On Monday 20 Apr 2015 13:33:16 xuw2015@xxxxxxxxx wrote: > From: George Wang <xuw2015@xxxxxxxxx> > > PPC64 arch use such following IOC values " > \#define _IOC_NONE 1U > \#define _IOC_READ 2U > \#define _IOC_WRITE 4U > " comparing to the default IOC values " > \#define _IOC_NONE 0U > \#define _IOC_READ 2U > \#define _IOC_WRITE 1U" > > This means the value "_IOW*" will be negative when we store it in the int > variables. Such as the "BTRFS_IOC_QGROUP_CREATE", it will be "0x4010942e" on > X86_64, but "0x8010942e" on PPC64. > Notice that the IOC values are the "unsigned long" type, so we use the > "unsigned long" to store it, and this can insure the comparison between the > variable and BTRFS_IOC_* valid. > > Signed-off-by: George Wang <xuw2015@xxxxxxxxx> Tested-by: Chandan Rajendra <chandan@xxxxxxxxxxxxxxxxxx> -- chandan -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
