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From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: akshatzen <akshatzen@google.com>,
	Jack Wang <jinpu.wang@cloud.ionos.com>,
	Viswas G <Viswas.G@microchip.com>,
	Ruksar Devadi <Ruksar.devadi@microchip.com>,
	Radha Ramachandran <radha@google.com>,
	"Martin K . Petersen" <martin.petersen@oracle.com>,
	Sasha Levin <sashal@kernel.org>,
	linux-scsi@vger.kernel.org
Subject: [PATCH AUTOSEL 4.4 04/38] scsi: pm80xx: Avoid busywait in FW ready check
Date: Tue, 22 Dec 2020 21:24:42 -0500	[thread overview]
Message-ID: <20201223022516.2794471-4-sashal@kernel.org> (raw)
In-Reply-To: <20201223022516.2794471-1-sashal@kernel.org>

From: akshatzen <akshatzen@google.com>

[ Upstream commit 48cd6b38eb4f2874f091c4776ea1c26e7e4f967e ]

In function check_fw_ready() we busy wait using udelay. The CPU is not
released and we see need_resched failures.

Busy waiting is not necessary since we are in process context and we can
sleep instead. Replace udelay with msleep of 20 ms intervals while waiting
for firmware to become ready.

It has been verified that check_fw_ready is not being used in interrupt
context anywhere, hence it is safe to make this change.

Link: https://lore.kernel.org/r/20201102165528.26510-4-Viswas.G@microchip.com.com
Acked-by: Jack Wang <jinpu.wang@cloud.ionos.com>
Signed-off-by: akshatzen <akshatzen@google.com>
Signed-off-by: Viswas G <Viswas.G@microchip.com>
Signed-off-by: Ruksar Devadi <Ruksar.devadi@microchip.com>
Signed-off-by: Radha Ramachandran <radha@google.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/scsi/pm8001/pm80xx_hwi.c | 21 +++++++++++----------
 drivers/scsi/pm8001/pm80xx_hwi.h |  6 ++++++
 2 files changed, 17 insertions(+), 10 deletions(-)

diff --git a/drivers/scsi/pm8001/pm80xx_hwi.c b/drivers/scsi/pm8001/pm80xx_hwi.c
index df5f0bc295875..50e0890ddc678 100644
--- a/drivers/scsi/pm8001/pm80xx_hwi.c
+++ b/drivers/scsi/pm8001/pm80xx_hwi.c
@@ -692,6 +692,7 @@ static int mpi_init_check(struct pm8001_hba_info *pm8001_ha)
 
 /**
  * check_fw_ready - The LLDD check if the FW is ready, if not, return error.
+ * This function sleeps hence it must not be used in atomic context.
  * @pm8001_ha: our hba card information
  */
 static int check_fw_ready(struct pm8001_hba_info *pm8001_ha)
@@ -702,16 +703,16 @@ static int check_fw_ready(struct pm8001_hba_info *pm8001_ha)
 	int ret = 0;
 
 	/* reset / PCIe ready */
-	max_wait_time = max_wait_count = 100 * 1000;	/* 100 milli sec */
+	max_wait_time = max_wait_count = 5;	/* 100 milli sec */
 	do {
-		udelay(1);
+		msleep(FW_READY_INTERVAL);
 		value = pm8001_cr32(pm8001_ha, 0, MSGU_SCRATCH_PAD_1);
 	} while ((value == 0xFFFFFFFF) && (--max_wait_count));
 
 	/* check ila status */
-	max_wait_time = max_wait_count = 1000 * 1000;	/* 1000 milli sec */
+	max_wait_time = max_wait_count = 50;	/* 1000 milli sec */
 	do {
-		udelay(1);
+		msleep(FW_READY_INTERVAL);
 		value = pm8001_cr32(pm8001_ha, 0, MSGU_SCRATCH_PAD_1);
 	} while (((value & SCRATCH_PAD_ILA_READY) !=
 			SCRATCH_PAD_ILA_READY) && (--max_wait_count));
@@ -724,9 +725,9 @@ static int check_fw_ready(struct pm8001_hba_info *pm8001_ha)
 	}
 
 	/* check RAAE status */
-	max_wait_time = max_wait_count = 1800 * 1000;	/* 1800 milli sec */
+	max_wait_time = max_wait_count = 90;	/* 1800 milli sec */
 	do {
-		udelay(1);
+		msleep(FW_READY_INTERVAL);
 		value = pm8001_cr32(pm8001_ha, 0, MSGU_SCRATCH_PAD_1);
 	} while (((value & SCRATCH_PAD_RAAE_READY) !=
 				SCRATCH_PAD_RAAE_READY) && (--max_wait_count));
@@ -739,9 +740,9 @@ static int check_fw_ready(struct pm8001_hba_info *pm8001_ha)
 	}
 
