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dmaengine: idxd: remove interrupt disable for dev_lock
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The spinlock is not being used in hard interrupt context. There is no need
to disable irq when acquiring the lock. The interrupt thread handler also
is not in bottom half context, therefore we can also remove disabling of
the bh. Convert all dev_lock acquisition to plain spin_lock() calls.

Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Link: https://lore.kernel.org/r/162984026772.1939166.11504067782824765879.stgit@djiang5-desk3.ch.intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
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Dave Jiang authored and Vinod Koul committed Aug 29, 2021
1 parent f9f4082 commit cf84a4b
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Showing 4 changed files with 22 additions and 32 deletions.
5 changes: 2 additions & 3 deletions drivers/dma/idxd/cdev.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -218,14 +218,13 @@ static __poll_t idxd_cdev_poll(struct file *filp,
struct idxd_user_context *ctx = filp->private_data;
struct idxd_wq *wq = ctx->wq;
struct idxd_device *idxd = wq->idxd;
unsigned long flags;
__poll_t out = 0;

poll_wait(filp, &wq->err_queue, wait);
spin_lock_irqsave(&idxd->dev_lock, flags);
spin_lock(&idxd->dev_lock);
if (idxd->sw_err.valid)
out = EPOLLIN | EPOLLRDNORM;
spin_unlock_irqrestore(&idxd->dev_lock, flags);
spin_unlock(&idxd->dev_lock);

return out;
}
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31 changes: 12 additions & 19 deletions drivers/dma/idxd/device.c
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Original file line number Diff line number Diff line change
Expand Up @@ -341,19 +341,18 @@ int idxd_wq_set_pasid(struct idxd_wq *wq, int pasid)
int rc;
union wqcfg wqcfg;
unsigned int offset;
unsigned long flags;

rc = idxd_wq_disable(wq, false);
if (rc < 0)
return rc;

offset = WQCFG_OFFSET(idxd, wq->id, WQCFG_PASID_IDX);
spin_lock_irqsave(&idxd->dev_lock, flags);
spin_lock(&idxd->dev_lock);
wqcfg.bits[WQCFG_PASID_IDX] = ioread32(idxd->reg_base + offset);
wqcfg.pasid_en = 1;
wqcfg.pasid = pasid;
iowrite32(wqcfg.bits[WQCFG_PASID_IDX], idxd->reg_base + offset);
spin_unlock_irqrestore(&idxd->dev_lock, flags);
spin_unlock(&idxd->dev_lock);

rc = idxd_wq_enable(wq);
if (rc < 0)
Expand All @@ -368,19 +367,18 @@ int idxd_wq_disable_pasid(struct idxd_wq *wq)
int rc;
union wqcfg wqcfg;
unsigned int offset;
unsigned long flags;

rc = idxd_wq_disable(wq, false);
if (rc < 0)
return rc;

offset = WQCFG_OFFSET(idxd, wq->id, WQCFG_PASID_IDX);
spin_lock_irqsave(&idxd->dev_lock, flags);
spin_lock(&idxd->dev_lock);
wqcfg.bits[WQCFG_PASID_IDX] = ioread32(idxd->reg_base + offset);
wqcfg.pasid_en = 0;
wqcfg.pasid = 0;
iowrite32(wqcfg.bits[WQCFG_PASID_IDX], idxd->reg_base + offset);
spin_unlock_irqrestore(&idxd->dev_lock, flags);
spin_unlock(&idxd->dev_lock);

rc = idxd_wq_enable(wq);
if (rc < 0)
Expand Down Expand Up @@ -558,7 +556,6 @@ int idxd_device_disable(struct idxd_device *idxd)
{
struct device *dev = &idxd->pdev->dev;
u32 status;
unsigned long flags;

if (!idxd_is_enabled(idxd)) {
dev_dbg(dev, "Device is not enabled\n");
Expand All @@ -574,22 +571,20 @@ int idxd_device_disable(struct idxd_device *idxd)
return -ENXIO;
}

spin_lock_irqsave(&idxd->dev_lock, flags);
spin_lock(&idxd->dev_lock);
idxd_device_clear_state(idxd);
idxd->state = IDXD_DEV_DISABLED;
spin_unlock_irqrestore(&idxd->dev_lock, flags);
spin_unlock(&idxd->dev_lock);
return 0;
}

void idxd_device_reset(struct idxd_device *idxd)
{
unsigned long flags;

idxd_cmd_exec(idxd, IDXD_CMD_RESET_DEVICE, 0, NULL);
spin_lock_irqsave(&idxd->dev_lock, flags);
spin_lock(&idxd->dev_lock);
idxd_device_clear_state(idxd);
idxd->state = IDXD_DEV_DISABLED;
spin_unlock_irqrestore(&idxd->dev_lock, flags);
spin_unlock(&idxd->dev_lock);
}

