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authorGustavo A. R. Silva <gustavo@embeddedor.com>2020-02-24 19:14:06 +0300
committerMartin K. Petersen <martin.petersen@oracle.com>2020-03-12 06:07:56 +0300
commit5febf6d6ae4d488a5dc388c46d96c17f9556238f (patch)
tree220cb44bf3d7792bc6460d43b06e9a90506d1869 /include/scsi/scsi_device.h
parent5905d4648e7ec2cc9316b17290f21e8bd8a78c32 (diff)
downloadlinux-5febf6d6ae4d488a5dc388c46d96c17f9556238f.tar.xz
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/scsi_device.h')
-rw-r--r--include/scsi/scsi_device.h4
1 files changed, 2 insertions, 2 deletions
diff --git a/include/scsi/scsi_device.h b/include/scsi/scsi_device.h
index f146a4557787..579e24c92f2f 100644
--- a/include/scsi/scsi_device.h
+++ b/include/scsi/scsi_device.h
@@ -230,7 +230,7 @@ struct scsi_device {
struct mutex state_mutex;
enum scsi_device_state sdev_state;
struct task_struct *quiesced_by;
- unsigned long sdev_data[0];
+ unsigned long sdev_data[];
} __attribute__((aligned(sizeof(unsigned long))));
#define to_scsi_device(d) \
@@ -314,7 +314,7 @@ struct scsi_target {
char scsi_level;
enum scsi_target_state state;
void *hostdata; /* available to low-level driver */
- unsigned long starget_data[0]; /* for the transport */
+ unsigned long starget_data[]; /* for the transport */
/* starget_data must be the last element!!!! */
} __attribute__((aligned(sizeof(unsigned long))));