 	/* check iop0 status */
-	max_wait_time = max_wait_count = 600 * 1000;	/* 600 milli sec */
+	max_wait_time = max_wait_count = 30;	/* 600 milli sec */
 	do {
-		udelay(1);
+		msleep(FW_READY_INTERVAL);
 		value = pm8001_cr32(pm8001_ha, 0, MSGU_SCRATCH_PAD_1);
 	} while (((value & SCRATCH_PAD_IOP0_READY) != SCRATCH_PAD_IOP0_READY) &&
 			(--max_wait_count));
@@ -757,9 +758,9 @@ static int check_fw_ready(struct pm8001_hba_info *pm8001_ha)
 	if ((pm8001_ha->chip_id != chip_8008) &&
 			(pm8001_ha->chip_id != chip_8009)) {
 		/* 200 milli sec */
-		max_wait_time = max_wait_count = 200 * 1000;
+		max_wait_time = max_wait_count = 10;
 		do {
-			udelay(1);
+			msleep(FW_READY_INTERVAL);
 			value = pm8001_cr32(pm8001_ha, 0, MSGU_SCRATCH_PAD_1);
 		} while (((value & SCRATCH_PAD_IOP1_READY) !=
 				SCRATCH_PAD_IOP1_READY) && (--max_wait_count));
diff --git a/drivers/scsi/pm8001/pm80xx_hwi.h b/drivers/scsi/pm8001/pm80xx_hwi.h
index 411b414a9a0ef..85cdd6d9348a6 100644
--- a/drivers/scsi/pm8001/pm80xx_hwi.h
+++ b/drivers/scsi/pm8001/pm80xx_hwi.h
@@ -1534,3 +1534,9 @@ typedef struct SASProtocolTimerConfig SASProtocolTimerConfig_t;
 
 #define MEMBASE_II_SHIFT_REGISTER       0x1010
 #endif
+
+/**
+ * As we know sleep (1~20) ms may result in sleep longer than ~20 ms, hence we
+ * choose 20 ms interval.
+ */
+#define FW_READY_INTERVAL	20
-- 
2.27.0


  parent reply	other threads:[~2020-12-23  2:30 UTC|newest]

