2010-11-10 13:58:58

by Hillf Danton

Subject: [PATCH] fix the poll method of bsg file operations in Block layer SCSI generic driver

Though it looks like a typo, the check for POLLOUT is computed incorrectly.

Signed-off-by: Hillf Danton <[email protected]>
---

--- a/block/bsg.c 2010-09-13 07:07:38.000000000 +0800
+++ b/block/bsg.c 2010-11-10 21:40:30.000000000 +0800
@@ -874,6 +874,8 @@ static unsigned int bsg_poll(struct file
if (!list_empty(&bd->done_list))
mask |= POLLIN | POLLRDNORM;
if (bd->queued_cmds >= bd->max_queue)
+ ;
+ else
mask |= POLLOUT;
spin_unlock_irq(&bd->lock);

2010-11-10 14:49:10

by Davidlohr Bueso

Subject: Re: [PATCH] fix the poll method of bsg file operations in Block layer SCSI generic driver

On Wed, 2010-11-10 at 21:58 +0800, Hillf Danton wrote:
> Though it looks like a typo, the check for POLLOUT is computed incorrectly.
>
> Signed-off-by: Hillf Danton <[email protected]>
> ---
>
> --- a/block/bsg.c 2010-09-13 07:07:38.000000000 +0800
> +++ b/block/bsg.c 2010-11-10 21:40:30.000000000 +0800
> @@ -874,6 +874,8 @@ static unsigned int bsg_poll(struct file
> if (!list_empty(&bd->done_list))
> mask |= POLLIN | POLLRDNORM;
> if (bd->queued_cmds >= bd->max_queue)
> + ;
> + else
> mask |= POLLOUT;
> spin_unlock_irq(&bd->lock);

How about something more like this:

diff --git a/block/bsg.c b/block/bsg.c
index f20d6a7..2663db3 100644
--- a/block/bsg.c
+++ b/block/bsg.c
@@ -870,7 +870,7 @@ static unsigned int bsg_poll(struct file *file,
poll_table *wait)
spin_lock_irq(&bd->lock);
if (!list_empty(&bd->done_list))
mask |= POLLIN | POLLRDNORM;
- if (bd->queued_cmds >= bd->max_queue)
+ if (bd->queued_cmds < bd->max_queue)
mask |= POLLOUT;
spin_unlock_irq(&bd->lock);


Thanks,
Davidlohr



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2010-11-11 13:42:51

by Hillf Danton

Subject: Re: [PATCH] fix the poll method of bsg file operations in Block layer SCSI generic driver

On Wed, Nov 10, 2010 at 10:48 PM, Davidlohr Bueso <[email protected]> wrote:
> On Wed, 2010-11-10 at 21:58 +0800, Hillf Danton wrote:
>> Though it looks like a typo, the check for POLLOUT is computed incorrectly.
>>
>> Signed-off-by: Hillf Danton <[email protected]>
>> ---
>>
>> --- a/block/bsg.c     2010-09-13 07:07:38.000000000 +0800
>> +++ b/block/bsg.c     2010-11-10 21:40:30.000000000 +0800
>> @@ -874,6 +874,8 @@ static unsigned int bsg_poll(struct file
>>       if (!list_empty(&bd->done_list))
>>               mask |= POLLIN | POLLRDNORM;
>>       if (bd->queued_cmds >= bd->max_queue)
>> +             ;
>> +     else
>>               mask |= POLLOUT;
>>       spin_unlock_irq(&bd->lock);
>
> How about something more like this:
>
> diff --git a/block/bsg.c b/block/bsg.c
> index f20d6a7..2663db3 100644
> --- a/block/bsg.c
> +++ b/block/bsg.c
> @@ -870,7 +870,7 @@ static unsigned int bsg_poll(struct file *file,
> poll_table *wait)
>        spin_lock_irq(&bd->lock);
>        if (!list_empty(&bd->done_list))
>                mask |= POLLIN | POLLRDNORM;
> -       if (bd->queued_cmds >= bd->max_queue)
> +       if (bd->queued_cmds < bd->max_queue)
>                mask |= POLLOUT;
>        spin_unlock_irq(&bd->lock);
>
>
> Thanks,
> Davidlohr
>
cool, thanks//Hillf

>
>
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>>
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>
>