[PATCH v4 4/4] AHCI: Do not read HOST_IRQ_STAT reg in multi-MSI mode

[Alexander Gordeev]

As described in AHCI v1.0 specification chapter 10.6.2.2
"Multiple MSI Based Messages" generation of interrupts
is not controlled through the HOST_IRQ_STAT register.

Considering MMIO access is expensive remove unnecessary
reading and writing of HOST_IRQ_STAT register.

Further, serializing access to the host data is no longer
needed and the interrupt service routine can avoid competing
on the host lock.

Signed-off-by: Alexander Gordeev <***@redhat.com>
Suggested-by: "Jiang, Dave" <***@intel.com>
Cc: linux-***@vger.kernel.org
---
drivers/ata/ahci.h | 1 +
drivers/ata/libahci.c | 59 +++++++++++----------------------------------------
2 files changed, 13 insertions(+), 47 deletions(-)

diff --git a/drivers/ata/ahci.h b/drivers/ata/ahci.h
index 6a22055..e5c6048 100644
--- a/drivers/ata/ahci.h
+++ b/drivers/ata/ahci.h
@@ -305,6 +305,7 @@ struct ahci_port_priv {
unsigned int ncq_saw_dmas:1;
unsigned int ncq_saw_sdb:1;
u32 intr_status; /* interrupts to handle */
+ spinlock_t intr_lock; /* protects intr_status */
spinlock_t lock; /* protects parent ata_port */
u32 intr_mask; /* interrupts to enable */
bool fbs_supported; /* set iff FBS is supported */
diff --git a/drivers/ata/libahci.c b/drivers/ata/libahci.c
index 48175e5..fafa7f0 100644
--- a/drivers/ata/libahci.c
+++ b/drivers/ata/libahci.c
@@ -1797,11 +1797,14 @@ static irqreturn_t ahci_port_thread_fn(int irq, void *dev_instance)
unsigned long flags;
u32 status;

- spin_lock_irqsave(&ap->host->lock, flags);
+ spin_lock_irqsave(&pp->intr_lock, flags);
status = pp->intr_status;
if (status)
pp->intr_status = 0;
- spin_unlock_irqrestore(&ap->host->lock, flags);
+ spin_unlock_irqrestore(&pp->intr_lock, flags);
+
+ if (!status)
+ return IRQ_NONE;

spin_lock_bh(ap->lock);
ahci_handle_port_interrupt(ap, port_mmio, status);
@@ -1824,53 +1827,14 @@ static void ahci_update_intr_status(struct ata_port *ap)

static irqreturn_t ahci_multi_irqs_intr(int irq, void *dev_instance)
{
- struct ata_port *ap_this = dev_instance;
- struct ahci_port_priv *pp = ap_this->private_data;
- struct ata_host *host = ap_this->host;
- struct ahci_host_priv *hpriv = host->private_data;
- void __iomem *mmio = hpriv->mmio;
- unsigned int i;
- u32 irq_stat, irq_masked;
+ struct ata_port *ap = dev_instance;
+ struct ahci_port_priv *pp = ap->private_data;

VPRINTK("ENTER\n");

- spin_lock(&host->lock);
-
- irq_stat = readl(mmio + HOST_IRQ_STAT);
-
- if (!irq_stat) {
- u32 status = pp->intr_status;
-
- spin_unlock(&host->lock);
-
- VPRINTK("EXIT\n");
-
- return status ? IRQ_WAKE_THREAD : IRQ_NONE;
- }
-
- irq_masked = irq_stat & hpriv->port_map;
-
- for (i = 0; i < host->n_ports; i++) {
- struct ata_port *ap;
-
- if (!(irq_masked & (1 << i)))
- continue;
-
- ap = host->ports[i];
- if (ap) {
- ahci_update_intr_status(ap);
- VPRINTK("port %u\n", i);
- } else {
- VPRINTK("port %u (no irq)\n", i);
- if (ata_ratelimit())
- dev_warn(host->dev,
- "interrupt on disabled port %u\n", i);
- }
- }
-
- writel(irq_stat, mmio + HOST_IRQ_STAT);
-
- spin_unlock(&host->lock);
+ spin_lock(&pp->intr_lock);
+ ahci_update_intr_status(ap);
+ spin_unlock(&pp->intr_lock);

VPRINTK("EXIT\n");

@@ -2349,7 +2313,8 @@ static int ahci_port_start(struct ata_port *ap)
/*
* Switch to per-port locking in case each port has its own MSI vector.
*/
- if ((hpriv->flags & AHCI_HFLAG_MULTI_MSI)) {
+ if (hpriv->flags & AHCI_HFLAG_MULTI_MSI) {
+ spin_lock_init(&pp->intr_lock);
spin_lock_init(&pp->lock);
ap->lock = &pp->lock;
}

[Alexander Gordeev]

Sharing Last Message (SLM) mode is currently checked in two
functions: ahci_host_activate() and ahci_init_interrupts().
This update consolidates SLM mode check with activation of
multiple MSIs mode.

