[PATCH AUTOSEL 4.14 1/2] idmaengine: make FSL_EDMA and INTEL_IDMA64 depends on HAS_IOMEM

[PATCH AUTOSEL 4.14 1/2] idmaengine: make FSL_EDMA and INTEL_IDMA64 depends on HAS_IOMEM

[Sasha Levin]

From: Baoquan He <bhe@redhat.com>

[ Upstream commit b1e213a9e31c20206f111ec664afcf31cbfe0dbb ]

On s390 systems (aka mainframes), it has classic channel devices for
networking and permanent storage that are currently even more common
than PCI devices. Hence it could have a fully functional s390 kernel
with CONFIG_PCI=n, then the relevant iomem mapping functions
[including ioremap(), devm_ioremap(), etc.] are not available.

Here let FSL_EDMA and INTEL_IDMA64 depend on HAS_IOMEM so that it
won't be built to cause below compiling error if PCI is unset.

--------
ERROR: modpost: "devm_platform_ioremap_resource" [drivers/dma/fsl-edma.ko] undefined!
ERROR: modpost: "devm_platform_ioremap_resource" [drivers/dma/idma64.ko] undefined!
--------

Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202306211329.ticOJCSv-lkp@intel.com/
Signed-off-by: Baoquan He <bhe@redhat.com>
Cc: Vinod Koul <vkoul@kernel.org>
Cc: dmaengine@vger.kernel.org
Link: https://lore.kernel.org/r/20230707135852.24292-2-bhe@redhat.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/dma/Kconfig | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/dma/Kconfig b/drivers/dma/Kconfig
index 5ea37d133f241..6abb80b09db3b 100644
--- a/drivers/dma/Kconfig
+++ b/drivers/dma/Kconfig
@@ -209,6 +209,7 @@ config FSL_DMA
 config FSL_EDMA
 	tristate "Freescale eDMA engine support"
 	depends on OF
+	depends on HAS_IOMEM
 	select DMA_ENGINE
 	select DMA_VIRTUAL_CHANNELS
 	help
@@ -254,6 +255,7 @@ config IMX_SDMA
 
 config INTEL_IDMA64
 	tristate "Intel integrated DMA 64-bit support"
+	depends on HAS_IOMEM
 	select DMA_ENGINE
 	select DMA_VIRTUAL_CHANNELS
 	help
-- 
2.40.1

[PATCH AUTOSEL 4.14 2/2] scsi: qedi: Fix potential deadlock on &qedi_percpu->p_work_lock

[Sasha Levin]

From: Chengfeng Ye <dg573847474@gmail.com>

[ Upstream commit dd64f80587190265ca8a0f4be6c64c2fda6d3ac2 ]

As &qedi_percpu->p_work_lock is acquired by hard IRQ qedi_msix_handler(),
other acquisitions of the same lock under process context should disable
IRQ, otherwise deadlock could happen if the IRQ preempts the execution
while the lock is held in process context on the same CPU.

qedi_cpu_offline() is one such function which acquires the lock in process
context.

[Deadlock Scenario]
qedi_cpu_offline()
    ->spin_lock(&p->p_work_lock)
        <irq>
        ->qedi_msix_handler()
        ->edi_process_completions()
        ->spin_lock_irqsave(&p->p_work_lock, flags); (deadlock here)

This flaw was found by an experimental static analysis tool I am developing
for IRQ-related deadlocks.

The tentative patch fix the potential deadlock by spin_lock_irqsave()
under process context.

Signed-off-by: Chengfeng Ye <dg573847474@gmail.com>
Link: https://lore.kernel.org/r/20230726125655.4197-1-dg573847474@gmail.com
Acked-by: Manish Rangankar <mrangankar@marvell.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/scsi/qedi/qedi_main.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/scsi/qedi/qedi_main.c b/drivers/scsi/qedi/qedi_main.c
index 09f57ef35990c..b8b177018031c 100644
--- a/drivers/scsi/qedi/qedi_main.c
+++ b/drivers/scsi/qedi/qedi_main.c
@@ -1669,8 +1669,9 @@ static int qedi_cpu_offline(unsigned int cpu)
 	struct qedi_percpu_s *p = this_cpu_ptr(&qedi_percpu);
 	struct qedi_work *work, *tmp;
 	struct task_struct *thread;
+	unsigned long flags;
 
-	spin_lock_bh(&p->p_work_lock);
+	spin_lock_irqsave(&p->p_work_lock, flags);
 	thread = p->iothread;
 	p->iothread = NULL;
 
@@ -1681,7 +1682,7 @@ static int qedi_cpu_offline(unsigned int cpu)
 			kfree(work);
 	}
 
-	spin_unlock_bh(&p->p_work_lock);
+	spin_unlock_irqrestore(&p->p_work_lock, flags);
 	if (thread)
 		kthread_stop(thread);
 	return 0;
-- 
2.40.1