Messages in this thread | | | Date | Mon, 4 Aug 2014 04:07:47 -0700 | From | Christoph Hellwig <> | Subject | Re: [PATCH] Save command pool address of Scsi_Host |
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On Sat, Aug 02, 2014 at 12:24:34AM +0400, James Bottomley wrote: > Wait, that's not right at all. There looks to be a thinko in the > command pool handling code. We have both a cmd_pool in the host > structure and in the host template structure, but there's confusion > about which one we're supposed to be using.
For anything in the I/O path: shost->cmd_pool, for finding a pool created for a specific host template: template->cmd_pool.
> The origin of confusion seems to be the reference counting in the pool > itself ... you want the same pool for all hosts, since they can only > have one cmd_size, but you want it created on first host use and > destroyed again on the last one. > > If you take this patch, a host that attached, detaches and then attaches > a host will panic because it will use a freed pool structure.
Yes, it also needs to set hostt->cmd_pool to NULL when the last reference goes away.
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