Signed-off-by: Alexander Gordeev <***@redhat.com>
Cc: linux-***@vger.kernel.org
---
drivers/ata/ahci.c | 18 +++++++-----------
drivers/ata/ahci.h | 2 +-
2 files changed, 8 insertions(+), 12 deletions(-)

diff --git a/drivers/ata/ahci.c b/drivers/ata/ahci.c
index c880699..f68a995 100644
--- a/drivers/ata/ahci.c
+++ b/drivers/ata/ahci.c
@@ -1211,6 +1211,9 @@ static int ahci_init_interrupts(struct pci_dev *pdev, unsigned int n_ports,
goto single_msi;
}

+ if (nvec > 1)
+ hpriv->flags |= AHCI_HFLAG_MULTI_MSI;
+
return nvec;

single_msi:
@@ -1227,7 +1230,6 @@ intx:
* ahci_host_activate - start AHCI host, request IRQs and register it
* @host: target ATA host
* @irq: base IRQ number to request
- * @n_msis: number of MSIs allocated for this host
* @irq_handler: irq_handler used when requesting IRQs
* @irq_flags: irq_flags used when requesting IRQs
*
@@ -1241,14 +1243,10 @@ intx:
* RETURNS:
* 0 on success, -errno otherwise.
*/
-int ahci_host_activate(struct ata_host *host, int irq, unsigned int n_msis)
+int ahci_host_activate(struct ata_host *host, int irq)
{
int i, rc;

- /* Sharing Last Message among several ports is not supported */
- if (n_msis < host->n_ports)
- return -EINVAL;
-
rc = ata_host_start(host);
if (rc)
return rc;
@@ -1296,7 +1294,7 @@ static int ahci_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
struct device *dev = &pdev->dev;
struct ahci_host_priv *hpriv;
struct ata_host *host;
- int n_ports, n_msis, i, rc;
+ int n_ports, i, rc;
int ahci_pci_bar = AHCI_PCI_BAR_STANDARD;

VPRINTK("ENTER\n");
@@ -1437,9 +1435,7 @@ static int ahci_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
*/
n_ports = max(ahci_nr_ports(hpriv->cap), fls(hpriv->port_map));

- n_msis = ahci_init_interrupts(pdev, n_ports, hpriv);
- if (n_msis > 1)
- hpriv->flags |= AHCI_HFLAG_MULTI_MSI;
+ ahci_init_interrupts(pdev, n_ports, hpriv);

host = ata_host_alloc_pinfo(&pdev->dev, ppi, n_ports);
if (!host)
@@ -1492,7 +1488,7 @@ static int ahci_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
pci_set_master(pdev);

if (hpriv->flags & AHCI_HFLAG_MULTI_MSI)
- return ahci_host_activate(host, pdev->irq, n_msis);
+ return ahci_host_activate(host, pdev->irq);

return ata_host_activate(host, pdev->irq, ahci_interrupt, IRQF_SHARED,
&ahci_sht);
diff --git a/drivers/ata/ahci.h b/drivers/ata/ahci.h
index 90156ff..a074c73 100644
--- a/drivers/ata/ahci.h
+++ b/drivers/ata/ahci.h
@@ -392,7 +392,7 @@ irqreturn_t ahci_interrupt(int irq, void *dev_instance);
irqreturn_t ahci_hw_interrupt(int irq, void *dev_instance);
irqreturn_t ahci_thread_fn(int irq, void *dev_instance);
void ahci_print_info(struct ata_host *host, const char *scc_s);
-int ahci_host_activate(struct ata_host *host, int irq, unsigned int n_msis);
+int ahci_host_activate(struct ata_host *host, int irq);
void ahci_error_handler(struct ata_port *ap);

static inline void __iomem *__ahci_port_base(struct ata_host *host,

[Alexander Gordeev]

Currently host activation done by calling either function
ahci_host_activate() or ata_host_activate(). Consolidate
the code by only calling ahci_host_activate() for all AHCI
devices.

Signed-off-by: Alexander Gordeev <***@redhat.com>
Cc: linux-***@vger.kernel.org
---
drivers/ata/acard-ahci.c | 3 +-
drivers/ata/ahci.c | 66 +--------------------------------
drivers/ata/ahci.h | 6 +--
drivers/ata/libahci.c | 84 +++++++++++++++++++++++++++++++++++++++---
drivers/ata/libahci_platform.c | 3 +-
5 files changed, 83 insertions(+), 79 deletions(-)

diff --git a/drivers/ata/acard-ahci.c b/drivers/ata/acard-ahci.c
index 25d0ac3..c962886 100644
--- a/drivers/ata/acard-ahci.c
+++ b/drivers/ata/acard-ahci.c
@@ -498,8 +498,7 @@ static int acard_ahci_init_one(struct pci_dev *pdev, const struct pci_device_id
acard_ahci_pci_print_info(host);

pci_set_master(pdev);
- return ata_host_activate(host, pdev->irq, ahci_interrupt, IRQF_SHARED,
- &acard_ahci_sht);
+ return ahci_host_activate(host, pdev->irq, &acard_ahci_sht);
}

module_pci_driver(acard_ahci_pci_driver);
diff --git a/drivers/ata/ahci.c b/drivers/ata/ahci.c
index f68a995..d0ac38b 100644
--- a/drivers/ata/ahci.c
+++ b/drivers/ata/ahci.c
@@ -1226,66 +1226,6 @@ intx:
return 0;
}

