diff options
| author | Gustavo A. R. Silva | 2020-05-07 14:00:33 -0500 |
|---|---|---|
| committer | Vignesh Raghavendra | 2020-05-26 13:30:06 +0530 |
| commit | 11399346ac39a26ade2a90303d38ad318163c665 (patch) | |
| tree | 8c76cf7bde365327f0650f132dbb85fadc0f36fd /include/linux/mtd | |
| parent | b359ed5184aebf9d987e54abc5dae7ac03ed29ae (diff) | |
mtd: Replace zero-length array with flexible-array
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]
sizeof(flexible-array-member) triggers a warning because flexible array
members have incomplete type[1]. There are some instances of code in
which the sizeof operator is being incorrectly/erroneously applied to
zero-length arrays and the result is zero. Such instances may be hiding
some bugs. So, this work (flexible-array member conversions) will also
help to get completely rid of those sorts of issues.
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 <gustavoars@kernel.org>
Acked-by: Miquel Raynal <miquel.raynal@bootlin.com>
Signed-off-by: Vignesh Raghavendra <vigneshr@ti.com>
Link: https://lore.kernel.org/r/20200507190033.GA15215@embeddedor
Diffstat (limited to 'include/linux/mtd')
| -rw-r--r-- | include/linux/mtd/cfi.h | 6 | ||||
| -rw-r--r-- | include/linux/mtd/qinfo.h | 2 |
2 files changed, 4 insertions, 4 deletions
diff --git a/include/linux/mtd/cfi.h b/include/linux/mtd/cfi.h index c98a21108688..fd1ecb821106 100644 --- a/include/linux/mtd/cfi.h +++ b/include/linux/mtd/cfi.h @@ -138,7 +138,7 @@ struct cfi_ident { uint16_t InterfaceDesc; uint16_t MaxBufWriteSize; uint8_t NumEraseRegions; - uint32_t EraseRegionInfo[0]; /* Not host ordered */ + uint32_t EraseRegionInfo[]; /* Not host ordered */ } __packed; /* Extended Query Structure for both PRI and ALT */ @@ -165,7 +165,7 @@ struct cfi_pri_intelext { uint16_t ProtRegAddr; uint8_t FactProtRegSize; uint8_t UserProtRegSize; - uint8_t extra[0]; + uint8_t extra[]; } __packed; struct cfi_intelext_otpinfo { @@ -286,7 +286,7 @@ struct cfi_private { map_word sector_erase_cmd; unsigned long chipshift; /* Because they're of the same type */ const char *im_name; /* inter_module name for cmdset_setup */ - struct flchip chips[0]; /* per-chip data structure for each chip */ + struct flchip chips[]; /* per-chip data structure for each chip */ }; uint32_t cfi_build_cmd_addr(uint32_t cmd_ofs, diff --git a/include/linux/mtd/qinfo.h b/include/linux/mtd/qinfo.h index df5b9fddea16..2e3f43788d48 100644 --- a/include/linux/mtd/qinfo.h +++ b/include/linux/mtd/qinfo.h @@ -24,7 +24,7 @@ struct lpddr_private { struct qinfo_chip *qinfo; int numchips; unsigned long chipshift; - struct flchip chips[0]; + struct flchip chips[]; }; /* qinfo_query_info structure contains request information for |