Thread overview: 40+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-12-23  2:24 [PATCH AUTOSEL 4.4 01/38] locks: Fix UBSAN undefined behaviour in flock64_to_posix_lock Sasha Levin
2020-12-23  2:24 ` [PATCH AUTOSEL 4.4 02/38] tomoyo: fix clang pointer arithmetic warning Sasha Levin
2020-12-23  2:24 ` [PATCH AUTOSEL 4.4 03/38] staging: wimax: depends on NET Sasha Levin
2020-12-23  2:38   ` Jakub Kicinski
2020-12-23 14:14     ` Sasha Levin
2020-12-23  2:24 ` Sasha Levin [this message]
2020-12-23  2:24 ` [PATCH AUTOSEL 4.4 05/38] scsi: pm80xx: Fix pm8001_mpi_get_nvmd_resp() race condition Sasha Levin
2020-12-23  2:24 ` [PATCH AUTOSEL 4.4 06/38] staging: rtl8192u: fix wrong judgement in rtl8192_rx_isr Sasha Levin
2020-12-23  2:24 ` [PATCH AUTOSEL 4.4 07/38] mips: ar7: add missing iounmap() on error in ar7_gpio_init Sasha Levin
2020-12-23  2:24 ` [PATCH AUTOSEL 4.4 08/38] locktorture: Prevent hangs for invalid arguments Sasha Levin
2020-12-23  2:24 ` [PATCH AUTOSEL 4.4 09/38] rcutorture: " Sasha Levin
2020-12-23  2:24 ` [PATCH AUTOSEL 4.4 10/38] drm: panel: simple: add missing platform_driver_unregister() in panel_simple_init Sasha Levin
2020-12-23  2:24 ` [PATCH AUTOSEL 4.4 11/38] Bluetooth: hidp: use correct wait queue when removing ctrl_wait Sasha Levin
2020-12-23  2:24 ` [PATCH AUTOSEL 4.4 12/38] net: skb_vlan_untag(): don't reset transport offset if set by GRO layer Sasha Levin
2020-12-23  2:24 ` [PATCH AUTOSEL 4.4 13/38] MIPS: BMC47xx: fix kconfig dependency bug for BCM47XX_SSB Sasha Levin
2020-12-23  2:24 ` [PATCH AUTOSEL 4.4 14/38] jfs: Fix memleak in dbAdjCtl Sasha Levin
2020-12-23  2:24 ` [PATCH AUTOSEL 4.4 15/38] media: zr364xx: propagate errors from zr364xx_start_readpipe() Sasha Levin
2020-12-23  2:24 ` [PATCH AUTOSEL 4.4 16/38] media: isif: reset global state Sasha Levin
2020-12-23  2:24 ` [PATCH AUTOSEL 4.4 17/38] mmc: tmio: do not print real IOMEM pointer Sasha Levin
2020-12-23  2:24 ` [PATCH AUTOSEL 4.4 18/38] ARM: OMAP2+: Fix memleak in omap2xxx_clkt_vps_init Sasha Levin
2020-12-23  2:24 ` [PATCH AUTOSEL 4.4 19/38] tick/broadcast: Serialize access to tick_next_period Sasha Levin
2020-12-23  2:24 ` [PATCH AUTOSEL 4.4 20/38] ALSA: usb-audio: Don't call usb_set_interface() at trigger callback Sasha Levin
2020-12-23  2:24 ` [PATCH AUTOSEL 4.4 21/38] rxrpc: Don't leak the service-side session key to userspace Sasha Levin
2020-12-23  2:25 ` [PATCH AUTOSEL 4.4 22/38] ARM: dts: hisilicon: fix errors detected by snps-dw-apb-uart.yaml Sasha Levin
2020-12-23  2:25 ` [PATCH AUTOSEL 4.4 23/38] ARM: dts: hisilicon: fix errors detected by usb yaml Sasha Levin
2020-12-23  2:25 ` [PATCH AUTOSEL 4.4 24/38] ARM: dts: hisilicon: fix errors detected by simple-bus.yaml Sasha Levin
2020-12-23  2:25 ` [PATCH AUTOSEL 4.4 25/38] brcmsmac: ampdu: Check BA window size before checking block ack Sasha Levin
2020-12-23  2:25 ` [PATCH AUTOSEL 4.4 26/38] iommu/tegra-smmu: Expand mutex protection range Sasha Levin
2020-12-23  2:25 ` [PATCH AUTOSEL 4.4 27/38] crypto: qce - Fix SHA result buffer corruption issues Sasha Levin
2020-12-23  2:25 ` [PATCH AUTOSEL 4.4 28/38] media: gp8psk: initialize stats at power control logic Sasha Levin
2020-12-23  2:25 ` [PATCH AUTOSEL 4.4 29/38] net/lapb: fix t1 timer handling for LAPB_STATE_0 Sasha Levin
2020-12-23  2:25 ` [PATCH AUTOSEL 4.4 30/38] x86/mce: Panic for LMCE only if mca_cfg.tolerant < 3 Sasha Levin
2020-12-23  2:25 ` [PATCH AUTOSEL 4.4 31/38] mwifiex: Fix possible buffer overflows in mwifiex_cmd_802_11_ad_hoc_start Sasha Levin
2020-12-23  2:25 ` [PATCH AUTOSEL 4.4 32/38] misc: vmw_vmci: fix kernel info-leak by initializing dbells in vmci_ctx_get_chkpt_doorbells() Sasha Levin
2020-12-23  2:25 ` [PATCH AUTOSEL 4.4 33/38] iwlwifi: trans: consider firmware dead after errors Sasha Levin
2020-12-23  2:25 ` [PATCH AUTOSEL 4.4 34/38] iwlwifi: add an extra firmware state in the transport Sasha Levin
2020-12-23  2:25 ` [PATCH AUTOSEL 4.4 35/38] mac80211: disallow band-switch during CSA Sasha Levin
2020-12-23  2:25 ` [PATCH AUTOSEL 4.4 36/38] mac80211: don't filter out beacons once we start CSA Sasha Levin
2020-12-23  2:25 ` [PATCH AUTOSEL 4.4 37/38] ALSA: hda/hdmi: packet buffer index must be set before reading value Sasha Levin
2020-12-23  2:25 ` [PATCH AUTOSEL 4.4 38/38] PCI: Add function 1 DMA alias quirk for Marvell 9215 SATA controller Sasha Levin

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