From 3627668c2e2c9459cff874ad34b82d251038da48 Mon Sep 17 00:00:00 2001 From: "Ahmed S. Darwish" Date: Thu, 26 Nov 2020 14:29:45 +0100 Subject: scsi: qla4xxx: Remove in_interrupt() from qla4_82xx_idc_lock() qla4_82xx_idc_lock() spins on a certain hardware state until it is updated. At the end of each spin, if in_interrupt() is true, it does 20 loops of cpu_relax(). Otherwise, it yields the CPU. While in_interrupt() is ill-defined and does not provide what the name suggests, it is not needed here: qla4_82xx_idc_lock() is always called from process context. Below is an analysis of its callers: - ql4_nx.c: qla4_82xx_need_reset_handler(), 1-second msleep() in a loop. - ql4_nx.c: qla4_82xx_isp_reset(), calls qla4_8xxx_device_state_handler(), which has multiple msleep()s. Beside direct calls, qla4_82xx_idc_lock() is also bound to isp_operations ->idc_lock() hook. Other functions which are bound to the same hook, e.g. qla4_83xx_drv_lock(), also have an msleep(). For completeness, below is an analysis of all callers of that hook: - ql4_83xx.c: qla4_83xx_need_reset_handler(), has an msleep() - ql4_83xx.c: qla4_83xx_isp_reset(), calls qla4_8xxx_device_state_handler(), which has multiple msleep()s. - ql4_83xx.c: qla4_83xx_disable_pause(), all process context callers: => ql4_mbx.c: qla4xxx_mailbox_command(), msleep(), mutex_lock() => ql4_os.c: qla4xxx_recover_adapter(), schedule_timeout() in loop => ql4_os.c: qla4xxx_do_dpc(), workqueue context - ql4_attr.c: qla4_8xxx_sysfs_write_fw_dump(), sysfs bin_attribute ->write() hook, process context - ql4_mbx.c: qla4xxx_mailbox_command(), earlier discussed - ql4_nx.c: qla4_8xxx_device_bootstrap(), callers: => ql4_83xx.c: qla4_83xx_need_reset_handler(), process, msleep() => ql4_nx.c: qla4_8xxx_device_state_handler(), earlier discussed - ql4_nx.c: qla4_8xxx_need_qsnt_handler(), callers: => ql4_nx.c: qla4_8xxx_device_state_handler(), multiple msleep()s => ql4_os.c: qla4xxx_do_dpc(), workqueue context - ql4_nx.c: qla4_8xxx_update_idc_reg(), callers: => ql4_nx.c: qla4_8xxx_device_state_handler(), earlier discussed => ql4_os.c: qla4_8xxx_error_recovery(), only called by qla4xxx_pci_slot_reset(), which is bound to PCI ->slot_reset() process-context hook - ql4_nx.c: qla4_8xxx_device_state_handler(), earlier discussed - ql4_os.c: qla4xxx_recover_adapter(), earlier discussed - ql4_os.c: qla4xxx_do_dpc(), earlier discussed Remove the in_interrupt() check. Mark, qla4_82xx_idc_lock(), and the ->idc_lock() hook itself, with "Context: task, can sleep". Change qla4_82xx_idc_lock() implementation to sleep 100ms, instead of a schedule(), for each spin. This is more deterministic, and it matches other PCI HW locking functions in the driver. Link: https://lore.kernel.org/r/20201126132952.2287996-8-bigeasy@linutronix.de Cc: Nilesh Javali Cc: Manish Rangankar Cc: Reviewed-by: Daniel Wagner Signed-off-by: Ahmed S. Darwish Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Martin K. Petersen --- drivers/scsi/qla4xxx/ql4_def.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers/scsi/qla4xxx/ql4_def.h') diff --git a/drivers/scsi/qla4xxx/ql4_def.h b/drivers/scsi/qla4xxx/ql4_def.h index f5b382ed0a1b..921054748388 100644 --- a/drivers/scsi/qla4xxx/ql4_def.h +++ b/drivers/scsi/qla4xxx/ql4_def.h @@ -435,7 +435,7 @@ struct isp_operations { void (*wr_reg_direct) (struct scsi_qla_host *, ulong, uint32_t); int (*rd_reg_indirect) (struct scsi_qla_host *, uint32_t, uint32_t *); int (*wr_reg_indirect) (struct scsi_qla_host *, uint32_t, uint32_t); - int (*idc_lock) (struct scsi_qla_host *); + int (*idc_lock) (struct scsi_qla_host *); /* Context: task, can sleep */ void (*idc_unlock) (struct scsi_qla_host *); void (*rom_lock_recovery) (struct scsi_qla_host *); void (*queue_mailbox_command) (struct scsi_qla_host *, uint32_t *, int); -- cgit v1.2.3