From 817a7c996786f803a8b5528ca11a842eed88e01f Mon Sep 17 00:00:00 2001 From: Sebastian Andrzej Siewior Date: Thu, 26 Nov 2020 14:29:52 +0100 Subject: scsi: message: fusion: Remove in_interrupt() usage in mptsas_cleanup_fw_event_q() mptsas_cleanup_fw_event_q() uses in_interrupt() to determine if it is safe to cancel a worker item. Aside of that in_interrupt() is deprecated as it does not provide what the name suggests. It covers more than hard/soft interrupt servicing context and is semantically ill defined. Looking closer there are a few problems with the current construct: - It could be invoked from an interrupt handler / non-blocking context because cancel_delayed_work() has no such restriction. Also, mptsas_free_fw_event() has no such restriction. - The list is accessed unlocked. It may dequeue a valid work-item but at the time of invoking cancel_delayed_work() the memory may be released or reused because the worker has already run. mptsas_cleanup_fw_event_q() is invoked via mptsas_shutdown() which is always invoked from preemtible context on device shutdown. It is also invoked via mptsas_ioc_reset(, MPT_IOC_POST_RESET) which is a MptResetHandlers callback. The only caller here are mpt_SoftResetHandler(), mpt_HardResetHandler() and mpt_Soft_Hard_ResetHandler(). All these functions have a `sleepFlag' argument and each caller uses caller uses `CAN_SLEEP' here and according to current documentation: | @sleepFlag: Indicates if sleep or schedule must be called So it is safe to sleep. Add mptsas_hotplug_event::users member. Initialize it to one by default so mptsas_free_fw_event() will free the memory. mptsas_cleanup_fw_event_q() will increment its value for items it dequeues and then it may keep a pointer after dropping the lock. Invoke cancel_delayed_work_sync() to cancel the work item and wait if the worker is currently busy. Free the memory afterwards since it owns the last reference to it. Link: https://lore.kernel.org/r/20201126132952.2287996-15-bigeasy@linutronix.de Cc: Sathya Prakash Cc: Sreekanth Reddy Cc: Suganath Prabu Subramani Cc: MPT-FusionLinux.pdl@broadcom.com Reviewed-by: Daniel Wagner Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Martin K. Petersen --- drivers/message/fusion/mptsas.c | 45 ++++++++++++++++++++++++++++++++--------- drivers/message/fusion/mptsas.h | 1 + 2 files changed, 36 insertions(+), 10 deletions(-) (limited to 'drivers/message/fusion') diff --git a/drivers/message/fusion/mptsas.c b/drivers/message/fusion/mptsas.c index 18b91ea1a353..5eb0b3361e4e 100644 --- a/drivers/message/fusion/mptsas.c +++ b/drivers/message/fusion/mptsas.c @@ -289,6 +289,7 @@ mptsas_add_fw_event(MPT_ADAPTER *ioc, struct fw_event_work *fw_event, spin_lock_irqsave(&ioc->fw_event_lock, flags); list_add_tail(&fw_event->list, &ioc->fw_event_list); + fw_event->users = 1; INIT_DELAYED_WORK(&fw_event->work, mptsas_firmware_event_work); devtprintk(ioc, printk(MYIOC_s_DEBUG_FMT "%s: add (fw_event=0x%p)" "on cpuid %d\n", ioc->name, __func__, @@ -314,6 +315,15 @@ mptsas_requeue_fw_event(MPT_ADAPTER *ioc, struct fw_event_work *fw_event, spin_unlock_irqrestore(&ioc->fw_event_lock, flags); } +static void __mptsas_free_fw_event(MPT_ADAPTER *ioc, + struct fw_event_work *fw_event) +{ + devtprintk(ioc, printk(MYIOC_s_DEBUG_FMT "%s: kfree (fw_event=0x%p)\n", + ioc->name, __func__, fw_event)); + list_del(&fw_event->list); + kfree(fw_event); +} + /* free memory associated to a sas firmware event */ static void mptsas_free_fw_event(MPT_ADAPTER *ioc, struct fw_event_work *fw_event) @@ -321,10 +331,9 @@ mptsas_free_fw_event(MPT_ADAPTER *ioc, struct fw_event_work *fw_event) unsigned long flags; spin_lock_irqsave(&ioc->fw_event_lock, flags); - devtprintk(ioc, printk(MYIOC_s_DEBUG_FMT "%s: kfree (fw_event=0x%p)\n", - ioc->name, __func__, fw_event)); - list_del(&fw_event->list); - kfree(fw_event); + fw_event->users--; + if (!fw_event->users) + __mptsas_free_fw_event(ioc, fw_event); spin_unlock_irqrestore(&ioc->fw_event_lock, flags); } @@ -333,9 +342,10 @@ mptsas_free_fw_event(MPT_ADAPTER *ioc, struct fw_event_work *fw_event) static void mptsas_cleanup_fw_event_q(MPT_ADAPTER *ioc) { - struct fw_event_work *fw_event, *next; + struct fw_event_work *fw_event; struct mptsas_target_reset_event *target_reset_list, *n; MPT_SCSI_HOST *hd = shost_priv(ioc->sh); + unsigned long flags; /* flush the target_reset_list */ if (!list_empty(&hd->target_reset_list)) { @@ -350,14 +360,29 @@ mptsas_cleanup_fw_event_q(MPT_ADAPTER *ioc) } } - if (list_empty(&ioc->fw_event_list) || - !ioc->fw_event_q || in_interrupt()) + if (list_empty(&ioc->fw_event_list) || !ioc->fw_event_q) return; - list_for_each_entry_safe(fw_event, next, &ioc->fw_event_list, list) { - if (cancel_delayed_work(&fw_event->work)) - mptsas_free_fw_event(ioc, fw_event); + spin_lock_irqsave(&ioc->fw_event_lock, flags); + + while (!list_empty(&ioc->fw_event_list)) { + bool canceled = false; + + fw_event = list_first_entry(&ioc->fw_event_list, + struct fw_event_work, list); + fw_event->users++; + spin_unlock_irqrestore(&ioc->fw_event_lock, flags); + if (cancel_delayed_work_sync(&fw_event->work)) + canceled = true; + + spin_lock_irqsave(&ioc->fw_event_lock, flags); + if (canceled) + fw_event->users--; + fw_event->users--; + WARN_ON_ONCE(fw_event->users); + __mptsas_free_fw_event(ioc, fw_event); } + spin_unlock_irqrestore(&ioc->fw_event_lock, flags); } diff --git a/drivers/message/fusion/mptsas.h b/drivers/message/fusion/mptsas.h index e35b13891fe4..71abf3477495 100644 --- a/drivers/message/fusion/mptsas.h +++ b/drivers/message/fusion/mptsas.h @@ -107,6 +107,7 @@ struct mptsas_hotplug_event { struct fw_event_work { struct list_head list; struct delayed_work work; + int users; MPT_ADAPTER *ioc; u32 event; u8 retries; -- cgit v1.2.3-59-g8ed1b