[PATCH][next] brcmfmac: Replace zero-length array with flexible-array member
From: Gustavo A. R. Silva <hidden>
Date: 2020-02-25 02:06:26
Also in:
linux-wireless, lkml
Subsystem:
broadcom brcm80211 ieee802.11 wireless drivers, the rest · Maintainers:
Arend van Spriel, Linus Torvalds
The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:
struct foo {
int stuff;
struct boo array[];
};
By making use of the mechanism above, we will get a compiler warning
in case the flexible array does not occur last in the structure, which
will help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.
Also, notice that, dynamic memory allocations won't be affected by
this change:
"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]
This issue was found with the help of Coccinelle.
[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour")
Signed-off-by: Gustavo A. R. Silva <redacted>
---
drivers/net/wireless/broadcom/brcm80211/brcmfmac/firmware.h | 2 +-
drivers/net/wireless/broadcom/brcm80211/brcmfmac/fweh.c | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/firmware.h b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/firmware.h
index 3347439543bb..46c66415b4a6 100644
--- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/firmware.h
+++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/firmware.h@@ -60,7 +60,7 @@ struct brcmf_fw_request { u16 bus_nr; u32 n_items; const char *board_type; - struct brcmf_fw_item items[0]; + struct brcmf_fw_item items[]; }; struct brcmf_fw_name {
diff --git a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/fweh.c b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/fweh.c
index 79c8a858b6d6..a5cced2c89ac 100644
--- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/fweh.c
+++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/fweh.c@@ -32,7 +32,7 @@ struct brcmf_fweh_queue_item { u8 ifaddr[ETH_ALEN]; struct brcmf_event_msg_be emsg; u32 datalen; - u8 data[0]; + u8 data[]; }; /**
--
2.25.0