Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Pull vfs updates from Al Viro:
 "This the bunch that sat in -next + lock_parent() fix.  This is the
  minimal set; there's more pending stuff.

  In particular, I really hope to get acct.c fixes merged this cycle -
  we need that to deal sanely with delayed-mntput stuff.  In the next
  pile, hopefully - that series is fairly short and localized
  (kernel/acct.c, fs/super.c and fs/namespace.c).  In this pile: more
  iov_iter work.  Most of prereqs for ->splice_write with sane locking
  order are there and Kent's dio rewrite would also fit nicely on top of
  this pile"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (70 commits)
  lock_parent: don't step on stale ->d_parent of all-but-freed one
  kill generic_file_splice_write()
  ceph: switch to iter_file_splice_write()
  shmem: switch to iter_file_splice_write()
  nfs: switch to iter_splice_write_file()
  fs/splice.c: remove unneeded exports
  ocfs2: switch to iter_file_splice_write()
  ->splice_write() via ->write_iter()
  bio_vec-backed iov_iter
  optimize copy_page_{to,from}_iter()
  bury generic_file_aio_{read,write}
  lustre: get rid of messing with iovecs
  ceph: switch to ->write_iter()
  ceph_sync_direct_write: stop poking into iov_iter guts
  ceph_sync_read: stop poking into iov_iter guts
  new helper: copy_page_from_iter()
  fuse: switch to ->write_iter()
  btrfs: switch to ->write_iter()
  ocfs2: switch to ->write_iter()
  xfs: switch to ->write_iter()
  ...

1 files changed, 42 insertions, 116 deletions

diff --git a/mm/filemap.c b/mm/filemap.c
index 7fadf1c62838..dafb06f70a09 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -1665,96 +1665,42 @@ out:
         return written ? written : error;
 }
 
-/*
- * Performs necessary checks before doing a write
- * @iov:        io vector request
- * @nr_segs:    number of segments in the iovec
- * @count:      number of bytes to write
- * @access_flags: type of access: %VERIFY_READ or %VERIFY_WRITE
- *
- * Adjust number of segments and amount of bytes to write (nr_segs should be
- * properly initialized first). Returns appropriate error code that caller
- * should return or zero in case that write should be allowed.
- */
-int generic_segment_checks(const struct iovec *iov,
-                        unsigned long *nr_segs, size_t *count, int access_flags)
-{
-        unsigned long   seg;
-        size_t cnt = 0;
-        for (seg = 0; seg < *nr_segs; seg++) {
-                const struct iovec *iv = &iov[seg];
-
-                /*
-                 * If any segment has a negative length, or the cumulative
-                 * length ever wraps negative then return -EINVAL.
-                 */
-                cnt += iv->iov_len;
-                if (unlikely((ssize_t)(cnt|iv->iov_len) < 0))
-                        return -EINVAL;
-                if (access_ok(access_flags, iv->iov_base, iv->iov_len))
-                        continue;
-                if (seg == 0)
-                        return -EFAULT;
-                *nr_segs = seg;
-                cnt -= iv->iov_len;     /* This segment is no good */
-                break;
-        }
-        *count = cnt;
-        return 0;
-}
-EXPORT_SYMBOL(generic_segment_checks);
-
 /**
- * generic_file_aio_read - generic filesystem read routine
+ * generic_file_read_iter - generic filesystem read routine
  * @iocb:       kernel I/O control block
- * @iov:        io vector request
- * @nr_segs:    number of segments in the iovec
- * @pos:        current file position
+ * @iter:       destination for the data read
  *
- * This is the "read()" routine for all filesystems
+ * This is the "read_iter()" routine for all filesystems
  * that can use the page cache directly.
  */
 ssize_t
-generic_file_aio_read(struct kiocb *iocb, const struct iovec *iov,
-                unsigned long nr_segs, loff_t pos)
+generic_file_read_iter(struct kiocb *iocb, struct iov_iter *iter)
 {
-        struct file *filp = iocb->ki_filp;
-        ssize_t retval;
-        size_t count;
+        struct file *file = iocb->ki_filp;
+        ssize_t retval = 0;
         loff_t *ppos = &iocb->ki_pos;
-        struct iov_iter i;
-
-        count = 0;
-        retval = generic_segment_checks(iov, &nr_segs, &count, VERIFY_WRITE);
-        if (retval)
-                return retval;
-        iov_iter_init(&i, iov, nr_segs, count, 0);
+        loff_t pos = *ppos;
 
         /* coalesce the iovecs and go direct-to-BIO for O_DIRECT */
-        if (filp->f_flags & O_DIRECT) {
+        if (file->f_flags & O_DIRECT) {
+                struct address_space *mapping = file->f_mapping;
+                struct inode *inode = mapping->host;
+                size_t count = iov_iter_count(iter);
                 loff_t size;
-                struct address_space *mapping;
-                struct inode *inode;
 
-                mapping = filp->f_mapping;
-                inode = mapping->host;
                 if (!count)
                         goto out; /* skip atime */
                 size = i_size_read(inode);
                 retval = filemap_write_and_wait_range(mapping, pos,
-                                        pos + iov_length(iov, nr_segs) - 1);
+                                        pos + count - 1);
                 if (!retval) {
-                        retval = mapping->a_ops->direct_IO(READ, iocb,
-                                                           iov, pos, nr_segs);
+                        struct iov_iter data = *iter;
+                        retval = mapping->a_ops->direct_IO(READ, iocb, &data, pos);
                 }
+
                 if (retval > 0) {
                         *ppos = pos + retval;
-                        count -= retval;
-                        /*
-                         * If we did a short DIO read we need to skip the
-                         * section of the iov that we've already read data into.
-                         */
-                        iov_iter_advance(&i, retval);
+                        iov_iter_advance(iter, retval);
                 }
 
