dm snapshot: use unsigned integer chunk size

Use unsigned integer chunk size.

Maximum chunk size is 512kB, there won't ever be need to use 4GB chunk size,
so the number can be 32-bit. This fixes compiler failure on 32-bit systems
with large block devices.

Cc: stable@kernel.org
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Reviewed-by: Jonathan Brassow <jbrassow@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>

1 files changed, 11 insertions, 9 deletions

diff --git a/drivers/md/dm-exception-store.c b/drivers/md/dm-exception-store.c
index e5de762..932d1b1 100644
--- a/drivers/md/dm-exception-store.c
+++ b/drivers/md/dm-exception-store.c
@@ -155,7 +155,8 @@ static int set_chunk_size(struct dm_exception_store *store,
 	char *value;
 
 	chunk_size_ulong = simple_strtoul(chunk_size_arg, &value, 10);
-	if (*chunk_size_arg == '\0' || *value != '\0') {
+	if (*chunk_size_arg == '\0' || *value != '\0' ||
+	    chunk_size_ulong > UINT_MAX) {
 		*error = "Invalid chunk size";
 		return -EINVAL;
 	}
@@ -171,34 +172,35 @@ static int set_chunk_size(struct dm_exception_store *store,
 	 */
 	chunk_size_ulong = round_up(chunk_size_ulong, PAGE_SIZE >> 9);
 
-	return dm_exception_store_set_chunk_size(store, chunk_size_ulong,
+	return dm_exception_store_set_chunk_size(store,
+						 (unsigned) chunk_size_ulong,
 						 error);
 }
 
 int dm_exception_store_set_chunk_size(struct dm_exception_store *store,
-				      unsigned long chunk_size_ulong,
+				      unsigned chunk_size,
 				      char **error)
 {
 	/* Check chunk_size is a power of 2 */
-	if (!is_power_of_2(chunk_size_ulong)) {
+	if (!is_power_of_2(chunk_size)) {
 		*error = "Chunk size is not a power of 2";
 		return -EINVAL;
 	}
 
 	/* Validate the chunk size against the device block size */
-	if (chunk_size_ulong % (bdev_logical_block_size(store->cow->bdev) >> 9)) {
+	if (chunk_size % (bdev_logical_block_size(store->cow->bdev) >> 9)) {
 		*error = "Chunk size is not a multiple of device blocksize";
 		return -EINVAL;
 	}
 
-	if (chunk_size_ulong > INT_MAX >> SECTOR_SHIFT) {
+	if (chunk_size > INT_MAX >> SECTOR_SHIFT) {
 		*error = "Chunk size is too high";
 		return -EINVAL;
 	}
 
-	store->chunk_size = chunk_size_ulong;
-	store->chunk_mask = chunk_size_ulong - 1;
-	store->chunk_shift = ffs(chunk_size_ulong) - 1;
+	store->chunk_size = chunk_size;
+	store->chunk_mask = chunk_size - 1;
+	store->chunk_shift = ffs(chunk_size) - 1;
 
 	return 0;
 }