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freebsd-skq/sys/dev/xen/blkfront/blkfront.c
Pedro F. Giffuni 453130d9bf sys/dev: minor spelling fixes. 
Most affect comments, very few have user-visible effects.
2016-05-03 03:41:25 +00:00

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/*
* XenBSD block device driver
*
* Copyright (c) 2010-2013 Spectra Logic Corporation
* Copyright (c) 2009 Scott Long, Yahoo!
* Copyright (c) 2009 Frank Suchomel, Citrix
* Copyright (c) 2009 Doug F. Rabson, Citrix
* Copyright (c) 2005 Kip Macy
* Copyright (c) 2003-2004, Keir Fraser & Steve Hand
* Modifications by Mark A. Williamson are (c) Intel Research Cambridge
*
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to
* deal in the Software without restriction, including without limitation the
* rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
* sell copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
* DEALINGS IN THE SOFTWARE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/malloc.h>
#include <sys/kernel.h>
#include <vm/vm.h>
#include <vm/pmap.h>
#include <sys/bio.h>
#include <sys/bus.h>
#include <sys/conf.h>
#include <sys/module.h>
#include <sys/sysctl.h>
#include <machine/bus.h>
#include <sys/rman.h>
#include <machine/resource.h>
#include <machine/intr_machdep.h>
#include <machine/vmparam.h>
#include <sys/bus_dma.h>
#include <xen/xen-os.h>
#include <xen/hypervisor.h>
#include <xen/xen_intr.h>
#include <xen/gnttab.h>
#include <xen/interface/grant_table.h>
#include <xen/interface/io/protocols.h>
#include <xen/xenbus/xenbusvar.h>
#include <machine/_inttypes.h>
#include <geom/geom_disk.h>
#include <dev/xen/blkfront/block.h>
#include "xenbus_if.h"
/*--------------------------- Forward Declarations ---------------------------*/
static void xbd_closing(device_t);
static void xbd_startio(struct xbd_softc *sc);
/*---------------------------------- Macros ----------------------------------*/
#if 0
#define DPRINTK(fmt, args...) printf("[XEN] %s:%d: " fmt ".\n", __func__, __LINE__, ##args)
#else
#define DPRINTK(fmt, args...)
#endif
#define XBD_SECTOR_SHFT 9
/*---------------------------- Global Static Data ----------------------------*/
static MALLOC_DEFINE(M_XENBLOCKFRONT, "xbd", "Xen Block Front driver data");
static int xbd_enable_indirect = 1;
SYSCTL_NODE(_hw, OID_AUTO, xbd, CTLFLAG_RD, 0, "xbd driver parameters");
SYSCTL_INT(_hw_xbd, OID_AUTO, xbd_enable_indirect, CTLFLAG_RDTUN,
&xbd_enable_indirect, 0, "Enable xbd indirect segments");
/*---------------------------- Command Processing ----------------------------*/
static void
xbd_freeze(struct xbd_softc *sc, xbd_flag_t xbd_flag)
{
if (xbd_flag != XBDF_NONE && (sc->xbd_flags & xbd_flag) != 0)
return;
sc->xbd_flags |= xbd_flag;
sc->xbd_qfrozen_cnt++;
}
static void
xbd_thaw(struct xbd_softc *sc, xbd_flag_t xbd_flag)
{
if (xbd_flag != XBDF_NONE && (sc->xbd_flags & xbd_flag) == 0)
return;
if (sc->xbd_qfrozen_cnt == 0)
panic("%s: Thaw with flag 0x%x while not frozen.",
__func__, xbd_flag);
sc->xbd_flags &= ~xbd_flag;
sc->xbd_qfrozen_cnt--;
}
static void
xbd_cm_freeze(struct xbd_softc *sc, struct xbd_command *cm, xbdc_flag_t cm_flag)
{
if ((cm->cm_flags & XBDCF_FROZEN) != 0)
return;
cm->cm_flags |= XBDCF_FROZEN|cm_flag;
xbd_freeze(sc, XBDF_NONE);
}
static void
xbd_cm_thaw(struct xbd_softc *sc, struct xbd_command *cm)
{
if ((cm->cm_flags & XBDCF_FROZEN) == 0)
return;
cm->cm_flags &= ~XBDCF_FROZEN;
xbd_thaw(sc, XBDF_NONE);
}
static inline void
xbd_flush_requests(struct xbd_softc *sc)
{
int notify;
RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&sc->xbd_ring, notify);
if (notify)
xen_intr_signal(sc->xen_intr_handle);
}
static void
xbd_free_command(struct xbd_command *cm)
{
KASSERT((cm->cm_flags & XBDCF_Q_MASK) == XBD_Q_NONE,
("Freeing command that is still on queue %d.",
cm->cm_flags & XBDCF_Q_MASK));
cm->cm_flags = XBDCF_INITIALIZER;
cm->cm_bp = NULL;
cm->cm_complete = NULL;
xbd_enqueue_cm(cm, XBD_Q_FREE);
xbd_thaw(cm->cm_sc, XBDF_CM_SHORTAGE);
}
static void
xbd_mksegarray(bus_dma_segment_t *segs, int nsegs,
grant_ref_t * gref_head, int otherend_id, int readonly,
grant_ref_t * sg_ref, struct blkif_request_segment *sg)
{
struct blkif_request_segment *last_block_sg = sg + nsegs;
vm_paddr_t buffer_ma;
uint64_t fsect, lsect;
int ref;
while (sg < last_block_sg) {
KASSERT(segs->ds_addr % (1 << XBD_SECTOR_SHFT) == 0,
("XEN disk driver I/O must be sector aligned"));
KASSERT(segs->ds_len % (1 << XBD_SECTOR_SHFT) == 0,
("XEN disk driver I/Os must be a multiple of "
"the sector length"));
buffer_ma = segs->ds_addr;
fsect = (buffer_ma & PAGE_MASK) >> XBD_SECTOR_SHFT;
lsect = fsect + (segs->ds_len >> XBD_SECTOR_SHFT) - 1;
KASSERT(lsect <= 7, ("XEN disk driver data cannot "
"cross a page boundary"));
/* install a grant reference. */
ref = gnttab_claim_grant_reference(gref_head);
/*
* GNTTAB_LIST_END == 0xffffffff, but it is private
* to gnttab.c.
