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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 /include/scsi/srp.h | |
| parent | scsi: ufs: Simplify two tests (diff) | |
| download | wireguard-linux-5febf6d6ae4d488a5dc388c46d96c17f9556238f.tar.xz wireguard-linux-5febf6d6ae4d488a5dc388c46d96c17f9556238f.zip | |
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 'include/scsi/srp.h')
| -rw-r--r-- | include/scsi/srp.h | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/include/scsi/srp.h b/include/scsi/srp.h index 9220758d5087..177d8026e96f 100644 --- a/include/scsi/srp.h +++ b/include/scsi/srp.h @@ -109,7 +109,7 @@ struct srp_direct_buf { struct srp_indirect_buf { struct srp_direct_buf table_desc; __be32 len; - struct srp_direct_buf desc_list[0]; + struct srp_direct_buf desc_list[]; } __attribute__((packed)); /* Immediate data buffer descriptor as defined in SRP2. */ @@ -244,7 +244,7 @@ struct srp_cmd { u8 reserved4; u8 add_cdb_len; u8 cdb[16]; - u8 add_data[0]; + u8 add_data[]; }; enum { @@ -274,7 +274,7 @@ struct srp_rsp { __be32 data_in_res_cnt; __be32 sense_data_len; __be32 resp_data_len; - u8 data[0]; + u8 data[]; } __attribute__((packed)); struct srp_cred_req { @@ -306,7 +306,7 @@ struct srp_aer_req { struct scsi_lun lun; __be32 sense_data_len; u32 reserved3; - u8 sense_data[0]; + u8 sense_data[]; } __attribute__((packed)); struct srp_aer_rsp { |