Re: [PATCH 20/23] scsi_dh_alua: Recheck state on unit attention

2015-09-23 Thread Hannes Reinecke 
On 09/22/2015 09:57 PM, Ewan Milne wrote:
> On Thu, 2015-08-27 at 14:41 +0200, Hannes Reinecke wrote:
>> When we receive a unit attention code of 'ALUA state changed'
>> we should recheck the state, as it might be due to an implicit
>> ALUA state transition.
>> At the same time a workqueue item might already be queued, which
>> should be started immediately to avoid any delays.
>>
>> Signed-off-by: Hannes Reinecke 
>> ---
>>  drivers/scsi/device_handler/scsi_dh_alua.c | 48 
>> +++---
>>  1 file changed, 24 insertions(+), 24 deletions(-)
>>
>> diff --git a/drivers/scsi/device_handler/scsi_dh_alua.c 
>> b/drivers/scsi/device_handler/scsi_dh_alua.c
>> index 85fd597..8717fd3 100644
>> --- a/drivers/scsi/device_handler/scsi_dh_alua.c
>> +++ b/drivers/scsi/device_handler/scsi_dh_alua.c
>> @@ -118,7 +118,7 @@ static char print_alua_state(int);
>>  static void alua_rtpg_work(struct work_struct *work);
>>  static void alua_stpg_work(struct work_struct *work);
>>  static void alua_qdata_work(struct work_struct *work);
>> -static void alua_check(struct scsi_device *sdev);
>> +static void alua_check(struct scsi_device *sdev, bool force);
>>  
>>  static void release_port_group(struct kref *kref)
>>  {
>> @@ -423,7 +423,7 @@ static char print_alua_state(int state)
>>  }
>>  
>>  static int alua_check_sense(struct scsi_device *sdev,
>> -struct scsi_sense_hdr *sense_hdr)
>> + struct scsi_sense_hdr *sense_hdr)
>>  {
>>  switch (sense_hdr->sense_key) {
>>  case NOT_READY:
>> @@ -432,36 +432,34 @@ static int alua_check_sense(struct scsi_device *sdev,
>>   * LUN Not Accessible - ALUA state transition
>>   * Kickoff worker to update internal state.
>>   */
>> -alua_check(sdev);
>> -return ADD_TO_MLQUEUE;
>> +alua_check(sdev, false);
>> +return NEEDS_RETRY;
>>  }
>>  break;
>>  case UNIT_ATTENTION:
>> -if (sense_hdr->asc == 0x29 && sense_hdr->ascq == 0x00)
>> -/*
>> - * Power On, Reset, or Bus Device Reset, just retry.
>> - */
>> -return ADD_TO_MLQUEUE;
>> -if (sense_hdr->asc == 0x29 && sense_hdr->ascq == 0x04)
>> -/*
>> - * Device internal reset
>> - */
>> -return ADD_TO_MLQUEUE;
>> -if (sense_hdr->asc == 0x2a && sense_hdr->ascq == 0x01)
>> +if (sense_hdr->asc == 0x29 && sense_hdr->ascq == 0x00) {
>>  /*
>> - * Mode Parameter Changed
>> + * Power On, Reset, or Bus Device Reset.
>> + * Might have obscured a state transition,
>> + * so schedule a recheck.
>>   */
>> +alua_check(sdev, true);
>>  return ADD_TO_MLQUEUE;
>> -if (sense_hdr->asc == 0x2a && sense_hdr->ascq == 0x06)
>> +}
>> +if (sense_hdr->asc == 0x2a && sense_hdr->ascq == 0x06) {
>>  /*
>>   * ALUA state changed
>>   */
>> +alua_check(sdev, true);
>>  return ADD_TO_MLQUEUE;
>> -if (sense_hdr->asc == 0x2a && sense_hdr->ascq == 0x07)
>> +}
>> +if (sense_hdr->asc == 0x2a && sense_hdr->ascq == 0x07) {
>>  /*
>>   * Implicit ALUA state transition failed
>>   */
>> +alua_check(sdev, true);
>>  return ADD_TO_MLQUEUE;
>> +}
>>  break;
>>  }
>>  
>> @@ -811,7 +809,7 @@ static void alua_qdata_work(struct work_struct *work)
>>  
>>  static void alua_rtpg_queue(struct alua_port_group *pg,
>>  struct scsi_device *sdev,
>> -struct alua_queue_data *qdata)
>> +struct alua_queue_data *qdata, bool force)
>>  {
>>  int start_queue = 0;
>>  unsigned long flags;
>> @@ -832,7 +830,9 @@ static void alua_rtpg_queue(struct alua_port_group *pg,
>>  pg->rtpg_sdev = sdev;
>>  scsi_device_get(sdev);
>>  start_queue = 1;
>> -}
>> +} else if (!(pg->flags & ALUA_PG_RUN_RTPG) && force)
>> +start_queue = 1;
>> +
>>  spin_unlock_irqrestore(&pg->rtpg_lock, flags);
>>  
>>  if (start_queue)
>> @@ -873,7 +873,7 @@ static int alua_initialize(struct scsi_device *sdev, 
>> struct alua_dh_data *h)
>>  mutex_unlock(&h->init_mutex);
>>  if (pg) {
>>  pg->expiry = 0;
>> -alua_rtpg_queue(pg, sdev, NULL);
>> +alua_rtpg_queue(pg, sdev, NULL, true);
>>  kref_put(&pg->kref, release_port_group);
>>  }
>>  return er

