From 25df73d93323e20c1f05700776fe3df75d3b27b2 Mon Sep 17 00:00:00 2001 From: Bart Van Assche Date: Wed, 22 Mar 2023 12:53:59 -0700 Subject: scsi: ata: Declare SCSI host templates const Make it explicit that ATA host templates are not modified. Reviewed-by: Linus Walleij Acked-by: Damien Le Moal Reviewed-by: Serge Semin (for DWC AHCI SATA) Reviewed-by: John Garry Reviewed-by: Jon Hunter (for Tegra) Cc: Christoph Hellwig Cc: Ming Lei Cc: Hannes Reinecke Cc: John Garry Cc: Mike Christie Signed-off-by: Bart Van Assche Link: https://lore.kernel.org/r/20230322195515.1267197-5-bvanassche@acm.org Signed-off-by: Martin K. Petersen --- include/linux/libata.h | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) (limited to 'include/linux/libata.h') diff --git a/include/linux/libata.h b/include/linux/libata.h index a759dfbdcc91..311cd93377c7 100644 --- a/include/linux/libata.h +++ b/include/linux/libata.h @@ -1065,10 +1065,10 @@ extern void ata_host_get(struct ata_host *host); extern void ata_host_put(struct ata_host *host); extern int ata_host_start(struct ata_host *host); extern int ata_host_register(struct ata_host *host, - struct scsi_host_template *sht); + const struct scsi_host_template *sht); extern int ata_host_activate(struct ata_host *host, int irq, irq_handler_t irq_handler, unsigned long irq_flags, - struct scsi_host_template *sht); + const struct scsi_host_template *sht); extern void ata_host_detach(struct ata_host *host); extern void ata_host_init(struct ata_host *, struct device *, struct ata_port_operations *); extern int ata_scsi_detect(struct scsi_host_template *sht); @@ -1980,10 +1980,10 @@ extern int ata_pci_sff_prepare_host(struct pci_dev *pdev, struct ata_host **r_host); extern int ata_pci_sff_activate_host(struct ata_host *host, irq_handler_t irq_handler, - struct scsi_host_template *sht); + const struct scsi_host_template *sht); extern int ata_pci_sff_init_one(struct pci_dev *pdev, const struct ata_port_info * const * ppi, - struct scsi_host_template *sht, void *host_priv, int hflags); + const struct scsi_host_template *sht, void *host_priv, int hflags); #endif /* CONFIG_PCI */ #ifdef CONFIG_ATA_BMDMA @@ -2019,7 +2019,7 @@ extern int ata_pci_bmdma_prepare_host(struct pci_dev *pdev, struct ata_host **r_host); extern int ata_pci_bmdma_init_one(struct pci_dev *pdev, const struct ata_port_info * const * ppi, - struct scsi_host_template *sht, + const struct scsi_host_template *sht, void *host_priv, int hflags); #endif /* CONFIG_PCI */ #endif /* CONFIG_ATA_BMDMA */ -- cgit v1.2.3-70-g09d2 From 6aa0365a3c8512587fffd42fe438768709ddef8e Mon Sep 17 00:00:00 2001 From: Damien Le Moal Date: Thu, 15 Jun 2023 17:18:53 +0900 Subject: ata: libata-scsi: Avoid deadlock on rescan after device resume When an ATA port is resumed from sleep, the port is reset and a power management request issued to libata EH to reset the port and rescanning the device(s) attached to the port. Device rescanning is done by scheduling an ata_scsi_dev_rescan() work, which will execute scsi_rescan_device(). However, scsi_rescan_device() takes the generic device lock, which is also taken by dpm_resume() when the SCSI device is resumed as well. If a device rescan execution starts before the completion of the SCSI device resume, the rcu locking used to refresh the cached VPD pages of the device, combined with the generic device locking from scsi_rescan_device() and from dpm_resume() can cause a deadlock. Avoid this situation by changing struct ata_port scsi_rescan_task to be a delayed work instead of a simple work_struct. ata_scsi_dev_rescan() is modified to check if the SCSI device associated with the ATA device that must be rescanned is not suspended. If the SCSI device is still suspended, ata_scsi_dev_rescan() returns early and reschedule itself for execution after an arbitrary delay of 5ms. Reported-by: