/**
* Unlink the memory descriptor from any ME it may be linked to and release
* the internal resources associated with it. As a result, active messages
* associated with the MD may get aborted.
*
* This function does not free the memory region associated with the MD;
* i.e., the memory the user allocated for this MD. If the ME associated with
* this MD is not NULL and was created with auto unlink enabled, the ME is
* unlinked as well (see LNetMEAttach()).
*
* Explicitly unlinking a MD via this function call has the same behavior as
* a MD that has been automatically unlinked, except that no LNET_EVENT_UNLINK
* is generated in the latter case.
*
* An unlinked event can be reported in two ways:
* - If there's no pending operations on the MD, it's unlinked immediately
* and an LNET_EVENT_UNLINK event is logged before this function returns.
* - Otherwise, the MD is only marked for deletion when this function
* returns, and the unlinked event will be piggybacked on the event of
* the completion of the last operation by setting the unlinked field of
* the event. No dedicated LNET_EVENT_UNLINK event is generated.
*
* Note that in both cases the unlinked field of the event is always set; no
* more event will happen on the MD after such an event is logged.
*
* \param mdh A handle for the MD to be unlinked.
*
* \retval 0 On success.
* \retval -ENOENT If \a mdh does not point to a valid MD object.
*/
int
LNetMDUnlink (lnet_handle_md_t mdh)
{
lnet_event_t ev;
lnet_libmd_t *md;
int cpt;
LASSERT(the_lnet.ln_init);
LASSERT(the_lnet.ln_refcount > 0);
cpt = lnet_cpt_of_cookie(mdh.cookie);
lnet_res_lock(cpt);
md = lnet_handle2md(&mdh);
if (md == NULL) {
lnet_res_unlock(cpt);
return -ENOENT;
}
md->md_flags |= LNET_MD_FLAG_ABORTED;
/* If the MD is busy, lnet_md_unlink just marks it for deletion, and
* when the LND is done, the completion event flags that the MD was
* unlinked. Otherwise, we enqueue an event now... */
if (md->md_eq != NULL && md->md_refcount == 0) {
lnet_build_unlink_event(md, &ev);
lnet_eq_enqueue_event(md->md_eq, &ev);
}
lnet_md_unlink(md);
lnet_res_unlock(cpt);
return 0;
}
/* must be called with lnet_res_lock held */
void
lnet_md_unlink(struct lnet_libmd *md)
{
if (!(md->md_flags & LNET_MD_FLAG_ZOMBIE)) {
/* first unlink attempt... */
struct lnet_me *me = md->md_me;
md->md_flags |= LNET_MD_FLAG_ZOMBIE;
/*
* Disassociate from ME (if any),
* and unlink it if it was created
* with LNET_UNLINK
*/
if (me) {
/* detach MD from portal */
lnet_ptl_detach_md(me, md);
if (me->me_unlink == LNET_UNLINK)
lnet_me_unlink(me);
}
/* ensure all future handle lookups fail */
lnet_res_lh_invalidate(&md->md_lh);
}
if (md->md_refcount) {
CDEBUG(D_NET, "Queueing unlink of md %p\n", md);
return;
}
CDEBUG(D_NET, "Unlinking md %p\n", md);
if (md->md_eq) {
int cpt = lnet_cpt_of_cookie(md->md_lh.lh_cookie);
LASSERT(*md->md_eq->eq_refs[cpt] > 0);
(*md->md_eq->eq_refs[cpt])--;
}
LASSERT(!list_empty(&md->md_list));
list_del_init(&md->md_list);
lnet_md_free(md);
}
/**
* Create a memory descriptor and attach it to a ME
*
* \param meh A handle for a ME to associate the new MD with.
* \param umd Provides initial values for the user-visible parts of a MD.
* Other than its use for initialization, there is no linkage between this
* structure and the MD maintained by the LNet.
* \param unlink A flag to indicate whether the MD is automatically unlinked
* when it becomes inactive, either because the operation threshold drops to
* zero or because the available memory becomes less than \a umd.max_size.
* (Note that the check for unlinking a MD only occurs after the completion
* of a successful operation on the MD.) The value LNET_UNLINK enables auto
* unlinking; the value LNET_RETAIN disables it.
* \param handle On successful returns, a handle to the newly created MD is
* saved here. This handle can be used later in LNetMDUnlink().
*
* \retval 0 On success.
* \retval -EINVAL If \a umd is not valid.
* \retval -ENOMEM If new MD cannot be allocated.
* \retval -ENOENT Either \a meh or \a umd.eq_handle does not point to a
* valid object. Note that it's OK to supply a NULL \a umd.eq_handle by
* calling LNetInvalidateHandle() on it.
