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Date: Wed, 07 Oct 2015 18:28:05 +0800
From: Bob Liu <bob.liu@...cle.com>
To: Roger Pau Monné <roger.pau@...rix.com>
CC: xen-devel@...ts.xen.org, david.vrabel@...rix.com,
linux-kernel@...r.kernel.org, konrad.wilk@...cle.com,
felipe.franciosi@...rix.com, axboe@...com, hch@...radead.org,
avanzini.arianna@...il.com, rafal.mielniczuk@...rix.com,
boris.ostrovsky@...cle.com, jonathan.davies@...rix.com
Subject: Re: [PATCH v3 4/9] xen/blkfront: pseudo support for multi hardware
queues/rings
On 10/05/2015 06:52 PM, Roger Pau Monné wrote:
> El 05/09/15 a les 14.39, Bob Liu ha escrit:
>> Prepare patch for multi hardware queues/rings, the ring number was set to 1 by
>> force.
>>
>> * Use 'nr_rings' in per dev_info to identify how many hw queues/rings are
>> supported, and a pointer *rinfo for all its rings.
>> * Rename 'nr_ring_pages' => 'pages_per_ring' to distinguish from 'nr_rings'
>> better.
>>
>> Signed-off-by: Bob Liu <bob.liu@...cle.com>
>> ---
>> drivers/block/xen-blkfront.c | 513 +++++++++++++++++++++++++-----------------
>> 1 file changed, 308 insertions(+), 205 deletions(-)
>>
>> diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
>> index bf416d5..bf45c99 100644
>> --- a/drivers/block/xen-blkfront.c
>> +++ b/drivers/block/xen-blkfront.c
>> @@ -107,7 +107,7 @@ static unsigned int xen_blkif_max_ring_order;
>> module_param_named(max_ring_page_order, xen_blkif_max_ring_order, int, S_IRUGO);
>> MODULE_PARM_DESC(max_ring_page_order, "Maximum order of pages to be used for the shared ring");
>>
>> -#define BLK_RING_SIZE(dinfo) __CONST_RING_SIZE(blkif, PAGE_SIZE * (dinfo)->nr_ring_pages)
>> +#define BLK_RING_SIZE(dinfo) __CONST_RING_SIZE(blkif, PAGE_SIZE * (dinfo)->pages_per_ring)
>> #define BLK_MAX_RING_SIZE __CONST_RING_SIZE(blkif, PAGE_SIZE * XENBUS_MAX_RING_PAGES)
>> /*
>> * ring-ref%i i=(-1UL) would take 11 characters + 'ring-ref' is 8, so 19
>> @@ -157,9 +157,10 @@ struct blkfront_dev_info {
>> unsigned int feature_persistent:1;
>> unsigned int max_indirect_segments;
>> int is_ready;
>> - unsigned int nr_ring_pages;
>> + unsigned int pages_per_ring;
>
> Why do you rename this field? nr_ring_pages seems more consistent with
> the nr_rings field that you add below IMO, but that might be a matter of
> taste.
>
I think after nr_rings introduced, nr_ring_pages is not suitable any more because it may misread to
nr-ring pages in total instead of per-ring.
So I prefer rename it to pages_per_ring.
>> struct blk_mq_tag_set tag_set;
>> - struct blkfront_ring_info rinfo;
>> + struct blkfront_ring_info *rinfo;
>> + unsigned int nr_rings;
>> };
>>
>> static unsigned int nr_minors;
>> @@ -191,7 +192,7 @@ static DEFINE_SPINLOCK(minor_lock);
>> ((_segs + SEGS_PER_INDIRECT_FRAME - 1)/SEGS_PER_INDIRECT_FRAME)
>>
>> static int blkfront_setup_indirect(struct blkfront_ring_info *rinfo);
>> -static int blkfront_gather_backend_features(struct blkfront_dev_info *dinfo);
>> +static void __blkfront_gather_backend_features(struct blkfront_dev_info *dinfo);
>>
>> static int get_id_from_freelist(struct blkfront_ring_info *rinfo)
>> {
>> @@ -668,7 +669,7 @@ static int blk_mq_init_hctx(struct blk_mq_hw_ctx *hctx, void *data,
>> {
>> struct blkfront_dev_info *dinfo = (struct blkfront_dev_info *)data;
>>
>> - hctx->driver_data = &dinfo->rinfo;
>> + hctx->driver_data = &dinfo->rinfo[index];
>> return 0;
>> }
>>
>> @@ -927,8 +928,8 @@ static int xlvbd_alloc_gendisk(blkif_sector_t capacity,
>>
>> static void xlvbd_release_gendisk(struct blkfront_dev_info *dinfo)
>> {
>> - unsigned int minor, nr_minors;
>> - struct blkfront_ring_info *rinfo = &dinfo->rinfo;
>> + unsigned int minor, nr_minors, i;
>> + struct blkfront_ring_info *rinfo;
>>
>> if (dinfo->rq == NULL)
>> return;
>> @@ -936,11 +937,15 @@ static void xlvbd_release_gendisk(struct blkfront_dev_info *dinfo)
>> /* No more blkif_request(). */
>> blk_mq_stop_hw_queues(dinfo->rq);
>>
>> - /* No more gnttab callback work. */
>> - gnttab_cancel_free_callback(&rinfo->callback);
>> + for (i = 0; i < dinfo->nr_rings; i++) {
>
> I would be tempted to declare rinfo only inside the for loop, to limit
> the scope:
Will update.