-/**
- * ahci_host_activate - start AHCI host, request IRQs and register it
- * @host: target ATA host
- * @irq: base IRQ number to request
- * @irq_handler: irq_handler used when requesting IRQs
- * @irq_flags: irq_flags used when requesting IRQs
- *
- * Similar to ata_host_activate, but requests IRQs according to AHCI-1.1
- * when multiple MSIs were allocated. That is one MSI per port, starting
- * from @irq.
- *
- * LOCKING:
- * Inherited from calling layer (may sleep).
- *
- * RETURNS:
- * 0 on success, -errno otherwise.
- */
-int ahci_host_activate(struct ata_host *host, int irq)
-{
- int i, rc;
-
- rc = ata_host_start(host);
- if (rc)
- return rc;
-
- for (i = 0; i < host->n_ports; i++) {
- struct ahci_port_priv *pp = host->ports[i]->private_data;
-
- /* Do not receive interrupts sent by dummy ports */
- if (!pp) {
- disable_irq(irq + i);
- continue;
- }
-
- rc = devm_request_threaded_irq(host->dev, irq + i,
- ahci_hw_interrupt,
- ahci_thread_fn, IRQF_SHARED,
- pp->irq_desc, host->ports[i]);
- if (rc)
- goto out_free_irqs;
- }
-
- for (i = 0; i < host->n_ports; i++)
- ata_port_desc(host->ports[i], "irq %d", irq + i);
-
- rc = ata_host_register(host, &ahci_sht);
- if (rc)
- goto out_free_all_irqs;
-
- return 0;
-
-out_free_all_irqs:
- i = host->n_ports;
-out_free_irqs:
- for (i--; i >= 0; i--)
- devm_free_irq(host->dev, irq + i, host->ports[i]);
-
- return rc;
-}
-
static int ahci_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
{
unsigned int board_id = ent->driver_data;
@@ -1487,11 +1427,7 @@ static int ahci_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)

pci_set_master(pdev);

- if (hpriv->flags & AHCI_HFLAG_MULTI_MSI)
- return ahci_host_activate(host, pdev->irq);
-
- return ata_host_activate(host, pdev->irq, ahci_interrupt, IRQF_SHARED,
- &ahci_sht);
+ return ahci_host_activate(host, pdev->irq, &ahci_sht);
}

module_pci_driver(ahci_pci_driver);
diff --git a/drivers/ata/ahci.h b/drivers/ata/ahci.h
index a074c73..6a22055 100644
--- a/drivers/ata/ahci.h
+++ b/drivers/ata/ahci.h
@@ -388,11 +388,9 @@ int ahci_port_resume(struct ata_port *ap);
void ahci_set_em_messages(struct ahci_host_priv *hpriv,
struct ata_port_info *pi);
int ahci_reset_em(struct ata_host *host);
-irqreturn_t ahci_interrupt(int irq, void *dev_instance);
-irqreturn_t ahci_hw_interrupt(int irq, void *dev_instance);
-irqreturn_t ahci_thread_fn(int irq, void *dev_instance);
void ahci_print_info(struct ata_host *host, const char *scc_s);
-int ahci_host_activate(struct ata_host *host, int irq);
+int ahci_host_activate(struct ata_host *host, int irq,
+ struct scsi_host_template *sht);
void ahci_error_handler(struct ata_port *ap);

static inline void __iomem *__ahci_port_base(struct ata_host *host,
diff --git a/drivers/ata/libahci.c b/drivers/ata/libahci.c
index b784e9d..0080551 100644
--- a/drivers/ata/libahci.c
+++ b/drivers/ata/libahci.c
@@ -1789,7 +1789,7 @@ static void ahci_port_intr(struct ata_port *ap)
ahci_handle_port_interrupt(ap, port_mmio, status);
}

-irqreturn_t ahci_thread_fn(int irq, void *dev_instance)
+static irqreturn_t ahci_thread_fn(int irq, void *dev_instance)
{
struct ata_port *ap = dev_instance;
struct ahci_port_priv *pp = ap->private_data;
@@ -1809,7 +1809,6 @@ irqreturn_t ahci_thread_fn(int irq, void *dev_instance)

return IRQ_HANDLED;
}
-EXPORT_SYMBOL_GPL(ahci_thread_fn);

static void ahci_hw_port_interrupt(struct ata_port *ap)
{
@@ -1823,7 +1822,7 @@ static void ahci_hw_port_interrupt(struct ata_port *ap)
pp->intr_status |= status;
}

-irqreturn_t ahci_hw_interrupt(int irq, void *dev_instance)
+static irqreturn_t ahci_hw_interrupt(int irq, void *dev_instance)
{
struct ata_port *ap_this = dev_instance;
struct ahci_port_priv *pp = ap_this->private_data;
@@ -1877,9 +1876,8 @@ irqreturn_t ahci_hw_interrupt(int irq, void *dev_instance)

return IRQ_WAKE_THREAD;
}
-EXPORT_SYMBOL_GPL(ahci_hw_interrupt);

-irqreturn_t ahci_interrupt(int irq, void *dev_instance)
+static irqreturn_t ahci_interrupt(int irq, void *dev_instance)
{
struct ata_host *host = dev_instance;
struct ahci_host_priv *hpriv;
@@ -1938,7 +1936,6 @@ irqreturn_t ahci_interrupt(int irq, void *dev_instance)

return IRQ_RETVAL(handled);
}
-EXPORT_SYMBOL_GPL(ahci_interrupt);

unsigned int ahci_qc_issue(struct ata_queued_cmd *qc)
{
@@ -2472,6 +2469,81 @@ void ahci_set_em_messages(struct ahci_host_priv *hpriv,
}
EXPORT_SYMBOL_GPL(ahci_set_em_messages);