Re: [PATCH 20/23] scsi_dh_alua: Recheck state on unit attention

2015-09-22 Thread Ewan Milne 
On Thu, 2015-08-27 at 14:41 +0200, Hannes Reinecke wrote:
> When we receive a unit attention code of 'ALUA state changed'
> we should recheck the state, as it might be due to an implicit
> ALUA state transition.
> At the same time a workqueue item might already be queued, which
> should be started immediately to avoid any delays.
> 
> Signed-off-by: Hannes Reinecke 
> ---
>  drivers/scsi/device_handler/scsi_dh_alua.c | 48 
> +++---
>  1 file changed, 24 insertions(+), 24 deletions(-)
> 
> diff --git a/drivers/scsi/device_handler/scsi_dh_alua.c 
> b/drivers/scsi/device_handler/scsi_dh_alua.c
> index 85fd597..8717fd3 100644
> --- a/drivers/scsi/device_handler/scsi_dh_alua.c
> +++ b/drivers/scsi/device_handler/scsi_dh_alua.c
> @@ -118,7 +118,7 @@ static char print_alua_state(int);
>  static void alua_rtpg_work(struct work_struct *work);
>  static void alua_stpg_work(struct work_struct *work);
>  static void alua_qdata_work(struct work_struct *work);
> -static void alua_check(struct scsi_device *sdev);
> +static void alua_check(struct scsi_device *sdev, bool force);
>  
>  static void release_port_group(struct kref *kref)
>  {
> @@ -423,7 +423,7 @@ static char print_alua_state(int state)
>  }
>  
>  static int alua_check_sense(struct scsi_device *sdev,
> - struct scsi_sense_hdr *sense_hdr)
> +  struct scsi_sense_hdr *sense_hdr)
>  {
>   switch (sense_hdr->sense_key) {
>   case NOT_READY:
> @@ -432,36 +432,34 @@ static int alua_check_sense(struct scsi_device *sdev,
>* LUN Not Accessible - ALUA state transition
>* Kickoff worker to update internal state.
>*/
> - alua_check(sdev);
> - return ADD_TO_MLQUEUE;
> + alua_check(sdev, false);
> + return NEEDS_RETRY;
>   }
>   break;
>   case UNIT_ATTENTION:
> - if (sense_hdr->asc == 0x29 && sense_hdr->ascq == 0x00)
> - /*
> -  * Power On, Reset, or Bus Device Reset, just retry.
> -  */
> - return ADD_TO_MLQUEUE;
> - if (sense_hdr->asc == 0x29 && sense_hdr->ascq == 0x04)
> - /*
> -  * Device internal reset
> -  */
> - return ADD_TO_MLQUEUE;
> - if (sense_hdr->asc == 0x2a && sense_hdr->ascq == 0x01)
> + if (sense_hdr->asc == 0x29 && sense_hdr->ascq == 0x00) {
>   /*
> -  * Mode Parameter Changed
> +  * Power On, Reset, or Bus Device Reset.
> +  * Might have obscured a state transition,
> +  * so schedule a recheck.
>*/
> + alua_check(sdev, true);
>   return ADD_TO_MLQUEUE;
> - if (sense_hdr->asc == 0x2a && sense_hdr->ascq == 0x06)
> + }
> + if (sense_hdr->asc == 0x2a && sense_hdr->ascq == 0x06) {
>   /*
>* ALUA state changed
>*/
> + alua_check(sdev, true);
>   return ADD_TO_MLQUEUE;
