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loop: Consolidate size calculation logic into lo_calculate_size()

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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: Rajeev Mishra <rajeevm@hpe.com>
Reviewed-by: Yu Kuai <yukuai3@huawei.com>
Link: https://lore.kernel.org/r/20250818184821.115033-2-rajeevm@hpe.com
[axboe: massage commit message]
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Rajeev Mishra
2025-08-18 18:48:20 +00:00
committed by Jens Axboe
parent 7242169037
commit 8aa5a3b68a
1 changed files with 9 additions and 17 deletions
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26
drivers/block/loop.c
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@@ -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 @@ out_unfreeze:
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;