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[47.54.130.67]) by smtp.gmail.com with ESMTPSA id 6a1803df08f44-8cecd06d600sm203777536d6.35.2026.06.09.06.04.18 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 09 Jun 2026 06:04:18 -0700 (PDT) Received: from jgg by wakko with local (Exim 4.97) (envelope-from ) id 1wWw7u-00000001vgP-1tLR; Tue, 09 Jun 2026 10:04:18 -0300 Date: Tue, 9 Jun 2026 10:04:18 -0300 From: Jason Gunthorpe To: Rik van Riel Cc: linux-kernel@vger.kernel.org, kernel-team@meta.com, robin.murphy@arm.com, joro@8bytes.org, will@kernel.org, iommu@lists.linux.dev, kyle@mcmartin.ca, Rik van Riel Subject: Re: [PATCH v3 3/3] iova: defer maple tree erase on GFP_ATOMIC failure Message-ID: <20260609130418.GI2764304@ziepe.ca> References: <20260603033653.4144138-1-riel@surriel.com> <20260603033653.4144138-4-riel@surriel.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20260603033653.4144138-4-riel@surriel.com> On Tue, Jun 02, 2026 at 11:35:48PM -0400, Rik van Riel wrote: > +/* > + * Remove an IOVA entry from the maple tree. Returns true on success. > + * On failure (maple tree node allocation under GFP_ATOMIC failed), > + * returns false — the entry remains in the tree and the caller must > + * not free the struct iova. > + */ > +static bool remove_iova(struct iova_domain *iovad, struct iova *iova) > { > MA_STATE(mas, &iovad->mtree, iova->pfn_lo, iova->pfn_hi); > > @@ -165,7 +175,36 @@ static void remove_iova(struct iova_domain *iovad, struct iova *iova) > if (iova->pfn_lo < iovad->dma_32bit_pfn) > iovad->max32_alloc_size = iovad->dma_32bit_pfn; > > - mas_store_gfp(&mas, NULL, GFP_ATOMIC); > + if (mas_store_gfp(&mas, NULL, GFP_ATOMIC)) > + return false; But why does it use mas_store(NULL) instead of mas_erase()? I thought the iova alloc/free has to be pair wise, we don't split allocations? Jason