Re: [f2fs-dev] [PATCH v1 3/5] treewide: use get_random_u32() when possible
From: "Jason A. Donenfeld" <Jason@zx2c4.com>
Date: 2022-10-06 13:08:53
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On Thu, Oct 6, 2022 at 7:01 AM Andy Shevchenko [off-list ref] wrote:
On Thu, Oct 06, 2022 at 06:33:15AM -0600, Jason A. Donenfeld wrote:quoted
On Thu, Oct 06, 2022 at 10:43:31AM +0200, Jan Kara wrote:...quoted
quoted
The code here is effectively doing the parent_group = prandom_u32_max(ngroups); Similarly here we can use prandom_u32_max(ngroups) like: if (qstr) { ... parent_group = hinfo.hash % ngroups; } else parent_group = prandom_u32_max(ngroups);Nice catch. I'll move these to patch #1.I believe coccinelle is able to handle this kind of code as well
I'd be extremely surprised. The details were kind of non obvious. I just spent a decent amount of time manually checking those blocks, to make sure we didn't wind up with different behavior, given the variable reuse. Jason