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Date: Tue, 7 Jan 2025 14:51:53 +0100
From: Christoph Hellwig <hch@lst.de>
To: Nilay Shroff <nilay@linux.ibm.com>
Cc: Christoph Hellwig <hch@lst.de>, Jens Axboe <axboe@kernel.dk>,
	Damien Le Moal <dlemoal@kernel.org>, Ming Lei <ming.lei@redhat.com>,
	linux-block@vger.kernel.org, linux-nvme@lists.infradead.org,
	nbd@other.debian.org, linux-scsi@vger.kernel.org,
	usb-storage@lists.one-eyed-alien.net
Subject: Re: [PATCH 3/8] block: don't update BLK_FEAT_POLL in
 __blk_mq_update_nr_hw_queues
Message-ID: <20250107135153.GB22046@lst.de>
References: <20250107063120.1011593-1-hch@lst.de> <20250107063120.1011593-4-hch@lst.de> <220cdd33-527f-405d-90af-2abaace36645@linux.ibm.com> <20250107082145.GA15960@lst.de> <90ae40c5-b695-4e17-8293-6a61648ed24a@linux.ibm.com>
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On Tue, Jan 07, 2025 at 02:53:40PM +0530, Nilay Shroff wrote:
> When I applied you patch on my system and access io_poll attribute
> of one of my nvme disk, I see it returns 1, though I didn't configure 
> poll queue for the disk. With this patch, as we're now always setting 
> BLK_FEAT_POLL (under blk_mq_alloc_queue()) it return 1. So when I haven't
> configured poll queue for NVMe driver, shouldn't it return 0 when I access 
> /sys/block/nvmeXnY/queue/io_poll ?  

While that was the case with the previous RFC series it should not be
the case with this version, as the nvme driver does not enable the
poll tag set map unless poll queues are enabled.  I also double checked
that I do not see it on any of my test setups.