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Commit 27c1ce8b authored by Keith Busch's avatar Keith Busch Committed by Bjorn Helgaas
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PCI/AER: Use kfifo for tracking events instead of reimplementing it 



The kernel provides a generic FIFO implementation, so no need to reinvent
that capability in a driver.  Replace the AER-specific implementation with
the kernel-provided kfifo.  Since the interrupt handler producer and work
queue consumer run single threaded, there is no need for additional
locking, so remove that lock, too.

Signed-off-by: default avatarKeith Busch <keith.busch@intel.com>
Signed-off-by: default avatarBjorn Helgaas <bhelgaas@google.com>
parent fcd4d369

drivers/pci/pcie/aer.c

+11 −77
Original line number Diff line number Diff line
@@ -30,7 +30,7 @@ 
#include "../pci.h"

#include "portdrv.h"



#define AER_ERROR_SOURCES_MAX		100

#define AER_ERROR_SOURCES_MAX		128



#define AER_MAX_TYPEOF_COR_ERRS		16	/* as per PCI_ERR_COR_STATUS */

#define AER_MAX_TYPEOF_UNCOR_ERRS	26	/* as per PCI_ERR_UNCOR_STATUS*/
@@ -43,14 +43,8 @@ struct aer_err_source { 
struct aer_rpc {

	struct pci_dev *rpd;		/* Root Port device */

	struct work_struct dpc_handler;

	struct aer_err_source e_sources[AER_ERROR_SOURCES_MAX];

	unsigned short prod_idx;	/* Error Producer Index */

	unsigned short cons_idx;	/* Error Consumer Index */

	DECLARE_KFIFO(aer_fifo, struct aer_err_source, AER_ERROR_SOURCES_MAX);

	int isr;

	spinlock_t e_lock;		/*

					 * Lock access to Error Status/ID Regs

					 * and error producer/consumer index

					 */

	struct mutex rpc_mutex;		/*

					 * only one thread could do

					 * recovery on the same
@@ -1217,35 +1211,6 @@ static void aer_isr_one_error(struct aer_rpc *rpc, 
	}

}



/**

 * get_e_source - retrieve an error source

 * @rpc: pointer to the root port which holds an error

 * @e_src: pointer to store retrieved error source

 *

 * Return 1 if an error source is retrieved, otherwise 0.

 *

 * Invoked by DPC handler to consume an error.

 */

static int get_e_source(struct aer_rpc *rpc, struct aer_err_source *e_src)

{

	unsigned long flags;



	/* Lock access to Root error producer/consumer index */

	spin_lock_irqsave(&rpc->e_lock, flags);

	if (rpc->prod_idx == rpc->cons_idx) {

		spin_unlock_irqrestore(&rpc->e_lock, flags);

		return 0;

	}



	*e_src = rpc->e_sources[rpc->cons_idx];

	rpc->cons_idx++;

	if (rpc->cons_idx == AER_ERROR_SOURCES_MAX)

		rpc->cons_idx = 0;

	spin_unlock_irqrestore(&rpc->e_lock, flags);



	return 1;

}



/**

 * aer_isr - consume errors detected by root port

 * @work: definition of this work item
@@ -1258,7 +1223,7 @@ static void aer_isr(struct work_struct *work) 
	struct aer_err_source uninitialized_var(e_src);



	mutex_lock(&rpc->rpc_mutex);

	while (get_e_source(rpc, &e_src))

	while (kfifo_get(&rpc->aer_fifo, &e_src))

		aer_isr_one_error(rpc, &e_src);

	mutex_unlock(&rpc->rpc_mutex);

}
@@ -1272,51 +1237,23 @@ static void aer_isr(struct work_struct *work) 
 */

irqreturn_t aer_irq(int irq, void *context)

{

	unsigned int status, id;

	struct pcie_device *pdev = (struct pcie_device *)context;

	struct aer_rpc *rpc = get_service_data(pdev);

	int next_prod_idx;

	unsigned long flags;

	int pos;



	pos = pdev->port->aer_cap;

	/*

	 * Must lock access to Root Error Status Reg, Root Error ID Reg,

	 * and Root error producer/consumer index

	 */

	spin_lock_irqsave(&rpc->e_lock, flags);

	struct pci_dev *rp = rpc->rpd;

	struct aer_err_source e_src = {};

	int pos = rp->aer_cap;



	/* Read error status */

	pci_read_config_dword(pdev->port, pos + PCI_ERR_ROOT_STATUS, &status);

	if (!(status & (PCI_ERR_ROOT_UNCOR_RCV|PCI_ERR_ROOT_COR_RCV))) {

		spin_unlock_irqrestore(&rpc->e_lock, flags);

	pci_read_config_dword(rp, pos + PCI_ERR_ROOT_STATUS, &e_src.status);

	if (!(e_src.status & (PCI_ERR_ROOT_UNCOR_RCV|PCI_ERR_ROOT_COR_RCV)))

		return IRQ_NONE;

	}



	/* Read error source and clear error status */

	pci_read_config_dword(pdev->port, pos + PCI_ERR_ROOT_ERR_SRC, &id);

	pci_write_config_dword(pdev->port, pos + PCI_ERR_ROOT_STATUS, status);

	pci_read_config_dword(rp, pos + PCI_ERR_ROOT_ERR_SRC, &e_src.id);

	pci_write_config_dword(rp, pos + PCI_ERR_ROOT_STATUS, e_src.status);



	/* Store error source for later DPC handler */

	next_prod_idx = rpc->prod_idx + 1;

	if (next_prod_idx == AER_ERROR_SOURCES_MAX)

		next_prod_idx = 0;

	if (next_prod_idx == rpc->cons_idx) {

		/*

		 * Error Storm Condition - possibly the same error occurred.

		 * Drop the error.

		 */

		spin_unlock_irqrestore(&rpc->e_lock, flags);

	if (!kfifo_put(&rpc->aer_fifo, e_src))

		return IRQ_HANDLED;

	}

	rpc->e_sources[rpc->prod_idx].status =  status;

	rpc->e_sources[rpc->prod_idx].id = id;

	rpc->prod_idx = next_prod_idx;

	spin_unlock_irqrestore(&rpc->e_lock, flags);



	/*  Invoke DPC handler */

	schedule_work(&rpc->dpc_handler);



	return IRQ_HANDLED;

}

EXPORT_SYMBOL_GPL(aer_irq);
@@ -1441,9 +1378,6 @@ static struct aer_rpc *aer_alloc_rpc(struct pcie_device *dev) 
	if (!rpc)

		return NULL;



	/* Initialize Root lock access, e_lock, to Root Error Status Reg */

	spin_lock_init(&rpc->e_lock);



	rpc->rpd = dev->port;

	INIT_WORK(&rpc->dpc_handler, aer_isr);

	mutex_init(&rpc->rpc_mutex);