>
> struct blkfront_ring_info *rinfo = &dinfo->rinfo[i];
>
>> + rinfo = &dinfo->rinfo[i];
>>
>> - /* Flush gnttab callback work. Must be done with no locks held. */
>> - flush_work(&rinfo->work);
>> + /* No more gnttab callback work. */
>> + gnttab_cancel_free_callback(&rinfo->callback);
>> +
>> + /* Flush gnttab callback work. Must be done with no locks held. */
>> + flush_work(&rinfo->work);
>> + }
>>
>> del_gendisk(dinfo->gd);
>>
>> @@ -977,8 +982,8 @@ static void blkif_free(struct blkfront_dev_info *dinfo, int suspend)
>> {
>> struct grant *persistent_gnt;
>> struct grant *n;
>> - int i, j, segs;
>> - struct blkfront_ring_info *rinfo = &dinfo->rinfo;
>> + int i, j, segs, r_index;
>> + struct blkfront_ring_info *rinfo;
>>
>> /* Prevent new requests being issued until we fix things up. */
>> spin_lock_irq(&dinfo->io_lock);
>> @@ -988,100 +993,103 @@ static void blkif_free(struct blkfront_dev_info *dinfo, int suspend)
>> if (dinfo->rq)
>> blk_mq_stop_hw_queues(dinfo->rq);
>>
>> - /* Remove all persistent grants */
>> - if (!list_empty(&rinfo->grants)) {
>> - list_for_each_entry_safe(persistent_gnt, n,
>> - &rinfo->grants, node) {
>> - list_del(&persistent_gnt->node);
>> - if (persistent_gnt->gref != GRANT_INVALID_REF) {
>> - gnttab_end_foreign_access(persistent_gnt->gref,
>> - 0, 0UL);
>> - rinfo->persistent_gnts_c--;
>> + for (r_index = 0; r_index < dinfo->nr_rings; r_index++) {
>> + rinfo = &dinfo->rinfo[r_index];
>
> struct blkfront_ring_info *rinfo = &dinfo->rinfo[r_index];
>
> Would it be helpful to place all this code inside of a helper function,
> ie: blkif_free_ring?
>
Sure, will update.
>> +
>> + /* Remove all persistent grants */
>> + if (!list_empty(&rinfo->grants)) {
>> + list_for_each_entry_safe(persistent_gnt, n,
>> + &rinfo->grants, node) {
>> + list_del(&persistent_gnt->node);
>> + if (persistent_gnt->gref != GRANT_INVALID_REF) {
>> + gnttab_end_foreign_access(persistent_gnt->gref,
>> + 0, 0UL);
>> + rinfo->persistent_gnts_c--;
>> + }
>> + if (dinfo->feature_persistent)
>> + __free_page(pfn_to_page(persistent_gnt->pfn));
>> + kfree(persistent_gnt);
>> }
>> - if (dinfo->feature_persistent)
>> - __free_page(pfn_to_page(persistent_gnt->pfn));
>> - kfree(persistent_gnt);
>> }
>> - }
>> - BUG_ON(rinfo->persistent_gnts_c != 0);
>> + BUG_ON(rinfo->persistent_gnts_c != 0);
>>
>> - /*
>> - * Remove indirect pages, this only happens when using indirect
>> - * descriptors but not persistent grants
>> - */
>> - if (!list_empty(&rinfo->indirect_pages)) {
>> - struct page *indirect_page, *n;
>> -
>> - BUG_ON(dinfo->feature_persistent);
>> - list_for_each_entry_safe(indirect_page, n, &rinfo->indirect_pages, lru) {
>> - list_del(&indirect_page->lru);
>> - __free_page(indirect_page);
>> - }
>> - }
>> -
>> - for (i = 0; i < BLK_RING_SIZE(dinfo); i++) {
>> /*
>> - * Clear persistent grants present in requests already
>> - * on the shared ring
>> + * Remove indirect pages, this only happens when using indirect
>> + * descriptors but not persistent grants
>> */
>> - if (!rinfo->shadow[i].request)
>> - goto free_shadow;
>> -
>> - segs = rinfo->shadow[i].req.operation == BLKIF_OP_INDIRECT ?
