* [PATCH] Update scsi host to use ida for host number
@ 2015-08-31 20:28 leeman.duncan
2015-09-01 7:16 ` Hannes Reinecke
` (2 more replies)
0 siblings, 3 replies; 5+ messages in thread
From: leeman.duncan @ 2015-08-31 20:28 UTC (permalink / raw)
To: linux-scsi; +Cc: hare, JBottomley, Lee Duncan
From: Lee Duncan <lduncan@suse.com>
Each Scsi_host instance gets a host number starting
at 0, but this is implemented with an atomic integer,
and rollover doesn't seem to have been considered.
Another side-effect of this design is that scsi host
numbers used by iscsi are never reused, thereby making
rollover more likely. This patch converts Scsi_host
instances to use ida to manage their instance
numbers.
This also means that host instance numbers will be
reused, when available.
Signed-off-by: Lee Duncan <lduncan@suse.com>
---
drivers/scsi/hosts.c | 43 +++++++++++++++++++++++++++++++++++--------
1 file changed, 35 insertions(+), 8 deletions(-)
diff --git a/drivers/scsi/hosts.c b/drivers/scsi/hosts.c
index 8bb173e01084..dade75478541 100644
--- a/drivers/scsi/hosts.c
+++ b/drivers/scsi/hosts.c
@@ -33,7 +33,7 @@
#include <linux/transport_class.h>
#include <linux/platform_device.h>
#include <linux/pm_runtime.h>
-
+#include <linux/idr.h>
#include <scsi/scsi_device.h>
#include <scsi/scsi_host.h>
#include <scsi/scsi_transport.h>
@@ -42,7 +42,8 @@
#include "scsi_logging.h"
-static atomic_t scsi_host_next_hn = ATOMIC_INIT(0); /* host_no for next new host */
+static DEFINE_SPINLOCK(host_index_lock);
+static DEFINE_IDA(host_index_ida);
static void scsi_host_cls_release(struct device *dev)
@@ -337,6 +338,10 @@ static void scsi_host_dev_release(struct device *dev)
kfree(shost->shost_data);
+ spin_lock(&host_index_lock);
+ ida_remove(&host_index_ida, shost->host_no);
+ spin_unlock(&host_index_lock);
+
if (parent)
put_device(parent);
kfree(shost);
@@ -353,6 +358,22 @@ static struct device_type scsi_host_type = {
.release = scsi_host_dev_release,
};
+static int host_get_index(int *index)
+{
+ int error = -ENOMEM;
+
+ do {
+ if (!ida_pre_get(&host_index_ida, GFP_KERNEL))
+ break;
+ spin_lock(&host_index_lock);
+ error = ida_get_new(&host_index_ida, index);
+ spin_unlock(&host_index_lock);
+ } while (error == -EAGAIN);
+
+ return error;
+}
+
+
/**
* scsi_host_alloc - register a scsi host adapter instance.
* @sht: pointer to scsi host template
@@ -370,6 +391,8 @@ struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
{
struct Scsi_Host *shost;
gfp_t gfp_mask = GFP_KERNEL;
+ int index;
+ int error;
if (sht->unchecked_isa_dma && privsize)
gfp_mask |= __GFP_DMA;
@@ -388,11 +411,11 @@ struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
init_waitqueue_head(&shost->host_wait);
mutex_init(&shost->scan_mutex);
- /*
- * subtract one because we increment first then return, but we need to
- * know what the next host number was before increment
- */
- shost->host_no = atomic_inc_return(&scsi_host_next_hn) - 1;
+ error = host_get_index(&index);
+ if (error < 0)
+ goto fail_kfree;
+ shost->host_no = index;
+
shost->dma_channel = 0xff;
/* These three are default values which can be overridden */
@@ -477,7 +500,7 @@ struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
shost_printk(KERN_WARNING, shost,
"error handler thread failed to spawn, error = %ld\n",
PTR_ERR(shost->ehandler));
- goto fail_kfree;
+ goto fail_free_index;
}
shost->tmf_work_q = alloc_workqueue("scsi_tmf_%d",
@@ -493,6 +516,10 @@ struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
fail_kthread:
kthread_stop(shost->ehandler);
+ fail_free_index:
+ spin_lock(&host_index_lock);
+ ida_remove(&host_index_ida, index);
+ spin_unlock(&host_index_lock);
fail_kfree:
kfree(shost);
return NULL;
--
2.1.4
^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH] Update scsi host to use ida for host number
2015-08-31 20:28 [PATCH] Update scsi host to use ida for host number leeman.duncan
@ 2015-09-01 7:16 ` Hannes Reinecke
2015-09-01 8:13 ` Johannes Thumshirn
2015-09-01 8:23 ` Sagi Grimberg
2 siblings, 0 replies; 5+ messages in thread
From: Hannes Reinecke @ 2015-09-01 7:16 UTC (permalink / raw)
To: leeman.duncan, linux-scsi; +Cc: JBottomley, Lee Duncan
On 08/31/2015 10:28 PM, leeman.duncan@gmail.com wrote:
> From: Lee Duncan <lduncan@suse.com>
>
> Each Scsi_host instance gets a host number starting
> at 0, but this is implemented with an atomic integer,
> and rollover doesn't seem to have been considered.
