| Message ID | 1d1054de-8b47-a6bb-a264-8456705e5875@gmail.com |
|---|---|
| State | Accepted |
| Commit | 1de93d5d521717cbb77cc9796a4df141d800d608 |
| Headers | show |
| Series | i2c: i801: Replace waitqueue with completion API | expand |
Hi Heiner, Adding Daniel Kurtz, who wrote the original wait queue-based code, to Cc. I'm not sure if Daniel is still into kernel code though. On Sat, 22 May 2021 00:02:43 +0200, Heiner Kallweit wrote: > Using the completion API is more intuitive and it allows to simplify > the code. Note that we don't have to set priv->status = 0 any longer > with the completion API. OK, but you need to call reinit_completion() instead, which has the same cost. So that's not a good argument ;-) > Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com> > --- > drivers/i2c/busses/i2c-i801.c | 48 ++++++++++++++--------------------- > 1 file changed, 19 insertions(+), 29 deletions(-) > > diff --git a/drivers/i2c/busses/i2c-i801.c b/drivers/i2c/busses/i2c-i801.c > index bfea94d02..738204d77 100644 > --- a/drivers/i2c/busses/i2c-i801.c > +++ b/drivers/i2c/busses/i2c-i801.c > @@ -103,7 +103,7 @@ > #include <linux/dmi.h> > #include <linux/slab.h> > #include <linux/string.h> > -#include <linux/wait.h> > +#include <linux/completion.h> > #include <linux/err.h> > #include <linux/platform_device.h> > #include <linux/platform_data/itco_wdt.h> > @@ -270,7 +270,7 @@ struct i801_priv { > unsigned int features; > > /* isr processing */ > - wait_queue_head_t waitq; > + struct completion done; > u8 status; > > /* Command state used by isr for byte-by-byte block transactions */ > @@ -496,24 +496,19 @@ static int i801_wait_byte_done(struct i801_priv *priv) > static int i801_transaction(struct i801_priv *priv, int xact) > { > int status; > - int result; > + unsigned long result; > const struct i2c_adapter *adap = &priv->adapter; > > - result = i801_check_pre(priv); > - if (result < 0) > - return result; > + status = i801_check_pre(priv); > + if (status < 0) > + return status; > > if (priv->features & FEATURE_IRQ) { > + reinit_completion(&priv->done); > outb_p(xact | SMBHSTCNT_INTREN | SMBHSTCNT_START, > SMBHSTCNT(priv)); > - result = wait_event_timeout(priv->waitq, > - (status = priv->status), > - adap->timeout); > - if (!result) > - status = -ETIMEDOUT; > - > - priv->status = 0; > - return i801_check_post(priv, status); > + result = wait_for_completion_timeout(&priv->done, adap->timeout); > + return i801_check_post(priv, result ? priv->status : -ETIMEDOUT); > } > > /* the current contents of SMBHSTCNT can be overwritten, since PEC, > @@ -638,7 +633,7 @@ static irqreturn_t i801_host_notify_isr(struct i801_priv *priv) > * DEV_ERR - Invalid command, NAK or communication timeout > * BUS_ERR - SMI# transaction collision > * FAILED - transaction was canceled due to a KILL request > - * When any of these occur, update ->status and wake up the waitq. > + * When any of these occur, update ->status and signal completion. > * ->status must be cleared before kicking off the next transaction. > * > * 2) For byte-by-byte (I2C read/write) transactions, one BYTE_DONE interrupt > @@ -675,7 +670,7 @@ static irqreturn_t i801_isr(int irq, void *dev_id) > if (status) { > outb_p(status, SMBHSTSTS(priv)); > priv->status = status; > - wake_up(&priv->waitq); > + complete(&priv->done); > } > > return IRQ_HANDLED; > @@ -694,15 +689,15 @@ static int i801_block_transaction_byte_by_byte(struct i801_priv *priv, > int i, len; > int smbcmd; > int status; > - int result; > + unsigned long result; > const struct i2c_adapter *adap = &priv->adapter; > > if (command == I2C_SMBUS_BLOCK_PROC_CALL) > return -EOPNOTSUPP; > > - result = i801_check_pre(priv); > - if (result < 0) > - return result; > + status = i801_check_pre(priv); > + if (status < 0) > + return status; > > len = data->block[0]; > > @@ -726,15 +721,10 @@ static int i801_block_transaction_byte_by_byte(struct i801_priv *priv, > priv->count = 0; > priv->data = &data->block[1]; > > + reinit_completion(&priv->done); > outb_p(priv->cmd | SMBHSTCNT_START, SMBHSTCNT(priv)); > - result = wait_event_timeout(priv->waitq, > - (status = priv->status), > - adap->timeout); > - if (!result) > - status = -ETIMEDOUT; > - > - priv->status = 0; > - return i801_check_post(priv, status); > + result = wait_for_completion_timeout(&priv->done, adap->timeout); > + return i801_check_post(priv, result ? priv->status : -ETIMEDOUT); > } > > for (i = 1; i <= len; i++) { > @@ -1889,7 +1879,7 @@ static int i801_probe(struct pci_dev *dev, const struct pci_device_id *id) > } > > if (priv->features & FEATURE_IRQ) { > - init_waitqueue_head(&priv->waitq); > + init_completion(&priv->done); > > err = devm_request_irq(&dev->dev, dev->irq, i801_isr, > IRQF_SHARED, The clean-up isn't massive but I agree the code is a bit more pleasant to read after the change, and I also see the binary size shrink a bit, so I vote for it. Reviewed-by: Jean Delvare <jdelvare@suse.de> Tested-by: Jean Delvare <jdelvare@suse.de> -- Jean Delvare SUSE L3 Support
On 25.05.2021 14:12, Jean Delvare wrote: > Hi Heiner, > > Adding Daniel Kurtz, who wrote the original wait queue-based code, to > Cc. I'm not sure if Daniel is still into kernel code though. > > On Sat, 22 May 2021 00:02:43 +0200, Heiner Kallweit wrote: >> Using the completion API is more intuitive and it allows to simplify >> the code. Note that we don't have to set priv->status = 0 any longer >> with the completion API. > > OK, but you need to call reinit_completion() instead, which has the > same cost. So that's not a good argument ;-) > Maybe my comment wasn't clear enough. I didn't want to say that we save something but that it's safe from a functional point of view to remove clearing priv->status. >> Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com> >> --- >> drivers/i2c/busses/i2c-i801.c | 48 ++++++++++++++--------------------- >> 1 file changed, 19 insertions(+), 29 deletions(-) >> >> diff --git a/drivers/i2c/busses/i2c-i801.c b/drivers/i2c/busses/i2c-i801.c >> index bfea94d02..738204d77 100644 >> --- a/drivers/i2c/busses/i2c-i801.c >> +++ b/drivers/i2c/busses/i2c-i801.c >> @@ -103,7 +103,7 @@ >> #include <linux/dmi.h> >> #include <linux/slab.h> >> #include <linux/string.h> >> -#include <linux/wait.h> >> +#include <linux/completion.h> >> #include <linux/err.h> >> #include <linux/platform_device.h> >> #include <linux/platform_data/itco_wdt.h> >> @@ -270,7 +270,7 @@ struct i801_priv { >> unsigned int features; >> >> /* isr processing */ >> - wait_queue_head_t waitq; >> + struct completion done; >> u8 status; >> >> /* Command state used by isr for byte-by-byte block transactions */ >> @@ -496,24 +496,19 @@ static int i801_wait_byte_done(struct i801_priv *priv) >> static int i801_transaction(struct i801_priv *priv, int xact) >> { >> int status; >> - int result; >> + unsigned long result; >> const struct i2c_adapter *adap = &priv->adapter; >> >> - result = i801_check_pre(priv); >> - if (result < 0) >> - return result; >> + status = i801_check_pre(priv); >> + if (status < 0) >> + return status; >> >> if (priv->features & FEATURE_IRQ) { >> + reinit_completion(&priv->done); >> outb_p(xact | SMBHSTCNT_INTREN | SMBHSTCNT_START, >> SMBHSTCNT(priv)); >> - result = wait_event_timeout(priv->waitq, >> - (status = priv->status), >> - adap->timeout); >> - if (!result) >> - status = -ETIMEDOUT; >> - >> - priv->status = 0; >> - return i801_check_post(priv, status); >> + result = wait_for_completion_timeout(&priv->done, adap->timeout); >> + return i801_check_post(priv, result ? priv->status : -ETIMEDOUT); >> } >> >> /* the current contents of SMBHSTCNT can be overwritten, since PEC, >> @@ -638,7 +633,7 @@ static irqreturn_t i801_host_notify_isr(struct i801_priv *priv) >> * DEV_ERR - Invalid command, NAK or communication timeout >> * BUS_ERR - SMI# transaction collision >> * FAILED - transaction was canceled due to a KILL request >> - * When any of these occur, update ->status and wake up the waitq. >> + * When any of these occur, update ->status and signal completion. >> * ->status must be cleared before kicking off the next