Re: Patch 2/5

Lino Sanfilippo <[email protected]> Thu, 28 Oct 2010 18:09:02 +0200
Newsgroups gmane.linux.dazuko.devel
Message-ID <[email protected]>
John Ogness wrote:
> On 2010-07-08, Lino Sanfilippo <[email protected]> wrote:
>   
>> This patch enables behaviour compatible with BSD signal semantics by
>> making the read() calls on the dazukofs devices restartable across
>> signals.
>>     
>
> It is not clear to me that this is proper behavior for read() return
> values. I have decided not to apply this patch for 3.1.4-rc1.
>
> John Ogness
>   
Hi,

Userspace will (in most cases) still see -EINTR if interrupted by a 
signal (in fact
-ERESTARTSYS should never be seen by userspace).
The exception is if a signal handler has been installed with the 
SA_RESTART flag
set, the kernel will try to restart the interrupted system call (read() 
from dazukofs
device in our case) and not notify userspace.
This is a feature that has been introduced by BSD and is also supported 
by Linux.
I thought it would be nice if dazukofs would support those semantics, 
too (i know
some device drivers do, but I dont think its something a device _has_ to 
support...)

Regards,
Lino


Geschäftsführender Gesellschafter: Tjark Auerbach
Sitz der Gesellschaft: Tettnang
Handelsregister: Amtsgericht Ulm, HRB 630992
ALLGEMEINE GESCHÄFTSBEDINGUNGEN
Es gelten unsere Allgemeinen Geschäftsbedingungen
(AGB). Sie finden sie in der jeweils gültigen Fassung
im Internet unter http://www.avira.com/de/standard-terms-conditions-business-de
***************************************************