> Another side-effect of this design is that scsi host
> numbers used by iscsi are never reused, thereby making
> rollover more likely. This patch converts Scsi_host
> instances to use ida to manage their instance
> numbers.
>
> This also means that host instance numbers will be
> reused, when available.
>
> Signed-off-by: Lee Duncan <lduncan@suse.com>
> ---
> drivers/scsi/hosts.c | 43 +++++++++++++++++++++++++++++++++++--------
> 1 file changed, 35 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/scsi/hosts.c b/drivers/scsi/hosts.c
> index 8bb173e01084..dade75478541 100644
> --- a/drivers/scsi/hosts.c
> +++ b/drivers/scsi/hosts.c
> @@ -33,7 +33,7 @@
> #include <linux/transport_class.h>
> #include <linux/platform_device.h>
> #include <linux/pm_runtime.h>
> -
> +#include <linux/idr.h>
> #include <scsi/scsi_device.h>
> #include <scsi/scsi_host.h>
> #include <scsi/scsi_transport.h>
> @@ -42,7 +42,8 @@
> #include "scsi_logging.h"
>
>
> -static atomic_t scsi_host_next_hn = ATOMIC_INIT(0); /* host_no for next new host */
> +static DEFINE_SPINLOCK(host_index_lock);
> +static DEFINE_IDA(host_index_ida);
>
>
> static void scsi_host_cls_release(struct device *dev)
> @@ -337,6 +338,10 @@ static void scsi_host_dev_release(struct device *dev)
>
> kfree(shost->shost_data);
>
> + spin_lock(&host_index_lock);
> + ida_remove(&host_index_ida, shost->host_no);
> + spin_unlock(&host_index_lock);
> +
> if (parent)
> put_device(parent);
> kfree(shost);
> @@ -353,6 +358,22 @@ static struct device_type scsi_host_type = {
> .release = scsi_host_dev_release,
> };
>
> +static int host_get_index(int *index)
> +{
> + int error = -ENOMEM;
> +
> + do {
> + if (!ida_pre_get(&host_index_ida, GFP_KERNEL))
> + break;
> + spin_lock(&host_index_lock);
> + error = ida_get_new(&host_index_ida, index);
> + spin_unlock(&host_index_lock);
> + } while (error == -EAGAIN);
> +
> + return error;
> +}
> +
> +
> /**
> * scsi_host_alloc - register a scsi host adapter instance.
