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| author | Gustavo A. R. Silva <gustavo@embeddedor.com> | 2020-02-24 10:14:06 -0600 |
|---|---|---|
| committer | Martin K. Petersen <martin.petersen@oracle.com> | 2020-03-11 23:07:56 -0400 |
| commit | 5febf6d6ae4d488a5dc388c46d96c17f9556238f (patch) | |
| tree | 220cb44bf3d7792bc6460d43b06e9a90506d1869 /drivers/scsi/ipr.h | |
| parent | 5905d4648e7ec2cc9316b17290f21e8bd8a78c32 (diff) | |
| download | linux-5febf6d6ae4d488a5dc388c46d96c17f9556238f.tar.bz2 | |
scsi: Replace zero-length array with flexible-array member
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")
Link: https://lore.kernel.org/r/20200224161406.GA21454@embeddedor
Reviewed-by: Lee Duncan <lduncan@suse.com>
Reviewed-by: Satish Kharat <satishkh@cisco.com>
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Diffstat (limited to 'drivers/scsi/ipr.h')
| -rw-r--r-- | drivers/scsi/ipr.h | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/drivers/scsi/ipr.h b/drivers/scsi/ipr.h index a67baeb36d1f..fd3929a19ab5 100644 --- a/drivers/scsi/ipr.h +++ b/drivers/scsi/ipr.h @@ -451,12 +451,12 @@ struct ipr_config_table_hdr64 { struct ipr_config_table { struct ipr_config_table_hdr hdr; - struct ipr_config_table_entry dev[0]; + struct ipr_config_table_entry dev[]; }__attribute__((packed, aligned (4))); struct ipr_config_table64 { struct ipr_config_table_hdr64 hdr64; - struct ipr_config_table_entry64 dev[0]; + struct ipr_config_table_entry64 dev[]; }__attribute__((packed, aligned (8))); struct ipr_config_table_entry_wrapper { @@ -792,7 +792,7 @@ struct ipr_mode_page28 { struct ipr_mode_page_hdr hdr; u8 num_entries; u8 entry_length; - struct ipr_dev_bus_entry bus[0]; + struct ipr_dev_bus_entry bus[]; }__attribute__((packed)); struct ipr_mode_page24 { |