*/
KASSERT(ref != ~0, ("grant_reference failed"));
gnttab_grant_foreign_access_ref(
ref,
otherend_id,
buffer_ma >> PAGE_SHIFT,
readonly);
*sg_ref = ref;
*sg = (struct blkif_request_segment) {
.gref = ref,
.first_sect = fsect,
.last_sect = lsect
};
sg++;
sg_ref++;
segs++;
}
}
static void
xbd_queue_cb(void *arg, bus_dma_segment_t *segs, int nsegs, int error)
{
struct xbd_softc *sc;
struct xbd_command *cm;
int op;
cm = arg;
sc = cm->cm_sc;
if (error) {
cm->cm_bp->bio_error = EIO;
biodone(cm->cm_bp);
xbd_free_command(cm);
return;
}
KASSERT(nsegs <= sc->xbd_max_request_segments,
("Too many segments in a blkfront I/O"));
if (nsegs <= BLKIF_MAX_SEGMENTS_PER_REQUEST) {
blkif_request_t *ring_req;
/* Fill out a blkif_request_t structure. */
ring_req = (blkif_request_t *)
RING_GET_REQUEST(&sc->xbd_ring, sc->xbd_ring.req_prod_pvt);
sc->xbd_ring.req_prod_pvt++;
ring_req->id = cm->cm_id;
ring_req->operation = cm->cm_operation;
ring_req->sector_number = cm->cm_sector_number;
ring_req->handle = (blkif_vdev_t)(uintptr_t)sc->xbd_disk;
ring_req->nr_segments = nsegs;
cm->cm_nseg = nsegs;
xbd_mksegarray(segs, nsegs, &cm->cm_gref_head,
xenbus_get_otherend_id(sc->xbd_dev),
cm->cm_operation == BLKIF_OP_WRITE,
cm->cm_sg_refs, ring_req->seg);
} else {
blkif_request_indirect_t *ring_req;
/* Fill out a blkif_request_indirect_t structure. */
ring_req = (blkif_request_indirect_t *)
RING_GET_REQUEST(&sc->xbd_ring, sc->xbd_ring.req_prod_pvt);
sc->xbd_ring.req_prod_pvt++;
ring_req->id = cm->cm_id;
ring_req->operation = BLKIF_OP_INDIRECT;
ring_req->indirect_op = cm->cm_operation;
ring_req->sector_number = cm->cm_sector_number;
ring_req->handle = (blkif_vdev_t)(uintptr_t)sc->xbd_disk;
ring_req->nr_segments = nsegs;
cm->cm_nseg = nsegs;
xbd_mksegarray(segs, nsegs, &cm->cm_gref_head,
xenbus_get_otherend_id(sc->xbd_dev),
cm->cm_operation == BLKIF_OP_WRITE,
cm->cm_sg_refs, cm->cm_indirectionpages);
memcpy(ring_req->indirect_grefs, &cm->cm_indirectionrefs,
sizeof(grant_ref_t) * sc->xbd_max_request_indirectpages);
}
if (cm->cm_operation == BLKIF_OP_READ)
op = BUS_DMASYNC_PREREAD;
else if (cm->cm_operation == BLKIF_OP_WRITE)
op = BUS_DMASYNC_PREWRITE;
else
op = 0;
bus_dmamap_sync(sc->xbd_io_dmat, cm->cm_map, op);
gnttab_free_grant_references(cm->cm_gref_head);
xbd_enqueue_cm(cm, XBD_Q_BUSY);
/*
* If bus dma had to asynchronously call us back to dispatch
* this command, we are no longer executing in the context of
* xbd_startio(). Thus we cannot rely on xbd_startio()'s call to
* xbd_flush_requests() to publish this command to the backend
* along with any other commands that it could batch.
*/
if ((cm->cm_flags & XBDCF_ASYNC_MAPPING) != 0)
xbd_flush_requests(sc);
return;
}
static int
xbd_queue_request(struct xbd_softc *sc, struct xbd_command *cm)
{
int error;
if (cm->cm_bp != NULL)
error = bus_dmamap_load_bio(sc->xbd_io_dmat, cm->cm_map,
cm->cm_bp, xbd_queue_cb, cm, 0);
else
error = bus_dmamap_load(sc->xbd_io_dmat, cm->cm_map,
cm->cm_data, cm->cm_datalen, xbd_queue_cb, cm, 0);
if (error == EINPROGRESS) {
/*
* Maintain queuing order by freezing the queue. The next
* command may not require as many resources as the command
* we just attempted to map, so we can't rely on bus dma
* blocking for it too.
*/
xbd_cm_freeze(sc, cm, XBDCF_ASYNC_MAPPING);
return (0);
}
return (error);
}
static void
xbd_restart_queue_callback(void *arg)
{
struct xbd_softc *sc = arg;
mtx_lock(&sc->xbd_io_lock);
xbd_thaw(sc, XBDF_GNT_SHORTAGE);
xbd_startio(sc);
mtx_unlock(&sc->xbd_io_lock);
}
static struct xbd_command *
xbd_bio_command(struct xbd_softc *sc)
{
struct xbd_command *cm;
struct bio *bp;
if (__predict_false(sc->xbd_state != XBD_STATE_CONNECTED))
return (NULL);
bp = xbd_dequeue_bio(sc);
if (bp == NULL)
return (NULL);
if ((cm = xbd_dequeue_cm(sc, XBD_Q_FREE)) == NULL) {
xbd_freeze(sc, XBDF_CM_SHORTAGE);
xbd_requeue_bio(sc, bp);
return (NULL);
}
if (gnttab_alloc_grant_references(sc->xbd_max_request_segments,
&cm->cm_gref_head) != 0) {
gnttab_request_free_callback(&sc->xbd_callback,
xbd_restart_queue_callback, sc,
sc->xbd_max_request_segments);
xbd_freeze(sc, XBDF_GNT_SHORTAGE);
xbd_requeue_bio(sc, bp);
xbd_enqueue_cm(cm, XBD_Q_FREE);
return (NULL);
}
cm->cm_bp = bp;
cm->cm_sector_number = (blkif_sector_t)bp->bio_pblkno;
switch (bp->bio_cmd) {
case BIO_READ:
cm->cm_operation = BLKIF_OP_READ;
break;
case BIO_WRITE:
cm->cm_operation = BLKIF_OP_WRITE;
if ((bp->bio_flags & BIO_ORDERED) != 0) {
if ((sc->xbd_flags & XBDF_BARRIER) != 0) {
cm->cm_operation = BLKIF_OP_WRITE_BARRIER;
} else {
/*
* Single step this command.
*/
cm->cm_flags |= XBDCF_Q_FREEZE;
if (xbd_queue_length(sc, XBD_Q_BUSY) != 0) {
/*
* Wait for in-flight requests to
* finish.
