __generic_file_write_iter(iocb, &from);
+}
 EXPORT_SYMBOL(__generic_file_aio_write);
 
 /**
- * generic_file_aio_write - write data to a file
+ * generic_file_write_iter - write data to a file
  * @iocb:      IO state structure
- * @iov:       vector with data to write
- * @nr_segs:   number of segments in the vector
- * @pos:       position in file where to write
+ * @from:      iov_iter with data to write
  *
- * This is a wrapper around __generic_file_aio_write() to be used by most
+ * This is a wrapper around __generic_file_write_iter() to be used by most
  * filesystems. It takes care of syncing the file in case of O_SYNC file
  * and acquires i_mutex as needed.
  */
-ssize_t generic_file_aio_write(struct kiocb *iocb, const struct iovec *iov,
-               unsigned long nr_segs, loff_t pos)
+ssize_t generic_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
 {
        struct file *file = iocb->ki_filp;
        struct inode *inode = file->f_mapping->host;
        ssize_t ret;
 
-       BUG_ON(iocb->ki_pos != pos);
-
        mutex_lock(&inode->i_mutex);
-       ret = __generic_file_aio_write(iocb, iov, nr_segs);
+       ret = __generic_file_write_iter(iocb, from);
        mutex_unlock(&inode->i_mutex);
 
        if (ret > 0) {
@@ -2684,6 +2684,19 @@ ssize_t generic_file_aio_write(struct kiocb *iocb, const struct iovec *iov,
        }
        return ret;
 }
+EXPORT_SYMBOL(generic_file_write_iter);
+
+ssize_t generic_file_aio_write(struct kiocb *iocb, const struct iovec *iov,
+               unsigned long nr_segs, loff_t pos)
+{
+       size_t count = iov_length(iov, nr_segs);
+       struct iov_iter from;
+
+       BUG_ON(iocb->ki_pos != pos);
+
+       iov_iter_init(&from, WRITE, iov, nr_segs, count);
+       return generic_file_write_iter(iocb, &from);
+}
 EXPORT_SYMBOL(generic_file_aio_write);
 
 /**