                 /*
@@ -1765,17 +1711,17 @@ generic_file_aio_read(struct kiocb *iocb, const struct iovec *iov,
                  * and return.  Otherwise fallthrough to buffered io for
                  * the rest of the read.
                  */
-                if (retval < 0 || !count || *ppos >= size) {
-                        file_accessed(filp);
+                if (retval < 0 || !iov_iter_count(iter) || *ppos >= size) {
+                        file_accessed(file);
                         goto out;
                 }
         }
 
-        retval = do_generic_file_read(filp, ppos, &i, retval);
+        retval = do_generic_file_read(file, ppos, iter, retval);
 out:
         return retval;
 }
-EXPORT_SYMBOL(generic_file_aio_read);
+EXPORT_SYMBOL(generic_file_read_iter);
 
 #ifdef CONFIG_MMU
 /**
@@ -2386,9 +2332,7 @@ int pagecache_write_end(struct file *file, struct address_space *mapping,
 EXPORT_SYMBOL(pagecache_write_end);
 
 ssize_t
-generic_file_direct_write(struct kiocb *iocb, const struct iovec *iov,
-                unsigned long *nr_segs, loff_t pos,
-                size_t count, size_t ocount)
+generic_file_direct_write(struct kiocb *iocb, struct iov_iter *from, loff_t pos)
 {
         struct file     *file = iocb->ki_filp;
         struct address_space *mapping = file->f_mapping;
@@ -2396,11 +2340,9 @@ generic_file_direct_write(struct kiocb *iocb, const struct iovec *iov,
         ssize_t         written;
         size_t          write_len;
         pgoff_t         end;
+        struct iov_iter data;
 
-        if (count != ocount)
-                *nr_segs = iov_shorten((struct iovec *)iov, *nr_segs, count);
-
-        write_len = iov_length(iov, *nr_segs);
+        write_len = iov_iter_count(from);
         end = (pos + write_len - 1) >> PAGE_CACHE_SHIFT;
 
         written = filemap_write_and_wait_range(mapping, pos, pos + write_len - 1);
@@ -2427,7 +2369,8 @@ generic_file_direct_write(struct kiocb *iocb, const struct iovec *iov,
                 }
         }
 
-        written = mapping->a_ops->direct_IO(WRITE, iocb, iov, pos, *nr_segs);
+        data = *from;
+        written = mapping->a_ops->direct_IO(WRITE, iocb, &data, pos);
 
         /*
          * Finally, try again to invalidate clean pages which might have been
@@ -2444,6 +2387,7 @@ generic_file_direct_write(struct kiocb *iocb, const struct iovec *iov,
 
         if (written > 0) {
                 pos += written;
+                iov_iter_advance(from, written);
                 if (pos > i_size_read(inode) && !S_ISBLK(inode->i_mode)) {
                         i_size_write(inode, pos);
                         mark_inode_dirty(inode);
@@ -2568,10 +2512,9 @@ 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
@@ -2585,26 +2528,16 @@ 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 ocount;          /* original count */
-        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;
-
-        ocount = 0;
-        err = generic_segment_checks(iov, &nr_segs, &ocount, VERIFY_READ);
-        if (err)
-                return err;
-
-        count = ocount;
+        size_t          count = iov_iter_count(from);
 
         /* We can write back this queue in page reclaim */
         current->backing_dev_info = mapping->backing_dev_info;
@@ -2615,6 +2548,8 @@ ssize_t __generic_file_aio_write(struct kiocb *iocb, const struct iovec *iov,
         if (count == 0)
                 goto out;
 
+        iov_iter_truncate(from, count);
+
         err = file_remove_suid(file);
         if (err)
                 goto out;
@@ -2623,17 +2558,13 @@ ssize_t __generic_file_aio_write(struct kiocb *iocb, const struct iovec *iov,
         if (err)
                 goto out;
 
-        iov_iter_init(&from, iov, nr_segs, count, 0);
-
         /* coalesce the iovecs and go direct-to-BIO for O_DIRECT */
         if (unlikely(file->f_flags & O_DIRECT)) {
                 loff_t endbyte;
 
-                written = generic_file_direct_write(iocb, iov, &from.nr_segs, pos,
-                                                        count, ocount);
+                written = generic_file_direct_write(iocb, from, pos);
                 if (written < 0 || written == count)
                         goto out;
-                iov_iter_advance(&from, written);
 
                 /*
                  * direct-io write to a hole: fall through to buffered I/O
@@ -2642,7 +2573,7 @@ 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
@@ -2674,7 +2605,7 @@ 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;
         }
@@ -2682,30 +2613,25 @@ out:
         current->backing_dev_info = NULL;
         return written ? written : err;
 }
-EXPORT_SYMBOL(__generic_file_aio_write);
+EXPORT_SYMBOL(__generic_file_write_iter);
 
 /**
- * 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) {
@@ -2717,7 +2643,7 @@ ssize_t generic_file_aio_write(struct kiocb *iocb, const struct iovec *iov,
         }
         return ret;
 }
-EXPORT_SYMBOL(generic_file_aio_write);
+EXPORT_SYMBOL(generic_file_write_iter);
 
 /**
  * try_to_release_page() - release old fs-specific metadata on a page