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Message-ID: <1410755647.4764.60.camel@Centos6.3-64>
Date: Mon, 15 Sep 2014 12:34:07 +0800
From: Ching Huang <ching2048@...ca.com.tw>
To: Tomas Henzl <thenzl@...hat.com>
Cc: hch@...radead.org, jbottomley@...allels.com,
dan.carpenter@...cle.com, agordeev@...hat.com,
linux-scsi@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v4 2/2] arcmsr: simplify of updating doneq_index and
postq_index
On Fri, 2014-09-12 at 16:05 +0200, Tomas Henzl wrote:
> On 09/12/2014 10:22 AM, Ching Huang wrote:
> > From: Ching Huang <ching2048@...ca.com.tw>
> >
> > This patch is to modify previous patch 16/17 and it is relative to
> > http://git.infradead.org/users/hch/scsi-queue.git/tree/arcmsr-for-3.18:/drivers/scsi/arcmsr
> >
> > change in v4:
> > 1. clean up of duplicate variable declaration in switch.
> > 2. simplify of updating doneq_index and postq_index
> > 3. fix spin_lock area in arcmsr_hbaD_polling_ccbdone
>
> The intention of the doneq_lock is to protect the pmu->doneq_index and the associated buffer,
> right? Why is the spinlock not used on other places accessing the doneq_index
> like arcmsr_done4abort_postqueue or arcmsr_hbaD_postqueue_isr ?
In fact, in original code arcmsr_hbaD_postqueue_isr has spinlock with a larger area.
As to arcmsr_done4abort_postqueue, it should be protected as below.
@@ -1182,35 +1178,25 @@ static void arcmsr_done4abort_postqueue(
break;
case ACB_ADAPTER_TYPE_D: {
struct MessageUnit_D *pmu = acb->pmuD;
- uint32_t ccb_cdb_phy, outbound_write_pointer;
- uint32_t doneq_index, index_stripped, addressLow, residual;
- bool error;
- struct CommandControlBlock *pCCB;
+ uint32_t outbound_write_pointer;
+ uint32_t doneq_index, index_stripped, addressLow, residual, toggle;
+ unsigned long flags;
- outbound_write_pointer = pmu->done_qbuffer[0].addressLow + 1;
- doneq_index = pmu->doneq_index;
residual = atomic_read(&acb->ccboutstandingcount);
for (i = 0; i < residual; i++) {
- while ((doneq_index & 0xFFF) !=
+ spin_lock_irqsave(&acb->doneq_lock, flags);
+ outbound_write_pointer =
+ pmu->done_qbuffer[0].addressLow + 1;
+ doneq_index = pmu->doneq_index;
+ if ((doneq_index & 0xFFF) !=
(outbound_write_pointer & 0xFFF)) {
- if (doneq_index & 0x4000) {
- index_stripped = doneq_index & 0xFFF;
- index_stripped += 1;
- index_stripped %=
- ARCMSR_MAX_ARC1214_DONEQUEUE;
- pmu->doneq_index = index_stripped ?
- (index_stripped | 0x4000) :
- (index_stripped + 1);
- } else {
- index_stripped = doneq_index;
- index_stripped += 1;
- index_stripped %=
- ARCMSR_MAX_ARC1214_DONEQUEUE;
- pmu->doneq_index = index_stripped ?