> - if (sense_hdr->asc == 0x2a && sense_hdr->ascq == 0x07)
> + }
> + if (sense_hdr->asc == 0x2a && sense_hdr->ascq == 0x07) {
>   /*
>* Implicit ALUA state transition failed
>*/
> + alua_check(sdev, true);
>   return ADD_TO_MLQUEUE;
> + }
>   break;
>   }
>  
> @@ -811,7 +809,7 @@ static void alua_qdata_work(struct work_struct *work)
>  
>  static void alua_rtpg_queue(struct alua_port_group *pg,
>   struct scsi_device *sdev,
> - struct alua_queue_data *qdata)
> + struct alua_queue_data *qdata, bool force)
>  {
>   int start_queue = 0;
>   unsigned long flags;
> @@ -832,7 +830,9 @@ static void alua_rtpg_queue(struct alua_port_group *pg,
>   pg->rtpg_sdev = sdev;
>   scsi_device_get(sdev);
>   start_queue = 1;
> - }
> + } else if (!(pg->flags & ALUA_PG_RUN_RTPG) && force)
> + start_queue = 1;
> +
>   spin_unlock_irqrestore(&pg->rtpg_lock, flags);
>  
>   if (start_queue)
> @@ -873,7 +873,7 @@ static int alua_initialize(struct scsi_device *sdev, 
> struct alua_dh_data *h)
>   mutex_unlock(&h->init_mutex);
>   if (pg) {
>   pg->expiry = 0;
> - alua_rtpg_queue(pg, sdev, NULL);
> + alua_rtpg_queue(pg, sdev, NULL, true);
>   kref_put(&pg->kref, release_port_group);
>   }
>   return error;
> @@ -982,7 +982,7 @@ static int alua_activate(struct scsi_device *sdev,
>

Re: [PATCH 20/23] scsi_dh_alua: Recheck state on unit attention

2015-09-01 Thread Christoph Hellwig 
> - alua_check(sdev);
> - return ADD_TO_MLQUEUE;
> + alua_check(sdev, false);
> + return NEEDS_RETRY;

What's the reason for the change in return value here?
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[PATCH 20/23] scsi_dh_alua: Recheck state on unit attention

2015-08-27 Thread Hannes Reinecke 
When we receive a unit attention code of 'ALUA state changed'
we should recheck the state, as it might be due to an implicit
ALUA state transition.
At the same time a workqueue item might already be queued, which
should be started immediately to avoid any delays.

Signed-off-by: Hannes Reinecke 
---
 drivers/scsi/device_handler/scsi_dh_alua.c | 48 +++---
 1 file changed, 24 insertions(+), 24 deletions(-)

diff --git a/drivers/scsi/device_handler/scsi_dh_alua.c 
b/drivers/scsi/device_handler/scsi_dh_alua.c
index 85fd597..8717fd3 100644
--- a/drivers/scsi/device_handler/scsi_dh_alua.c
+++ b/drivers/scsi/device_handler/scsi_dh_alua.c
@@ -118,7 +118,7 @@ static char print_alua_state(int);
 static void alua_rtpg_work(struct work_struct *work);
 static void alua_stpg_work(struct work_struct *work);
 static void alua_qdata_work(struct work_struct *work);
-static void alua_check(struct scsi_device *sdev);
+static void alua_check(struct scsi_device *sdev, bool force);
 