+static int ahci_host_activate_multi_irqs(struct ata_host *host, int irq,
+ struct scsi_host_template *sht)
+{
+ int i, rc;
+
+ rc = ata_host_start(host);
+ if (rc)
+ return rc;
+
+ for (i = 0; i < host->n_ports; i++) {
+ struct ahci_port_priv *pp = host->ports[i]->private_data;
+
+ /* Do not receive interrupts sent by dummy ports */
+ if (!pp) {
+ disable_irq(irq + i);
+ continue;
+ }
+
+ rc = devm_request_threaded_irq(host->dev, irq + i,
+ ahci_hw_interrupt,
+ ahci_thread_fn, IRQF_SHARED,
+ pp->irq_desc, host->ports[i]);
+ if (rc)
+ goto out_free_irqs;
+ }
+
+ for (i = 0; i < host->n_ports; i++)
+ ata_port_desc(host->ports[i], "irq %d", irq + i);
+
+ rc = ata_host_register(host, sht);
+ if (rc)
+ goto out_free_all_irqs;
+
+ return 0;
+
+out_free_all_irqs:
+ i = host->n_ports;
+out_free_irqs:
+ for (i--; i >= 0; i--)
+ devm_free_irq(host->dev, irq + i, host->ports[i]);
+
+ return rc;
+}
+
+/**
+ * ahci_host_activate - start AHCI host, request IRQs and register it
+ * @host: target ATA host
+ * @irq: base IRQ number to request
+ * @sht: scsi_host_template to use when registering the host
+ *
+ * Similar to ata_host_activate, but requests IRQs according to AHCI-1.1
+ * when multiple MSIs were allocated. That is one MSI per port, starting
+ * from @irq.
+ *
+ * LOCKING:
+ * Inherited from calling layer (may sleep).
+ *
+ * RETURNS:
+ * 0 on success, -errno otherwise.
+ */
+int ahci_host_activate(struct ata_host *host, int irq,
+ struct scsi_host_template *sht)
+{
+ struct ahci_host_priv *hpriv = host->private_data;
+ int rc;
+
+ if (hpriv->flags & AHCI_HFLAG_MULTI_MSI)
+ rc = ahci_host_activate_multi_irqs(host, irq, sht);
+ else
+ rc = ata_host_activate(host, irq, ahci_interrupt,
+ IRQF_SHARED, sht);
+ return rc;
+}
+EXPORT_SYMBOL_GPL(ahci_host_activate);
+
MODULE_AUTHOR("Jeff Garzik");
MODULE_DESCRIPTION("Common AHCI SATA low-level routines");
MODULE_LICENSE("GPL");
diff --git a/drivers/ata/libahci_platform.c b/drivers/ata/libahci_platform.c
index c7f787e..0b03f90 100644
--- a/drivers/ata/libahci_platform.c
+++ b/drivers/ata/libahci_platform.c
@@ -493,8 +493,7 @@ int ahci_platform_init_host(struct platform_device *pdev,
ahci_init_controller(host);
ahci_print_info(host, "platform");

- return ata_host_activate(host, irq, ahci_interrupt, IRQF_SHARED,
- &ahci_platform_sht);
+ return ahci_host_activate(host, irq, &ahci_platform_sht);
}
EXPORT_SYMBOL_GPL(ahci_platform_init_host);

[Tejun Heo]

Post by Alexander Gordeev
-/**
- * ahci_host_activate - start AHCI host, request IRQs and register it
- *
- * Similar to ata_host_activate, but requests IRQs according to AHCI-1.1
- * when multiple MSIs were allocated. That is one MSI per port, starting
- *
- * Inherited from calling layer (may sleep).
- *
- * 0 on success, -errno otherwise.
- */
-int ahci_host_activate(struct ata_host *host, int irq)
-{
- int i, rc;
-
- rc = ata_host_start(host);
- if (rc)
- return rc;
-
- for (i = 0; i < host->n_ports; i++) {
- struct ahci_port_priv *pp = host->ports[i]->private_data;
-
- /* Do not receive interrupts sent by dummy ports */
- if (!pp) {
- disable_irq(irq + i);
- continue;
- }
-
- rc = devm_request_threaded_irq(host->dev, irq + i,
- ahci_hw_interrupt,
- ahci_thread_fn, IRQF_SHARED,
- pp->irq_desc, host->ports[i]);
- if (rc)
- goto out_free_irqs;
- }
-
- for (i = 0; i < host->n_ports; i++)
- ata_port_desc(host->ports[i], "irq %d", irq + i);
-
- rc = ata_host_register(host, &ahci_sht);
- if (rc)
- goto out_free_all_irqs;
-
- return 0;
-
- i = host->n_ports;
- for (i--; i >= 0; i--)
- devm_free_irq(host->dev, irq + i, host->ports[i]);
-
- return rc;
-}

It's generally a bad idea to mix code movement w/ other changes. I'm
applying this one but please separate code movements to separate
patches from now on.

Thanks.

[Alexander Gordeev]

Post by Tejun Heo
It's generally a bad idea to mix code movement w/ other changes. I'm
applying this one but please separate code movements to separate
patches from now on.

This patch lacks the hunk below, which causes build error.

