Re: Problem with SIMPLEQ_INSERT_TAIL

"J. Hannken-Illjes" <[email protected]> Mon, 22 Jan 2024 12:37:22 +0100
Newsgroups	gmane.os.netbsd.devel.kernel
Message-ID	<[email protected]>
> On 22. Jan 2024, at 11:52, Stephan <[email protected]> wrote:
> 
> Hello,
> 
> I am working on the semaphore part of my Haiku compat layer. I took
> uipc_sem.c as a reference, where control structures are organized in a
> dynamically allocated array and not as part of a list.
> 
> However, I like to maintain a "free list" in the form of a SIMPLEQ, on
> which unused semaphores are maintained for fast allocation.
> 
> There is an issue in the initialization function, where each structure
> is inserted into the free queue. I spent some time on this, but have
> been unable to find the cause. Maybe I am overlooking something
> trivial or there is something special I just don´t know.
> 
> The compiler says:
> 
> In file included from /home/stephan/src/sys/sys/siginfo.h:38,
>                 from /home/stephan/src/sys/sys/signal.h:112,
>                 from ./machine/frame.h:75,
>                 from ./x86/cpu.h:56,
>                 from ./machine/cpu.h:42,
>                 from ./machine/param.h:11,
>                 from /home/stephan/src/sys/sys/param.h:142,
>                 from /home/stephan/src/sys/kern/uipc_hsem.c:32:
> /home/stephan/src/sys/kern/uipc_hsem.c: In function 'khsem_init':
> /home/stephan/src/sys/sys/queue.h:347:19: error: assignment to 'struct
> khsem **' from incompatible pointer type 'struct kshem **'
> [-Werror=incompatible-pointer-types]
>  347 |  (head)->sqh_last = &(elm)->field.sqe_next;   \
>      |                   ^
> /home/stephan/src/sys/kern/uipc_hsem.c:68:9: note: in expansion of
> macro 'SIMPLEQ_INSERT_TAIL'
>   68 |         SIMPLEQ_INSERT_TAIL(&khsem_freeq, &hsems[i], khs_entry);
>      |         ^~~~~~~~~~~~~~~~~~~
> 
> 
> 
> The relevant code snippet is this:
> 
> const int khsem_max = 8192;
> 
> static kmutex_t                 khsem_mutex               __cacheline_aligned;
> static struct khsem             *hsems                    __read_mostly;
> static SIMPLEQ_HEAD(, khsem)    khsem_freeq;
> 
> 
> int
> khsem_init(void)
> {
>    int i, sz;
> 
>    SIMPLEQ_INIT(&khsem_freeq);
>    mutex_init(&khsem_mutex, MUTEX_DEFAULT, IPL_NONE);
> 
>    sz = ALIGN(khsem_max * sizeof(struct khsem));
>    sz = round_page(sz);
> 
>    // XXX allocate memory
> 
>    for (i = 0; i < khsem_max; i++) {
>        hsems[i].khs_id = i;
>        mutex_init(&hsems[i].khs_interlock, MUTEX_DEFAULT, IPL_NONE);
>        cv_init(&hsems[i].khs_cv, "acquire_sem");
> 
>        SIMPLEQ_INSERT_TAIL(&khsem_freeq, &hsems[i], khs_entry); //
> <<---- DOES NOT COMPILE
>    }
> 
> }
> 
> 
> The control structure looks like this:
> 
> struct khsem {
>  sem_id                  khs_id;             /* id of this semaphore */
>  SIMPLEQ_ENTRY(kshem)    khs_entry;          /* free list entry */

Use SIMPLEQ_ENTRY(khsem) here ( s/sh/hs/ )?

>  kmutex_t                khs_interlock;      /* lock on this semaphore */
>  kcondvar_t              khs_cv;             /* CV for wait events */
>  pid_t                   khs_owner;          /* owning process */
>  char                    *khs_name;          /* name of this semaphore */
>  size_t                  khs_namelen;        /* length of name */
>  int                     khs_state;          /* state of this port */
>  int                     khs_waiters;
>  int                     khs_count;          /* current count */
>  lwpid_t                 khs_latest_holder;  /* latest holder LWP id */
>  uid_t                   khs_uid;            /* creator uid */
>  gid_t                   khs_gid;            /* creator gid */
> };
> 
> 
> 
> Any help is appreciated ;)
> 
> Thanks,
> 
> Stephan

--
J. Hannken-Illjes - [email protected]
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