>> - rinfo->shadow[i].req.u.indirect.nr_segments :
>> - rinfo->shadow[i].req.u.rw.nr_segments;
>> - for (j = 0; j < segs; j++) {
>> - persistent_gnt = rinfo->shadow[i].grants_used[j];
>> - gnttab_end_foreign_access(persistent_gnt->gref, 0, 0UL);
>> - if (dinfo->feature_persistent)
>> - __free_page(pfn_to_page(persistent_gnt->pfn));
>> - kfree(persistent_gnt);
>> + if (!list_empty(&rinfo->indirect_pages)) {
>> + struct page *indirect_page, *n;
>> +
>> + BUG_ON(dinfo->feature_persistent);
>> + list_for_each_entry_safe(indirect_page, n, &rinfo->indirect_pages, lru) {
>> + list_del(&indirect_page->lru);
>> + __free_page(indirect_page);
>> + }
>> }
>>
>> - if (rinfo->shadow[i].req.operation != BLKIF_OP_INDIRECT)
>> + for (i = 0; i < BLK_RING_SIZE(dinfo); i++) {
>> /*
>> - * If this is not an indirect operation don't try to
>> - * free indirect segments
>> + * Clear persistent grants present in requests already
>> + * on the shared ring
>> */
>> - goto free_shadow;
>> + if (!rinfo->shadow[i].request)
>> + goto free_shadow;
>> +
>> + segs = rinfo->shadow[i].req.operation == BLKIF_OP_INDIRECT ?
>> + rinfo->shadow[i].req.u.indirect.nr_segments :
>> + rinfo->shadow[i].req.u.rw.nr_segments;
>> + for (j = 0; j < segs; j++) {
>> + persistent_gnt = rinfo->shadow[i].grants_used[j];
>> + gnttab_end_foreign_access(persistent_gnt->gref, 0, 0UL);
>> + if (dinfo->feature_persistent)
>> + __free_page(pfn_to_page(persistent_gnt->pfn));
>> + kfree(persistent_gnt);
>> + }
>>
>> - for (j = 0; j < INDIRECT_GREFS(segs); j++) {
>> - persistent_gnt = rinfo->shadow[i].indirect_grants[j];
>> - gnttab_end_foreign_access(persistent_gnt->gref, 0, 0UL);
>> - __free_page(pfn_to_page(persistent_gnt->pfn));
>> - kfree(persistent_gnt);
>> - }
>> + if (rinfo->shadow[i].req.operation != BLKIF_OP_INDIRECT)
>> + /*
>> + * If this is not an indirect operation don't try to
>> + * free indirect segments
>> + */
>> + goto free_shadow;
>> +
>> + for (j = 0; j < INDIRECT_GREFS(segs); j++) {
>> + persistent_gnt = rinfo->shadow[i].indirect_grants[j];
>> + gnttab_end_foreign_access(persistent_gnt->gref, 0, 0UL);
>> + __free_page(pfn_to_page(persistent_gnt->pfn));
>> + kfree(persistent_gnt);
>> + }
>>
>> free_shadow:
>> - kfree(rinfo->shadow[i].grants_used);
>> - rinfo->shadow[i].grants_used = NULL;
>> - kfree(rinfo->shadow[i].indirect_grants);
>> - rinfo->shadow[i].indirect_grants = NULL;
>> - kfree(rinfo->shadow[i].sg);
>> - rinfo->shadow[i].sg = NULL;
>> - }
>> + kfree(rinfo->shadow[i].grants_used);
>> + rinfo->shadow[i].grants_used = NULL;
>> + kfree(rinfo->shadow[i].indirect_grants);