 static void release_port_group(struct kref *kref)
 {
@@ -423,7 +423,7 @@ static char print_alua_state(int state)
 }
 
 static int alua_check_sense(struct scsi_device *sdev,
-   struct scsi_sense_hdr *sense_hdr)
+struct scsi_sense_hdr *sense_hdr)
 {
switch (sense_hdr->sense_key) {
case NOT_READY:
@@ -432,36 +432,34 @@ static int alua_check_sense(struct scsi_device *sdev,
 * LUN Not Accessible - ALUA state transition
 * Kickoff worker to update internal state.
 */
-   alua_check(sdev);
-   return ADD_TO_MLQUEUE;
+   alua_check(sdev, false);
+   return NEEDS_RETRY;
}
break;
case UNIT_ATTENTION:
-   if (sense_hdr->asc == 0x29 && sense_hdr->ascq == 0x00)
-   /*
-* Power On, Reset, or Bus Device Reset, just retry.
-*/
-   return ADD_TO_MLQUEUE;
-   if (sense_hdr->asc == 0x29 && sense_hdr->ascq == 0x04)
-   /*
-* Device internal reset
-*/
-   return ADD_TO_MLQUEUE;
-   if (sense_hdr->asc == 0x2a && sense_hdr->ascq == 0x01)
+   if (sense_hdr->asc == 0x29 && sense_hdr->ascq == 0x00) {
/*
-* Mode Parameter Changed
+* Power On, Reset, or Bus Device Reset.
+* Might have obscured a state transition,
+* so schedule a recheck.
 */
+   alua_check(sdev, true);
return ADD_TO_MLQUEUE;
-   if (sense_hdr->asc == 0x2a && sense_hdr->ascq == 0x06)
+   }
+   if (sense_hdr->asc == 0x2a && sense_hdr->ascq == 0x06) {
/*
 * ALUA state changed
 */
+   alua_check(sdev, true);
return ADD_TO_MLQUEUE;
-   if (sense_hdr->asc == 0x2a && sense_hdr->ascq == 0x07)
+   }
+   if (sense_hdr->asc == 0x2a && sense_hdr->ascq == 0x07) {
/*
 * Implicit ALUA state transition failed
 */
+   alua_check(sdev, true);
return ADD_TO_MLQUEUE;
+   }
break;
}
 
@@ -811,7 +809,7 @@ static void alua_qdata_work(struct work_struct *work)
 
 static void alua_rtpg_queue(struct alua_port_group *pg,
struct scsi_device *sdev,
-   struct alua_queue_data *qdata)
+   struct alua_queue_data *qdata, bool force)
 {
int start_queue = 0;
unsigned long flags;
@@ -832,7 +830,9 @@ static void alua_rtpg_queue(struct alua_port_group *pg,
pg->rtpg_sdev = sdev;
scsi_device_get(sdev);
start_queue = 1;
-   }
+   } else if (!(pg->flags & ALUA_PG_RUN_RTPG) && force)
+   start_queue = 1;
+
spin_unlock_irqrestore(&pg->rtpg_lock, flags);
 
if (start_queue)
@@ -873,7 +873,7 @@ static int alua_initialize(struct scsi_device *sdev, struct 
alua_dh_data *h)
mutex_unlock(&h->init_mutex);
if (pg) {
pg->expiry = 0;
-   alua_rtpg_queue(pg, sdev, NULL);
+   alua_rtpg_queue(pg, sdev, NULL, true);
kref_put(&pg->kref, release_port_group);
}
return error;
@@ -982,7 +982,7 @@ static int alua_activate(struct scsi_device *sdev,
pg->flags |= ALUA_OPTIMIZE_STPG;
spin_unlock_irqrestore(&pg->rtpg_lock, flags);
}
-   alua_rtpg_queue(pg, s