From: Damien Le Moal <dlemoal@kernel.org>
To: Chaitanya Kulkarni <ckulkarnilinux@gmail.com>,
linux-block@vger.kernel.org
Cc: axboe@kernel.dk, hch@lst.de, kch@nvidia.com
Subject: Re: [PATCH 1/2] loop: respect REQ_NOWAIT for memory allocation
Date: Sun, 16 Nov 2025 12:50:30 +0900 [thread overview]
Message-ID: <6f76d0ec-a746-4eaf-abe9-86b51d2ff9db@kernel.org> (raw)
In-Reply-To: <20251116025229.29136-1-ckulkarnilinux@gmail.com>
On 11/16/25 11:52, Chaitanya Kulkarni wrote:
> 6. Loop driver:
> loop_queue_rq()
> lo_rw_aio()
> kmalloc_array(..., GFP_NOIO) <-- BLOCKS (REQ_NOWAIT violation)
> -> Should use GFP_NOWAIT when rq->cmd_flags & REQ_NOWAIT
Same comment as for zloop. Re-read the code and see that loop_queue_rq() calls
loop_queue_work(). That function has a memory allocation that is already marked
with GFP_NOWAIT, and that this function does not directly execute lo_rw_aio() as
that is done from loop_workfn(), in the work item context.
So again, no blocking violation that I can see here.
As far as I can tell, this patch is not needed.
--
Damien Le Moal
Western Digital Research
next prev parent reply other threads:[~2025-11-16 3:50 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-11-16 2:52 [PATCH 1/2] loop: respect REQ_NOWAIT for memory allocation Chaitanya Kulkarni
2025-11-16 2:52 ` [PATCH 2/2] zloop: " Chaitanya Kulkarni
2025-11-16 3:44 ` Damien Le Moal
2025-11-16 3:50 ` Damien Le Moal [this message]
2025-11-16 5:43 ` [PATCH 1/2] loop: " Chaitanya Kulkarni
2025-11-16 6:26 ` Damien Le Moal
2025-11-18 1:52 ` Chaitanya Kulkarni
2025-11-18 5:21 ` hch
2025-11-18 13:57 ` Jens Axboe
2025-11-19 0:39 ` Chaitanya Kulkarni
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