>> + rinfo->shadow[i].indirect_grants = NULL;
>> + kfree(rinfo->shadow[i].sg);
>> + rinfo->shadow[i].sg = NULL;
>> + }
>>
>> - /* No more gnttab callback work. */
>> - gnttab_cancel_free_callback(&rinfo->callback);
>> - spin_unlock_irq(&dinfo->io_lock);
>> + /* No more gnttab callback work. */
>> + gnttab_cancel_free_callback(&rinfo->callback);
>> + spin_unlock_irq(&dinfo->io_lock);
>>
>> - /* Flush gnttab callback work. Must be done with no locks held. */
>> - flush_work(&rinfo->work);
>> + /* Flush gnttab callback work. Must be done with no locks held. */
>> + flush_work(&rinfo->work);
>>
>> - /* Free resources associated with old device channel. */
>> - for (i = 0; i < dinfo->nr_ring_pages; i++) {
>> - if (rinfo->ring_ref[i] != GRANT_INVALID_REF) {
>> - gnttab_end_foreign_access(rinfo->ring_ref[i], 0, 0);
>> - rinfo->ring_ref[i] = GRANT_INVALID_REF;
>> + /* Free resources associated with old device channel. */
>> + for (i = 0; i < dinfo->pages_per_ring; i++) {
>> + if (rinfo->ring_ref[i] != GRANT_INVALID_REF) {
>> + gnttab_end_foreign_access(rinfo->ring_ref[i], 0, 0);
>> + rinfo->ring_ref[i] = GRANT_INVALID_REF;
>> + }
>> }
>> - }
>> - free_pages((unsigned long)rinfo->ring.sring, get_order(dinfo->nr_ring_pages * PAGE_SIZE));
>> - rinfo->ring.sring = NULL;
>> -
>> - if (rinfo->irq)
>> - unbind_from_irqhandler(rinfo->irq, rinfo);
>> - rinfo->evtchn = rinfo->irq = 0;
>> + free_pages((unsigned long)rinfo->ring.sring, get_order(dinfo->pages_per_ring * PAGE_SIZE));
>> + rinfo->ring.sring = NULL;
>>
>> + if (rinfo->irq)
>> + unbind_from_irqhandler(rinfo->irq, rinfo);
>> + rinfo->evtchn = rinfo->irq = 0;
>> + }
>> }
>>
>> static void blkif_completion(struct blk_shadow *s, struct blkfront_ring_info *rinfo,
>> @@ -1276,6 +1284,26 @@ static irqreturn_t blkif_interrupt(int irq, void *dev_id)
>> return IRQ_HANDLED;
>> }
>>
>> +static void destroy_blkring(struct xenbus_device *dev,
>> + struct blkfront_ring_info *rinfo)
>> +{
>> + int i;
>> +
>> + if (rinfo->irq)
>> + unbind_from_irqhandler(rinfo->irq, rinfo);
>> + if (rinfo->evtchn)
>> + xenbus_free_evtchn(dev, rinfo->evtchn);
>> +
>> + for (i = 0; i < rinfo->dinfo->pages_per_ring; i++) {
>> + if (rinfo->ring_ref[i] != GRANT_INVALID_REF) {
>> + gnttab_end_foreign_access(rinfo->ring_ref[i], 0, 0);
>> + rinfo->ring_ref[i] = GRANT_INVALID_REF;
>> + }
>> + }
>> + free_pages((unsigned long)rinfo->ring.sring,
>> + get_order(rinfo->dinfo->pages_per_ring * PAGE_SIZE));
>> + rinfo->ring.sring = NULL;
>> +}
>>
>> static int setup_blkring(struct xenbus_device *dev,
>> struct blkfront_ring_info *rinfo)
