| Message ID | 20231213-wmi_host_mem_chunks_flexarray-v1-5-92922d92fa2c@quicinc.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | cb188e862c1ce195ce8beaac10b554c33847f4c8 |
| Delegated to: | Kalle Valo |
| Headers | show |
| Series | wifi: ath10k: use flexible arrays | expand |
On Wed, Dec 13, 2023 at 09:06:43AM -0800, Jeff Johnson wrote: > Currently struct wmi_tdls_peer_capabilities defines: > struct wmi_channel peer_chan_list[1]; > > Per the guidance in [1] this should be a flexible array, and at one > point Gustavo was trying to fix this [2], but had questions about the > correct behavior when the associated peer_chan_len is 0. > > I have been unable to determine if firmware requires that at least one > record be present even if peer_chan_len is 0. But since that is the > current behavior, follow the example from [3] and replace the > one-element array with a union that contains both a flexible array and > a single instance of the array element. This results in a struct that > has the same footprint as the original, so no other driver changes are > required. > > No functional changes, compile tested only. > > [1] https://docs.kernel.org/process/deprecated.html#zero-length-and-one-element-arrays > [2] https://lore.kernel.org/linux-wireless/626ae2e7-66f8-423b-b17f-e75c1a6d29b3@embeddedor.com/ > [3] https://lore.kernel.org/linux-wireless/202308301529.AC90A9EF98@keescook/ > > Signed-off-by: Jeff Johnson <quic_jjohnson@quicinc.com> Again, good to keep the struct the same size. Reviewed-by: Kees Cook <keescook@chromium.org>
On 12/13/23 11:06, Jeff Johnson wrote: > Currently struct wmi_tdls_peer_capabilities defines: > struct wmi_channel peer_chan_list[1]; > > Per the guidance in [1] this should be a flexible array, and at one > point Gustavo was trying to fix this [2], but had questions about the > correct behavior when the associated peer_chan_len is 0. > > I have been unable to determine if firmware requires that at least one > record be present even if peer_chan_len is 0. But since that is the > current behavior, follow the example from [3] and replace the > one-element array with a union that contains both a flexible array and > a single instance of the array element. This results in a struct that > has the same footprint as the original, so no other driver changes are > required. > > No functional changes, compile tested only. > > [1] https://docs.kernel.org/process/deprecated.html#zero-length-and-one-element-arrays > [2] https://lore.kernel.org/linux-wireless/626ae2e7-66f8-423b-b17f-e75c1a6d29b3@embeddedor.com/ > [3] https://lore.kernel.org/linux-wireless/202308301529.AC90A9EF98@keescook/ > > Signed-off-by: Jeff Johnson <quic_jjohnson@quicinc.com> Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org> Thanks! -- Gustavo > --- > drivers/net/wireless/ath/ath10k/wmi.h | 8 +++++++- > 1 file changed, 7 insertions(+), 1 deletion(-) > > diff --git a/drivers/net/wireless/ath/ath10k/wmi.h b/drivers/net/wireless/ath/ath10k/wmi.h > index e16410e348ca..b64b6e214bae 100644 > --- a/drivers/net/wireless/ath/ath10k/wmi.h > +++ b/drivers/net/wireless/ath/ath10k/wmi.h > @@ -7162,7 +7162,13 @@ struct wmi_tdls_peer_capabilities { > __le32 is_peer_responder; > __le32 pref_offchan_num; > __le32 pref_offchan_bw; > - struct wmi_channel peer_chan_list[1]; > + union { > + /* to match legacy implementation allocate room for > + * at least one record even if peer_chan_len is 0 > + */ > + struct wmi_channel peer_chan_min_allocation; > + DECLARE_FLEX_ARRAY(struct wmi_channel, peer_chan_list); > + }; > } __packed; > > struct wmi_10_4_tdls_peer_update_cmd { >
diff --git a/drivers/net/wireless/ath/ath10k/wmi.h b/drivers/net/wireless/ath/ath10k/wmi.h index e16410e348ca..b64b6e214bae 100644 --- a/drivers/net/wireless/ath/ath10k/wmi.h +++ b/drivers/net/wireless/ath/ath10k/wmi.h @@ -7162,7 +7162,13 @@ struct wmi_tdls_peer_capabilities { __le32 is_peer_responder; __le32 pref_offchan_num; __le32 pref_offchan_bw; - struct wmi_channel peer_chan_list[1]; + union { + /* to match legacy implementation allocate room for + * at least one record even if peer_chan_len is 0 + */ + struct wmi_channel peer_chan_min_allocation; + DECLARE_FLEX_ARRAY(struct wmi_channel, peer_chan_list); + }; } __packed; struct wmi_10_4_tdls_peer_update_cmd {
Currently struct wmi_tdls_peer_capabilities defines: struct wmi_channel peer_chan_list[1]; Per the guidance in [1] this should be a flexible array, and at one point Gustavo was trying to fix this [2], but had questions about the correct behavior when the associated peer_chan_len is 0. I have been unable to determine if firmware requires that at least one record be present even if peer_chan_len is 0. But since that is the current behavior, follow the example from [3] and replace the one-element array with a union that contains both a flexible array and a single instance of the array element. This results in a struct that has the same footprint as the original, so no other driver changes are required. No functional changes, compile tested only. [1] https://docs.kernel.org/process/deprecated.html#zero-length-and-one-element-arrays [2] https://lore.kernel.org/linux-wireless/626ae2e7-66f8-423b-b17f-e75c1a6d29b3@embeddedor.com/ [3] https://lore.kernel.org/linux-wireless/202308301529.AC90A9EF98@keescook/ Signed-off-by: Jeff Johnson <quic_jjohnson@quicinc.com> --- drivers/net/wireless/ath/ath10k/wmi.h | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-)