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Push down Giant one layer. In the days of yore, back when Penitums

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were the new kids on the block and F00F hacks were all the rage, one
needed to take out Giant to do anything moderately complicated with
the VM, mappings and such. So the pccard / cardbus code held Giant for
the entire insertion or removal process.

Today, the VM is MP safe. The lock is only needed for dealing with
newbus things. Move locking and unlocking Giant to be only around
adding and probing devices in pccard and cardbus.
This commit is contained in:
Warner Losh 2018-03-20 22:01:18 +00:00
parent c176562d38
commit 4e96c99bdf
3 changed files with 4 additions and 9 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
sys/dev/cardbus/cardbus.c
View File

@ -197,6 +197,7 @@ cardbus_attach_card(device_t cbdev)
domain = pcib_get_domain(cbdev);
bus = pcib_get_bus(cbdev);
slot = 0;
mtx_lock(&Giant);
/* For each function, set it up and try to attach a driver to it */
for (func = 0; func <= cardbusfunchigh; func++) {
struct cardbus_devinfo *dinfo;
@ -230,6 +231,7 @@ cardbus_attach_card(device_t cbdev)
else
pci_cfg_save(dinfo->pci.cfg.dev, &dinfo->pci, 1);
}
mtx_unlock(&Giant);
if (cardattached > 0)
return (0);
/* POWER_DISABLE_SOCKET(brdev, cbdev); */

2
sys/dev/pccard/pccard.c
View File

@ -236,6 +236,7 @@ pccard_attach_card(device_t dev)
DEVPRINTF((dev, "Card has %d functions. pccard_mfc is %d\n", i + 1,
pccard_mfc(sc)));
mtx_lock(&Giant);
STAILQ_FOREACH(pf, &sc->card.pf_head, pf_list) {
if (STAILQ_EMPTY(&pf->cfe_head))
continue;
@ -248,6 +249,7 @@ pccard_attach_card(device_t dev)
pf->dev = child;
pccard_probe_and_attach_child(dev, child, pf);
}
mtx_unlock(&Giant);
return (0);
}

9
sys/dev/pccbb/pccbb.c
View File

@ -470,14 +470,6 @@ cbb_event_thread(void *arg)
sc->flags |= CBB_KTHREAD_RUNNING;
while ((sc->flags & CBB_KTHREAD_DONE) == 0) {
mtx_unlock(&sc->mtx);
/*
* We take out Giant here because we need it deep,
* down in the bowels of the vm system for mapping the
* memory we need to read the CIS. In addition, since
* we are adding/deleting devices from the dev tree,
* and that code isn't MP safe, we have to hold Giant.
*/
mtx_lock(&Giant);
status = cbb_get(sc, CBB_SOCKET_STATE);
DPRINTF(("Status is 0x%x\n", status));
if (!CBB_CARD_PRESENT(status)) {
@ -503,7 +495,6 @@ cbb_event_thread(void *arg)
not_a_card = 0; /* We know card type */
cbb_insert(sc);
}
mtx_unlock(&Giant);
/*
* First time through we need to tell mountroot that we're