transaction. >> * >> * 2) For byte-by-byte (I2C read/write) transactions, one BYTE_DONE interrupt >> @@ -675,7 +670,7 @@ static irqreturn_t i801_isr(int irq, void *dev_id) >> if (status) { >> outb_p(status, SMBHSTSTS(priv)); >> priv->status = status; >> - wake_up(&priv->waitq); >> + complete(&priv->done); >> } >> >> return IRQ_HANDLED; >> @@ -694,15 +689,15 @@ static int i801_block_transaction_byte_by_byte(struct i801_priv *priv, >> int i, len; >> int smbcmd; >> int status; >> - int result; >> + unsigned long result; >> const struct i2c_adapter *adap = &priv->adapter; >> >> if (command == I2C_SMBUS_BLOCK_PROC_CALL) >> return -EOPNOTSUPP; >> >> - result = i801_check_pre(priv); >> - if (result < 0) >> - return result; >> + status = i801_check_pre(priv); >> + if (status < 0) >> + return status; >> >> len = data->block[0]; >> >> @@ -726,15 +721,10 @@ static int i801_block_transaction_byte_by_byte(struct i801_priv *priv, >> priv->count = 0; >> priv->data = &data->block[1]; >> >> + reinit_completion(&priv->done); >> outb_p(priv->cmd | SMBHSTCNT_START, SMBHSTCNT(priv)); >> - result = wait_event_timeout(priv->waitq, >> - (status = priv->status), >> - adap->timeout); >> - if (!result) >> - status = -ETIMEDOUT; >> - >> - priv->status = 0; >> - return i801_check_post(priv, status); >> + result = wait_for_completion_timeout(&priv->done, adap->timeout); >> + return i801_check_post(priv, result ? priv->status : -ETIMEDOUT); >> } >> >> for (i = 1; i <= len; i++) { >> @@ -1889,7 +1879,7 @@ static int i801_probe(struct pci_dev *dev, const struct pci_device_id *id) >> } >> >> if (priv->features & FEATURE_IRQ) { >> - init_waitqueue_head(&priv->waitq); >> + init_completion(&priv->done); >> >> err = devm_request_irq(&dev->dev, dev->irq, i801_isr, >> IRQF_SHARED, > > The clean-up isn't massive but I agree the code is a bit more pleasant > to read after the change, and I also see the binary size shrink a bit, > so I vote for it. > > Reviewed-by: Jean Delvare <jdelvare@suse.de> > Tested-by: Jean Delvare <jdelvare@suse.de> >
Hi Jean, Heiner, On Tue, May 25, 2021 at 11:01 PM Heiner Kallweit <hkallweit1@gmail.com> wrote: > > On 25.05.2021 14:12, Jean Delvare wrote: > > Hi Heiner, > > > > Adding Daniel Kurtz, who wrote the original wait queue-based code, to > > Cc. I'm not sure if Daniel is still into kernel code though. Thanks for thinking of me! I'm still into kernel code, but I do a lot more reading than writing these days. > > > > On Sat, 22 May 2021 00:02:43 +0200, Heiner Kallweit wrote: > >> Using the completion API is more intuitive and it allows to simplify > >> the code. Note that we don't have to set priv->status = 0 any longer > >> with the completion API. > > > > OK, but you need to call reinit_completion() instead, which has the > > same cost. So that's not a good argument ;-) > > > Maybe my comment wasn't clear enough. I didn't want to say that we > save something but that it's safe from a functional point of view > to remove clearing priv->status. > > >> Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com> > >> --- > >> drivers/i2c/busses/i2c-i801.c | 48 ++++++++++++++--------------------- > >> 1 file changed, 19 insertions(+), 29 deletions(-) > >> > >> diff --git a/drivers/i2c/busses/i2c-i801.c b/drivers/i2c/busses/i2c-i801.c > >> index bfea94d02..738204d77 100644 > >> --- a/drivers/i2c/busses/i2c-i801.c > >> +++ b/drivers/i2c/busses/i2c-i801.c > >> @@ -103,7 +103,7 @@ > >> #include <linux/dmi.h> > >> #include <linux/slab.h> > >> #include <linux/string.h> > >> -#include <linux/wait.h> > >> +#include <linux/completion.h> > >> #include <linux/err.h> > >> #include <linux/platform_device.h> > >> #include <linux/platform_data/itco_wdt.h> > >> @@ -270,7 +270,7 @@ struct i801_priv { > >> unsigned int features; > >> > >> /* isr processing */ > >> - wait_queue_head_t waitq; > >> + struct completion done; > >> u8 status; > >> > >> /* Command state used by isr for byte-by-byte block transactions */ > >> @@ -496,24 +496,19 @@ static int i801_wait_byte_done(struct i801_priv *priv) > >> static