Merge git://oss.sgi.com:8090/oss/git/rc-fixes (0ee10a44) · Commits · e / devices / android_kernel_xiaomi_markw

fs/direct-io.c

+12 −9

Original line number	Diff line number	Diff line
		@@ -1155,15 +1155,16 @@ direct_io_worker(int rw, struct kiocb iocb, struct inode inode,
		* For writes, i_mutex is not held on entry; it is never taken.
		*
		* DIO_LOCKING (simple locking for regular files)
		* For writes we are called under i_mutex and return with i_mutex held, even though
		* it is internally dropped.
		* For writes we are called under i_mutex and return with i_mutex held, even
		* though it is internally dropped.
		* For reads, i_mutex is not held on entry, but it is taken and dropped before
		* returning.
		*
		* DIO_OWN_LOCKING (filesystem provides synchronisation and handling of
		* uninitialised data, allowing parallel direct readers and writers)
		* For writes we are called without i_mutex, return without it, never touch it.
		* For reads, i_mutex is held on entry and will be released before returning.
		* For reads we are called under i_mutex and return with i_mutex held, even
		* though it may be internally dropped.
		*
		* Additional i_alloc_sem locking requirements described inline below.
		*/
		@@ -1182,7 +1183,8 @@ __blockdev_direct_IO(int rw, struct kiocb iocb, struct inode inode,
		ssize_t retval = -EINVAL;
		loff_t end = offset;
		struct dio *dio;
		int reader_with_isem = (rw == READ && dio_lock_type == DIO_OWN_LOCKING);
		int release_i_mutex = 0;
		int acquire_i_mutex = 0;

		if (rw & WRITE)
		current->flags \|= PF_SYNCWRITE;
		@@ -1225,7 +1227,6 @@ __blockdev_direct_IO(int rw, struct kiocb iocb, struct inode inode,
		* writers need to grab i_alloc_sem only (i_mutex is already held)
		* For regular files using DIO_OWN_LOCKING,
		* neither readers nor writers take any locks here
		* (i_mutex is already held and release for writers here)
		*/
		dio->lock_type = dio_lock_type;
		if (dio_lock_type != DIO_NO_LOCKING) {
		@@ -1236,7 +1237,7 @@ __blockdev_direct_IO(int rw, struct kiocb iocb, struct inode inode,
		mapping = iocb->ki_filp->f_mapping;
		if (dio_lock_type != DIO_OWN_LOCKING) {
		mutex_lock(&inode->i_mutex);
		reader_with_isem = 1;
		release_i_mutex = 1;
		}

		retval = filemap_write_and_wait_range(mapping, offset,
		@@ -1248,7 +1249,7 @@ __blockdev_direct_IO(int rw, struct kiocb iocb, struct inode inode,

		if (dio_lock_type == DIO_OWN_LOCKING) {
		mutex_unlock(&inode->i_mutex);
		reader_with_isem = 0;
		acquire_i_mutex = 1;
		}
		}

		@@ -1269,11 +1270,13 @@ __blockdev_direct_IO(int rw, struct kiocb iocb, struct inode inode,
		nr_segs, blkbits, get_blocks, end_io, dio);

		if (rw == READ && dio_lock_type == DIO_LOCKING)
		reader_with_isem = 0;
		release_i_mutex = 0;

		out:
		if (reader_with_isem)
		if (release_i_mutex)
		mutex_unlock(&inode->i_mutex);
		else if (acquire_i_mutex)
		mutex_lock(&inode->i_mutex);
		if (rw & WRITE)
		current->flags &= ~PF_SYNCWRITE;
		return retval;