loopdev: ignore negative offset when calculate loop device size

[karo-tx-linux.git] / drivers / block / loop.c

diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index 1b1b0c981a85e2d9f296d027e3078bc31edfb0ee..bef9d63b0c838d7f0da1d6b8c64a534026d4b18e 100644 (file)
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -162,12 +162,13 @@ static struct loop_func_table *xfer_funcs[MAX_LO_CRYPT] = {
 
 static loff_t get_size(loff_t offset, loff_t sizelimit, struct file *file)
 {
-       loff_t size, loopsize;
+       loff_t loopsize;
 
        /* Compute loopsize in bytes */
-       size = i_size_read(file->f_mapping->host);
-       loopsize = size - offset;
-       /* offset is beyond i_size, wierd but possible */
+       loopsize = i_size_read(file->f_mapping->host);
+       if (offset > 0)
+               loopsize -= offset;
+       /* offset is beyond i_size, weird but possible */
        if (loopsize < 0)
                return 0;