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Commit 43cade80 authored by Omar Sandoval's avatar Omar Sandoval Committed by Jens Axboe
Browse files

loop: fold loop_switch() into callers 



The comments here are really outdated, and blk-mq made flushing much
simpler, so just fold the two cases into the callers.

Reviewed-by: default avatarMing Lei <ming.lei@redhat.com>
Reviewed-by: default avatarHannes Reinecke <hare@suse.com>
Signed-off-by: default avatarOmar Sandoval <osandov@fb.com>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 89e4fdec

drivers/block/loop.c

+11 −65
Original line number Diff line number Diff line
@@ -546,72 +546,12 @@ static int do_req_filebacked(struct loop_device *lo, struct request *rq) 
	}

}



struct switch_request {

	struct file *file;

	struct completion wait;

};



static inline void loop_update_dio(struct loop_device *lo)

{

	__loop_update_dio(lo, io_is_direct(lo->lo_backing_file) |

			lo->use_dio);

}



/*

 * Do the actual switch; called from the BIO completion routine

 */

static void do_loop_switch(struct loop_device *lo, struct switch_request *p)

{

	struct file *file = p->file;

	struct file *old_file = lo->lo_backing_file;

	struct address_space *mapping;



	/* if no new file, only flush of queued bios requested */

	if (!file)

		return;



	mapping = file->f_mapping;

	mapping_set_gfp_mask(old_file->f_mapping, lo->old_gfp_mask);

	lo->lo_backing_file = file;

	lo->old_gfp_mask = mapping_gfp_mask(mapping);

	mapping_set_gfp_mask(mapping, lo->old_gfp_mask & ~(__GFP_IO|__GFP_FS));

	loop_update_dio(lo);

}



/*

 * loop_switch performs the hard work of switching a backing store.

 * First it needs to flush existing IO, it does this by sending a magic

 * BIO down the pipe. The completion of this BIO does the actual switch.

 */

static int loop_switch(struct loop_device *lo, struct file *file)

{

	struct switch_request w;



	w.file = file;



	/* freeze queue and wait for completion of scheduled requests */

	blk_mq_freeze_queue(lo->lo_queue);



	/* do the switch action */

	do_loop_switch(lo, &w);



	/* unfreeze */

	blk_mq_unfreeze_queue(lo->lo_queue);



	return 0;

}



/*

 * Helper to flush the IOs in loop, but keeping loop thread running

 */

static int loop_flush(struct loop_device *lo)

{

	/* loop not yet configured, no running thread, nothing to flush */

	if (lo->lo_state != Lo_bound)

		return 0;

	return loop_switch(lo, NULL);

}



static void loop_reread_partitions(struct loop_device *lo,

				   struct block_device *bdev)

{
@@ -676,9 +616,14 @@ static int loop_change_fd(struct loop_device *lo, struct block_device *bdev, 
		goto out_putf;



	/* and ... switch */

	error = loop_switch(lo, file);

	if (error)

		goto out_putf;

	blk_mq_freeze_queue(lo->lo_queue);

	mapping_set_gfp_mask(old_file->f_mapping, lo->old_gfp_mask);

	lo->lo_backing_file = file;

	lo->old_gfp_mask = mapping_gfp_mask(file->f_mapping);

	mapping_set_gfp_mask(file->f_mapping,

			     lo->old_gfp_mask & ~(__GFP_IO|__GFP_FS));

	loop_update_dio(lo);

	blk_mq_unfreeze_queue(lo->lo_queue);



	fput(old_file);

	if (lo->lo_flags & LO_FLAGS_PARTSCAN)
@@ -1601,12 +1546,13 @@ static void lo_release(struct gendisk *disk, fmode_t mode) 
		err = loop_clr_fd(lo);

		if (!err)

			return;

	} else {

	} else if (lo->lo_state == Lo_bound) {

		/*

		 * Otherwise keep thread (if running) and config,

		 * but flush possible ongoing bios in thread.

		 */

		loop_flush(lo);

		blk_mq_freeze_queue(lo->lo_queue);

		blk_mq_unfreeze_queue(lo->lo_queue);

	}



	mutex_unlock(&lo->lo_ctl_mutex);