Re: 答复: [iscsi] Deadlock occurred when network is in error

Bart Van Assche
2017-08-15T21:45:49Z

On Tue, 2017-08-15 at 02:16 +0000, Tangchen (UVP) wrote:
> But I'm not using mq, and I run into these two problems in a non-mq system.
> The patch you pointed out is fix for mq, so I don't think it can resolve this problem.
>
> IIUC, mq is for SSD ? I'm not using ssd, so mq is disabled.

Hello Tangchen,

Please post replies below the original e-mail instead of above - that is the
reply style used on all Linux-related mailing lists I know of. From
https://en.wikipedia.org/wiki/Posting_style:

A: Because it messes up the order in which people normally read text.
Q: Why is top-posting such a bad thing?
A: Top-posting.
Q: What is the most annoying thing in e-mail?

Regarding your question: sorry but I quoted the wrong commit in my previous
e-mail. The commit I should have referred to is 255ee9320e5d ("scsi: Make
__scsi_remove_device go straight from BLOCKED to DEL"). That patch not only
affects scsi-mq but also the single-queue code in the SCSI core.

blk-mq/scsi-mq was introduced for SSDs but is not only intended for SSDs.
The plan is to remove the blk-sq/scsi-sq code once the blk-mq/scsi-mq code
works at least as fast as the single queue code for all supported devices.
That includes hard disks.

Bart.