Completes the implemenation of the core shared memory logic: shmget(), shmctl(), shmat(), and shmdt(). This is still some unfinish platform-specific code that needs to be done before we can begin testing.
This commit is contained in:
Gregory Nutt
parent
d546ebabe4
commit
0f97d81f8d
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@ -42,6 +42,12 @@
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#include <sys/shm.h>
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#include <errno.h>
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#include <nuttx/sched.h>
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#include <nuttx/arch.h>
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#include <nuttx/pgalloc.h>
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#include "shm/shm.h"
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#ifdef CONFIG_MM_SHM
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/****************************************************************************
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@ -94,7 +100,8 @@
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* Returned Value:
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* Upon successful completion, shmat() will increment the value of
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* shm_nattch in the data structure associated with the shared memory ID
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* of the attached shared memory segment and return the segment's start address.
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* of the attached shared memory segment and return the segment's start
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* address.
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*
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* Otherwise, the shared memory segment will not be attached, shmat() will
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* return -1, and errno will be set to indicate the error.
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@ -119,8 +126,91 @@
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FAR void *shmat(int shmid, FAR const void *shmaddr, int shmflg)
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{
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#warning Not implemented
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set_errno(ENOSYS);
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FAR struct shm_region_s *region;
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FAR struct task_group_s *group;
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FAR struct tcb_s *tcb;
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uintptr_t vaddr;
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unsigned int npages;
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int ret;
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/* Get the region associated with the shmid */
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DEBUGASSERT(shmid >= 0 && shmid < CONFIG_ARCH_SHM_MAXREGIONS);
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region = &g_shminfo.si_region[shmid];
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DEBUGASSERT((region->sr_flags & SRFLAG_INUSE) != 0);
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/* Get the TCB and group containing our virtual memory allocator */
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tcb = sched_self();
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DEBUGASSERT(tcb && tcb->group);
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group = tcb->group;
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DEBUGASSERT(group->tg_shm.gs_handle != NULL &&
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group->tg_shm.gs_vaddr[shmid] == 0);
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/* Get exclusive access to the region data structure */
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ret = sem_wait(®ion->sr_sem);
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if (ret < 0)
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{
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shmdbg("sem_wait failed: %d\n", ret);
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goto errout;
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}
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/* Set aside a virtual address space to span this physical region */
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vaddr = (uintptr_t)gran_alloc(group->tg_shm.gs_handle,
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region->sr_ds.shm_segsz);
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if (vaddr == 0)
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{
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shmdbg("gran_alloc() failed\n");
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ret = -ENOMEM;
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goto errout_with_semaphore;
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}
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/* Convert the region size to pages */
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npages = MM_PGALIGNUP(region->sr_ds.shm_segsz);
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/* Attach, i.e, map, on shared memory region to the user virtual address. */
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ret = up_shmat(region->sr_pages, npages, vaddr);
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if (ret < 0)
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{
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shmdbg("up_shmat() failed\n");
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goto errout_with_vaddr;
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}
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/* Save the virtual address of the region. We will need that in shmat()
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* to do the reverse lookup: Give the virtual address of the region to
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* detach, we need to get the region table index.
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*/
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group->tg_shm.gs_vaddr[shmid] = vaddr;
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/* Increment the count of processes attached to this region */
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region->sr_ds.shm_nattch++;
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/* Save the process ID of the the last operation */
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region->sr_ds.shm_lpid = tcb->pid;
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/* Save the time of the last shmat() */
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region->sr_ds.shm_atime = time(NULL);
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/* Release our lock on the entry */
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sem_post(®ion->sr_sem);
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return (FAR void *)vaddr;
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errout_with_vaddr:
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gran_free(group->tg_shm.gs_handle, (FAR void *)vaddr,
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region->sr_ds.shm_segsz);
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errout_with_semaphore:
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sem_post(®ion->sr_sem);
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set_errno(-ret);
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errout:
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return (FAR void *)ERROR;
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}
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@ -33,17 +33,23 @@
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*
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****************************************************************************/
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <nuttx/config.h>
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#include <sys/shm.h>
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#include <errno.h>
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#ifdef CONFIG_MM_SHM
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <nuttx/config.h>
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#include <sys/shm.h>
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#include <errno.h>
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#include <nuttx/arch.h>
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#include <nuttx/sched.h>
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#include <nuttx/shm.h>
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#include "shm/shm.h"
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#ifdef CONFIG_MM_SHM
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/****************************************************************************
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* Pre-processor Definitions
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****************************************************************************/
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@ -87,13 +93,119 @@
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* The value of shmaddr is not the data segment start address of a
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* shared memory segment.