*/
xbd_freeze(sc, XBDF_WAIT_IDLE);
xbd_requeue_cm(cm, XBD_Q_READY);
return (NULL);
}
}
}
break;
case BIO_FLUSH:
if ((sc->xbd_flags & XBDF_FLUSH) != 0)
cm->cm_operation = BLKIF_OP_FLUSH_DISKCACHE;
else if ((sc->xbd_flags & XBDF_BARRIER) != 0)
cm->cm_operation = BLKIF_OP_WRITE_BARRIER;
else
panic("flush request, but no flush support available");
break;
default:
panic("unknown bio command %d", bp->bio_cmd);
}
return (cm);
}
/*
* Dequeue buffers and place them in the shared communication ring.
* Return when no more requests can be accepted or all buffers have
* been queued.
*
* Signal XEN once the ring has been filled out.
*/
static void
xbd_startio(struct xbd_softc *sc)
{
struct xbd_command *cm;
int error, queued = 0;
mtx_assert(&sc->xbd_io_lock, MA_OWNED);
if (sc->xbd_state != XBD_STATE_CONNECTED)
return;
while (!RING_FULL(&sc->xbd_ring)) {
if (sc->xbd_qfrozen_cnt != 0)
break;
cm = xbd_dequeue_cm(sc, XBD_Q_READY);
if (cm == NULL)
cm = xbd_bio_command(sc);
if (cm == NULL)
break;
if ((cm->cm_flags & XBDCF_Q_FREEZE) != 0) {
/*
* Single step command. Future work is
* held off until this command completes.
*/
xbd_cm_freeze(sc, cm, XBDCF_Q_FREEZE);
}
if ((error = xbd_queue_request(sc, cm)) != 0) {
printf("xbd_queue_request returned %d\n", error);
break;
}
queued++;
}
if (queued != 0)
xbd_flush_requests(sc);
}
static void
xbd_bio_complete(struct xbd_softc *sc, struct xbd_command *cm)
{
struct bio *bp;
bp = cm->cm_bp;
if (__predict_false(cm->cm_status != BLKIF_RSP_OKAY)) {
disk_err(bp, "disk error" , -1, 0);
printf(" status: %x\n", cm->cm_status);
bp->bio_flags |= BIO_ERROR;
}
if (bp->bio_flags & BIO_ERROR)
bp->bio_error = EIO;
else
bp->bio_resid = 0;
xbd_free_command(cm);
biodone(bp);
}
static void
xbd_int(void *xsc)
{
struct xbd_softc *sc = xsc;
struct xbd_command *cm;
blkif_response_t *bret;
RING_IDX i, rp;
int op;
mtx_lock(&sc->xbd_io_lock);
if (__predict_false(sc->xbd_state == XBD_STATE_DISCONNECTED)) {
mtx_unlock(&sc->xbd_io_lock);
return;
}
again:
rp = sc->xbd_ring.sring->rsp_prod;
rmb(); /* Ensure we see queued responses up to 'rp'. */
for (i = sc->xbd_ring.rsp_cons; i != rp;) {
bret = RING_GET_RESPONSE(&sc->xbd_ring, i);
cm = &sc->xbd_shadow[bret->id];
xbd_remove_cm(cm, XBD_Q_BUSY);
gnttab_end_foreign_access_references(cm->cm_nseg,
cm->cm_sg_refs);
i++;
if (cm->cm_operation == BLKIF_OP_READ)
op = BUS_DMASYNC_POSTREAD;
else if (cm->cm_operation == BLKIF_OP_WRITE ||
cm->cm_operation == BLKIF_OP_WRITE_BARRIER)
op = BUS_DMASYNC_POSTWRITE;
else
op = 0;
bus_dmamap_sync(sc->xbd_io_dmat, cm->cm_map, op);
bus_dmamap_unload(sc->xbd_io_dmat, cm->cm_map);
/*
* Release any hold this command has on future command
* dispatch.
*/
xbd_cm_thaw(sc, cm);
/*
* Directly call the i/o complete routine to save an
* an indirection in the common case.
*/
cm->cm_status = bret->status;
if (cm->cm_bp)
xbd_bio_complete(sc, cm);
else if (cm->cm_complete != NULL)
cm->cm_complete(cm);
else
xbd_free_command(cm);
}
sc->xbd_ring.rsp_cons = i;
if (i != sc->xbd_ring.req_prod_pvt) {
int more_to_do;
RING_FINAL_CHECK_FOR_RESPONSES(&sc->xbd_ring, more_to_do);
if (more_to_do)
goto again;
} else {
sc->xbd_ring.sring->rsp_event = i + 1;
}
if (xbd_queue_length(sc, XBD_Q_BUSY) == 0)
xbd_thaw(sc, XBDF_WAIT_IDLE);
xbd_startio(sc);
if (__predict_false(sc->xbd_state == XBD_STATE_SUSPENDED))
wakeup(&sc->xbd_cm_q[XBD_Q_BUSY]);
mtx_unlock(&sc->xbd_io_lock);
}
/*------------------------------- Dump Support -------------------------------*/
/**
* Quiesce the disk writes for a dump file before allowing the next buffer.
*/
static void
xbd_quiesce(struct xbd_softc *sc)
{
int mtd;
// While there are outstanding requests
while (xbd_queue_length(sc, XBD_Q_BUSY) != 0) {
RING_FINAL_CHECK_FOR_RESPONSES(&sc->xbd_ring, mtd);
if (mtd) {
/* Received request completions, update queue. */
xbd_int(sc);
}
if (xbd_queue_length(sc, XBD_Q_BUSY) != 0) {
/*
* Still pending requests, wait for the disk i/o
* to complete.
*/
HYPERVISOR_yield();
}
}
}
/* Kernel dump function for a paravirtualized disk device */
static void
xbd_dump_complete(struct xbd_command *cm)
{
xbd_enqueue_cm(cm, XBD_Q_COMPLETE);
}
static int
xbd_dump(void *arg, void *virtual, vm_offset_t physical, off_t offset,
size_t length)
{
struct disk *dp = arg;
struct xbd_softc *sc = dp->d_drv1;
struct xbd_command *cm;
size_t chunk;
int sbp;
int rc = 0;
if (length <= 0)
return (rc);
xbd_quiesce(sc); /* All quiet on the western front. */
/*
* If this lock is held, then this module is failing, and a
* successful kernel dump is highly unlikely anyway.
