svn commit: r317370 - head/sys/cam/ctl

[Alexander Motin]

Author: mav
Date: Mon Apr 24 12:52:42 2017
New Revision: 317370
URL: https://svnweb.freebsd.org/changeset/base/317370

Log:
  Change ctl_free_lun() locking.
  
  This fixes potential callout_drain() sleep under non-sleepable lock.
  
  PR:           218167
  MFC after:    2 weeks

Modified:
  head/sys/cam/ctl/ctl.c

Modified: head/sys/cam/ctl/ctl.c
==============================================================================
--- head/sys/cam/ctl/ctl.c      Mon Apr 24 12:44:04 2017        (r317369)
+++ head/sys/cam/ctl/ctl.c      Mon Apr 24 12:52:42 2017        (r317370)
@@ -4731,18 +4731,20 @@ ctl_free_lun(struct ctl_lun *lun)
        struct ctl_lun *nlun;
        int i;
 
-       mtx_assert(&softc->ctl_lock, MA_OWNED);
+       KASSERT(TAILQ_EMPTY(&lun->ooa_queue),
+           ("Freeing a LUN %p with outstanding I/O!\n", lun));
 
+       mtx_lock(&softc->ctl_lock);
        STAILQ_REMOVE(&softc->lun_list, lun, ctl_lun, links);
-
        ctl_clear_mask(softc->ctl_lun_mask, lun->lun);
-
        softc->ctl_luns[lun->lun] = NULL;
-
-       if (!TAILQ_EMPTY(&lun->ooa_queue))
-               panic("Freeing a LUN %p with outstanding I/O!!\n", lun);
-
        softc->num_luns--;
+       STAILQ_FOREACH(nlun, &softc->lun_list, links) {
+               mtx_lock(&nlun->lun_lock);
+               ctl_est_ua_all(nlun, -1, CTL_UA_LUN_CHANGE);
+               mtx_unlock(&nlun->lun_lock);
+       }
+       mtx_unlock(&softc->ctl_lock);
 
        /*
         * Tell the backend to free resources, if this LUN has a backend.
@@ -4752,7 +4754,6 @@ ctl_free_lun(struct ctl_lun *lun)
 
        lun->ie_reportcnt = UINT32_MAX;
        callout_drain(&lun->ie_callout);
-
        ctl_tpc_lun_shutdown(lun);
        mtx_destroy(&lun->lun_lock);
        free(lun->lun_devid, M_CTL);
@@ -4765,12 +4766,6 @@ ctl_free_lun(struct ctl_lun *lun)
        if (lun->flags & CTL_LUN_MALLOCED)
                free(lun, M_CTL);
 
-       STAILQ_FOREACH(nlun, &softc->lun_list, links) {
-               mtx_lock(&nlun->lun_lock);
-               ctl_est_ua_all(nlun, -1, CTL_UA_LUN_CHANGE);
-               mtx_unlock(&nlun->lun_lock);
-       }
-
        return (0);
 }
 
@@ -5027,9 +5022,7 @@ ctl_invalidate_lun(struct ctl_be_lun *be
         */
        if (TAILQ_EMPTY(&lun->ooa_queue)) {
                mtx_unlock(&lun->lun_lock);
-               mtx_lock(&softc->ctl_lock);
                ctl_free_lun(lun);
-               mtx_unlock(&softc->ctl_lock);
        } else
                mtx_unlock(&lun->lun_lock);
 
@@ -13068,9 +13061,7 @@ ctl_process_done(union ctl_io *io)
        if ((lun->flags & CTL_LUN_INVALID)
         && TAILQ_EMPTY(&lun->ooa_queue)) {
                mtx_unlock(&lun->lun_lock);
-               mtx_lock(&softc->ctl_lock);
                ctl_free_lun(lun);
-               mtx_unlock(&softc->ctl_lock);
        } else
                mtx_unlock(&lun->lun_lock);
 
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