Re: [PATCH 4.4 52/97] mtip32xx: use runtime tag to initialize command header

On Fri, 2018-03-23 at 10:54 +0100, Greg Kroah-Hartman wrote:

4.4-stable review patch.  If anyone has any objections, please let me know.

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From: Ming Lei ming.lei@redhat.com

[ Upstream commit a4e84aae8139aca9fbfbced1f45c51ca81b57488 ]

mtip32xx supposes that 'request_idx' passed to .init_request() is tag of the request, and use that as request's tag to initialize command header.

After MQ IO scheduler is in, request tag assigned isn't same with the request index anymore, so cause strange hardware failure on mtip32xx, even whole system panic is triggered.

[...]

MQ IO schedulers were introduced in 4.11, so this shouldn't be needed in older branches. It also causes a performance regression (fixed upstream). Please revert this for 4.4 and 4.9.

Ben.