Commit 8aa5a3b6 authored by Rajeev Mishra's avatar Rajeev Mishra Committed by Jens Axboe
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loop: Consolidate size calculation logic into lo_calculate_size() 



Renamed get_size to lo_calculate_size and merged the logic from get_size
and get_loop_size into a single function. Update all callers to use
lo_calculate_size. This is done in preparation for improving the size
detection logic.

Signed-off-by: default avatarRajeev Mishra <rajeevm@hpe.com>
Reviewed-by: default avatarYu Kuai <yukuai3@huawei.com>
Link: https://lore.kernel.org/r/20250818184821.115033-2-rajeevm@hpe.com


[axboe: massage commit message]
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 72421690

drivers/block/loop.c

+9 −17
Original line number Diff line number Diff line
@@ -137,20 +137,18 @@ static void loop_global_unlock(struct loop_device *lo, bool global) 
static int max_part;

static int part_shift;



static loff_t get_size(loff_t offset, loff_t sizelimit, struct file *file)

static loff_t lo_calculate_size(struct loop_device *lo, struct file *file)

{

	loff_t loopsize;



	/* Compute loopsize in bytes */

	loopsize = i_size_read(file->f_mapping->host);

	if (offset > 0)

		loopsize -= offset;

	if (lo->lo_offset > 0)

		loopsize -= lo->lo_offset;

	/* offset is beyond i_size, weird but possible */

	if (loopsize < 0)

		return 0;



	if (sizelimit > 0 && sizelimit < loopsize)

		loopsize = sizelimit;

	if (lo->lo_sizelimit > 0 && lo->lo_sizelimit < loopsize)

		loopsize = lo->lo_sizelimit;

	/*

	 * Unfortunately, if we want to do I/O on the device,

	 * the number of 512-byte sectors has to fit into a sector_t.
@@ -158,11 +156,6 @@ static loff_t get_size(loff_t offset, loff_t sizelimit, struct file *file) 
	return loopsize >> 9;

}



static loff_t get_loop_size(struct loop_device *lo, struct file *file)

{

	return get_size(lo->lo_offset, lo->lo_sizelimit, file);

}



/*

 * We support direct I/O only if lo_offset is aligned with the logical I/O size

 * of backing device, and the logical block size of loop is bigger than that of
@@ -569,7 +562,7 @@ static int loop_change_fd(struct loop_device *lo, struct block_device *bdev, 
	error = -EINVAL;



	/* size of the new backing store needs to be the same */

	if (get_loop_size(lo, file) != get_loop_size(lo, old_file))

	if (lo_calculate_size(lo, file) != lo_calculate_size(lo, old_file))

		goto out_err;



	/*
@@ -1063,7 +1056,7 @@ static int loop_configure(struct loop_device *lo, blk_mode_t mode, 
	loop_update_dio(lo);

	loop_sysfs_init(lo);



	size = get_loop_size(lo, file);

	size = lo_calculate_size(lo, file);

	loop_set_size(lo, size);



	/* Order wrt reading lo_state in loop_validate_file(). */
@@ -1255,8 +1248,7 @@ loop_set_status(struct loop_device *lo, const struct loop_info64 *info) 
	if (partscan)

		clear_bit(GD_SUPPRESS_PART_SCAN, &lo->lo_disk->state);

	if (!err && size_changed) {

		loff_t new_size = get_size(lo->lo_offset, lo->lo_sizelimit,

					   lo->lo_backing_file);

		loff_t new_size = lo_calculate_size(lo, lo->lo_backing_file);

		loop_set_size(lo, new_size);

	}

out_unlock:
@@ -1399,7 +1391,7 @@ static int loop_set_capacity(struct loop_device *lo) 
	if (unlikely(lo->lo_state != Lo_bound))

		return -ENXIO;



	size = get_loop_size(lo, lo->lo_backing_file);

	size = lo_calculate_size(lo, lo->lo_backing_file);

	loop_set_size(lo, size);



	return 0;