--- a/drivers/ata/sata_highbank.c
+++ b/drivers/ata/sata_highbank.c
@@ -568,8 +568,7 @@ static int ahci_highbank_probe(struct platform_device *pdev)
ahci_init_controller(host);
ahci_print_info(host, "platform");

- rc = ata_host_activate(host, irq, ahci_interrupt, 0,
- &ahci_highbank_platform_sht);
+ rc = ahci_host_activate(host, irq, &ahci_highbank_platform_sht);
if (rc)
goto err0;

Post by Tejun Heo
Thanks.
--
tejun

[Alexander Gordeev]

Currently host activation done by calling either function
ahci_host_activate() or ata_host_activate(). Consolidate
the code by only calling ahci_host_activate() for all AHCI
devices.

Signed-off-by: Alexander Gordeev <***@redhat.com>
Cc: linux-***@vger.kernel.org
---
drivers/ata/acard-ahci.c | 3 +-
drivers/ata/ahci.c | 66 +--------------------------------
drivers/ata/ahci.h | 6 +--
drivers/ata/libahci.c | 84 +++++++++++++++++++++++++++++++++++++++---
drivers/ata/libahci_platform.c | 3 +-
drivers/ata/sata_highbank.c | 3 +-
6 files changed, 84 insertions(+), 81 deletions(-)

diff --git a/drivers/ata/acard-ahci.c b/drivers/ata/acard-ahci.c
index 25d0ac3..c962886 100644
--- a/drivers/ata/acard-ahci.c
+++ b/drivers/ata/acard-ahci.c
@@ -498,8 +498,7 @@ static int acard_ahci_init_one(struct pci_dev *pdev, const struct pci_device_id
acard_ahci_pci_print_info(host);

pci_set_master(pdev);
- return ata_host_activate(host, pdev->irq, ahci_interrupt, IRQF_SHARED,
- &acard_ahci_sht);
+ return ahci_host_activate(host, pdev->irq, &acard_ahci_sht);
}

module_pci_driver(acard_ahci_pci_driver);
diff --git a/drivers/ata/ahci.c b/drivers/ata/ahci.c
index f68a995..d0ac38b 100644
--- a/drivers/ata/ahci.c
+++ b/drivers/ata/ahci.c
@@ -1226,66 +1226,6 @@ intx:
return 0;
}

-/**
- * ahci_host_activate - start AHCI host, request IRQs and register it
- * @host: target ATA host
- * @irq: base IRQ number to request
- * @irq_handler: irq_handler used when requesting IRQs
- * @irq_flags: irq_flags used when requesting IRQs
- *
- * Similar to ata_host_activate, but requests IRQs according to AHCI-1.1
- * when multiple MSIs were allocated. That is one MSI per port, starting
- * from @irq.
- *
- * LOCKING:
- * Inherited from calling layer (may sleep).
- *
- * RETURNS:
- * 0 on success, -errno otherwise.
- */
-int ahci_host_activate(struct ata_host *host, int irq)
-{
- int i, rc;
-
- rc = ata_host_start(host);
- if (rc)
- return rc;
-
- for (i = 0; i < host->n_ports; i++) {
- struct ahci_port_priv *pp = host->ports[i]->private_data;
-
- /* Do not receive interrupts sent by dummy ports */
- if (!pp) {
- disable_irq(irq + i);
- continue;
- }
-
- rc = devm_request_threaded_irq(host->dev, irq + i,
- ahci_hw_interrupt,
- ahci_thread_fn, IRQF_SHARED,
- pp->irq_desc, host->ports[i]);
- if (rc)
- goto out_free_irqs;
- }
-
- for (i = 0; i < host->n_ports; i++)
- ata_port_desc(host->ports[i], "irq %d", irq + i);
-
- rc = ata_host_register(host, &ahci_sht);
- if (rc)
- goto out_free_all_irqs;
-
- return 0;
-
-out_free_all_irqs:
- i = host->n_ports;
-out_free_irqs:
- for (i--; i >= 0; i--)
- devm_free_irq(host->dev, irq + i, host->ports[i]);
-
- return rc;
-}
-
static int ahci_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
{
unsigned int board_id = ent->driver_data;
@@ -1487,11 +1427,7 @@ static int ahci_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)

pci_set_master(pdev);

- if (hpriv->flags & AHCI_HFLAG_MULTI_MSI)
- return ahci_host_activate(host, pdev->irq);
-
- return ata_host_activate(host, pdev->irq, ahci_interrupt, IRQF_SHARED,
- &ahci_sht);
+ return ahci_host_activate(host, pdev->irq, &ahci_sht);
}

module_pci_driver(ahci_pci_driver);
diff --git a/drivers/ata/ahci.h b/drivers/ata/ahci.h
index a074c73..6a22055 100644
--- a/drivers/ata/ahci.h
+++ b/drivers/ata/ahci.h
@@ -388,11 +388,9 @@ int ahci_port_resume(struct ata_port *ap);
void ahci_set_em_messages(struct ahci_host_priv *hpriv,
struct ata_port_info *pi);
int ahci_reset_em(struct ata_host *host);
-irqreturn_t ahci_interrupt(int irq, void *dev_instance);
-irqreturn_t ahci_hw_interrupt(int irq, void *dev_instance);
-irqreturn_t ahci_thread_fn(int irq, void *dev_instance);
void ahci_print_info(struct ata_host *host, const char *scc_s);
-int ahci_host_activate(struct ata_host *host, int irq);
+int ahci_host_activate(struct ata_host *host, int irq,
+ struct scsi_host_template *sht);
void ahci_error_handler(struct ata_port *ap);

static inline void __iomem *__ahci_port_base(struct ata_host *host,
diff --git a/drivers/ata/libahci.c b/drivers/ata/libahci.c
index b784e9d..0080551 100644
--- a/drivers/ata/libahci.c
+++ b/drivers/ata/libahci.c
@@ -1789,7 +1789,7 @@ static void ahci_port_intr(struct ata_port *ap)
ahci_handle_port_interrupt(ap, port_mmio, status);
}

