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[37.6.163.90]) by smtp.gmail.com with ESMTPSA id vq7-20020a170907a4c700b00a2cf537042asm13522660ejc.192.2024.01.24.01.32.51 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 24 Jan 2024 01:32:51 -0800 (PST) Date: Wed, 24 Jan 2024 11:25:40 +0200 From: Manos Pitsidianakis To: qemu-devel@nongnu.org, Philippe Mathieu-Daud=?UTF-8?B?w6kg?= Cc: Paolo Bonzini , Christian Schoenebeck , Fam Zheng , Greg Kurz , Richard Henderson , "Michael S. Tsirkin" , Gerd Hoffmann , Alex Williamson , C=?UTF-8?B?w6k=?= dric Le Goater , Philippe Mathieu-Daud=?UTF-8?B?w6kg?= Subject: Re: [PATCH 5/6] hw/vfio/common: Use RCU_READ macros User-Agent: meli 0.8.5-rc.3 References: <20240124074201.8239-1-philmd@linaro.org> <20240124074201.8239-6-philmd@linaro.org> In-Reply-To: <20240124074201.8239-6-philmd@linaro.org> Message-ID: <7reip.7d0x82au0t9p@linaro.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=utf-8; format=flowed Received-SPF: pass client-ip=2a00:1450:4864:20::62a; envelope-from=manos.pitsidianakis@linaro.org; helo=mail-ej1-x62a.google.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On Wed, 24 Jan 2024 09:42, Philippe Mathieu-Daudé wrote: >Replace the manual rcu_read_(un)lock calls by the >*RCU_READ_LOCK_GUARD macros (See commit ef46ae67ba >"docs/style: call out the use of GUARD macros"). > >Signed-off-by: Philippe Mathieu-Daudé >--- > hw/vfio/common.c | 34 ++++++++++++++++------------------ > 1 file changed, 16 insertions(+), 18 deletions(-) > >diff --git a/hw/vfio/common.c b/hw/vfio/common.c >index 4aa86f563c..09878a3603 100644 >--- a/hw/vfio/common.c >+++ b/hw/vfio/common.c >@@ -308,13 +308,13 @@ static void vfio_iommu_map_notify(IOMMUNotifier *n, IOMMUTLBEntry *iotlb) > return; > } > >- rcu_read_lock(); >+ RCU_READ_LOCK_GUARD(); > > if ((iotlb->perm & IOMMU_RW) != IOMMU_NONE) { > bool read_only; > > if (!vfio_get_xlat_addr(iotlb, &vaddr, NULL, &read_only)) { >- goto out; >+ return; Since this is the only early return, we could alternatively do: - if (!vfio_get_xlat_addr(iotlb, &vaddr, NULL, &read_only)) { + if (vfio_get_xlat_addr(iotlb, &vaddr, NULL, &read_only)) { remove the goto/return, and wrap the rest of the codeflow in this if's brackets. And then we could use WITH_RCU_READ_LOCK_GUARD instead. That'd increase the code indentation however. > } > /* > * vaddr is only valid until rcu_read_unlock(). But after >@@ -343,8 +343,6 @@ static void vfio_iommu_map_notify(IOMMUNotifier *n, IOMMUTLBEntry *iotlb) > vfio_set_migration_error(ret); > } > } >-out: >- rcu_read_unlock(); > } > > static void vfio_ram_discard_notify_discard(RamDiscardListener *rdl, >@@ -1223,23 +1221,23 @@ static void vfio_iommu_map_dirty_notify(IOMMUNotifier *n, IOMMUTLBEntry *iotlb) > if (iotlb->target_as != &address_space_memory) { > error_report("Wrong target AS \"%s\", only system memory is allowed", > iotlb->target_as->name ? iotlb->target_as->name : "none"); >- goto out; >- } >- >- rcu_read_lock(); >- if (vfio_get_xlat_addr(iotlb, NULL, &translated_addr, NULL)) { >- ret = vfio_get_dirty_bitmap(bcontainer, iova, iotlb->addr_mask + 1, >- translated_addr); >- if (ret) { >- error_report("vfio_iommu_map_dirty_notify(%p, 0x%"HWADDR_PRIx", " >- "0x%"HWADDR_PRIx") = %d (%s)", >- bcontainer, iova, iotlb->addr_mask + 1, ret, >- strerror(-ret)); >+ } else { >+ WITH_RCU_READ_LOCK_GUARD() { >+ if (vfio_get_xlat_addr(iotlb, NULL, &translated_addr, NULL)) { >+ ret = vfio_get_dirty_bitmap(bcontainer, iova, >+ iotlb->addr_mask + 1, >+ translated_addr); >+ if (ret) { >+ error_report("vfio_iommu_map_dirty_notify(%p," >+ " 0x%"HWADDR_PRIx >+ ", 0x%"HWADDR_PRIx") = %d (%s)", >+ bcontainer, iova, iotlb->addr_mask + 1, ret, >+ strerror(-ret)); >+ } >+ } > } > } >- rcu_read_unlock(); > >-out: > if (ret) { > vfio_set_migration_error(ret); > } >-- >2.41.0 > Reviewed-by: Manos Pitsidianakis