*/
mtx_lock(&sc->xbd_io_lock);
/* Split the 64KB block as needed */
for (sbp=0; length > 0; sbp++) {
cm = xbd_dequeue_cm(sc, XBD_Q_FREE);
if (cm == NULL) {
mtx_unlock(&sc->xbd_io_lock);
device_printf(sc->xbd_dev, "dump: no more commands?\n");
return (EBUSY);
}
if (gnttab_alloc_grant_references(sc->xbd_max_request_segments,
&cm->cm_gref_head) != 0) {
xbd_free_command(cm);
mtx_unlock(&sc->xbd_io_lock);
device_printf(sc->xbd_dev, "no more grant allocs?\n");
return (EBUSY);
}
chunk = length > sc->xbd_max_request_size ?
sc->xbd_max_request_size : length;
cm->cm_data = virtual;
cm->cm_datalen = chunk;
cm->cm_operation = BLKIF_OP_WRITE;
cm->cm_sector_number = offset / dp->d_sectorsize;
cm->cm_complete = xbd_dump_complete;
xbd_enqueue_cm(cm, XBD_Q_READY);
length -= chunk;
offset += chunk;
virtual = (char *) virtual + chunk;
}
/* Tell DOM0 to do the I/O */
xbd_startio(sc);
mtx_unlock(&sc->xbd_io_lock);
/* Poll for the completion. */
xbd_quiesce(sc); /* All quite on the eastern front */
/* If there were any errors, bail out... */
while ((cm = xbd_dequeue_cm(sc, XBD_Q_COMPLETE)) != NULL) {
if (cm->cm_status != BLKIF_RSP_OKAY) {
device_printf(sc->xbd_dev,
"Dump I/O failed at sector %jd\n",
cm->cm_sector_number);
rc = EIO;
}
xbd_free_command(cm);
}
return (rc);
}
/*----------------------------- Disk Entrypoints -----------------------------*/
static int
xbd_open(struct disk *dp)
{
struct xbd_softc *sc = dp->d_drv1;
if (sc == NULL) {
printf("xbd%d: not found", dp->d_unit);
return (ENXIO);
}
sc->xbd_flags |= XBDF_OPEN;
sc->xbd_users++;
return (0);
}
static int
xbd_close(struct disk *dp)
{
struct xbd_softc *sc = dp->d_drv1;
if (sc == NULL)
return (ENXIO);
sc->xbd_flags &= ~XBDF_OPEN;
if (--(sc->xbd_users) == 0) {
/*
* Check whether we have been instructed to close. We will
* have ignored this request initially, as the device was
* still mounted.
*/
if (xenbus_get_otherend_state(sc->xbd_dev) ==
XenbusStateClosing)
xbd_closing(sc->xbd_dev);
}
return (0);
}
static int
xbd_ioctl(struct disk *dp, u_long cmd, void *addr, int flag, struct thread *td)
{
struct xbd_softc *sc = dp->d_drv1;
if (sc == NULL)
return (ENXIO);
return (ENOTTY);
}
/*
* Read/write routine for a buffer. Finds the proper unit, place it on
* the sortq and kick the controller.
*/
static void
xbd_strategy(struct bio *bp)
{
struct xbd_softc *sc = bp->bio_disk->d_drv1;
/* bogus disk? */
if (sc == NULL) {
bp->bio_error = EINVAL;
bp->bio_flags |= BIO_ERROR;
bp->bio_resid = bp->bio_bcount;
biodone(bp);
return;
}
/*
* Place it in the queue of disk activities for this disk
*/
mtx_lock(&sc->xbd_io_lock);
xbd_enqueue_bio(sc, bp);
xbd_startio(sc);
mtx_unlock(&sc->xbd_io_lock);
return;
}
/*------------------------------ Ring Management -----------------------------*/
static int
xbd_alloc_ring(struct xbd_softc *sc)
{
blkif_sring_t *sring;
uintptr_t sring_page_addr;
int error;
int i;
sring = malloc(sc->xbd_ring_pages * PAGE_SIZE, M_XENBLOCKFRONT,
M_NOWAIT|M_ZERO);
if (sring == NULL) {
xenbus_dev_fatal(sc->xbd_dev, ENOMEM, "allocating shared ring");
return (ENOMEM);
}
SHARED_RING_INIT(sring);
FRONT_RING_INIT(&sc->xbd_ring, sring, sc->xbd_ring_pages * PAGE_SIZE);
for (i = 0, sring_page_addr = (uintptr_t)sring;
i < sc->xbd_ring_pages;
i++, sring_page_addr += PAGE_SIZE) {
error = xenbus_grant_ring(sc->xbd_dev,
(vtophys(sring_page_addr) >> PAGE_SHIFT),
&sc->xbd_ring_ref[i]);
if (error) {
xenbus_dev_fatal(sc->xbd_dev, error,
"granting ring_ref(%d)", i);
return (error);
}
}
if (sc->xbd_ring_pages == 1) {
error = xs_printf(XST_NIL, xenbus_get_node(sc->xbd_dev),
"ring-ref", "%u", sc->xbd_ring_ref[0]);
if (error) {
xenbus_dev_fatal(sc->xbd_dev, error,
"writing %s/ring-ref",
xenbus_get_node(sc->xbd_dev));
return (error);
}
} else {
for (i = 0; i < sc->xbd_ring_pages; i++) {
char ring_ref_name[]= "ring_refXX";
snprintf(ring_ref_name, sizeof(ring_ref_name),
"ring-ref%u", i);
error = xs_printf(XST_NIL, xenbus_get_node(sc->xbd_dev),
ring_ref_name, "%u", sc->xbd_ring_ref[i]);
if (error) {
xenbus_dev_fatal(sc->xbd_dev, error,
"writing %s/%s",
xenbus_get_node(sc->xbd_dev),
ring_ref_name);
return (error);
}
}
}
error = xen_intr_alloc_and_bind_local_port(sc->xbd_dev,
xenbus_get_otherend_id(sc->xbd_dev), NULL, xbd_int, sc,
INTR_TYPE_BIO | INTR_MPSAFE, &sc->xen_intr_handle);
if (error) {
xenbus_dev_fatal(sc->xbd_dev, error,
"xen_intr_alloc_and_bind_local_port failed");
return (error);
}
return (0);
}
static void
xbd_free_ring(struct xbd_softc *sc)
{
int i;
if (sc->xbd_ring.sring == NULL)
return;
for (i = 0; i < sc->xbd_ring_pages; i++) {
if (sc->xbd_ring_ref[i] != GRANT_REF_INVALID) {
gnttab_end_foreign_access_ref(sc->xbd_ring_ref[i]);
sc->xbd_ring_ref[i] = GRANT_REF_INVALID;
}
}
free(sc->xbd_ring.sring, M_XENBLOCKFRONT);
sc->xbd_ring.sring = NULL;
}