>> @@ -1283,10 +1311,10 @@ static int setup_blkring(struct xenbus_device *dev,
>> struct blkif_sring *sring;
>> int err, i;
>> struct blkfront_dev_info *dinfo = rinfo->dinfo;
>> - unsigned long ring_size = dinfo->nr_ring_pages * PAGE_SIZE;
>> + unsigned long ring_size = dinfo->pages_per_ring * PAGE_SIZE;
>> grant_ref_t gref[XENBUS_MAX_RING_PAGES];
>>
>> - for (i = 0; i < dinfo->nr_ring_pages; i++)
>> + for (i = 0; i < dinfo->pages_per_ring; i++)
>> rinfo->ring_ref[i] = GRANT_INVALID_REF;
>>
>> sring = (struct blkif_sring *)__get_free_pages(GFP_NOIO | __GFP_HIGH,
>> @@ -1298,13 +1326,13 @@ static int setup_blkring(struct xenbus_device *dev,
>> SHARED_RING_INIT(sring);
>> FRONT_RING_INIT(&rinfo->ring, sring, ring_size);
>>
>> - err = xenbus_grant_ring(dev, rinfo->ring.sring, dinfo->nr_ring_pages, gref);
>> + err = xenbus_grant_ring(dev, rinfo->ring.sring, dinfo->pages_per_ring, gref);
>> if (err < 0) {
>> free_pages((unsigned long)sring, get_order(ring_size));
>> rinfo->ring.sring = NULL;
>> goto fail;
>> }
>> - for (i = 0; i < dinfo->nr_ring_pages; i++)
>> + for (i = 0; i < dinfo->pages_per_ring; i++)
>> rinfo->ring_ref[i] = gref[i];
>>
>> err = xenbus_alloc_evtchn(dev, &rinfo->evtchn);
>> @@ -1322,7 +1350,7 @@ static int setup_blkring(struct xenbus_device *dev,
>>
>> return 0;
>> fail:
>> - blkif_free(dinfo, 0);
>> + destroy_blkring(dev, rinfo);
>
> blkif_free used to clean a lot more than what destroy_blkring does, is
> this right?
>
I think it's fine because we are still in the early setup stage.
But to minial the changes I'll not introduce destroy_blkring() in next version any more.
And blkif_free() will be deleted here, because talk_to_blkback() will call blkif_free() anyway if return err.
>> return err;
>> }
>>
>> @@ -1333,65 +1361,76 @@ static int talk_to_blkback(struct xenbus_device *dev,
>> {
>> const char *message = NULL;
>> struct xenbus_transaction xbt;
>> - int err, i;
>> + int err, i, r_index;
>> unsigned int max_page_order = 0;
>> unsigned int ring_page_order = 0;
>> - struct blkfront_ring_info *rinfo = &dinfo->rinfo;
>> + struct blkfront_ring_info *rinfo;
>>
>> err = xenbus_scanf(XBT_NIL, dinfo->xbdev->otherend,
>> "max-ring-page-order", "%u", &max_page_order);
>> if (err != 1)
>> - dinfo->nr_ring_pages = 1;
>> + dinfo->pages_per_ring = 1;
>> else {
>> ring_page_order = min(xen_blkif_max_ring_order, max_page_order);
>> - dinfo->nr_ring_pages = 1 << ring_page_order;
>> + dinfo->pages_per_ring = 1 << ring_page_order;
>
> As said above, I think nr_ring_pages is perfectly fine, and avoids all
> this ponintless changes.