-irqreturn_t ahci_thread_fn(int irq, void *dev_instance)
+static irqreturn_t ahci_thread_fn(int irq, void *dev_instance)
{
struct ata_port *ap = dev_instance;
struct ahci_port_priv *pp = ap->private_data;
@@ -1809,7 +1809,6 @@ irqreturn_t ahci_thread_fn(int irq, void *dev_instance)

return IRQ_HANDLED;
}
-EXPORT_SYMBOL_GPL(ahci_thread_fn);

static void ahci_hw_port_interrupt(struct ata_port *ap)
{
@@ -1823,7 +1822,7 @@ static void ahci_hw_port_interrupt(struct ata_port *ap)
pp->intr_status |= status;
}

-irqreturn_t ahci_hw_interrupt(int irq, void *dev_instance)
+static irqreturn_t ahci_hw_interrupt(int irq, void *dev_instance)
{
struct ata_port *ap_this = dev_instance;
struct ahci_port_priv *pp = ap_this->private_data;
@@ -1877,9 +1876,8 @@ irqreturn_t ahci_hw_interrupt(int irq, void *dev_instance)

return IRQ_WAKE_THREAD;
}
-EXPORT_SYMBOL_GPL(ahci_hw_interrupt);

-irqreturn_t ahci_interrupt(int irq, void *dev_instance)
+static irqreturn_t ahci_interrupt(int irq, void *dev_instance)
{
struct ata_host *host = dev_instance;
struct ahci_host_priv *hpriv;
@@ -1938,7 +1936,6 @@ irqreturn_t ahci_interrupt(int irq, void *dev_instance)

return IRQ_RETVAL(handled);
}
-EXPORT_SYMBOL_GPL(ahci_interrupt);

unsigned int ahci_qc_issue(struct ata_queued_cmd *qc)
{
@@ -2472,6 +2469,81 @@ void ahci_set_em_messages(struct ahci_host_priv *hpriv,
}
EXPORT_SYMBOL_GPL(ahci_set_em_messages);

+static int ahci_host_activate_multi_irqs(struct ata_host *host, int irq,
+ struct scsi_host_template *sht)
+{
+ int i, rc;
+
+ rc = ata_host_start(host);
+ if (rc)
+ return rc;
+
+ for (i = 0; i < host->n_ports; i++) {
+ struct ahci_port_priv *pp = host->ports[i]->private_data;
+
+ /* Do not receive interrupts sent by dummy ports */
+ if (!pp) {
+ disable_irq(irq + i);
+ continue;
+ }
+
+ rc = devm_request_threaded_irq(host->dev, irq + i,
+ ahci_hw_interrupt,
+ ahci_thread_fn, IRQF_SHARED,
+ pp->irq_desc, host->ports[i]);
+ if (rc)
+ goto out_free_irqs;
+ }
+
+ for (i = 0; i < host->n_ports; i++)
+ ata_port_desc(host->ports[i], "irq %d", irq + i);
+
+ rc = ata_host_register(host, sht);
+ if (rc)
+ goto out_free_all_irqs;
+
+ return 0;
+
+out_free_all_irqs:
+ i = host->n_ports;
+out_free_irqs:
+ for (i--; i >= 0; i--)
+ devm_free_irq(host->dev, irq + i, host->ports[i]);
+
+ return rc;
+}
+
+/**
+ * ahci_host_activate - start AHCI host, request IRQs and register it
+ * @host: target ATA host
+ * @irq: base IRQ number to request
+ * @sht: scsi_host_template to use when registering the host
+ *
+ * Similar to ata_host_activate, but requests IRQs according to AHCI-1.1
+ * when multiple MSIs were allocated. That is one MSI per port, starting
+ * from @irq.
+ *
+ * LOCKING:
+ * Inherited from calling layer (may sleep).
+ *
+ * RETURNS:
+ * 0 on success, -errno otherwise.
+ */
+int ahci_host_activate(struct ata_host *host, int irq,
+ struct scsi_host_template *sht)
+{
+ struct ahci_host_priv *hpriv = host->private_data;
+ int rc;
+
+ if (hpriv->flags & AHCI_HFLAG_MULTI_MSI)
+ rc = ahci_host_activate_multi_irqs(host, irq, sht);
+ else
+ rc = ata_host_activate(host, irq, ahci_interrupt,
+ IRQF_SHARED, sht);
+ return rc;
+}
+EXPORT_SYMBOL_GPL(ahci_host_activate);
+
MODULE_AUTHOR("Jeff Garzik");
MODULE_DESCRIPTION("Common AHCI SATA low-level routines");
MODULE_LICENSE("GPL");
diff --git a/drivers/ata/libahci_platform.c b/drivers/ata/libahci_platform.c
index c7f787e..0b03f90 100644
--- a/drivers/ata/libahci_platform.c
+++ b/drivers/ata/libahci_platform.c
@@ -493,8 +493,7 @@ int ahci_platform_init_host(struct platform_device *pdev,
ahci_init_controller(host);
ahci_print_info(host, "platform");