- index_stripped :
- ((index_stripped | 0x4000) + 1);
- }
+ toggle = doneq_index & 0x4000;
+ index_stripped = (doneq_index & 0xFFF) + 1;
+ index_stripped %= ARCMSR_MAX_ARC1214_DONEQUEUE;
+ pmu->doneq_index = index_stripped ? (index_stripped | toggle) :
+ ((toggle ^ 0x4000) + 1);
doneq_index = pmu->doneq_index;
+ spin_unlock_irqrestore(&acb->doneq_lock, flags);
addressLow = pmu->done_qbuffer[doneq_index &
0xFFF].addressLow;
ccb_cdb_phy = (addressLow & 0xFFFFFFF0);
@@ -1224,11 +1210,10 @@ static void arcmsr_done4abort_postqueue(
arcmsr_drain_donequeue(acb, pCCB, error);
writel(doneq_index,
pmu->outboundlist_read_pointer);
+ } else {
+ spin_unlock_irqrestore(&acb->doneq_lock, flags);
+ mdelay(10);
}
- mdelay(10);
- outbound_write_pointer =
- pmu->done_qbuffer[0].addressLow + 1;
- doneq_index = pmu->doneq_index;
}
pmu->postq_index = 0;
pmu->doneq_index = 0x40FF;
> And in arcmsr_hbaD_polling_ccbdone the code looks so:
>
> spin_unlock_irqrestore(&acb->doneq_lock, flags);
> doneq_index = pmu->doneq_index;
> flag_ccb = pmu->done_qbuffer[doneq_index & 0xFFF].addressLow;
> you unlock^ and after that is the value read and used
> Seems to me that I probably don't understand what the spinlock should protect.
> Could you explain ?
You are right. above code should change to
doneq_index = pmu->doneq_index;
spin_unlock_irqrestore(&acb->doneq_lock, flags);
flag_ccb = pmu->done_qbuffer[doneq_index & 0xFFF].addressLow;
> Thanks,
> Tomas
>
>
>
> >
> > Signed-off-by: Ching Huang <ching2048@...ca.com.tw>
> > ---
> >
> > diff -uprN a/drivers/scsi/arcmsr/arcmsr_hba.c b/drivers/scsi/arcmsr/arcmsr_hba.c
> > --- a/drivers/scsi/arcmsr/arcmsr_hba.c 2014-09-12 12:43:16.956653000 +0800
> > +++ b/drivers/scsi/arcmsr/arcmsr_hba.c 2014-09-12 15:00:23.516069000 +0800
> > @@ -1121,7 +1121,7 @@ static void arcmsr_drain_donequeue(struc
> > static void arcmsr_done4abort_postqueue(struct AdapterControlBlock *acb)
> > {
> > int i = 0;
> > - uint32_t flag_ccb;
> > + uint32_t flag_ccb, ccb_cdb_phy;
> > struct ARCMSR_CDB *pARCMSR_CDB;
> > bool error;
> > struct CommandControlBlock *pCCB;
> > @@ -1165,10 +1165,6 @@ static void arcmsr_done4abort_postqueue(
> > break;
> > case ACB_ADAPTER_TYPE_C: {
> > struct MessageUnit_C __iomem *reg = acb->pmuC;
> > - struct ARCMSR_CDB *pARCMSR_CDB;
> > - uint32_t flag_ccb, ccb_cdb_phy;
> > - bool error;
> > - struct CommandControlBlock *pCCB;
> > while ((readl(®->host_int_status) & ARCMSR_HBCMU_OUTBOUND_POSTQUEUE_ISR) && (i++ < ARCMSR_MAX_OUTSTANDING_CMD)) {
> > /*need to do*/
> > flag_ccb = readl(®->outbound_queueport_low);
> > @@ -1182,10 +1178,8 @@ static void arcmsr_done4abort_postqueue(
> > break;
> > case ACB_ADAPTER_TYPE_D: {
> > struct MessageUnit_D *pmu = acb->pmuD;
> > - uint32_t ccb_cdb_phy, outbound_write_pointer;
> > - uint32_t doneq_index, index_stripped, addressLow, residual;
> > - bool error;
> > - struct CommandControlBlock *pCCB;
> > + uint32_t outbound_write_pointer;
> > + uint32_t doneq_index, index_stripped, addressLow, residual, toggle;
> >
> > outbound_write_pointer = pmu->done_qbuffer[0].addressLow + 1;
> > doneq_index = pmu->doneq_index;
> > @@ -1193,23 +1187,11 @@ static void arcmsr_done4abort_postqueue(
> > for (i = 0; i < residual; i++) {
> > while ((doneq_index & 0xFFF) !=
> > (outbound_write_pointer & 0xFFF)) {
> > - if (doneq_index & 0x4000) {
> > - index_stripped = doneq_index & 0xFFF;
> > - index_stripped += 1;
> > - index_stripped %=
> > - ARCMSR_MAX_ARC1214_DONEQUEUE;
> > - pmu->doneq_index = index_stripped ?