> * @sht: pointer to scsi host template
> @@ -370,6 +391,8 @@ struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
> {
> struct Scsi_Host *shost;
> gfp_t gfp_mask = GFP_KERNEL;
> + int index;
> + int error;
>
> if (sht->unchecked_isa_dma && privsize)
> gfp_mask |= __GFP_DMA;
> @@ -388,11 +411,11 @@ struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
> init_waitqueue_head(&shost->host_wait);
> mutex_init(&shost->scan_mutex);
>
> - /*
> - * subtract one because we increment first then return, but we need to
> - * know what the next host number was before increment
> - */
> - shost->host_no = atomic_inc_return(&scsi_host_next_hn) - 1;
> + error = host_get_index(&index);
> + if (error < 0)
> + goto fail_kfree;
> + shost->host_no = index;
> +
> shost->dma_channel = 0xff;
>
> /* These three are default values which can be overridden */
> @@ -477,7 +500,7 @@ struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
> shost_printk(KERN_WARNING, shost,
> "error handler thread failed to spawn, error = %ld\n",
> PTR_ERR(shost->ehandler));
> - goto fail_kfree;
> + goto fail_free_index;
> }
>
> shost->tmf_work_q = alloc_workqueue("scsi_tmf_%d",
> @@ -493,6 +516,10 @@ struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
>
> fail_kthread:
> kthread_stop(shost->ehandler);
> + fail_free_index:
> + spin_lock(&host_index_lock);
> + ida_remove(&host_index_ida, index);
> + spin_unlock(&host_index_lock);
> fail_kfree:
> kfree(shost);
> return NULL;
>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Cheers,
Hannes
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] Update scsi host to use ida for host number
2015-08-31 20:28 [PATCH] Update scsi host to use ida for host number leeman.duncan
2015-09-01 7:16 ` Hannes Reinecke
@ 2015-09-01 8:13 ` Johannes Thumshirn
2015-09-01 8:23 ` Sagi Grimberg
2 siblings, 0 replies; 5+ messages in thread
From: Johannes Thumshirn @ 2015-09-01 8:13 UTC (permalink / raw)
To: leeman.duncan; +Cc: linux-scsi, hare, JBottomley, Lee Duncan
leeman.duncan@gmail.com writes:
> From: Lee Duncan <lduncan@suse.com>
>
> Each Scsi_host instance gets a host number starting
> at 0, but this is implemented with an atomic integer,
> and rollover doesn't seem to have been considered.
> Another side-effect of this design is that scsi host
> numbers used by iscsi are never reused, thereby making
> rollover more likely. This patch converts Scsi_host
> instances to use ida to manage their instance
> numbers.
>
> This also means that host instance numbers will be
> reused, when available.
>
> Signed-off-by: Lee Duncan <lduncan@suse.com>
> ---
> drivers/scsi/hosts.c | 43 +++++++++++++++++++++++++++++++++++--------
> 1 file changed, 35 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/scsi/hosts.c b/drivers/scsi/hosts.c
> index 8bb173e01084..dade75478541 100644
> --- a/drivers/scsi/hosts.c
> +++ b/drivers/scsi/hosts.c
> @@ -33,7 +33,7 @@
> #include <linux/transport_class.h>
> #include <linux/platform_device.h>
> #include <linux/pm_runtime.h>
> -
> +#include <linux/idr.h>
> #include <scsi/scsi_device.h>
> #include <scsi/scsi_host.h>
> #include <scsi/scsi_transport.h>
> @@ -42,7 +42,8 @@
> #include "scsi_logging.h"
>
>
> -static atomic_t scsi_host_next_hn = ATOMIC_INIT(0); /* host_no for next new host */
> +static DEFINE_SPINLOCK(host_index_lock);
> +static DEFINE_IDA(host_index_ida);
>
>
> static void scsi_host_cls_release(struct device *dev)
> @@ -337,6 +338,10 @@ static void scsi_host_dev_release(struct device *dev)
>
> kfree(shost->shost_data);
>
> + spin_lock(&host_index_lock);
> + ida_remove(&host_index_ida, shost->host_no);
> + spin_unlock(&host_index_lock);
> +
> if (parent)
> put_device(parent);
> kfree(shost);
> @@ -353,6 +358,22 @@ static struct device_type scsi_host_type = {
> .release = scsi_host_dev_release,
> };
>
> +static int host_get_index(int *index)
> +{
> + int error = -ENOMEM;
> +
> + do {
> + if (!ida_pre_get(&host_index_ida, GFP_KERNEL))
> + break;
> + spin_lock(&host_index_lock);
> + error = ida_get_new(&host_index_ida, index);
> + spin_unlock(&host_index_lock);
> + } while (error == -EAGAIN);
> +
> + return error;
> +}
> +
> +
> /**
> * scsi_host_alloc - register a scsi host adapter instance.
