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Sat, 08 Aug 2020 21:08:18 -0800 Received: from MTKMBS02N2.mediatek.inc (172.21.101.101) by MTKMBS62N1.mediatek.inc (172.29.193.41) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Sat, 8 Aug 2020 22:08:31 -0700 Received: from mtkcas08.mediatek.inc (172.21.101.126) by mtkmbs02n2.mediatek.inc (172.21.101.101) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Sun, 9 Aug 2020 13:07:33 +0800 Received: from mtksdccf07.mediatek.inc (172.21.84.99) by mtkcas08.mediatek.inc (172.21.101.73) with Microsoft SMTP Server id 15.0.1497.2 via Frontend Transport; Sun, 9 Aug 2020 13:07:33 +0800 From: Stanley Chu To: , , , , , Subject: [PATCH v3] scsi: ufs: Fix possible infinite loop in ufshcd_hold Date: Sun, 9 Aug 2020 13:07:34 +0800 Message-ID: <20200809050734.18740-1-stanley.chu@mediatek.com> X-Mailer: git-send-email 2.18.0 MIME-Version: 1.0 X-TM-SNTS-SMTP: BE00B5FA824ED99B1C6B9E2F0B73FA1E619CF8E4178918B797D1658D07BEBB112000:8 X-MTK: N X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200809_010844_472227_8DF9D06E X-CRM114-Status: GOOD ( 13.42 ) X-Spam-Score: -0.2 (/) X-Spam-Report: SpamAssassin version 3.4.4 on merlin.infradead.org summary: Content analysis details: (-0.2 points) pts rule name description ---- ---------------------- -------------------------------------------------- 0.0 SPF_HELO_NONE SPF: HELO does not publish an SPF Record -0.0 SPF_PASS SPF: sender matches SPF record 0.0 MIME_BASE64_TEXT RAW: Message text disguised using base64 encoding -0.1 DKIM_VALID_AU Message has a valid DKIM or DK signature from author's domain 0.1 DKIM_SIGNED Message has a DKIM or DK signature, not necessarily valid -0.1 DKIM_VALID_EF Message has a valid DKIM or DK signature from envelope-from domain -0.1 DKIM_VALID Message has at least one valid DKIM or DK signature 0.0 UNPARSEABLE_RELAY Informational: message has unparseable relay lines X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Stanley Chu , andy.teng@mediatek.com, cc.chou@mediatek.com, chun-hung.wu@mediatek.com, kuohong.wang@mediatek.com, linux-kernel@vger.kernel.org, cang@codeaurora.org, linux-mediatek@lists.infradead.org, peter.wang@mediatek.com, matthias.bgg@gmail.com, beanhuo@micron.com, chaotian.jing@mediatek.com, linux-arm-kernel@lists.infradead.org, asutoshd@codeaurora.org Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org In ufshcd_suspend(), after clk-gating is suspended and link is set as Hibern8 state, ufshcd_hold() is still possibly invoked before ufshcd_suspend() returns. For example, MediaTek's suspend vops may issue UIC commands which would call ufshcd_hold() during the command issuing flow. Now if UFSHCD_CAP_HIBERN8_WITH_CLK_GATING capability is enabled, then ufshcd_hold() may enter infinite loops because there is no clk-ungating work scheduled or pending. In this case, ufshcd_hold() shall just bypass, and keep the link as Hibern8 state. Co-Developed-by: Andy Teng Reviewed-by: Avri Altman Signed-off-by: Stanley Chu --- Changes since v2: - Rebase to the latest Martin's queue branch - Add missing Reviewed tag since Avri's letter is not showing up in LKML and Patchwork --- drivers/scsi/ufs/ufshcd.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c index 307622284239..b4f948027b3e 100644 --- a/drivers/scsi/ufs/ufshcd.c +++ b/drivers/scsi/ufs/ufshcd.c @@ -1561,6 +1561,7 @@ static void ufshcd_ungate_work(struct work_struct *work) int ufshcd_hold(struct ufs_hba *hba, bool async) { int rc = 0; + bool flush_result; unsigned long flags; if (!ufshcd_is_clkgating_allowed(hba)) @@ -1592,7 +1593,9 @@ int ufshcd_hold(struct ufs_hba *hba, bool async) break; } spin_unlock_irqrestore(hba->host->host_lock, flags); - flush_work(&hba->clk_gating.ungate_work); + flush_result = flush_work(&hba->clk_gating.ungate_work); + if (hba->clk_gating.is_suspended && !flush_result) + goto out; spin_lock_irqsave(hba->host->host_lock, flags); goto start; }