> > - (index_stripped | 0x4000) :
> > - (index_stripped + 1);
> > - } else {
> > - index_stripped = doneq_index;
> > - index_stripped += 1;
> > - index_stripped %=
> > - ARCMSR_MAX_ARC1214_DONEQUEUE;
> > - pmu->doneq_index = index_stripped ?
> > - index_stripped :
> > - ((index_stripped | 0x4000) + 1);
> > - }
> > + toggle = doneq_index & 0x4000;
> > + index_stripped = (doneq_index & 0xFFF) + 1;
> > + index_stripped %= ARCMSR_MAX_ARC1214_DONEQUEUE;
> > + pmu->doneq_index = index_stripped ? (index_stripped | toggle) :
> > + ((toggle ^ 0x4000) + 1);
> > doneq_index = pmu->doneq_index;
> > addressLow = pmu->done_qbuffer[doneq_index &
> > 0xFFF].addressLow;
> > @@ -1461,7 +1443,7 @@ static void arcmsr_post_ccb(struct Adapt
> > case ACB_ADAPTER_TYPE_D: {
> > struct MessageUnit_D *pmu = acb->pmuD;
> > u16 index_stripped;
> > - u16 postq_index;
> > + u16 postq_index, toggle;
> > unsigned long flags;
> > struct InBound_SRB *pinbound_srb;
> >
> > @@ -1472,19 +1454,11 @@ static void arcmsr_post_ccb(struct Adapt
> > pinbound_srb->addressLow = dma_addr_lo32(cdb_phyaddr);
> > pinbound_srb->length = ccb->arc_cdb_size >> 2;
> > arcmsr_cdb->msgContext = dma_addr_lo32(cdb_phyaddr);
> > - if (postq_index & 0x4000) {
> > - index_stripped = postq_index & 0xFF;
> > - index_stripped += 1;
> > - index_stripped %= ARCMSR_MAX_ARC1214_POSTQUEUE;
> > - pmu->postq_index = index_stripped ?
> > - (index_stripped | 0x4000) : index_stripped;
> > - } else {
> > - index_stripped = postq_index;
> > - index_stripped += 1;
> > - index_stripped %= ARCMSR_MAX_ARC1214_POSTQUEUE;
> > - pmu->postq_index = index_stripped ? index_stripped :
> > - (index_stripped | 0x4000);
> > - }
> > + toggle = postq_index & 0x4000;
> > + index_stripped = postq_index + 1;
> > + index_stripped &= (ARCMSR_MAX_ARC1214_POSTQUEUE - 1);
> > + pmu->postq_index = index_stripped ? (index_stripped | toggle) :
> > + (toggle ^ 0x4000);
> > writel(postq_index, pmu->inboundlist_write_pointer);
> > spin_unlock_irqrestore(&acb->postq_lock, flags);
> > break;
> > @@ -1999,7 +1973,7 @@ static void arcmsr_hbaC_postqueue_isr(st
> >
> > static void arcmsr_hbaD_postqueue_isr(struct AdapterControlBlock *acb)
> > {
> > - u32 outbound_write_pointer, doneq_index, index_stripped;
> > + u32 outbound_write_pointer, doneq_index, index_stripped, toggle;
> > uint32_t addressLow, ccb_cdb_phy;
> > int error;
> > struct MessageUnit_D *pmu;
> > @@ -2013,21 +1987,11 @@ static void arcmsr_hbaD_postqueue_isr(st
> > doneq_index = pmu->doneq_index;
> > if ((doneq_index & 0xFFF) != (outbound_write_pointer & 0xFFF)) {
> > do {
> > - if (doneq_index & 0x4000) {
> > - index_stripped = doneq_index & 0xFFF;
> > - index_stripped += 1;
> > - index_stripped %= ARCMSR_MAX_ARC1214_DONEQUEUE;
> > - pmu->doneq_index = index_stripped
> > - ? (index_stripped | 0x4000) :
> > - (index_stripped + 1);
> > - } else {
