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[37.6.1.138]) by smtp.gmail.com with ESMTPSA id x1-20020a1709064bc100b00a2c70caccbasm14988706ejv.107.2024.01.24.01.21.51 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 24 Jan 2024 01:21:51 -0800 (PST) Date: Wed, 24 Jan 2024 11:17:07 +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 4/6] hw/scsi/virtio-scsi: Use RCU_READ macro User-Agent: meli 0.8.5-rc.3 References: <20240124074201.8239-1-philmd@linaro.org> <20240124074201.8239-5-philmd@linaro.org> In-Reply-To: <20240124074201.8239-5-philmd@linaro.org> Message-ID: <7re0d.o8r1pancklv@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::629; envelope-from=manos.pitsidianakis@linaro.org; helo=mail-ej1-x629.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 09:41, Philippe Mathieu-Daudé wrote: >Replace the manual rcu_read_(un)lock calls by the >WITH_RCU_READ_LOCK_GUARD macro (See commit ef46ae67ba >"docs/style: call out the use of GUARD macros"). > >Signed-off-by: Philippe Mathieu-Daudé >--- > hw/scsi/virtio-scsi.c | 12 ++++++------ > 1 file changed, 6 insertions(+), 6 deletions(-) > >diff --git a/hw/scsi/virtio-scsi.c b/hw/scsi/virtio-scsi.c >index 690aceec45..998227404a 100644 >--- a/hw/scsi/virtio-scsi.c >+++ b/hw/scsi/virtio-scsi.c >@@ -343,14 +343,14 @@ static void virtio_scsi_do_one_tmf_bh(VirtIOSCSIReq *req) > target = req->req.tmf.lun[1]; > qatomic_inc(&s->resetting); > >- rcu_read_lock(); >- QTAILQ_FOREACH_RCU(kid, &s->bus.qbus.children, sibling) { >- SCSIDevice *d1 = SCSI_DEVICE(kid->child); >- if (d1->channel == 0 && d1->id == target) { >- device_cold_reset(&d1->qdev); >+ WITH_RCU_READ_LOCK_GUARD() { >+ QTAILQ_FOREACH_RCU(kid, &s->bus.qbus.children, sibling) { >+ SCSIDevice *d1 = SCSI_DEVICE(kid->child); >+ if (d1->channel == 0 && d1->id == target) { >+ device_cold_reset(&d1->qdev); >+ } > } > } >- rcu_read_unlock(); > > qatomic_dec(&s->resetting); > break; >-- >2.41.0 > Unrelated to your patch: I just noticed in hw/scsi/virtio-scsi.c, s->resetting is used to flag whether the bus is resetting; but there's no check if a resetting is taking place before starting another. Is this single threaded code so it's not necessary? As for the patch: Reviewed-by: Manos Pitsidianakis