| Message ID | 20240224151658.8272-1-erick.archer@gmx.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | bcachefs: Prefer struct_size over open coded arithmetic | expand |
On Sat, Feb 24, 2024 at 04:16:58PM +0100, Erick Archer wrote: > This is an effort to get rid of all multiplications from allocation > functions in order to prevent integer overflows [1][2]. > > As the "t" variable is a pointer to "struct journal_seq_blacklist_table" > and this structure ends in a flexible array: there's no reason to break these out into multiple patches, just send me a single patch when you're done - thanks!
diff --git a/fs/bcachefs/journal_seq_blacklist.c b/fs/bcachefs/journal_seq_blacklist.c index 024c9b1b323f..2c2490aa15fe 100644 --- a/fs/bcachefs/journal_seq_blacklist.c +++ b/fs/bcachefs/journal_seq_blacklist.c @@ -165,8 +165,7 @@ int bch2_blacklist_table_initialize(struct bch_fs *c) if (!bl) return 0; - t = kzalloc(sizeof(*t) + sizeof(t->entries[0]) * nr, - GFP_KERNEL); + t = kzalloc(struct_size(t, entries, nr), GFP_KERNEL); if (!t) return -BCH_ERR_ENOMEM_blacklist_table_init;
This is an effort to get rid of all multiplications from allocation functions in order to prevent integer overflows [1][2]. As the "t" variable is a pointer to "struct journal_seq_blacklist_table" and this structure ends in a flexible array: struct journal_seq_blacklist_table { [...] struct journal_seq_blacklist_table_entry { u64 start; u64 end; bool dirty; } entries[]; }; the preferred way in the kernel is to use the struct_size() helper to do the arithmetic instead of the argument "size + size * count" in the kzalloc() function. This way, the code is more readable and safer. Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#open-coded-arithmetic-in-allocator-arguments [1] Link: https://github.com/KSPP/linux/issues/160 [2] Signed-off-by: Erick Archer <erick.archer@gmx.com> --- fs/bcachefs/journal_seq_blacklist.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) -- 2.25.1