Commit 03339dd1 authored by Guennadi Liakhovetski's avatar Guennadi Liakhovetski Committed by James Bottomley

[PATCH] tmscsim: host_lock use in LLD

While reviewing tmscsim, I noticed something, I didn't quite like /
understand. The driver takes the host_lock (with irqsave) at the entry to
the ISR, and releases it at the exit. And inside the ISR there are
potentially long busy-waits... Like

 	int ctr = 6000000; /* only try for about a second */
 	while( --ctr && !((dstate = DC390_read8 (DMA_Status)) &
 				DMA_XFER_DONE) && pSRB->SGToBeXferLen );

The attached patch is attempting to fix those places. Not sure if this is
a proper fix though. In my understanding, after looking through the code,
the host_lock is used to protect host-specific data and host-registers.
The ->queuecommand is already called with it help, so, one just,
basically, have to protect other contexts - interrupt, timer,... So, looks
mostly right.
Signed-off-by: default avatarJames Bottomley <James.Bottomley@SteelEye.com>
parent 679be37d
......@@ -227,7 +227,6 @@ DC390_Interrupt( int irq, void *dev_id, struct pt_regs *regs)
#if DMA_INT
UCHAR dstatus;
#endif
DC390_IFLAGS;
pACB = (PACB)dev_id;
for (pACB2 = dc390_pACB_start; (pACB2 && pACB2 != pACB); pACB2 = pACB2->pNextACB);
......@@ -244,9 +243,9 @@ DC390_Interrupt( int irq, void *dev_id, struct pt_regs *regs)
DEBUG1(printk (KERN_DEBUG "sstatus=%02x,", sstatus));
#if DMA_INT
DC390_LOCK_IO(pACB->pScsiHost);
spin_lock_irq(pACB->pScsiHost->host_lock);
dstatus = dc390_dma_intr (pACB);
DC390_UNLOCK_IO(pACB->pScsiHost);
spin_unlock_irq(pACB->pScsiHost->host_lock);
DEBUG1(printk (KERN_DEBUG "dstatus=%02x,", dstatus));
if (! (dstatus & SCSI_INTERRUPT))
......@@ -260,7 +259,7 @@ DC390_Interrupt( int irq, void *dev_id, struct pt_regs *regs)
//DC390_write32 (DMA_ScsiBusCtrl, EN_INT_ON_PCI_ABORT);
#endif
DC390_LOCK_IO(pACB->pScsiHost);
spin_lock_irq(pACB->pScsiHost->host_lock);
istate = DC390_read8 (Intern_State);
istatus = DC390_read8 (INT_Status); /* This clears Scsi_Status, Intern_State and INT_Status ! */
......@@ -328,11 +327,10 @@ DC390_Interrupt( int irq, void *dev_id, struct pt_regs *regs)
DEBUG1(printk (KERN_INFO "DC390: [%i]%s(1) (%02x)\n", phase, dc390_p1_str[phase], sstatus));
stateV = (void *) dc390_phase1[phase];
( *stateV )( pACB, pSRB, &sstatus );
goto unlock;
}
unlock:
DC390_UNLOCK_IO(pACB->pScsiHost);
spin_unlock_irq(pACB->pScsiHost->host_lock);
return IRQ_HANDLED;
}
......@@ -363,10 +361,20 @@ dc390_DataOut_0( PACB pACB, PSRB pSRB, PUCHAR psstatus)
if( sstatus & COUNT_2_ZERO )
{
int ctr = 6000000; /* only try for about a second */
while( --ctr && !((dstate = DC390_read8 (DMA_Status)) & DMA_XFER_DONE) && pSRB->SGToBeXferLen );
if (!ctr) printk (KERN_CRIT "DC390: Deadlock in DataOut_0: DMA aborted unfinished: %06x bytes remain!!\n", DC390_read32 (DMA_Wk_ByteCntr));
dc390_laststatus &= ~0xff000000; dc390_laststatus |= dstate << 24;
unsigned long timeout = jiffies + HZ;
/* Function called from the ISR with the host_lock held and interrupts disabled */
if (pSRB->SGToBeXferLen)
while (time_before(jiffies, timeout) && !((dstate = DC390_read8 (DMA_Status)) & DMA_XFER_DONE)) {
spin_unlock_irq(pACB->pScsiHost->host_lock);
udelay(50);
spin_lock_irq(pACB->pScsiHost->host_lock);
}
if (!time_before(jiffies, timeout))
printk (KERN_CRIT "DC390: Deadlock in DataOut_0: DMA aborted unfinished: %06x bytes remain!!\n",
DC390_read32 (DMA_Wk_ByteCntr));
dc390_laststatus &= ~0xff000000;
dc390_laststatus |= dstate << 24;
pSRB->TotalXferredLen += pSRB->SGToBeXferLen;
pSRB->SGIndex++;
if( pSRB->SGIndex < pSRB->SGcount )