void idxd_device_drain_pasid(struct idxd_device *idxd, int pasid)
Expand Down Expand Up @@ -1164,7 +1159,6 @@ int __drv_enable_wq(struct idxd_wq *wq)
{
struct idxd_device *idxd = wq->idxd;
struct device *dev = &idxd->pdev->dev;
unsigned long flags;
int rc = -ENXIO;

lockdep_assert_held(&wq->wq_lock);
Expand Down Expand Up @@ -1216,10 +1210,10 @@ int __drv_enable_wq(struct idxd_wq *wq)
}

rc = 0;
spin_lock_irqsave(&idxd->dev_lock, flags);
spin_lock(&idxd->dev_lock);
if (test_bit(IDXD_FLAG_CONFIGURABLE, &idxd->flags))
rc = idxd_device_config(idxd);
spin_unlock_irqrestore(&idxd->dev_lock, flags);
spin_unlock(&idxd->dev_lock);
if (rc < 0) {
dev_dbg(dev, "Writing wq %d config failed: %d\n", wq->id, rc);
goto err;
Expand Down Expand Up @@ -1288,7 +1282,6 @@ void drv_disable_wq(struct idxd_wq *wq)
int idxd_device_drv_probe(struct idxd_dev *idxd_dev)
{
struct idxd_device *idxd = idxd_dev_to_idxd(idxd_dev);
unsigned long flags;
int rc = 0;

/*
Expand All @@ -1302,10 +1295,10 @@ int idxd_device_drv_probe(struct idxd_dev *idxd_dev)
}

/* Device configuration */
spin_lock_irqsave(&idxd->dev_lock, flags);
spin_lock(&idxd->dev_lock);
if (test_bit(IDXD_FLAG_CONFIGURABLE, &idxd->flags))
rc = idxd_device_config(idxd);
spin_unlock_irqrestore(&idxd->dev_lock, flags);
spin_unlock(&idxd->dev_lock);
if (rc < 0)
return -ENXIO;

Expand Down
8 changes: 4 additions & 4 deletions drivers/dma/idxd/irq.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -64,7 +64,7 @@ static int process_misc_interrupts(struct idxd_device *idxd, u32 cause)
bool err = false;

if (cause & IDXD_INTC_ERR) {
spin_lock_bh(&idxd->dev_lock);
spin_lock(&idxd->dev_lock);
for (i = 0; i < 4; i++)
idxd->sw_err.bits[i] = ioread64(idxd->reg_base +
IDXD_SWERR_OFFSET + i * sizeof(u64));
Expand All @@ -89,7 +89,7 @@ static int process_misc_interrupts(struct idxd_device *idxd, u32 cause)
}
}

spin_unlock_bh(&idxd->dev_lock);
spin_unlock(&idxd->dev_lock);
val |= IDXD_INTC_ERR;

for (i = 0; i < 4; i++)
Expand Down Expand Up @@ -133,15 +133,15 @@ static int process_misc_interrupts(struct idxd_device *idxd, u32 cause)
INIT_WORK(&idxd->work, idxd_device_reinit);
queue_work(idxd->wq, &idxd->work);
} else {
spin_lock_bh(&idxd->dev_lock);
spin_lock(&idxd->dev_lock);
idxd_wqs_quiesce(idxd);
idxd_wqs_unmap_portal(idxd);
idxd_device_clear_state(idxd);
dev_err(&idxd->pdev->dev,
"idxd halted, need %s.\n",
gensts.reset_type == IDXD_DEVICE_RESET_FLR ?
"FLR" : "system reset");
spin_unlock_bh(&idxd->dev_lock);
spin_unlock(&idxd->dev_lock);
return -ENXIO;
}
}
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10 changes: 4 additions & 6 deletions drivers/dma/idxd/sysfs.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1099,16 +1099,15 @@ static ssize_t clients_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct idxd_device *idxd = confdev_to_idxd(dev);
unsigned long flags;
int count = 0, i;

spin_lock_irqsave(&idxd->dev_lock, flags);
spin_lock(&idxd->dev_lock);
for (i = 0; i < idxd->max_wqs; i++) {
struct idxd_wq *wq = idxd->wqs[i];

count += wq->client_count;
}
spin_unlock_irqrestore(&idxd->dev_lock, flags);
spin_unlock(&idxd->dev_lock);

return sysfs_emit(buf, "%d\n", count);
}
Expand Down Expand Up @@ -1146,12 +1145,11 @@ static ssize_t errors_show(struct device *dev,
{
struct idxd_device *idxd = confdev_to_idxd(dev);
int i, out = 0;
unsigned long flags;

spin_lock_irqsave(&idxd->dev_lock, flags);
spin_lock(&idxd->dev_lock);
for (i = 0; i < 4; i++)
out += sysfs_emit_at(buf, out, "%#018llx ", idxd->sw_err.bits[i]);
spin_unlock_irqrestore(&idxd->dev_lock, flags);
spin_unlock(&idxd->dev_lock);
out--;
out += sysfs_emit_at(buf, out, "\n");
return out;
Expand Down

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