Tasklets have long been deprecated as being too heavy on the system
by running in irq context - and this is not a performance critical
path. If a higher priority process wants to run, it must wait for
the tasklet to finish before doing so. A more suitable equivalent
is to converted to threaded irq instead and do the ack sequence
in task context.
Cc: Kashyap Desai <kashyap.desai@xxxxxxxxxxxx>
Cc: Sumit Saxena <sumit.saxena@xxxxxxxxxxxx>
Cc: Shivasharan S <shivasharan.srikanteshwara@xxxxxxxxxxxx>
Cc: megaraidlinux.pdl@xxxxxxxxxxxx
Signed-off-by: Davidlohr Bueso <dave@xxxxxxxxxxxx>
---
drivers/scsi/megaraid/mega_common.h | 2 --
drivers/scsi/megaraid/megaraid_mbox.c | 52 ++++++++++-----------------
2 files changed, 19 insertions(+), 35 deletions(-)
diff --git a/drivers/scsi/megaraid/mega_common.h b/drivers/scsi/megaraid/mega_common.h
index 2ad0aa2f837d..3e56f74061b4 100644
--- a/drivers/scsi/megaraid/mega_common.h
+++ b/drivers/scsi/megaraid/mega_common.h
@@ -95,7 +95,6 @@ typedef struct {
/**
* struct adapter_t - driver's initialization structure
- * @aram dpc_h : tasklet handle
* @pdev : pci configuration pointer for kernel
* @host : pointer to host structure of mid-layer
* @lock : synchronization lock for mid-layer and driver
@@ -149,7 +148,6 @@ typedef struct {
#define VERSION_SIZE 16
typedef struct {
- struct tasklet_struct dpc_h;
struct pci_dev *pdev;
struct Scsi_Host *host;
spinlock_t lock;
diff --git a/drivers/scsi/megaraid/megaraid_mbox.c b/drivers/scsi/megaraid/megaraid_mbox.c
index 2a339d4a7e9d..b76f67887592 100644
--- a/drivers/scsi/megaraid/megaraid_mbox.c
+++ b/drivers/scsi/megaraid/megaraid_mbox.c
@@ -118,8 +118,7 @@ static void megaraid_mbox_prepare_epthru(adapter_t *, scb_t *,
struct scsi_cmnd *);
static irqreturn_t megaraid_isr(int, void *);
-
-static void megaraid_mbox_dpc(unsigned long);
+static irqreturn_t megaraid_mbox_dpc(int, void *);
static ssize_t megaraid_mbox_app_hndl_show(struct device *, struct device_attribute *attr, char *);
static ssize_t megaraid_mbox_ld_show(struct device *, struct device_attribute *attr, char *);
@@ -764,9 +763,8 @@ megaraid_init_mbox(adapter_t *adapter)
*/
/* request IRQ and register the interrupt service routine */
- if (request_irq(adapter->irq, megaraid_isr, IRQF_SHARED, "megaraid",
- adapter)) {
-
+ if (request_threaded_irq(adapter->irq, megaraid_isr, megaraid_mbox_dpc,
+ IRQF_SHARED, "megaraid", adapter)) {
con_log(CL_ANN, (KERN_WARNING
"megaraid: Couldn't register IRQ %d!\n", adapter->irq));
goto out_alloc_cmds;
@@ -879,10 +877,6 @@ megaraid_init_mbox(adapter_t *adapter)
}
}
- // setup tasklet for DPC
- tasklet_init(&adapter->dpc_h, megaraid_mbox_dpc,
- (unsigned long)adapter);
-
con_log(CL_DLEVEL1, (KERN_INFO
"megaraid mbox hba successfully initialized\n"));
@@ -917,8 +911,6 @@ megaraid_fini_mbox(adapter_t *adapter)
// flush all caches
megaraid_mbox_flush_cache(adapter);
- tasklet_kill(&adapter->dpc_h);
-
megaraid_sysfs_free_resources(adapter);
megaraid_free_cmd_packets(adapter);
@@ -2027,7 +2019,7 @@ megaraid_mbox_prepare_epthru(adapter_t *adapter, scb_t *scb,
*
* Returns: 1 if the interrupt is valid, 0 otherwise
*/
-static int
+static irqreturn_t
megaraid_ack_sequence(adapter_t *adapter)
{
mraid_device_t *raid_dev = ADAP2RAIDDEV(adapter);
@@ -2036,7 +2028,7 @@ megaraid_ack_sequence(adapter_t *adapter)
uint8_t nstatus;
uint8_t completed[MBOX_MAX_FIRMWARE_STATUS];
struct list_head clist;
- int handled;
+ int ret = IRQ_NONE;
uint32_t dword;
unsigned long flags;
int i, j;
@@ -2048,7 +2040,6 @@ megaraid_ack_sequence(adapter_t *adapter)
INIT_LIST_HEAD(&clist);
// loop till F/W has more commands for us to complete
- handled = 0;
spin_lock_irqsave(MAILBOX_LOCK(raid_dev), flags);
do {
/*
@@ -2056,9 +2047,10 @@ megaraid_ack_sequence(adapter_t *adapter)
* interrupt line low.
*/
dword = RDOUTDOOR(raid_dev);
- if (dword != 0x10001234) break;
+ if (dword != 0x10001234)
+ break;
- handled = 1;
+ ret = IRQ_WAKE_THREAD;
WROUTDOOR(raid_dev, 0x10001234);
@@ -2124,12 +2116,7 @@ megaraid_ack_sequence(adapter_t *adapter)
spin_unlock_irqrestore(COMPLETED_LIST_LOCK(adapter), flags);
-
- // schedule the DPC if there is some work for it
- if (handled)
- tasklet_schedule(&adapter->dpc_h);
-
- return handled;
+ return ret;
}
@@ -2144,29 +2131,27 @@ static irqreturn_t
megaraid_isr(int irq, void *devp)
{
adapter_t *adapter = devp;
- int handled;
+ int ret;
- handled = megaraid_ack_sequence(adapter);
+ ret = megaraid_ack_sequence(adapter);
/* Loop through any pending requests */
if (!adapter->quiescent) {
megaraid_mbox_runpendq(adapter, NULL);
}
- return IRQ_RETVAL(handled);
+ return ret;
}
/**
- * megaraid_mbox_dpc - the tasklet to complete the commands from completed list
- * @devp : pointer to HBA soft state
+ * megaraid_mbox_dpc - complete the commands from completed list
*
* Pick up the commands from the completed list and send back to the owners.
* This is a reentrant function and does not assume any locks are held while
- * it is being called.
+ * it is being called. Runs in process context.
*/
-static void
-megaraid_mbox_dpc(unsigned long devp)
+static irqreturn_t megaraid_mbox_dpc(int irq, void *devp)
{
adapter_t *adapter = (adapter_t *)devp;
mraid_device_t *raid_dev;
@@ -2188,7 +2173,8 @@ megaraid_mbox_dpc(unsigned long devp)
uioc_t *kioc;
- if (!adapter) return;
+ if (!adapter)
+ goto done;
raid_dev = ADAP2RAIDDEV(adapter);
@@ -2361,8 +2347,8 @@ megaraid_mbox_dpc(unsigned long devp)
// send the scsi packet back to kernel
scsi_done(scp);
}
-
- return;
+done:
+ return IRQ_HANDLED;
}
--
2.36.1
