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Re: [Qemu-devel] Node deletion in aio_set_fd_handler
From: |
Paolo Bonzini |
Subject: |
Re: [Qemu-devel] Node deletion in aio_set_fd_handler |
Date: |
Fri, 3 Aug 2018 08:13:58 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 |
On 03/08/2018 04:42, Fam Zheng wrote:
> Paolo, is this else branch dead code (or bug?):
>
> /* If the lock is held, just mark the node as deleted */
> if (qemu_lockcnt_count(&ctx->list_lock)) {
> node->deleted = 1;
> node->pfd.revents = 0;
> } else {
> /* Otherwise, delete it for real. We can't just mark it as
> * deleted because deleted nodes are only cleaned up while
> * no one is walking the handlers list.
> */
> QLIST_REMOVE(node, node);
> deleted = true;
> }
>
> Since we are in a qemu_lockcnt_lock/unlock section?
No, qemu_lockcnt_count returns the number of nested qemu_lockcnt_inc/dec
(read-side) sections. lock/unlock is for the write side.
The comment should be improved (e.g. "if a read is in progress, just
mark the node as deleted").
Paolo