> > - index_stripped = doneq_index;
> > - index_stripped += 1;
> > - index_stripped %= ARCMSR_MAX_ARC1214_DONEQUEUE;
> > - pmu->doneq_index = index_stripped
> > - ? index_stripped :
> > - ((index_stripped | 0x4000) + 1);
> > - }
> > + toggle = doneq_index & 0x4000;
> > + index_stripped = (doneq_index & 0xFFF) + 1;
> > + index_stripped %= ARCMSR_MAX_ARC1214_DONEQUEUE;
> > + pmu->doneq_index = index_stripped ? (index_stripped | toggle) :
> > + ((toggle ^ 0x4000) + 1);
> > doneq_index = pmu->doneq_index;
> > addressLow = pmu->done_qbuffer[doneq_index &
> > 0xFFF].addressLow;
> > @@ -2843,7 +2807,7 @@ static bool arcmsr_hbaD_get_config(struc
> > char __iomem *iop_firm_version;
> > char __iomem *iop_device_map;
> > u32 count;
> > - struct MessageUnit_D *reg ;
> > + struct MessageUnit_D *reg;
> > void *dma_coherent2;
> > dma_addr_t dma_coherent_handle2;
> > struct pci_dev *pdev = acb->pdev;
> > @@ -3176,7 +3140,7 @@ static int arcmsr_hbaD_polling_ccbdone(s
> > {
> > bool error;
> > uint32_t poll_ccb_done = 0, poll_count = 0, flag_ccb, ccb_cdb_phy;
> > - int rtn, doneq_index, index_stripped, outbound_write_pointer;
> > + int rtn, doneq_index, index_stripped, outbound_write_pointer, toggle;
> > unsigned long flags;
> > struct ARCMSR_CDB *arcmsr_cdb;
> > struct CommandControlBlock *pCCB;
> > @@ -3185,9 +3149,11 @@ static int arcmsr_hbaD_polling_ccbdone(s
> > polling_hbaD_ccb_retry:
> > poll_count++;
> > while (1) {
> > + spin_lock_irqsave(&acb->doneq_lock, flags);
> > outbound_write_pointer = pmu->done_qbuffer[0].addressLow + 1;
> > doneq_index = pmu->doneq_index;
> > if ((outbound_write_pointer & 0xFFF) == (doneq_index & 0xFFF)) {
> > + spin_unlock_irqrestore(&acb->doneq_lock, flags);
> > if (poll_ccb_done) {
> > rtn = SUCCESS;
> > break;
> > @@ -3200,21 +3166,11 @@ polling_hbaD_ccb_retry:
> > goto polling_hbaD_ccb_retry;
> > }
> > }
> > - spin_lock_irqsave(&acb->doneq_lock, flags);
> > - if (doneq_index & 0x4000) {
> > - index_stripped = doneq_index & 0xFFF;
> > - index_stripped += 1;
> > - index_stripped %= ARCMSR_MAX_ARC1214_DONEQUEUE;
> > - pmu->doneq_index = index_stripped ?
> > - (index_stripped | 0x4000) :
> > - (index_stripped + 1);
> > - } else {
> > - index_stripped = doneq_index;
> > - index_stripped += 1;
> > - index_stripped %= ARCMSR_MAX_ARC1214_DONEQUEUE;
> > - pmu->doneq_index = index_stripped ? index_stripped :
> > - ((index_stripped | 0x4000) + 1);
> > - }
> > + toggle = doneq_index & 0x4000;
> > + index_stripped = (doneq_index & 0xFFF) + 1;
> > + index_stripped %= ARCMSR_MAX_ARC1214_DONEQUEUE;
> > + pmu->doneq_index = index_stripped ? (index_stripped | toggle) :
> > + ((toggle ^ 0x4000) + 1);
> > spin_unlock_irqrestore(&acb->doneq_lock, flags);
> > doneq_index = pmu->doneq_index;
> > flag_ccb = pmu->done_qbuffer[doneq_index & 0xFFF].addressLow;
> >
> >
> > --
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