- return ata_host_activate(host, irq, ahci_interrupt, IRQF_SHARED,
- &ahci_platform_sht);
+ return ahci_host_activate(host, irq, &ahci_platform_sht);
}
EXPORT_SYMBOL_GPL(ahci_platform_init_host);

diff --git a/drivers/ata/sata_highbank.c b/drivers/ata/sata_highbank.c
index da3bc27..ce2b99a 100644
--- a/drivers/ata/sata_highbank.c
+++ b/drivers/ata/sata_highbank.c
@@ -568,8 +568,7 @@ static int ahci_highbank_probe(struct platform_device *pdev)
ahci_init_controller(host);
ahci_print_info(host, "platform");

- rc = ata_host_activate(host, irq, ahci_interrupt, 0,
- &ahci_highbank_platform_sht);
+ rc = ahci_host_activate(host, irq, &ahci_highbank_platform_sht);
if (rc)
goto err0;
--
1.8.3.1

[Tejun Heo]

Post by Alexander Gordeev
Currently host activation done by calling either function
ahci_host_activate() or ata_host_activate(). Consolidate
the code by only calling ahci_host_activate() for all AHCI
devices.

I reverted 2-3. Can you please respin the patches so that code
movement is separate from other changes?

Thanks.

[Alexander Gordeev]

Signed-off-by: Alexander Gordeev <***@redhat.com>
Cc: linux-***@vger.kernel.org
---
drivers/ata/libahci.c | 16 ++++++++--------
1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/drivers/ata/libahci.c b/drivers/ata/libahci.c
index 0080551..48175e5 100644
--- a/drivers/ata/libahci.c
+++ b/drivers/ata/libahci.c
@@ -1789,7 +1789,7 @@ static void ahci_port_intr(struct ata_port *ap)
ahci_handle_port_interrupt(ap, port_mmio, status);
}

-static irqreturn_t ahci_thread_fn(int irq, void *dev_instance)
+static irqreturn_t ahci_port_thread_fn(int irq, void *dev_instance)
{
struct ata_port *ap = dev_instance;
struct ahci_port_priv *pp = ap->private_data;
@@ -1810,7 +1810,7 @@ static irqreturn_t ahci_thread_fn(int irq, void *dev_instance)
return IRQ_HANDLED;
}

-static void ahci_hw_port_interrupt(struct ata_port *ap)
+static void ahci_update_intr_status(struct ata_port *ap)
{
void __iomem *port_mmio = ahci_port_base(ap);
struct ahci_port_priv *pp = ap->private_data;
@@ -1822,7 +1822,7 @@ static void ahci_hw_port_interrupt(struct ata_port *ap)
pp->intr_status |= status;
}

-static irqreturn_t ahci_hw_interrupt(int irq, void *dev_instance)
+static irqreturn_t ahci_multi_irqs_intr(int irq, void *dev_instance)
{
struct ata_port *ap_this = dev_instance;
struct ahci_port_priv *pp = ap_this->private_data;
@@ -1858,7 +1858,7 @@ static irqreturn_t ahci_hw_interrupt(int irq, void *dev_instance)

ap = host->ports[i];
if (ap) {
- ahci_hw_port_interrupt(ap);
+ ahci_update_intr_status(ap);
VPRINTK("port %u\n", i);
} else {
VPRINTK("port %u (no irq)\n", i);
@@ -1877,7 +1877,7 @@ static irqreturn_t ahci_hw_interrupt(int irq, void *dev_instance)
return IRQ_WAKE_THREAD;
}

-static irqreturn_t ahci_interrupt(int irq, void *dev_instance)
+static irqreturn_t ahci_single_irq_intr(int irq, void *dev_instance)
{
struct ata_host *host = dev_instance;
struct ahci_host_priv *hpriv;
@@ -2488,8 +2488,8 @@ static int ahci_host_activate_multi_irqs(struct ata_host *host, int irq,
}

rc = devm_request_threaded_irq(host->dev, irq + i,
- ahci_hw_interrupt,
- ahci_thread_fn, IRQF_SHARED,
+ ahci_multi_irqs_intr,
+ ahci_port_thread_fn, IRQF_SHARED,
pp->irq_desc, host->ports[i]);
if (rc)
goto out_free_irqs;
@@ -2538,7 +2538,7 @@ int ahci_host_activate(struct ata_host *host, int irq,
if (hpriv->flags & AHCI_HFLAG_MULTI_MSI)
rc = ahci_host_activate_multi_irqs(host, irq, sht);
else
- rc = ata_host_activate(host, irq, ahci_interrupt,
+ rc = ata_host_activate(host, irq, ahci_single_irq_intr,
IRQF_SHARED, sht);
return rc;
}

[Tejun Heo]

Applied 1-3 to libata/for-3.18.

Thanks.

[Tejun Heo]

Hello, Alexander.

Post by Alexander Gordeev
@@ -1797,11 +1797,14 @@ static irqreturn_t ahci_port_thread_fn(int irq, void *dev_instance)
unsigned long flags;
u32 status;
- spin_lock_irqsave(&ap->host->lock, flags);
+ spin_lock_irqsave(&pp->intr_lock, flags);
status = pp->intr_status;
if (status)
pp->intr_status = 0;
- spin_unlock_irqrestore(&ap->host->lock, flags);
+ spin_unlock_irqrestore(&pp->intr_lock, flags);

atomic_xchg() prolly is a better option here.