* \retval -EBUSY If the ME pointed to by \a meh is already associated with
* a MD.
*/
int
LNetMDAttach(lnet_handle_me_t meh, lnet_md_t umd,
lnet_unlink_t unlink, lnet_handle_md_t *handle)
{
CFS_LIST_HEAD (matches);
CFS_LIST_HEAD (drops);
struct lnet_me *me;
struct lnet_libmd *md;
int cpt;
int rc;
LASSERT (the_lnet.ln_init);
LASSERT (the_lnet.ln_refcount > 0);
if (lnet_md_validate(&umd) != 0)
return -EINVAL;
if ((umd.options & (LNET_MD_OP_GET | LNET_MD_OP_PUT)) == 0) {
CERROR("Invalid option: no MD_OP set\n");
return -EINVAL;
}
md = lnet_md_alloc(&umd);
if (md == NULL)
return -ENOMEM;
rc = lnet_md_build(md, &umd, unlink);
cpt = lnet_cpt_of_cookie(meh.cookie);
lnet_res_lock(cpt);
if (rc != 0)
goto failed;
me = lnet_handle2me(&meh);
if (me == NULL)
rc = -ENOENT;
else if (me->me_md != NULL)
rc = -EBUSY;
else
rc = lnet_md_link(md, umd.eq_handle, cpt);
if (rc != 0)
goto failed;
/* attach this MD to portal of ME and check if it matches any
* blocked msgs on this portal */
lnet_ptl_attach_md(me, md, &matches, &drops);
lnet_md2handle(handle, md);
lnet_res_unlock(cpt);
lnet_drop_delayed_msg_list(&drops, "Bad match");
lnet_recv_delayed_msg_list(&matches);
return 0;
failed:
lnet_md_free_locked(md);
lnet_res_unlock(cpt);
return rc;
}
/**
* Create a memory descriptor and attach it to a ME
*
* \param meh A handle for a ME to associate the new MD with.
* \param umd Provides initial values for the user-visible parts of a MD.
* Other than its use for initialization, there is no linkage between this
* structure and the MD maintained by the LNet.
* \param unlink A flag to indicate whether the MD is automatically unlinked
* when it becomes inactive, either because the operation threshold drops to
* zero or because the available memory becomes less than \a umd.max_size.
* (Note that the check for unlinking a MD only occurs after the completion
* of a successful operation on the MD.) The value LNET_UNLINK enables auto
* unlinking; the value LNET_RETAIN disables it.
* \param handle On successful returns, a handle to the newly created MD is
* saved here. This handle can be used later in LNetMDUnlink().
*
* \retval 0 On success.
* \retval -EINVAL If \a umd is not valid.
* \retval -ENOMEM If new MD cannot be allocated.
* \retval -ENOENT Either \a meh or \a umd.eq_handle does not point to a
* valid object. Note that it's OK to supply a NULL \a umd.eq_handle by
* calling LNetInvalidateHandle() on it.
* \retval -EBUSY If the ME pointed to by \a meh is already associated with
* a MD.
*/
int
LNetMDAttach(struct lnet_handle_me meh, struct lnet_md umd,
enum lnet_unlink unlink, struct lnet_handle_md *handle)
{
LIST_HEAD(matches);
LIST_HEAD(drops);
struct lnet_me *me;
struct lnet_libmd *md;
int cpt;
int rc;
LASSERT(the_lnet.ln_refcount > 0);
if (lnet_md_validate(&umd))
return -EINVAL;
if (!(umd.options & (LNET_MD_OP_GET | LNET_MD_OP_PUT))) {
CERROR("Invalid option: no MD_OP set\n");
return -EINVAL;
}
md = lnet_md_alloc(&umd);
if (!md)
return -ENOMEM;
rc = lnet_md_build(md, &umd, unlink);
if (rc)
goto out_free;
cpt = lnet_cpt_of_cookie(meh.cookie);
lnet_res_lock(cpt);
me = lnet_handle2me(&meh);
if (!me)
rc = -ENOENT;
else if (me->me_md)
rc = -EBUSY;
else
rc = lnet_md_link(md, umd.eq_handle, cpt);
if (rc)
goto out_unlock;
/*
* attach this MD to portal of ME and check if it matches any
* blocked msgs on this portal
*/
lnet_ptl_attach_md(me, md, &matches, &drops);
lnet_md2handle(handle, md);
lnet_res_unlock(cpt);
lnet_drop_delayed_msg_list(&drops, "Bad match");
lnet_recv_delayed_msg_list(&matches);
return 0;
out_unlock:
lnet_res_unlock(cpt);
out_free:
lnet_md_free(md);
return rc;
}