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Commit ed978a81 authored by Al Viro's avatar Al Viro
Browse files

new helper: generic_file_read_iter() 



iov_iter-using variant of generic_file_aio_read().  Some callers
converted.  Note that it's still not quite there for use as ->read_iter() -
we depend on having zero iter->iov_offset in O_DIRECT case.  Fortunately,
that's true for all converted callers (and for generic_file_aio_read() itself).

Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 23faa7b8

fs/ceph/file.c

+1 −14
Original line number Diff line number Diff line
@@ -833,24 +833,11 @@ again: 
		/* hmm, this isn't really async... */

		ret = ceph_sync_read(iocb, &i, &checkeof);

	} else {

		/*

		 * We can't modify the content of iov,

		 * so we only read from beginning.

		 *

		 * When we switch generic_file_aio_read() to iov_iter, the

		 * if () below will be removed -- AV

		 */

		if (read) {

			iocb->ki_pos = pos;

			len = iocb->ki_nbytes;

			read = 0;

			iov_iter_init(&i, iov, nr_segs, len, 0);

		}

		dout("aio_read %p %llx.%llx %llu~%u got cap refs on %s\n",

		     inode, ceph_vinop(inode), pos, (unsigned)len,

		     ceph_cap_string(got));



		ret = generic_file_aio_read(iocb, iov, nr_segs, pos);

		ret = generic_file_read_iter(iocb, &i);

	}

	dout("aio_read %p %llx.%llx dropping cap refs on %s = %d\n",

	     inode, ceph_vinop(inode), ceph_cap_string(got), (int)ret);

fs/nfs/file.c

+1 −1
Original line number Diff line number Diff line
@@ -184,7 +184,7 @@ nfs_file_read(struct kiocb *iocb, const struct iovec *iov, 


	result = nfs_revalidate_mapping(inode, iocb->ki_filp->f_mapping);

	if (!result) {

		result = generic_file_aio_read(iocb, iov, nr_segs, pos);

		result = generic_file_read_iter(iocb, &to);

		if (result > 0)

			nfs_add_stats(inode, NFSIOS_NORMALREADBYTES, result);

	}

include/linux/fs.h

+1 −0
Original line number Diff line number Diff line
@@ -2404,6 +2404,7 @@ extern int generic_file_remap_pages(struct vm_area_struct *, unsigned long addr, 
		unsigned long size, pgoff_t pgoff);

int generic_write_checks(struct file *file, loff_t *pos, size_t *count, int isblk);

extern ssize_t generic_file_aio_read(struct kiocb *, const struct iovec *, unsigned long, loff_t);

extern ssize_t generic_file_read_iter(struct kiocb *, struct iov_iter *);

extern ssize_t __generic_file_aio_write(struct kiocb *, const struct iovec *, unsigned long);

extern ssize_t generic_file_aio_write(struct kiocb *, const struct iovec *, unsigned long, loff_t);

extern ssize_t generic_file_direct_write(struct kiocb *, struct iov_iter *,

mm/filemap.c

+34 −33
Original line number Diff line number Diff line
@@ -1663,55 +1663,34 @@ out: 
	return written ? written : error;

}



/**

 * generic_file_aio_read - 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

 *

 * This is the "read()" 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;

	struct file *file = iocb->ki_filp;

	ssize_t retval = 0;

	size_t count;

	loff_t *ppos = &iocb->ki_pos;

	struct iov_iter i;



	count = iov_length(iov, nr_segs);

	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 + count - 1);

		if (!retval) {

			struct iov_iter data = i;

			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);

		}



		/*
@@ -1722,16 +1701,38 @@ 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_read_iter);



/**

 * generic_file_aio_read - 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

 *

 * This is the "read()" 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)

{

	size_t count = iov_length(iov, nr_segs);

	struct iov_iter i;



	iov_iter_init(&i, iov, nr_segs, count, 0);

	return generic_file_read_iter(iocb, &i);

}

EXPORT_SYMBOL(generic_file_aio_read);



#ifdef CONFIG_MMU