Messages in this thread | | | From | (Eric W. Biederman) | Date | Wed, 09 Dec 2020 16:06:21 -0600 | Subject | Re: [PATCH] files: rcu free files_struct |
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Matthew Wilcox <willy@infradead.org> writes:
> On Wed, Dec 09, 2020 at 12:04:38PM -0600, Eric W. Biederman wrote: >> @@ -397,8 +397,9 @@ static struct fdtable *close_files(struct files_struct * files) >> set = fdt->open_fds[j++]; >> while (set) { >> if (set & 1) { >> - struct file * file = xchg(&fdt->fd[i], NULL); >> + struct file * file = fdt->fd[i]; >> if (file) { >> + rcu_assign_pointer(fdt->fd[i], NULL); > > Assuming this is safe, you can use RCU_INIT_POINTER() here because you're > storing NULL, so you don't need the wmb() before storing the pointer.
Thanks. I was remembering there was a special case like and I had forgotten what the rule was.
Eric
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