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[142.167.219.86]) by smtp.gmail.com with ESMTPSA id af79cd13be357-7caf75b5334sm3266885a.80.2025.05.06.10.29.41 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 06 May 2025 10:29:42 -0700 (PDT) Received: from jgg by wakko with local (Exim 4.97) (envelope-from ) id 1uCM6v-00000000LGb-2K8I; Tue, 06 May 2025 14:29:41 -0300 Date: Tue, 6 May 2025 14:29:41 -0300 From: Jason Gunthorpe To: Lu Baolu Cc: Joerg Roedel , Will Deacon , Robin Murphy , Kevin Tian , iommu@lists.linux.dev, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 2/2] iommu/vt-d: Replace spin_lock with mutex to protect domain ida Message-ID: <20250506172941.GB33739@ziepe.ca> References: <20250430021135.2370244-1-baolu.lu@linux.intel.com> <20250430021135.2370244-3-baolu.lu@linux.intel.com> Precedence: bulk X-Mailing-List: iommu@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250430021135.2370244-3-baolu.lu@linux.intel.com> On Wed, Apr 30, 2025 at 10:11:35AM +0800, Lu Baolu wrote: > The domain ID allocator is currently protected by a spin_lock. However, > ida_alloc_range can potentially block if it needs to allocate memory to > grow its internal structures. > > Replace the spin_lock with a mutex which allows sleep on block. Thus, > the memory allocation flags can be updated from GFP_ATOMIC to GFP_KERNEL > to allow blocking memory allocations if necessary. > > Introduce a new mutex, did_lock, specifically for protecting the domain > ida. The existing spinlock will remain for protecting other intel_iommu > fields. > > Signed-off-by: Lu Baolu > Reviewed-by: Kevin Tian > --- > drivers/iommu/intel/dmar.c | 1 + > drivers/iommu/intel/iommu.c | 12 ++++-------- > drivers/iommu/intel/iommu.h | 2 ++ > 3 files changed, 7 insertions(+), 8 deletions(-) Reviewed-by: Jason Gunthorpe Jason