>
>> }
>>
>> - /* Create shared ring, alloc event channel. */
>> - err = setup_blkring(dev, rinfo);
>> - if (err)
>> - goto out;
>> + for (r_index = 0; r_index < dinfo->nr_rings; r_index++) {
>> + rinfo = &dinfo->rinfo[r_index];
>> + /* Create shared ring, alloc event channel. */
>> + err = setup_blkring(dev, rinfo);
>> + if (err)
>> + goto out;
>> + }
>>
>> again:
>> err = xenbus_transaction_start(&xbt);
>> if (err) {
>> xenbus_dev_fatal(dev, err, "starting transaction");
>> - goto destroy_blkring;
>> + goto out;
>> }
>>
>> - if (dinfo->nr_ring_pages == 1) {
>> - err = xenbus_printf(xbt, dev->nodename,
>> - "ring-ref", "%u", rinfo->ring_ref[0]);
>> - if (err) {
>> - message = "writing ring-ref";
>> - goto abort_transaction;
>> - }
>> - } else {
>> - err = xenbus_printf(xbt, dev->nodename,
>> - "ring-page-order", "%u", ring_page_order);
>> - if (err) {
>> - message = "writing ring-page-order";
>> - goto abort_transaction;
>> - }
>> -
>> - for (i = 0; i < dinfo->nr_ring_pages; i++) {
>> - char ring_ref_name[RINGREF_NAME_LEN];
>> + if (dinfo->nr_rings == 1) {
>> + rinfo = &dinfo->rinfo[0];
>>
>> - snprintf(ring_ref_name, RINGREF_NAME_LEN, "ring-ref%u", i);
>> - err = xenbus_printf(xbt, dev->nodename, ring_ref_name,
>> - "%u", rinfo->ring_ref[i]);
>> + if (dinfo->pages_per_ring == 1) {
>> + err = xenbus_printf(xbt, dev->nodename,
>> + "ring-ref", "%u", rinfo->ring_ref[0]);
>> if (err) {
>> message = "writing ring-ref";
>> goto abort_transaction;
>> }
>> + } else {
>> + err = xenbus_printf(xbt, dev->nodename,
>> + "ring-page-order", "%u", ring_page_order);
>> + if (err) {
>> + message = "writing ring-page-order";
>> + goto abort_transaction;
>> + }
>> +
>> + for (i = 0; i < dinfo->pages_per_ring; i++) {
>> + char ring_ref_name[RINGREF_NAME_LEN];
>> +
>> + snprintf(ring_ref_name, RINGREF_NAME_LEN, "ring-ref%u", i);
>> + err = xenbus_printf(xbt, dev->nodename, ring_ref_name,
>> + "%u", rinfo->ring_ref[i]);
>> + if (err) {
>> + message = "writing ring-ref";
>> + goto abort_transaction;
>> + }
>> + }
>> }
>> - }
>> - err = xenbus_printf(xbt, dev->nodename,
>> - "event-channel", "%u", rinfo->evtchn);
>> - if (err) {
>> - message = "writing event-channel";
>> + err = xenbus_printf(xbt, dev->nodename,
>> + "event-channel", "%u", rinfo->evtchn);
>> + if (err) {
>> + message = "writing event-channel";
>> + goto abort_transaction;
>> + }
>> + } else {
>> + /* Not supported at this stage */
>> goto abort_transaction;
>> }
>> +
>> err = xenbus_printf(xbt, dev->nodename, "protocol", "%s",
>> XEN_IO_PROTO_ABI_NATIVE);
>> if (err) {
>> @@ -1409,12 +1448,16 @@ again:
>> if (err == -EAGAIN)
>> goto again;
>> xenbus_dev_fatal(dev, err, "completing transaction");
>> - goto destroy_blkring;
>> + goto out;
>> }
>>
>> - for (i = 0; i < BLK_RING_SIZE(dinfo); i++)
>> - rinfo->shadow[i].req.u.rw.id = i+1;
>> - rinfo->shadow[BLK_RING_SIZE(dinfo)-1].req.u.rw.id = 0x0fffffff;
>> + for (r_index = 0; r_index < dinfo->nr_rings; r_index++) {
>> + rinfo = &dinfo->rinfo[r_index];
>> +
>> + for (i = 0; i < BLK_RING_SIZE(dinfo); i++)
>> + rinfo->shadow[i].req.u.rw.id = i+1;
>> + rinfo->shadow[BLK_RING_SIZE(dinfo)-1].req.u.rw.id = 0x0fffffff;
>> + }
>> xenbus_switch_state(dev, XenbusStateInitialised);
>>
>> return 0;
>> @@ -1423,9 +1466,9 @@ again:
>> xenbus_transaction_end(xbt, 1);
>> if (message)
>> xenbus_dev_fatal(dev, err, "%s", message);
>> - destroy_blkring:
>> - blkif_free(dinfo, 0);
>> out:
>> + while (--r_index >= 0)
>> + destroy_blkring(dev, &dinfo->rinfo[r_index]);
>
> The same as above, destroy_blkring does a different cleaning of what
> used to be done in blkif_free.
Will revert to blkif_free().
