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Subject[PATCH v3 1/9] loop: Factor out loop size validation
Date
Ensuring we don't truncate loff_t when casting to sector_t is done in
multiple places; factor it out.

Signed-off-by: Martijn Coenen <maco@android.com>
---
drivers/block/loop.c | 25 ++++++++++++++++++++-----
1 file changed, 20 insertions(+), 5 deletions(-)

diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index f1754262fc94..f812f11649d3 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -228,15 +228,30 @@ static void __loop_update_dio(struct loop_device *lo, bool dio)
blk_mq_unfreeze_queue(lo->lo_queue);
}

+/**
+ * loop_validate_size() - validates that the passed in size fits in a sector_t
+ * @size: size to validate
+ */
+static int
+loop_validate_size(loff_t size)
+{
+ if ((loff_t)(sector_t)size != size)
+ return -EFBIG;
+ else
+ return 0;
+}
+
static int
figure_loop_size(struct loop_device *lo, loff_t offset, loff_t sizelimit)
{
+ int err;
loff_t size = get_size(offset, sizelimit, lo->lo_backing_file);
- sector_t x = (sector_t)size;
struct block_device *bdev = lo->lo_device;

- if (unlikely((loff_t)x != size))
- return -EFBIG;
+ err = loop_validate_size(size);
+ if (err)
+ return err;
+
if (lo->lo_offset != offset)
lo->lo_offset = offset;
if (lo->lo_sizelimit != sizelimit)
@@ -1003,9 +1018,9 @@ static int loop_set_fd(struct loop_device *lo, fmode_t mode,
!file->f_op->write_iter)
lo_flags |= LO_FLAGS_READ_ONLY;

- error = -EFBIG;
size = get_loop_size(lo, file);
- if ((loff_t)(sector_t)size != size)
+ error = loop_validate_size(size);
+ if (error)
goto out_unlock;
error = loop_prepare_queue(lo);
if (error)
--
2.26.2.303.gf8c07b1a785-goog
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