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*
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****************************************************************************/
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****************************************************************************/
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int shmdt(FAR const void *shmaddr)
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{
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#warning Not implemented
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set_errno(ENOSYS);
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return ERROR;
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}
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{
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FAR struct shm_region_s *region;
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FAR struct task_group_s *group;
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FAR struct tcb_s *tcb;
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unsigned int npages;
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int shmid;
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int ret;
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/* Get the TCB and group containing our virtual memory allocator */
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tcb = sched_self();
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DEBUGASSERT(tcb && tcb->group);
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group = tcb->group;
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DEBUGASSERT(group->tg_shm.gs_handle != NULL);
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/* Perform the reverse lookup to get the shmid corresponding to this
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* shmaddr.
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*/
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for (shmid = 0;
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shmid < CONFIG_ARCH_SHM_MAXREGIONS &&
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group->tg_shm.gs_vaddr[shmid] != (uintptr_t)shmaddr;
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shmid++);
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if (shmid >= CONFIG_ARCH_SHM_MAXREGIONS)
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{
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shmdbg("No region matching this virtual address: %p\n", shmaddr);
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ret = -EINVAL;
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goto errout_with_errno;
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}
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/* Get the region associated with the shmid */
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region = &g_shminfo.si_region[shmid];
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DEBUGASSERT((region->sr_flags & SRFLAG_INUSE) != 0);
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/* Get exclusive access to the region data structure */
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ret = sem_wait(®ion->sr_sem);
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if (ret < 0)
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{
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shmdbg("sem_wait failed: %d\n", ret);
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goto errout;
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}
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/* Free the virtual address space */
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gran_free(group->tg_shm.gs_handle, (FAR void *)shmaddr,
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region->sr_ds.shm_segsz);
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/* Convert the region size to pages */
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npages = MM_PGALIGNUP(region->sr_ds.shm_segsz);
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/* Detach, i.e, unmap, on shared memory region from a user virtual
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* address.
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*/
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ret = up_shmdt((uintptr_t)shmaddr, npages);
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if (ret < 0)
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{
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shmdbg("up_shmdt() failed\n");
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}
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/* Indicate that there is no longer any mapping for this region. */
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group->tg_shm.gs_vaddr[shmid] = 0;
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/* Decrement the count of processes attached to this region.
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* If the count decrements to zero and there is a pending unlink,
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* then destroy the shared memory region now and stop any further
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* operations on it.
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*/
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DEBUGASSERT(region->sr_ds.shm_nattch > 0);
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if (region->sr_ds.shm_nattch <= 1)
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{
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region->sr_ds.shm_nattch = 0;
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if ((region->sr_flags & SRFLAG_UNLINKED) != 0)
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{
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shm_destroy(shmid);
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return OK;
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}
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}
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else
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{
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/* Just decrement the number of processes attached to the shared
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* memory region.
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*/
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region->sr_ds.shm_nattch--;
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}
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/* Save the process ID of the the last operation */
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region->sr_ds.shm_lpid = tcb->pid;
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/* Save the time of the last shmdt() */
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region->sr_ds.shm_dtime = time(NULL);
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/* Release our lock on the entry */
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sem_post(®ion->sr_sem);
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return OK;
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errout_with_errno:
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set_errno(-ret);
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errout:
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return ERROR;
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}
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#endif /* CONFIG_MM_SHM */
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