> * @sht: pointer to scsi host template
> @@ -370,6 +391,8 @@ struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
> {
> struct Scsi_Host *shost;
> gfp_t gfp_mask = GFP_KERNEL;
> + int index;
> + int error;
>
> if (sht->unchecked_isa_dma && privsize)
> gfp_mask |= __GFP_DMA;
> @@ -388,11 +411,11 @@ struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
> init_waitqueue_head(&shost->host_wait);
> mutex_init(&shost->scan_mutex);
>
> - /*
> - * subtract one because we increment first then return, but we need to
> - * know what the next host number was before increment
> - */
> - shost->host_no = atomic_inc_return(&scsi_host_next_hn) - 1;
> + error = host_get_index(&index);
> + if (error < 0)
> + goto fail_kfree;
> + shost->host_no = index;
> +
> shost->dma_channel = 0xff;
>
> /* These three are default values which can be overridden */
> @@ -477,7 +500,7 @@ struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
> shost_printk(KERN_WARNING, shost,
> "error handler thread failed to spawn, error = %ld\n",
> PTR_ERR(shost->ehandler));
> - goto fail_kfree;
> + goto fail_free_index;
> }
>
> shost->tmf_work_q = alloc_workqueue("scsi_tmf_%d",
> @@ -493,6 +516,10 @@ struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
>
> fail_kthread:
> kthread_stop(shost->ehandler);
> + fail_free_index:
> + spin_lock(&host_index_lock);
> + ida_remove(&host_index_ida, index);
> + spin_unlock(&host_index_lock);
> fail_kfree:
> kfree(shost);
> return NULL;
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
--
Johannes Thumshirn Storage
jthumshirn@suse.de +49 911 74053 689
SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: Felix Imendörffer, Jane Smithard, Graham Norton
HRB 21284 (AG Nürnberg)
Key fingerprint = EC38 9CAB C2C4 F25D 8600 D0D0 0393 969D 2D76 0850
--
To unsubscribe from this list: send the line "unsubscribe linux-scsi" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] Update scsi host to use ida for host number
2015-08-31 20:28 [PATCH] Update scsi host to use ida for host number leeman.duncan
2015-09-01 7:16 ` Hannes Reinecke
2015-09-01 8:13 ` Johannes Thumshirn
@ 2015-09-01 8:23 ` Sagi Grimberg
2015-09-01 17:26 ` Lee Duncan
2 siblings, 1 reply; 5+ messages in thread
From: Sagi Grimberg @ 2015-09-01 8:23 UTC (permalink / raw)
To: leeman.duncan, linux-scsi; +Cc: hare, JBottomley, Lee Duncan
On 8/31/2015 11:28 PM, leeman.duncan@gmail.com wrote:
> From: Lee Duncan <lduncan@suse.com>
>
> Each Scsi_host instance gets a host number starting
> at 0, but this is implemented with an atomic integer,
> and rollover doesn't seem to have been considered.
> Another side-effect of this design is that scsi host
> numbers used by iscsi are never reused, thereby making
> rollover more likely. This patch converts Scsi_host
> instances to use ida to manage their instance
> numbers.
>
> This also means that host instance numbers will be
> reused, when available.