Kai-Heng Feng Reported-by: Joe Breuer Closes: https://bugzilla.kernel.org/show_bug.cgi?id=217530 Fixes: a19a93e4c6a9 ("scsi: core: pm: Rely on the device driver core for async power management") Signed-off-by: Damien Le Moal Reviewed-by: Hannes Reinecke Tested-by: Kai-Heng Feng Tested-by: Joe Breuer --- drivers/ata/libata-core.c | 3 ++- drivers/ata/libata-eh.c | 2 +- drivers/ata/libata-scsi.c | 22 +++++++++++++++++++++- include/linux/libata.h | 2 +- 4 files changed, 25 insertions(+), 4 deletions(-) (limited to 'include/linux/libata.h') diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c index 8bf612bdd61a..b4f246f0cac7 100644 --- a/drivers/ata/libata-core.c +++ b/drivers/ata/libata-core.c @@ -5348,7 +5348,7 @@ struct ata_port *ata_port_alloc(struct ata_host *host) mutex_init(&ap->scsi_scan_mutex); INIT_DELAYED_WORK(&ap->hotplug_task, ata_scsi_hotplug); - INIT_WORK(&ap->scsi_rescan_task, ata_scsi_dev_rescan); + INIT_DELAYED_WORK(&ap->scsi_rescan_task, ata_scsi_dev_rescan); INIT_LIST_HEAD(&ap->eh_done_q); init_waitqueue_head(&ap->eh_wait_q); init_completion(&ap->park_req_pending); @@ -5954,6 +5954,7 @@ static void ata_port_detach(struct ata_port *ap) WARN_ON(!(ap->pflags & ATA_PFLAG_UNLOADED)); cancel_delayed_work_sync(&ap->hotplug_task); + cancel_delayed_work_sync(&ap->scsi_rescan_task); skip_eh: /* clean up zpodd on port removal */ diff --git a/drivers/ata/libata-eh.c b/drivers/ata/libata-eh.c index a6c901811802..6f8d14191593 100644 --- a/drivers/ata/libata-eh.c +++ b/drivers/ata/libata-eh.c @@ -2984,7 +2984,7 @@ static int ata_eh_revalidate_and_attach(struct ata_link *link, ehc->i.flags |= ATA_EHI_SETMODE; /* schedule the scsi_rescan_device() here */ - schedule_work(&(ap->scsi_rescan_task)); + schedule_delayed_work(&ap->scsi_rescan_task, 0); } else if (dev->class == ATA_DEV_UNKNOWN && ehc->tries[dev->devno] && ata_class_enabled(ehc->classes[dev->devno])) { diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c index 8ce90284eb34..551077cea4e4 100644 --- a/drivers/ata/libata-scsi.c +++ b/drivers/ata/libata-scsi.c @@ -4597,10 +4597,11 @@ int ata_scsi_user_scan(struct Scsi_Host *shost, unsigned int channel, void ata_scsi_dev_rescan(struct work_struct *work) { struct ata_port *ap = - container_of(work, struct ata_port, scsi_rescan_task); + container_of(work, struct ata_port, scsi_rescan_task.work); struct ata_link *link; struct ata_device *dev; unsigned long flags; + bool delay_rescan = false; mutex_lock(&ap->scsi_scan_mutex); spin_lock_irqsave(ap->lock, flags); @@ -4614,6 +4615,21 @@ void ata_scsi_dev_rescan(struct work_struct *work) if (scsi_device_get(sdev)) continue; + /* + * If the rescan work was scheduled because of a resume + * event, the port is already fully resumed, but the + * SCSI device may not yet be fully resumed. In such + * case, executing scsi_rescan_device() may cause a + * deadlock with the PM code on device_lock(). Prevent + * this by giving up and retrying rescan after a short + * delay. + */ + delay_rescan = sdev->sdev_gendev.power.is_suspended; + if (delay_rescan) { + scsi_device_put(sdev); + break; + } + spin_unlock_irqrestore(ap->lock, flags); scsi_rescan_device(&(sdev->sdev_gendev)); scsi_device_put(sdev); @@ -4623,4 +4639,8 @@ void ata_scsi_dev_rescan(struct work_struct *work) spin_unlock_irqrestore(ap->lock, flags); mutex_unlock(&ap->scsi_scan_mutex); + + if (delay_rescan) + schedule_delayed_work(&ap->scsi_rescan_task, + msecs_to_jiffies(5)); } diff --git a/include/linux/libata.h b/include/linux/libata.h index 311cd93377c7..dd5797fb6305 100644 --- a/include/linux/libata.h +++ b/include/linux/libata.h @@ -836,7 +836,7 @@ struct ata_port { struct mutex scsi_scan_mutex; struct delayed_work hotplug_task; - struct work_struct scsi_rescan_task; + struct delayed_work scsi_rescan_task; unsigned int hsm_task_state; -- cgit v1.2.3-70-g09d2