/*-------------------------- Initialization/Teardown -------------------------*/
static int
xbd_feature_string(struct xbd_softc *sc, char *features, size_t len)
{
struct sbuf sb;
int feature_cnt;
sbuf_new(&sb, features, len, SBUF_FIXEDLEN);
feature_cnt = 0;
if ((sc->xbd_flags & XBDF_FLUSH) != 0) {
sbuf_printf(&sb, "flush");
feature_cnt++;
}
if ((sc->xbd_flags & XBDF_BARRIER) != 0) {
if (feature_cnt != 0)
sbuf_printf(&sb, ", ");
sbuf_printf(&sb, "write_barrier");
feature_cnt++;
}
if ((sc->xbd_flags & XBDF_DISCARD) != 0) {
if (feature_cnt != 0)
sbuf_printf(&sb, ", ");
sbuf_printf(&sb, "discard");
feature_cnt++;
}
if ((sc->xbd_flags & XBDF_PERSISTENT) != 0) {
if (feature_cnt != 0)
sbuf_printf(&sb, ", ");
sbuf_printf(&sb, "persistent_grants");
feature_cnt++;
}
(void) sbuf_finish(&sb);
return (sbuf_len(&sb));
}
static int
xbd_sysctl_features(SYSCTL_HANDLER_ARGS)
{
char features[80];
struct xbd_softc *sc = arg1;
int error;
int len;
error = sysctl_wire_old_buffer(req, 0);
if (error != 0)
return (error);
len = xbd_feature_string(sc, features, sizeof(features));
/* len is -1 on error, which will make the SYSCTL_OUT a no-op. */
return (SYSCTL_OUT(req, features, len + 1/*NUL*/));
}
static void
xbd_setup_sysctl(struct xbd_softc *xbd)
{
struct sysctl_ctx_list *sysctl_ctx = NULL;
struct sysctl_oid *sysctl_tree = NULL;
struct sysctl_oid_list *children;
sysctl_ctx = device_get_sysctl_ctx(xbd->xbd_dev);
if (sysctl_ctx == NULL)
return;
sysctl_tree = device_get_sysctl_tree(xbd->xbd_dev);
if (sysctl_tree == NULL)
return;
children = SYSCTL_CHILDREN(sysctl_tree);
SYSCTL_ADD_UINT(sysctl_ctx, children, OID_AUTO,
"max_requests", CTLFLAG_RD, &xbd->xbd_max_requests, -1,
"maximum outstanding requests (negotiated)");
SYSCTL_ADD_UINT(sysctl_ctx, children, OID_AUTO,
"max_request_segments", CTLFLAG_RD,
&xbd->xbd_max_request_segments, 0,
"maximum number of pages per requests (negotiated)");
SYSCTL_ADD_UINT(sysctl_ctx, children, OID_AUTO,
"max_request_size", CTLFLAG_RD, &xbd->xbd_max_request_size, 0,
"maximum size in bytes of a request (negotiated)");
SYSCTL_ADD_UINT(sysctl_ctx, children, OID_AUTO,
"ring_pages", CTLFLAG_RD, &xbd->xbd_ring_pages, 0,
"communication channel pages (negotiated)");
SYSCTL_ADD_PROC(sysctl_ctx, children, OID_AUTO,
"features", CTLTYPE_STRING|CTLFLAG_RD, xbd, 0,
xbd_sysctl_features, "A", "protocol features (negotiated)");
}
/*
* Translate Linux major/minor to an appropriate name and unit
* number. For HVM guests, this allows us to use the same drive names
* with blkfront as the emulated drives, easing transition slightly.
*/
static void
xbd_vdevice_to_unit(uint32_t vdevice, int *unit, const char **name)
{
static struct vdev_info {
int major;
int shift;
int base;
const char *name;
} info[] = {
{3, 6, 0, "ada"}, /* ide0 */
{22, 6, 2, "ada"}, /* ide1 */
{33, 6, 4, "ada"}, /* ide2 */
{34, 6, 6, "ada"}, /* ide3 */
{56, 6, 8, "ada"}, /* ide4 */
{57, 6, 10, "ada"}, /* ide5 */
{88, 6, 12, "ada"}, /* ide6 */
{89, 6, 14, "ada"}, /* ide7 */
{90, 6, 16, "ada"}, /* ide8 */
{91, 6, 18, "ada"}, /* ide9 */
{8, 4, 0, "da"}, /* scsi disk0 */
{65, 4, 16, "da"}, /* scsi disk1 */
{66, 4, 32, "da"}, /* scsi disk2 */
{67, 4, 48, "da"}, /* scsi disk3 */
{68, 4, 64, "da"}, /* scsi disk4 */
{69, 4, 80, "da"}, /* scsi disk5 */
{70, 4, 96, "da"}, /* scsi disk6 */
{71, 4, 112, "da"}, /* scsi disk7 */
{128, 4, 128, "da"}, /* scsi disk8 */
{129, 4, 144, "da"}, /* scsi disk9 */
{130, 4, 160, "da"}, /* scsi disk10 */
{131, 4, 176, "da"}, /* scsi disk11 */
{132, 4, 192, "da"}, /* scsi disk12 */
{133, 4, 208, "da"}, /* scsi disk13 */
{134, 4, 224, "da"}, /* scsi disk14 */
{135, 4, 240, "da"}, /* scsi disk15 */
{202, 4, 0, "xbd"}, /* xbd */
{0, 0, 0, NULL},
};
int major = vdevice >> 8;
int minor = vdevice & 0xff;
int i;
if (vdevice & (1 << 28)) {
*unit = (vdevice & ((1 << 28) - 1)) >> 8;
*name = "xbd";
return;
}
for (i = 0; info[i].major; i++) {
if (info[i].major == major) {
*unit = info[i].base + (minor >> info[i].shift);
*name = info[i].name;
return;
}
}
*unit = minor >> 4;
*name = "xbd";
}
int
xbd_instance_create(struct xbd_softc *sc, blkif_sector_t sectors,
int vdevice, uint16_t vdisk_info, unsigned long sector_size,
unsigned long phys_sector_size)
{
char features[80];
int unit, error = 0;
const char *name;
xbd_vdevice_to_unit(vdevice, &unit, &name);
sc->xbd_unit = unit;
if (strcmp(name, "xbd") != 0)
device_printf(sc->xbd_dev, "attaching as %s%d\n", name, unit);
if (xbd_feature_string(sc, features, sizeof(features)) > 0) {
device_printf(sc->xbd_dev, "features: %s\n",
features);
}
sc->xbd_disk = disk_alloc();
sc->xbd_disk->d_unit = sc->xbd_unit;
sc->xbd_disk->d_open = xbd_open;
sc->xbd_disk->d_close = xbd_close;
sc->xbd_disk->d_ioctl = xbd_ioctl;
sc->xbd_disk->d_strategy = xbd_strategy;
sc->xbd_disk->d_dump = xbd_dump;
sc->xbd_disk->d_name = name;
