On Thu, Dec 17, 2020 at 02:13:37PM +0800, Qu Wenruo wrote: > > > On 2020/12/17 下午1:59, Nikolay Borisov wrote: > > > > > > On 17.12.20 г. 7:55 ч., Nikolay Borisov wrote: > >> > >> > >> On 17.12.20 г. 6:57 ч., Qu Wenruo wrote: > >>> In btrfs_invalidatepage() we re-declare @tree variable as > >>> btrfs_ordered_inode_tree. > >>> > >>> Remove such variable shadowing which can be very confusing. > >> > >> You can't do that, because lock_extent_bits expects extent_io_tree ! > >> > > > > Ok, nvm, you just factored the var at the beginning of the functions. > > OTOH since the ordered tree is used just for lock/unlock why not do > > spin_(un)lock(&inode->ordered_tree->lock); > > > Oh, that indeed looks better and since Su is also complaining about the > declaration at the beginning of the function, I guess that's the better > way to go.
The preferred style is to declare variables in the closest scope, so there's not a huge blob of declarations that are randomly used inside nested blocks. It's more like a recommendation, eg. when the function is short and there are a few variables used inside a for/while.