int i801_transaction(struct i801_priv *priv, int xact) > >> { > >> int status; > >> - int result; > >> + unsigned long result; > >> const struct i2c_adapter *adap = &priv->adapter; > >> > >> - result = i801_check_pre(priv); > >> - if (result < 0) > >> - return result; > >> + status = i801_check_pre(priv); > >> + if (status < 0) > >> + return status; > >> > >> if (priv->features & FEATURE_IRQ) { > >> + reinit_completion(&priv->done); > >> outb_p(xact | SMBHSTCNT_INTREN | SMBHSTCNT_START, > >> SMBHSTCNT(priv)); > >> - result = wait_event_timeout(priv->waitq, > >> - (status = priv->status), > >> - adap->timeout); > >> - if (!result) > >> - status = -ETIMEDOUT; > >> - > >> - priv->status = 0; > >> - return i801_check_post(priv, status); > >> + result = wait_for_completion_timeout(&priv->done, adap->timeout); > >> + return i801_check_post(priv, result ? priv->status : -ETIMEDOUT); > >> } > >> > >> /* the current contents of SMBHSTCNT can be overwritten, since PEC, > >> @@ -638,7 +633,7 @@ static irqreturn_t i801_host_notify_isr(struct i801_priv *priv) > >> * DEV_ERR - Invalid command, NAK or communication timeout > >> * BUS_ERR - SMI# transaction collision > >> * FAILED - transaction was canceled due to a KILL request > >> - * When any of these occur, update ->status and wake up the waitq. > >> + * When any of these occur, update ->status and signal completion. > >> * ->status must be cleared before kicking off the next transaction. > >> * > >> * 2) For byte-by-byte (I2C read/write) transactions, one BYTE_DONE interrupt > >> @@ -675,7 +670,7 @@ static irqreturn_t i801_isr(int irq, void *dev_id) > >> if (status) { > >> outb_p(status, SMBHSTSTS(priv)); > >> priv->status = status; > >> - wake_up(&priv->waitq); > >> + complete(&priv->done); > >> } > >> > >> return IRQ_HANDLED; > >> @@ -694,15 +689,15 @@ static int i801_block_transaction_byte_by_byte(struct i801_priv *priv, > >> int i, len; > >> int smbcmd; > >> int status; > >> - int result; > >> + unsigned long result; > >> const struct i2c_adapter *adap = &priv->adapter; > >> > >> if (command == I2C_SMBUS_BLOCK_PROC_CALL) > >> return -EOPNOTSUPP; > >> > >> - result = i801_check_pre(priv); > >> - if (result < 0) > >> - return result; > >> + status = i801_check_pre(priv); > >> + if (status < 0) > >> + return status; > >> > >> len = data->block[0]; > >> > >> @@ -726,15 +721,10 @@ static int i801_block_transaction_byte_by_byte(struct i801_priv *priv, > >> priv->count = 0; > >> priv->data = &data->block[1]; > >> > >> + reinit_completion(&priv->done); > >> outb_p(priv->cmd | SMBHSTCNT_START, SMBHSTCNT(priv)); > >> - result = wait_event_timeout(priv->waitq, > >> - (status = priv->status), > >> - adap->timeout); > >> - if (!result) > >> - status = -ETIMEDOUT; > >> - > >> - priv->status = 0; > >> - return i801_check_post(priv, status); > >> + result = wait_for_completion_timeout(&priv->done, adap->timeout); > >> + return i801_check_post(priv, result ? priv->status : -ETIMEDOUT); > >> } > >> > >> for (i = 1; i <= len; i++) { > >> @@ -1889,7 +1879,7 @@ static int i801_probe(struct pci_dev *dev, const struct pci_device_id *id) > >> } > >> > >> if (priv->features & FEATURE_IRQ) { > >> - init_waitqueue_head(&priv->waitq); > >> + init_completion(&priv->done); > >> > >> err = devm_request_irq(&dev->dev, dev->irq, i801_isr, > >> IRQF_SHARED, > > > > The clean-up isn't massive but I agree the code is a bit more pleasant > > to read after the change, and I also see the binary size shrink a bit, > > so I vote for it. > > > > Reviewed-by: Jean Delvare <jdelvare@suse.de> > > Tested-by: Jean Delvare <jdelvare@suse.de> > > > I agree, shorter and sweeter. Thanks for cleaning this up! Reviewed-by: Daniel Kurtz <djkurtz@chromium.org>
On Sat, May 22, 2021 at 12:02:43AM +0200, Heiner Kallweit wrote: > Using the completion API is more intuitive and it allows to simplify > the code. Note that we don't have to set priv->status = 0 any longer > with the completion API. > > Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com> Applied to for-next, thanks!