>
> Signed-off-by: Lee Duncan <lduncan@suse.com>
> ---
> drivers/scsi/hosts.c | 43 +++++++++++++++++++++++++++++++++++--------
> 1 file changed, 35 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/scsi/hosts.c b/drivers/scsi/hosts.c
> index 8bb173e01084..dade75478541 100644
> --- a/drivers/scsi/hosts.c
> +++ b/drivers/scsi/hosts.c
> @@ -33,7 +33,7 @@
> #include <linux/transport_class.h>
> #include <linux/platform_device.h>
> #include <linux/pm_runtime.h>
> -
> +#include <linux/idr.h>
> #include <scsi/scsi_device.h>
> #include <scsi/scsi_host.h>
> #include <scsi/scsi_transport.h>
> @@ -42,7 +42,8 @@
> #include "scsi_logging.h"
>
>
> -static atomic_t scsi_host_next_hn = ATOMIC_INIT(0); /* host_no for next new host */
> +static DEFINE_SPINLOCK(host_index_lock);
> +static DEFINE_IDA(host_index_ida);
>
>
> static void scsi_host_cls_release(struct device *dev)
> @@ -337,6 +338,10 @@ static void scsi_host_dev_release(struct device *dev)
>
> kfree(shost->shost_data);
>
> + spin_lock(&host_index_lock);
> + ida_remove(&host_index_ida, shost->host_no);
> + spin_unlock(&host_index_lock);
Why not get it in a symmetrical host_put_index()
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] Update scsi host to use ida for host number
2015-09-01 8:23 ` Sagi Grimberg
@ 2015-09-01 17:26 ` Lee Duncan
0 siblings, 0 replies; 5+ messages in thread
From: Lee Duncan @ 2015-09-01 17:26 UTC (permalink / raw)
To: Sagi Grimberg, linux-scsi; +Cc: hare, JBottomley, Johannes Thumshirn
On 09/01/2015 01:23 AM, Sagi Grimberg wrote:
> On 8/31/2015 11:28 PM, leeman.duncan@gmail.com wrote:
>> From: Lee Duncan <lduncan@suse.com>
>>
>> Each Scsi_host instance gets a host number starting
>> at 0, but this is implemented with an atomic integer,
>> and rollover doesn't seem to have been considered.
>> Another side-effect of this design is that scsi host
>> numbers used by iscsi are never reused, thereby making
>> rollover more likely. This patch converts Scsi_host
>> instances to use ida to manage their instance
>> numbers.
>>
>> This also means that host instance numbers will be
>> reused, when available.
>>
>> Signed-off-by: Lee Duncan <lduncan@suse.com>
>> ---
>> drivers/scsi/hosts.c | 43 +++++++++++++++++++++++++++++++++++--------
>> 1 file changed, 35 insertions(+), 8 deletions(-)
>>
>> diff --git a/drivers/scsi/hosts.c b/drivers/scsi/hosts.c
>> index 8bb173e01084..dade75478541 100644
>> --- a/drivers/scsi/hosts.c
>> +++ b/drivers/scsi/hosts.c
>> @@ -33,7 +33,7 @@
>> #include <linux/transport_class.h>
>> #include <linux/platform_device.h>
>> #include <linux/pm_runtime.h>
>> -
>> +#include <linux/idr.h>
>> #include <scsi/scsi_device.h>
>> #include <scsi/scsi_host.h>
>> #include <scsi/scsi_transport.h>
>> @@ -42,7 +42,8 @@
>> #include "scsi_logging.h"
>>
>>
>> -static atomic_t scsi_host_next_hn = ATOMIC_INIT(0); /* host_no for
>> next new host */
>> +static DEFINE_SPINLOCK(host_index_lock);
>> +static DEFINE_IDA(host_index_ida);
>>
>>
>> static void scsi_host_cls_release(struct device *dev)
>> @@ -337,6 +338,10 @@ static void scsi_host_dev_release(struct device
>> *dev)
>>
>> kfree(shost->shost_data);
>>
>> + spin_lock(&host_index_lock);
>> + ida_remove(&host_index_ida, shost->host_no);
>> + spin_unlock(&host_index_lock);
>
> Why not get it in a symmetrical host_put_index()
Seems like a reasonable suggestion. Since it's only 3 statements, I'll
make it an inline.
I will resubmit the patch, adding the two reviewed-by lines from Hannes
and Johannes, since the code will essentially be the same.
--
Lee Duncan
SUSE Labs
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2015-09-01 17:26 UTC | newest]
Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2015-08-31 20:28 [PATCH] Update scsi host to use ida for host number leeman.duncan
2015-09-01 7:16 ` Hannes Reinecke
2015-09-01 8:13 ` Johannes Thumshirn
2015-09-01 8:23 ` Sagi Grimberg
2015-09-01 17:26 ` Lee Duncan
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.