>
>> return err;
>> }
>>
>> @@ -1438,7 +1481,7 @@ again:
>> static int blkfront_probe(struct xenbus_device *dev,
>> const struct xenbus_device_id *id)
>> {
>> - int err, vdevice;
>> + int err, vdevice, r_index;
>> struct blkfront_dev_info *dinfo;
>> struct blkfront_ring_info *rinfo;
>>
>> @@ -1490,17 +1533,29 @@ static int blkfront_probe(struct xenbus_device *dev,
>> return -ENOMEM;
>> }
>>
>> - rinfo = &dinfo->rinfo;
>> mutex_init(&dinfo->mutex);
>> spin_lock_init(&dinfo->io_lock);
>> dinfo->xbdev = dev;
>> dinfo->vdevice = vdevice;
>> - INIT_LIST_HEAD(&rinfo->grants);
>> - INIT_LIST_HEAD(&rinfo->indirect_pages);
>> - rinfo->persistent_gnts_c = 0;
>> dinfo->connected = BLKIF_STATE_DISCONNECTED;
>> - rinfo->dinfo = dinfo;
>> - INIT_WORK(&rinfo->work, blkif_restart_queue);
>> +
>> + dinfo->nr_rings = 1;
>> + dinfo->rinfo = kzalloc(sizeof(*rinfo) * dinfo->nr_rings, GFP_KERNEL);
>> + if (!dinfo->rinfo) {
>> + xenbus_dev_fatal(dev, -ENOMEM, "allocating ring_info structure");
>> + kfree(dinfo);
>> + return -ENOMEM;
>> + }
>> +
>> + for (r_index = 0; r_index < dinfo->nr_rings; r_index++) {
>> + rinfo = &dinfo->rinfo[r_index];
>> +
>> + INIT_LIST_HEAD(&rinfo->grants);
>> + INIT_LIST_HEAD(&rinfo->indirect_pages);
>> + rinfo->persistent_gnts_c = 0;
>> + rinfo->dinfo = dinfo;
>> + INIT_WORK(&rinfo->work, blkif_restart_queue);
>> + }
>>
>> /* Front end dir is a number, which is used as the id. */
>> dinfo->handle = simple_strtoul(strrchr(dev->nodename, '/')+1, NULL, 0);
>> @@ -1526,7 +1581,7 @@ static void split_bio_end(struct bio *bio, int error)
>>
>> static int blkif_recover(struct blkfront_dev_info *dinfo)
>> {
>> - int i;
>> + int i, r_index;
>> struct request *req, *n;
>> struct blk_shadow *copy;
>> int rc;
>> @@ -1536,56 +1591,62 @@ static int blkif_recover(struct blkfront_dev_info *dinfo)
>> int pending, size;
>> struct split_bio *split_bio;
>> struct list_head requests;
>> - struct blkfront_ring_info *rinfo = &dinfo->rinfo;
>> -
>> - /* Stage 1: Make a safe copy of the shadow state. */
>> - copy = kmemdup(rinfo->shadow, sizeof(rinfo->shadow),
>> - GFP_NOIO | __GFP_REPEAT | __GFP_HIGH);
>> - if (!copy)
>> - return -ENOMEM;
>> -
>> - /* Stage 2: Set up free list. */
>> - memset(&rinfo->shadow, 0, sizeof(rinfo->shadow));
>> - for (i = 0; i < BLK_RING_SIZE(dinfo); i++)
>> - rinfo->shadow[i].req.u.rw.id = i+1;
>> - rinfo->shadow_free = rinfo->ring.req_prod_pvt;
>> - rinfo->shadow[BLK_RING_SIZE(dinfo)-1].req.u.rw.id = 0x0fffffff;
>> -
>> - rc = blkfront_gather_backend_features(dinfo);
>> - if (rc) {
>> - kfree(copy);
>> - return rc;
>> - }
>> + struct blkfront_ring_info *rinfo;
>>
>> + __blkfront_gather_backend_features(dinfo);
>> segs = dinfo->max_indirect_segments ? : BLKIF_MAX_SEGMENTS_PER_REQUEST;
>> blk_queue_max_segments(dinfo->rq, segs);
>> bio_list_init(&bio_list);
>> INIT_LIST_HEAD(&requests);
>> - for (i = 0; i < BLK_RING_SIZE(dinfo); i++) {
>> - /* Not in use? */
>> - if (!copy[i].request)
>> - continue;
>>
>> - /*
>> - * Get the bios in the request so we can re-queue them.
