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| author | Vincent Mailhol <mailhol.vincent@wanadoo.fr> | 2022-05-18 20:43:57 +0900 |
|---|---|---|
| committer | Marc Kleine-Budde <mkl@pengutronix.de> | 2022-05-19 22:15:51 +0200 |
| commit | 1a6dd9996699889313327be03981716a8337656b (patch) | |
| tree | f842e31f85eb610c2e3f952c5b4118d849d3c30d | |
| parent | 6c1e423a3c84953edcf91ff03ab97829b287184a (diff) | |
| download | linux-1a6dd9996699889313327be03981716a8337656b.tar.bz2 | |
can: mcp251xfd: silence clang's -Wunaligned-access warning
clang emits a -Wunaligned-access warning on union
mcp251xfd_tx_ojb_load_buf.
The reason is that field hw_tx_obj (not declared as packed) is being
packed right after a 16 bits field inside a packed struct:
| union mcp251xfd_tx_obj_load_buf {
| struct __packed {
| struct mcp251xfd_buf_cmd cmd;
| /* ^ 16 bits fields */
| struct mcp251xfd_hw_tx_obj_raw hw_tx_obj;
| /* ^ not declared as packed */
| } nocrc;
| struct __packed {
| struct mcp251xfd_buf_cmd_crc cmd;
| struct mcp251xfd_hw_tx_obj_raw hw_tx_obj;
| __be16 crc;
| } crc;
| } ____cacheline_aligned;
Starting from LLVM 14, having an unpacked struct nested in a packed
struct triggers a warning. c.f. [1].
This is a false positive because the field is always being accessed
with the relevant put_unaligned_*() function. Adding __packed to the
structure declaration silences the warning.
[1] https://github.com/llvm/llvm-project/issues/55520
Link: https://lore.kernel.org/all/20220518114357.55452-1-mailhol.vincent@wanadoo.fr
Signed-off-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr>
Reported-by: kernel test robot <lkp@intel.com>
Tested-by: Nathan Chancellor <nathan@kernel.org> # build
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
| -rw-r--r-- | drivers/net/can/spi/mcp251xfd/mcp251xfd.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/net/can/spi/mcp251xfd/mcp251xfd.h b/drivers/net/can/spi/mcp251xfd/mcp251xfd.h index 1d43bccc29bf..2b0309fedfac 100644 --- a/drivers/net/can/spi/mcp251xfd/mcp251xfd.h +++ b/drivers/net/can/spi/mcp251xfd/mcp251xfd.h @@ -441,7 +441,7 @@ struct mcp251xfd_hw_tef_obj { /* The tx_obj_raw version is used in spi async, i.e. without * regmap. We have to take care of endianness ourselves. */ -struct mcp251xfd_hw_tx_obj_raw { +struct __packed mcp251xfd_hw_tx_obj_raw { __le32 id; __le32 flags; u8 data[sizeof_field(struct canfd_frame, data)]; |