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AJvYcCWYD7n+3LQoGBUQLnDOxNYrHWvyBtjXT/Ule2n4XObxoaxy33fqfGD558agIkQg0i6wVwBNnp3p@vger.kernel.org X-Gm-Message-State: AOJu0Yxxa6fjUI1DUzMgVO4IppkggEccLVpV/WunO+HDcIH5qHCli7pA HgP0ZGyUARDY+L2LFR2zUyzpYVzDkLIsdhEqzpj5cFBZl7S11y6Ih0TlZDd/g58= X-Google-Smtp-Source: AGHT+IG3Z3RoW+4gVwOQPtL97jDrvwXJXpPy+ySiF1kDHRm4DfIx6MZYfO3x19vUvzG8fbDYEx7ERQ== X-Received: by 2002:a17:902:f64c:b0:20b:982e:73f5 with SMTP id d9443c01a7336-20bfdf6b4d7mr8219805ad.3.1727993190942; Thu, 03 Oct 2024 15:06:30 -0700 (PDT) Received: from [192.168.1.150] ([198.8.77.157]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-20beeca2235sm13554225ad.105.2024.10.03.15.06.29 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 03 Oct 2024 15:06:30 -0700 (PDT) Message-ID: Date: Thu, 3 Oct 2024 16:06:28 -0600 Precedence: bulk X-Mailing-List: cgroups@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2] blk_iocost: remove some duplicate irq disable/enables To: Tejun Heo Cc: Dan Carpenter , Waiman Long , Yu Kuai , Josef Bacik , cgroups@vger.kernel.org, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org, Christoph Hellwig References: <0a8fe25b-9b72-496d-b1fc-e8f773151e0a@redhat.com> <925f3337-cf9b-4dc1-87ea-f1e63168fbc4@stanley.mountain> <3083c357-9684-45d3-a9c7-2cd2912275a1@stanley.mountain> <68f3e5f8-895e-416b-88cf-284a263bd954@stanley.mountain> Content-Language: en-US From: Jens Axboe In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 10/3/24 3:30 PM, Tejun Heo wrote: > On Thu, Oct 03, 2024 at 11:22:09AM -1000, Tejun Heo wrote: >> Yeah, that should be spin_lock_irq() for consistency but at the same time it >> doesn't look like anything is actually grabbing that lock (or blkcg->lock >> nesting outside of it) from an IRQ context, so no actual deadlock scenario >> exists and lockdep doesn't trigger. > > Oh, wait, it's not that. blkg_conf_prep() implies queue_lock, so the IRQ is > disabled around it and adding _irq will trigger lockdep. Ah makes sense, didn't realize it was nested under the queue lock. Then it does look like it's just that one spot. -- Jens Axboe