sc->xbd_disk->d_drv1 = sc;
sc->xbd_disk->d_sectorsize = sector_size;
sc->xbd_disk->d_stripesize = phys_sector_size;
sc->xbd_disk->d_stripeoffset = 0;
sc->xbd_disk->d_mediasize = sectors * sector_size;
sc->xbd_disk->d_maxsize = sc->xbd_max_request_size;
sc->xbd_disk->d_flags = DISKFLAG_UNMAPPED_BIO;
if ((sc->xbd_flags & (XBDF_FLUSH|XBDF_BARRIER)) != 0) {
sc->xbd_disk->d_flags |= DISKFLAG_CANFLUSHCACHE;
device_printf(sc->xbd_dev,
"synchronize cache commands enabled.\n");
}
disk_create(sc->xbd_disk, DISK_VERSION);
return error;
}
static void
xbd_free(struct xbd_softc *sc)
{
int i;
/* Prevent new requests being issued until we fix things up. */
mtx_lock(&sc->xbd_io_lock);
sc->xbd_state = XBD_STATE_DISCONNECTED;
mtx_unlock(&sc->xbd_io_lock);
/* Free resources associated with old device channel. */
xbd_free_ring(sc);
if (sc->xbd_shadow) {
for (i = 0; i < sc->xbd_max_requests; i++) {
struct xbd_command *cm;
cm = &sc->xbd_shadow[i];
if (cm->cm_sg_refs != NULL) {
free(cm->cm_sg_refs, M_XENBLOCKFRONT);
cm->cm_sg_refs = NULL;
}
if (cm->cm_indirectionpages != NULL) {
gnttab_end_foreign_access_references(
sc->xbd_max_request_indirectpages,
&cm->cm_indirectionrefs[0]);
contigfree(cm->cm_indirectionpages, PAGE_SIZE *
sc->xbd_max_request_indirectpages,
M_XENBLOCKFRONT);
cm->cm_indirectionpages = NULL;
}
bus_dmamap_destroy(sc->xbd_io_dmat, cm->cm_map);
}
free(sc->xbd_shadow, M_XENBLOCKFRONT);
sc->xbd_shadow = NULL;
bus_dma_tag_destroy(sc->xbd_io_dmat);
xbd_initq_cm(sc, XBD_Q_FREE);
xbd_initq_cm(sc, XBD_Q_READY);
xbd_initq_cm(sc, XBD_Q_COMPLETE);
}
xen_intr_unbind(&sc->xen_intr_handle);
}
/*--------------------------- State Change Handlers --------------------------*/
static void
xbd_initialize(struct xbd_softc *sc)
{
const char *otherend_path;
const char *node_path;
uint32_t max_ring_page_order;
int error;
if (xenbus_get_state(sc->xbd_dev) != XenbusStateInitialising) {
/* Initialization has already been performed. */
return;
}
/*
* Protocol defaults valid even if negotiation for a
* setting fails.
*/
max_ring_page_order = 0;
sc->xbd_ring_pages = 1;
/*
* Protocol negotiation.
*
* \note xs_gather() returns on the first encountered error, so
* we must use independent calls in order to guarantee
* we don't miss information in a sparsly populated back-end
* tree.
*
* \note xs_scanf() does not update variables for unmatched
* fields.
*/
otherend_path = xenbus_get_otherend_path(sc->xbd_dev);
node_path = xenbus_get_node(sc->xbd_dev);
/* Support both backend schemes for relaying ring page limits. */
(void)xs_scanf(XST_NIL, otherend_path,
"max-ring-page-order", NULL, "%" PRIu32,
&max_ring_page_order);
sc->xbd_ring_pages = 1 << max_ring_page_order;
(void)xs_scanf(XST_NIL, otherend_path,
"max-ring-pages", NULL, "%" PRIu32,
&sc->xbd_ring_pages);
if (sc->xbd_ring_pages < 1)
sc->xbd_ring_pages = 1;
if (sc->xbd_ring_pages > XBD_MAX_RING_PAGES) {
device_printf(sc->xbd_dev,
"Back-end specified ring-pages of %u "
"limited to front-end limit of %u.\n",
sc->xbd_ring_pages, XBD_MAX_RING_PAGES);
sc->xbd_ring_pages = XBD_MAX_RING_PAGES;
}
if (powerof2(sc->xbd_ring_pages) == 0) {
uint32_t new_page_limit;
new_page_limit = 0x01 << (fls(sc->xbd_ring_pages) - 1);
device_printf(sc->xbd_dev,
"Back-end specified ring-pages of %u "
"is not a power of 2. Limited to %u.\n",
sc->xbd_ring_pages, new_page_limit);
sc->xbd_ring_pages = new_page_limit;
}
sc->xbd_max_requests =
BLKIF_MAX_RING_REQUESTS(sc->xbd_ring_pages * PAGE_SIZE);
if (sc->xbd_max_requests > XBD_MAX_REQUESTS) {
device_printf(sc->xbd_dev,
"Back-end specified max_requests of %u "
"limited to front-end limit of %zu.\n",
sc->xbd_max_requests, XBD_MAX_REQUESTS);
sc->xbd_max_requests = XBD_MAX_REQUESTS;
}
if (xbd_alloc_ring(sc) != 0)
return;
/* Support both backend schemes for relaying ring page limits. */
if (sc->xbd_ring_pages > 1) {
error = xs_printf(XST_NIL, node_path,
"num-ring-pages","%u",
sc->xbd_ring_pages);
if (error) {
xenbus_dev_fatal(sc->xbd_dev, error,
"writing %s/num-ring-pages",
node_path);
return;
}
error = xs_printf(XST_NIL, node_path,
"ring-page-order", "%u",
fls(sc->xbd_ring_pages) - 1);
if (error) {
xenbus_dev_fatal(sc->xbd_dev, error,
"writing %s/ring-page-order",
node_path);
return;
}
}
error = xs_printf(XST_NIL, node_path, "event-channel",
"%u", xen_intr_port(sc->xen_intr_handle));
if (error) {
xenbus_dev_fatal(sc->xbd_dev, error,
"writing %s/event-channel",
node_path);
return;
}
error = xs_printf(XST_NIL, node_path, "protocol",
"%s", XEN_IO_PROTO_ABI_NATIVE);
if (error) {
xenbus_dev_fatal(sc->xbd_dev, error,
"writing %s/protocol",
node_path);
return;
}
xenbus_set_state(sc->xbd_dev, XenbusStateInitialised);
}
/*
* Invoked when the backend is finally 'ready' (and has published
* the details about the physical device - #sectors, size, etc).