Post by Alexander Gordeev
+
+ if (!status)
+ return IRQ_NONE;
spin_lock_bh(ap->lock);
ahci_handle_port_interrupt(ap, port_mmio, status);
@@ -1824,53 +1827,14 @@ static void ahci_update_intr_status(struct ata_port *ap)
static irqreturn_t ahci_multi_irqs_intr(int irq, void *dev_instance)
{

...

Post by Alexander Gordeev
+ spin_lock(&pp->intr_lock);
+ ahci_update_intr_status(ap);
+ spin_unlock(&pp->intr_lock);

and atomic_or() in update_intr_status.

Thanks.

[Alexander Gordeev]

As described in AHCI v1.0 specification chapter 10.6.2.2
"Multiple MSI Based Messages" generation of interrupts
is not controlled through the HOST_IRQ_STAT register.

Considering MMIO access is expensive remove unnecessary
reading and writing of HOST_IRQ_STAT register.

Further, serializing access to the host data is no longer
needed and the interrupt service routine can avoid competing
on the host lock.

Signed-off-by: Alexander Gordeev <***@redhat.com>
Suggested-by: "Jiang, Dave" <***@intel.com>
Cc: "Jiang, Dave" <***@intel.com>
Cc: linux-***@vger.kernel.org
---
drivers/ata/ahci.h | 2 +-
drivers/ata/libahci.c | 67 ++++++---------------------------------------------
2 files changed, 9 insertions(+), 60 deletions(-)

diff --git a/drivers/ata/ahci.h b/drivers/ata/ahci.h
index 6a22055..40f0e34 100644
--- a/drivers/ata/ahci.h
+++ b/drivers/ata/ahci.h
@@ -304,7 +304,7 @@ struct ahci_port_priv {
unsigned int ncq_saw_d2h:1;
unsigned int ncq_saw_dmas:1;
unsigned int ncq_saw_sdb:1;
- u32 intr_status; /* interrupts to handle */
+ atomic_t intr_status; /* interrupts to handle */
spinlock_t lock; /* protects parent ata_port */
u32 intr_mask; /* interrupts to enable */
bool fbs_supported; /* set iff FBS is supported */
diff --git a/drivers/ata/libahci.c b/drivers/ata/libahci.c
index 48175e5..97683e4 100644
--- a/drivers/ata/libahci.c
+++ b/drivers/ata/libahci.c
@@ -1794,14 +1794,11 @@ static irqreturn_t ahci_port_thread_fn(int irq, void *dev_instance)
struct ata_port *ap = dev_instance;
struct ahci_port_priv *pp = ap->private_data;
void __iomem *port_mmio = ahci_port_base(ap);
- unsigned long flags;
u32 status;

- spin_lock_irqsave(&ap->host->lock, flags);
- status = pp->intr_status;
- if (status)
- pp->intr_status = 0;
- spin_unlock_irqrestore(&ap->host->lock, flags);
+ status = atomic_xchg(&pp->intr_status, 0);
+ if (!status)
+ return IRQ_NONE;

spin_lock_bh(ap->lock);
ahci_handle_port_interrupt(ap, port_mmio, status);
@@ -1810,67 +1807,19 @@ static irqreturn_t ahci_port_thread_fn(int irq, void *dev_instance)
return IRQ_HANDLED;
}

-static void ahci_update_intr_status(struct ata_port *ap)
+static irqreturn_t ahci_multi_irqs_intr(int irq, void *dev_instance)
{
+ struct ata_port *ap = dev_instance;
void __iomem *port_mmio = ahci_port_base(ap);
struct ahci_port_priv *pp = ap->private_data;
u32 status;

- status = readl(port_mmio + PORT_IRQ_STAT);
- writel(status, port_mmio + PORT_IRQ_STAT);
-
- pp->intr_status |= status;
-}
-
-static irqreturn_t ahci_multi_irqs_intr(int irq, void *dev_instance)
-{
- struct ata_port *ap_this = dev_instance;
- struct ahci_port_priv *pp = ap_this->private_data;
- struct ata_host *host = ap_this->host;
- struct ahci_host_priv *hpriv = host->private_data;
- void __iomem *mmio = hpriv->mmio;
- unsigned int i;
- u32 irq_stat, irq_masked;
-
VPRINTK("ENTER\n");

- spin_lock(&host->lock);
-
- irq_stat = readl(mmio + HOST_IRQ_STAT);
-
- if (!irq_stat) {
- u32 status = pp->intr_status;
-
- spin_unlock(&host->lock);
-
- VPRINTK("EXIT\n");
-
- return status ? IRQ_WAKE_THREAD : IRQ_NONE;
- }
-
- irq_masked = irq_stat & hpriv->port_map;
-
- for (i = 0; i < host->n_ports; i++) {
- struct ata_port *ap;
-
- if (!(irq_masked & (1 << i)))
- continue;
-
- ap = host->ports[i];
- if (ap) {
- ahci_update_intr_status(ap);
- VPRINTK("port %u\n", i);
- } else {
- VPRINTK("port %u (no irq)\n", i);
- if (ata_ratelimit())
- dev_warn(host->dev,
- "interrupt on disabled port %u\n", i);
- }
- }
-
- writel(irq_stat, mmio + HOST_IRQ_STAT);
+ status = readl(port_mmio + PORT_IRQ_STAT);
+ writel(status, port_mmio + PORT_IRQ_STAT);

- spin_unlock(&host->lock);
+ atomic_or(status, &pp->intr_status);

VPRINTK("EXIT\n");
--
1.8.3.1