......@@ -418,12 +426,23 @@ dc390_DataIn_0( PACB pACB, PSRB pSRB, PUCHAR psstatus)
if( sstatus & COUNT_2_ZERO )
{
int ctr = 6000000; /* only try for about a second */
int dstate = 0;
while( --ctr && !((dstate = DC390_read8 (DMA_Status)) & DMA_XFER_DONE) && pSRB->SGToBeXferLen );
if (!ctr) printk (KERN_CRIT "DC390: Deadlock in DataIn_0: DMA aborted unfinished: %06x bytes remain!!\n", DC390_read32 (DMA_Wk_ByteCntr));
if (!ctr) printk (KERN_CRIT "DC390: DataIn_0: DMA State: %i\n", dstate);
dc390_laststatus &= ~0xff000000; dc390_laststatus |= dstate << 24;
unsigned long timeout = jiffies + HZ;
/* Function called from the ISR with the host_lock held and interrupts disabled */
if (pSRB->SGToBeXferLen)
while (time_before(jiffies, timeout) && !((dstate = DC390_read8 (DMA_Status)) & DMA_XFER_DONE)) {
spin_unlock_irq(pACB->pScsiHost->host_lock);
udelay(50);
spin_lock_irq(pACB->pScsiHost->host_lock);
}
if (!time_before(jiffies, timeout)) {
printk (KERN_CRIT "DC390: Deadlock in DataIn_0: DMA aborted unfinished: %06x bytes remain!!\n",
DC390_read32 (DMA_Wk_ByteCntr));
printk (KERN_CRIT "DC390: DataIn_0: DMA State: %i\n", dstate);
}
dc390_laststatus &= ~0xff000000;
dc390_laststatus |= dstate << 24;
DEBUG1(ResidCnt = ((ULONG) DC390_read8 (CtcReg_High) << 16) \
+ ((ULONG) DC390_read8 (CtcReg_Mid) << 8) \
+ ((ULONG) DC390_read8 (CtcReg_Low)));
......@@ -1111,10 +1130,9 @@ dc390_Disconnect( PACB pACB )
pDCB = pACB->pActiveDCB;
if (!pDCB)
{
int j = 400;
DEBUG0(printk(KERN_ERR "ACB:%p->ActiveDCB:%p IOPort:%04x IRQ:%02x !\n",\
pACB, pDCB, pACB->IOPortBase, pACB->IRQLevel));
while (--j) udelay (1000);
mdelay(400);
DC390_read8 (INT_Status); /* Reset Pending INT */
DC390_write8 (ScsiCmd, EN_SEL_RESEL);
return;
......
......@@ -283,12 +283,6 @@ static struct pci_device_id tmscsim_pci_tbl[] = {
};
MODULE_DEVICE_TABLE(pci, tmscsim_pci_tbl);
#define USE_SPINLOCKS 1
#define DC390_IFLAGS unsigned long iflags
#define DC390_LOCK_IO(dev) spin_lock_irqsave (((struct Scsi_Host *)dev)->host_lock, iflags)
#define DC390_UNLOCK_IO(dev) spin_unlock_irqrestore (((struct Scsi_Host *)dev)->host_lock, iflags)
/* These macros are used for uniform access to 2.0.x and 2.1.x PCI config space*/
#define PDEV pdev
......@@ -863,11 +857,11 @@ static void dc390_Waiting_process ( PACB pACB )
static void DC390_waiting_timed_out (unsigned long ptr)
{
PACB pACB = (PACB)ptr;
DC390_IFLAGS;
unsigned long iflags;
DEBUG0(printk ("DC390: Debug: Waiting queue woken up by timer!\n"));
DC390_LOCK_IO(pACB->pScsiHost);
spin_lock_irqsave(pACB->pScsiHost->host_lock, iflags);
dc390_Waiting_process (pACB);
DC390_UNLOCK_IO(pACB->pScsiHost);
spin_unlock_irqrestore(pACB->pScsiHost->host_lock, iflags);
}
/***********************************************************************
......@@ -2026,12 +2020,12 @@ static int __devexit dc390_shutdown (struct Scsi_Host *host)
static void __devexit dc390_remove_one(struct pci_dev *dev)
{
struct Scsi_Host *scsi_host = pci_get_drvdata(dev);
DC390_IFLAGS;
unsigned long iflags;
PACB pACB = (PACB) scsi_host->hostdata;
scsi_remove_host(scsi_host);
DC390_LOCK_IO(scsi_host);
spin_lock_irqsave(scsi_host->host_lock, iflags);
/* TO DO: We should check for outstanding commands first. */
dc390_shutdown(scsi_host);
......@@ -2043,7 +2037,7 @@ static void __devexit dc390_remove_one(struct pci_dev *dev)
release_region(scsi_host->io_port, scsi_host->n_io_port);
dc390_freeDCBs(scsi_host);
DC390_UNLOCK_IO(scsi_host);
spin_unlock_irqrestore(scsi_host->host_lock, iflags);
pci_disable_device(dev);
scsi_host_put(scsi_host);
......
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