*/
static void
xbd_connect(struct xbd_softc *sc)
{
device_t dev = sc->xbd_dev;
unsigned long sectors, sector_size, phys_sector_size;
unsigned int binfo;
int err, feature_barrier, feature_flush;
int i, j;
if (sc->xbd_state == XBD_STATE_CONNECTED ||
sc->xbd_state == XBD_STATE_SUSPENDED)
return;
DPRINTK("blkfront.c:connect:%s.\n", xenbus_get_otherend_path(dev));
err = xs_gather(XST_NIL, xenbus_get_otherend_path(dev),
"sectors", "%lu", &sectors,
"info", "%u", &binfo,
"sector-size", "%lu", &sector_size,
NULL);
if (err) {
xenbus_dev_fatal(dev, err,
"reading backend fields at %s",
xenbus_get_otherend_path(dev));
return;
}
err = xs_gather(XST_NIL, xenbus_get_otherend_path(dev),
"physical-sector-size", "%lu", &phys_sector_size,
NULL);
if (err || phys_sector_size <= sector_size)
phys_sector_size = 0;
err = xs_gather(XST_NIL, xenbus_get_otherend_path(dev),
"feature-barrier", "%lu", &feature_barrier,
NULL);
if (err == 0 && feature_barrier != 0)
sc->xbd_flags |= XBDF_BARRIER;
err = xs_gather(XST_NIL, xenbus_get_otherend_path(dev),
"feature-flush-cache", "%lu", &feature_flush,
NULL);
if (err == 0 && feature_flush != 0)
sc->xbd_flags |= XBDF_FLUSH;
err = xs_gather(XST_NIL, xenbus_get_otherend_path(dev),
"feature-max-indirect-segments", "%" PRIu32,
&sc->xbd_max_request_segments, NULL);
if ((err != 0) || (xbd_enable_indirect == 0))
sc->xbd_max_request_segments = 0;
if (sc->xbd_max_request_segments > XBD_MAX_INDIRECT_SEGMENTS)
sc->xbd_max_request_segments = XBD_MAX_INDIRECT_SEGMENTS;
if (sc->xbd_max_request_segments > XBD_SIZE_TO_SEGS(MAXPHYS))
sc->xbd_max_request_segments = XBD_SIZE_TO_SEGS(MAXPHYS);
sc->xbd_max_request_indirectpages =
XBD_INDIRECT_SEGS_TO_PAGES(sc->xbd_max_request_segments);
if (sc->xbd_max_request_segments < BLKIF_MAX_SEGMENTS_PER_REQUEST)
sc->xbd_max_request_segments = BLKIF_MAX_SEGMENTS_PER_REQUEST;
sc->xbd_max_request_size =
XBD_SEGS_TO_SIZE(sc->xbd_max_request_segments);
/* Allocate datastructures based on negotiated values. */
err = bus_dma_tag_create(
bus_get_dma_tag(sc->xbd_dev), /* parent */
512, PAGE_SIZE, /* algnmnt, boundary */
BUS_SPACE_MAXADDR, /* lowaddr */
BUS_SPACE_MAXADDR, /* highaddr */
NULL, NULL, /* filter, filterarg */
sc->xbd_max_request_size,
sc->xbd_max_request_segments,
PAGE_SIZE, /* maxsegsize */
BUS_DMA_ALLOCNOW, /* flags */
busdma_lock_mutex, /* lockfunc */
&sc->xbd_io_lock, /* lockarg */
&sc->xbd_io_dmat);
if (err != 0) {
xenbus_dev_fatal(sc->xbd_dev, err,
"Cannot allocate parent DMA tag\n");
return;
}
/* Per-transaction data allocation. */
sc->xbd_shadow = malloc(sizeof(*sc->xbd_shadow) * sc->xbd_max_requests,
M_XENBLOCKFRONT, M_NOWAIT|M_ZERO);
if (sc->xbd_shadow == NULL) {
bus_dma_tag_destroy(sc->xbd_io_dmat);
xenbus_dev_fatal(sc->xbd_dev, ENOMEM,
"Cannot allocate request structures\n");
return;
}
for (i = 0; i < sc->xbd_max_requests; i++) {
struct xbd_command *cm;
void * indirectpages;
cm = &sc->xbd_shadow[i];
cm->cm_sg_refs = malloc(
sizeof(grant_ref_t) * sc->xbd_max_request_segments,
M_XENBLOCKFRONT, M_NOWAIT);
if (cm->cm_sg_refs == NULL)
break;
cm->cm_id = i;
cm->cm_flags = XBDCF_INITIALIZER;
cm->cm_sc = sc;
if (bus_dmamap_create(sc->xbd_io_dmat, 0, &cm->cm_map) != 0)
break;
if (sc->xbd_max_request_indirectpages > 0) {
indirectpages = contigmalloc(
PAGE_SIZE * sc->xbd_max_request_indirectpages,
M_XENBLOCKFRONT, M_ZERO, 0, ~0, PAGE_SIZE, 0);
} else {
indirectpages = NULL;
}
for (j = 0; j < sc->xbd_max_request_indirectpages; j++) {
if (gnttab_grant_foreign_access(
xenbus_get_otherend_id(sc->xbd_dev),
(vtophys(indirectpages) >> PAGE_SHIFT) + j,
1 /* grant read-only access */,
&cm->cm_indirectionrefs[j]))
break;
}
if (j < sc->xbd_max_request_indirectpages)
break;
cm->cm_indirectionpages = indirectpages;
xbd_free_command(cm);
}
if (sc->xbd_disk == NULL) {
device_printf(dev, "%juMB <%s> at %s",
(uintmax_t) sectors / (1048576 / sector_size),
device_get_desc(dev),
xenbus_get_node(dev));
bus_print_child_footer(device_get_parent(dev), dev);
xbd_instance_create(sc, sectors, sc->xbd_vdevice, binfo,
sector_size, phys_sector_size);
}
(void)xenbus_set_state(dev, XenbusStateConnected);
/* Kick pending requests. */
mtx_lock(&sc->xbd_io_lock);
sc->xbd_state = XBD_STATE_CONNECTED;
xbd_startio(sc);
sc->xbd_flags |= XBDF_READY;
mtx_unlock(&sc->xbd_io_lock);
}
/**
* Handle the change of state of the backend to Closing. We must delete our
* device-layer structures now, to ensure that writes are flushed through to
* the backend. Once this is done, we can switch to Closed in
* acknowledgement.