diff --git a/drivers/i2c/busses/i2c-i801.c b/drivers/i2c/busses/i2c-i801.c index bfea94d02..738204d77 100644 --- a/drivers/i2c/busses/i2c-i801.c +++ b/drivers/i2c/busses/i2c-i801.c @@ -103,7 +103,7 @@ #include <linux/dmi.h> #include <linux/slab.h> #include <linux/string.h> -#include <linux/wait.h> +#include <linux/completion.h> #include <linux/err.h> #include <linux/platform_device.h> #include <linux/platform_data/itco_wdt.h> @@ -270,7 +270,7 @@ struct i801_priv { unsigned int features; /* isr processing */ - wait_queue_head_t waitq; + struct completion done; u8 status; /* Command state used by isr for byte-by-byte block transactions */ @@ -496,24 +496,19 @@ static int i801_wait_byte_done(struct i801_priv *priv) static int i801_transaction(struct i801_priv *priv, int xact) { int status; - int result; + unsigned long result; const struct i2c_adapter *adap = &priv->adapter; - result = i801_check_pre(priv); - if (result < 0) - return result; + status = i801_check_pre(priv); + if (status < 0) + return status; if (priv->features & FEATURE_IRQ) { + reinit_completion(&priv->done); outb_p(xact | SMBHSTCNT_INTREN | SMBHSTCNT_START, SMBHSTCNT(priv)); - result = wait_event_timeout(priv->waitq, - (status = priv->status), - adap->timeout); - if (!result) - status = -ETIMEDOUT; - - priv->status = 0; - return i801_check_post(priv, status); + result = wait_for_completion_timeout(&priv->done, adap->timeout); + return i801_check_post(priv, result ? priv->status : -ETIMEDOUT); } /* the current contents of SMBHSTCNT can be overwritten, since PEC, @@ -638,7 +633,7 @@ static irqreturn_t i801_host_notify_isr(struct i801_priv *priv) * DEV_ERR - Invalid command, NAK or communication timeout * BUS_ERR - SMI# transaction collision * FAILED - transaction was canceled due to a KILL request - * When any of these occur, update ->status and wake up the waitq. + * When any of these occur, update ->status and signal completion. * ->status must be cleared before kicking off the next transaction. * * 2) For byte-by-byte (I2C read/write) transactions, one BYTE_DONE interrupt @@ -675,7 +670,7 @@ static irqreturn_t i801_isr(int irq, void *dev_id) if (status) { outb_p(status, SMBHSTSTS(priv)); priv->status = status; - wake_up(&priv->waitq); + complete(&priv->done); } return IRQ_HANDLED; @@ -694,15 +689,15 @@ static int i801_block_transaction_byte_by_byte(struct i801_priv *priv, int i, len; int smbcmd; int status; - int result; + unsigned long result; const struct i2c_adapter *adap = &priv->adapter; if (command == I2C_SMBUS_BLOCK_PROC_CALL) return -EOPNOTSUPP; - result = i801_check_pre(priv); - if (result < 0) - return result; + status = i801_check_pre(priv); + if (status < 0) + return status; len = data->block[0]; @@ -726,15 +721,10 @@ static int i801_block_transaction_byte_by_byte(struct i801_priv *priv, priv->count = 0; priv->data = &data->block[1]; + reinit_completion(&priv->done); outb_p(priv->cmd | SMBHSTCNT_START, SMBHSTCNT(priv)); - result = wait_event_timeout(priv->waitq, - (status = priv->status), - adap->timeout); - if (!result) - status = -ETIMEDOUT; - - priv->status = 0; - return i801_check_post(priv, status); + result = wait_for_completion_timeout(&priv->done, adap->timeout); + return i801_check_post(priv, result ? priv->status : -ETIMEDOUT); } for (i = 1; i <= len; i++) { @@ -1889,7 +1879,7 @@ static int i801_probe(struct pci_dev *dev, const struct pci_device_id *id) } if (priv->features & FEATURE_IRQ) { - init_waitqueue_head(&priv->waitq); + init_completion(&priv->done); err = devm_request_irq(&dev->dev, dev->irq, i801_isr, IRQF_SHARED,
Using the completion API is more intuitive and it allows to simplify the code. Note that we don't have to set priv->status = 0 any longer with the completion API. Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com> --- drivers/i2c/busses/i2c-i801.c | 48 ++++++++++++++--------------------- 1 file changed, 19 insertions(+), 29 deletions(-)