Date: Wed, 28 Mar 2007 18:55:47 GMT From: Scott Long <scottl@FreeBSD.org> To: Perforce Change Reviews <perforce@freebsd.org> Subject: PERFORCE change 116764 for review Message-ID: <200703281855.l2SItlu2011136@repoman.freebsd.org>
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http://perforce.freebsd.org/chv.cgi?CH=116764 Change 116764 by scottl@scottl-x64 on 2007/03/28 18:55:25 Lock the xpt_rescan functions. Affected files ... .. //depot/projects/scottl-camlock/src/sys/cam/cam_xpt.c#51 edit Differences ... ==== //depot/projects/scottl-camlock/src/sys/cam/cam_xpt.c#51 (text+ko) ==== @@ -247,6 +247,9 @@ STAILQ_HEAD(highpowerlist, ccb_hdr) highpowerq; int num_highpower; + /* queue for handling async rescan requests. */ + TAILQ_HEAD(, ccb_hdr) ccb_scanq; + /* Registered busses */ TAILQ_HEAD(,cam_eb) xpt_busses; u_int bus_generation; @@ -1405,22 +1408,40 @@ } /* thread to handle bus rescans */ -static TAILQ_HEAD(, ccb_hdr) ccb_scanq; static void xpt_scanner_thread(void *dummy) { - mtx_lock(&Giant); + cam_isrq_t queue; + union ccb *ccb; + struct cam_sim *sim; + for (;;) { - union ccb *ccb; - tsleep(&ccb_scanq, PRIBIO, "ccb_scanq", 0); - while ((ccb = (union ccb *)TAILQ_FIRST(&ccb_scanq)) != NULL) { - TAILQ_REMOVE(&ccb_scanq, &ccb->ccb_h, sim_links.tqe); + /* + * Wait for a rescan request to come in. When it does, splice + * it onto a queue from local storage so that the xpt lock + * doesn't need to be held while the requests are being + * processed. + */ + xpt_lock_buses(); + msleep(&xsoftc.ccb_scanq, &xsoftc.xpt_lock, PRIBIO, + "ccb_scanq", 0); + TAILQ_INIT(&queue); + TAILQ_CONCAT(&queue, &xsoftc.ccb_scanq, sim_links.tqe); + xpt_unlock_buses(); + + while ((ccb = (union ccb *)TAILQ_FIRST(&queue)) != NULL) { + TAILQ_REMOVE(&queue, &ccb->ccb_h, sim_links.tqe); + + sim = ccb->ccb_h.path->bus->sim; + mtx_lock(sim->mtx); + ccb->ccb_h.func_code = XPT_SCAN_BUS; ccb->ccb_h.cbfcnp = xptdone; xpt_setup_ccb(&ccb->ccb_h, ccb->ccb_h.path, 5); cam_periph_runccb(ccb, NULL, 0, 0, NULL); xpt_free_path(ccb->ccb_h.path); xpt_free_ccb(ccb); + mtx_unlock(sim->mtx); } } } @@ -1429,20 +1450,23 @@ xpt_rescan(union ccb *ccb) { struct ccb_hdr *hdr; - GIANT_REQUIRED; + /* * Don't make duplicate entries for the same paths. */ - TAILQ_FOREACH(hdr, &ccb_scanq, sim_links.tqe) { + xpt_lock_buses(); + TAILQ_FOREACH(hdr, &xsoftc.ccb_scanq, sim_links.tqe) { if (xpt_path_comp(hdr->path, ccb->ccb_h.path) == 0) { + xpt_unlock_buses(); xpt_print(ccb->ccb_h.path, "rescan already queued\n"); xpt_free_path(ccb->ccb_h.path); xpt_free_ccb(ccb); return; } } - TAILQ_INSERT_TAIL(&ccb_scanq, &ccb->ccb_h, sim_links.tqe); - wakeup(&ccb_scanq); + TAILQ_INSERT_TAIL(&xsoftc.ccb_scanq, &ccb->ccb_h, sim_links.tqe); + wakeup(&xsoftc.ccb_scanq); + xpt_unlock_buses(); } /* Functions accessed by the peripheral drivers */ @@ -1456,7 +1480,7 @@ TAILQ_INIT(&xsoftc.xpt_busses); TAILQ_INIT(&cam_bioq); - TAILQ_INIT(&ccb_scanq); + TAILQ_INIT(&xsoftc.ccb_scanq); STAILQ_INIT(&xsoftc.highpowerq); xsoftc.num_highpower = CAM_MAX_HIGHPOWER;
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