*/
static void
xbd_closing(device_t dev)
{
struct xbd_softc *sc = device_get_softc(dev);
xenbus_set_state(dev, XenbusStateClosing);
DPRINTK("xbd_closing: %s removed\n", xenbus_get_node(dev));
if (sc->xbd_disk != NULL) {
disk_destroy(sc->xbd_disk);
sc->xbd_disk = NULL;
}
xenbus_set_state(dev, XenbusStateClosed);
}
/*---------------------------- NewBus Entrypoints ----------------------------*/
static int
xbd_probe(device_t dev)
{
if (strcmp(xenbus_get_type(dev), "vbd") != 0)
return (ENXIO);
if (xen_hvm_domain() && xen_disable_pv_disks != 0)
return (ENXIO);
if (xen_hvm_domain()) {
int error;
char *type;
/*
* When running in an HVM domain, IDE disk emulation is
* disabled early in boot so that native drivers will
* not see emulated hardware. However, CDROM device
* emulation cannot be disabled.
*
* Through use of FreeBSD's vm_guest and xen_hvm_domain()
* APIs, we could modify the native CDROM driver to fail its
* probe when running under Xen. Unfortunatlely, the PV
* CDROM support in XenServer (up through at least version
* 6.2) isn't functional, so we instead rely on the emulated
* CDROM instance, and fail to attach the PV one here in
* the blkfront driver.
*/
error = xs_read(XST_NIL, xenbus_get_node(dev),
"device-type", NULL, (void **) &type);
if (error)
return (ENXIO);
if (strncmp(type, "cdrom", 5) == 0) {
free(type, M_XENSTORE);
return (ENXIO);
}
free(type, M_XENSTORE);
}
device_set_desc(dev, "Virtual Block Device");
device_quiet(dev);
return (0);
}
/*
* Setup supplies the backend dir, virtual device. We place an event
* channel and shared frame entries. We watch backend to wait if it's
* ok.
*/
static int
xbd_attach(device_t dev)
{
struct xbd_softc *sc;
const char *name;
uint32_t vdevice;
int error;
int i;
int unit;
/* FIXME: Use dynamic device id if this is not set. */
error = xs_scanf(XST_NIL, xenbus_get_node(dev),
"virtual-device", NULL, "%" PRIu32, &vdevice);
if (error)
error = xs_scanf(XST_NIL, xenbus_get_node(dev),
"virtual-device-ext", NULL, "%" PRIu32, &vdevice);
if (error) {
xenbus_dev_fatal(dev, error, "reading virtual-device");
device_printf(dev, "Couldn't determine virtual device.\n");
return (error);
}
xbd_vdevice_to_unit(vdevice, &unit, &name);
if (!strcmp(name, "xbd"))
device_set_unit(dev, unit);
sc = device_get_softc(dev);
mtx_init(&sc->xbd_io_lock, "blkfront i/o lock", NULL, MTX_DEF);
xbd_initqs(sc);
for (i = 0; i < XBD_MAX_RING_PAGES; i++)
sc->xbd_ring_ref[i] = GRANT_REF_INVALID;
sc->xbd_dev = dev;
sc->xbd_vdevice = vdevice;
sc->xbd_state = XBD_STATE_DISCONNECTED;
xbd_setup_sysctl(sc);
/* Wait for backend device to publish its protocol capabilities. */
xenbus_set_state(dev, XenbusStateInitialising);
return (0);
}
static int
xbd_detach(device_t dev)
{
struct xbd_softc *sc = device_get_softc(dev);
DPRINTK("%s: %s removed\n", __func__, xenbus_get_node(dev));
xbd_free(sc);
mtx_destroy(&sc->xbd_io_lock);
return 0;
}
static int
xbd_suspend(device_t dev)
{
struct xbd_softc *sc = device_get_softc(dev);
int retval;
int saved_state;
/* Prevent new requests being issued until we fix things up. */
mtx_lock(&sc->xbd_io_lock);
saved_state = sc->xbd_state;
sc->xbd_state = XBD_STATE_SUSPENDED;
/* Wait for outstanding I/O to drain. */
retval = 0;
while (xbd_queue_length(sc, XBD_Q_BUSY) != 0) {
if (msleep(&sc->xbd_cm_q[XBD_Q_BUSY], &sc->xbd_io_lock,
PRIBIO, "blkf_susp", 30 * hz) == EWOULDBLOCK) {
retval = EBUSY;
break;
}
}
mtx_unlock(&sc->xbd_io_lock);
if (retval != 0)
sc->xbd_state = saved_state;
return (retval);
}
static int
xbd_resume(device_t dev)
{
struct xbd_softc *sc = device_get_softc(dev);
DPRINTK("xbd_resume: %s\n", xenbus_get_node(dev));
xbd_free(sc);
xbd_initialize(sc);
return (0);
}
/**
* Callback received when the backend's state changes.
*/
static void
xbd_backend_changed(device_t dev, XenbusState backend_state)
{
struct xbd_softc *sc = device_get_softc(dev);
DPRINTK("backend_state=%d\n", backend_state);
switch (backend_state) {
case XenbusStateUnknown:
case XenbusStateInitialising:
case XenbusStateReconfigured:
case XenbusStateReconfiguring:
case XenbusStateClosed:
break;
case XenbusStateInitWait:
case XenbusStateInitialised:
xbd_initialize(sc);
break;
case XenbusStateConnected:
xbd_initialize(sc);
xbd_connect(sc);
break;
case XenbusStateClosing:
if (sc->xbd_users > 0)
xenbus_dev_error(dev, -EBUSY,
"Device in use; refusing to close");
else
xbd_closing(dev);
break;
}
}
/*---------------------------- NewBus Registration ---------------------------*/
static device_method_t xbd_methods[] = {
/* Device interface */
DEVMETHOD(device_probe, xbd_probe),
DEVMETHOD(device_attach, xbd_attach),
DEVMETHOD(device_detach, xbd_detach),
DEVMETHOD(device_shutdown, bus_generic_shutdown),
DEVMETHOD(device_suspend, xbd_suspend),
DEVMETHOD(device_resume, xbd_resume),
/* Xenbus interface */
DEVMETHOD(xenbus_otherend_changed, xbd_backend_changed),
{ 0, 0 }
};
static driver_t xbd_driver = {
"xbd",
xbd_methods,
sizeof(struct xbd_softc),
};
devclass_t xbd_devclass;
DRIVER_MODULE(xbd, xenbusb_front, xbd_driver, xbd_devclass, 0, 0);
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