On 5/30/16 22:33, Joe Perches wrote: > On Mon, 2016-05-30 at 22:21 +0800, Chen Gang wrote: >> On 5/29/16 23:08, Joe Perches wrote: >>> These !! uses are't necessary. >>> The compiler makes the bool return 0 or 1. >> No, they are not necessary. But for me, it will be more clearer, since >> in our kernel (at least in include/linux/), almost all Boolean functions >> use Boolean value or expression for return (and "!!" are often used). > > Opinions vary. >
OK, thanks. I shall send patch v2 for it within this week. > There seem to be fewer than 20 !! uses in bool return > functions in include/linux/ > [root@localhost linux]# pwd /upstream/linux-next/include/linux [root@localhost linux]# grep -rn '!!' * | grep return | wc -l 32 [root@localhost linux]# except 11 files which use int instead of bool as return value: ide.h:854 mlx4/driver.h:76 mlx5/device.h:744 mmzone.h:793 mtd/mtd.h:412 nilfs2_fs.h:568 nilfs2_fs.h:602 nilfs2_fs.h:667 nilfs2_fs.h:771 page-flags.h:711 pagemap.h:54 > Finding the quantity of bool conversions in include/linux > from something other than 0, 1, true, or false to 0 or 1 > is not trivial, but it is non-zero and seems rather more > than 20. > [root@localhost linux]# grep -rn "\<return\>" * | grep ' & ' | grep -v "==" | grep -v '||' | grep -v 'struct' | grep -v '!=' | grep -v ',' | grep -v '?' | grep -v '!' | grep -v '&&' | wc -l 259 After give a glance, more than 60% are not for bool functions (so I guess about 100 area hint). Thanks -- Chen Gang (陈刚) Managing Natural Environments is the Duty of Human Beings.