>> - */
>> - if (copy[i].request->cmd_flags &
>> - (REQ_FLUSH | REQ_FUA | REQ_DISCARD | REQ_SECURE)) {
>> + for (r_index = 0; r_index < dinfo->nr_rings; r_index++) {
>> + rinfo = &dinfo->rinfo[r_index];
>> +
>> + /* Stage 1: Make a safe copy of the shadow state. */
>> + copy = kmemdup(rinfo->shadow, sizeof(rinfo->shadow),
>> + GFP_NOIO | __GFP_REPEAT | __GFP_HIGH);
>> + if (!copy)
>> + return -ENOMEM;
>> +
>> + /* Stage 2: Set up free list. */
>> + memset(&rinfo->shadow, 0, sizeof(rinfo->shadow));
>> + for (i = 0; i < BLK_RING_SIZE(dinfo); i++)
>> + rinfo->shadow[i].req.u.rw.id = i+1;
>> + rinfo->shadow_free = rinfo->ring.req_prod_pvt;
>> + rinfo->shadow[BLK_RING_SIZE(dinfo)-1].req.u.rw.id = 0x0fffffff;
>> +
>> + rc = blkfront_setup_indirect(rinfo);
>> + if (rc) {
>> + kfree(copy);
>> + return rc;
>> + }
>> +
>> + for (i = 0; i < BLK_RING_SIZE(dinfo); i++) {
>> + /* Not in use? */
>> + if (!copy[i].request)
>> + continue;
>> +
>> /*
>> - * Flush operations don't contain bios, so
>> - * we need to requeue the whole request
>> + * Get the bios in the request so we can re-queue them.
>> */
>> - list_add(©[i].request->queuelist, &requests);
>> - continue;
>> + if (copy[i].request->cmd_flags &
>> + (REQ_FLUSH | REQ_FUA | REQ_DISCARD | REQ_SECURE)) {
>> + /*
>> + * Flush operations don't contain bios, so
>> + * we need to requeue the whole request
>> + */
>> + list_add(©[i].request->queuelist, &requests);
>> + continue;
>> + }
>> + merge_bio.head = copy[i].request->bio;
>> + merge_bio.tail = copy[i].request->biotail;
>> + bio_list_merge(&bio_list, &merge_bio);
>> + copy[i].request->bio = NULL;
>> + blk_end_request_all(copy[i].request, 0);
>> }
>> - merge_bio.head = copy[i].request->bio;
>> - merge_bio.tail = copy[i].request->biotail;
>> - bio_list_merge(&bio_list, &merge_bio);
>> - copy[i].request->bio = NULL;
>> - blk_end_request_all(copy[i].request, 0);
>> - }
>>
>> - kfree(copy);
>> + kfree(copy);
>> + }
>>
>> xenbus_switch_state(dinfo->xbdev, XenbusStateConnected);
>>
>> @@ -1594,8 +1655,12 @@ static int blkif_recover(struct blkfront_dev_info *dinfo)
>> /* Now safe for us to use the shared ring */
>> dinfo->connected = BLKIF_STATE_CONNECTED;
>>
>> - /* Kick any other new requests queued since we resumed */
>> - kick_pending_request_queues(rinfo);
>> + for (r_index = 0; r_index < dinfo->nr_rings; r_index++) {
>> + rinfo = &dinfo->rinfo[r_index];
>> +
>> + /* Kick any other new requests queued since we resumed */
>> + kick_pending_request_queues(rinfo);
>> + }
>>
>> list_for_each_entry_safe(req, n, &requests, queuelist) {
>> /* Requeue pending requests (flush or discard) */
>> @@ -1729,6 +1794,38 @@ static void blkfront_setup_discard(struct blkfront_dev_info *dinfo)
>> dinfo->feature_secdiscard = !!discard_secure;
>> }
>>
>> +static void blkfront_clean_ring(struct blkfront_ring_info *rinfo)
>> +{
>> + int i;
>> +
>> + for (i = 0; i < BLK_RING_SIZE(rinfo->dinfo); i++) {
>> + kfree(rinfo->shadow[i].grants_used);
>> + rinfo->shadow[i].grants_used = NULL;
>> + kfree(rinfo->shadow[i].sg);
>> + rinfo->shadow[i].sg = NULL;
>> + kfree(rinfo->shadow[i].indirect_grants);
>> + rinfo->shadow[i].indirect_grants = NULL;
>> + }
>> + if (!list_empty(&rinfo->indirect_pages)) {
>> + struct page *indirect_page, *n;
>> + list_for_each_entry_safe(indirect_page, n, &rinfo->indirect_pages, lru) {
>> + list_del(&indirect_page->lru);
>> + __free_page(indirect_page);
>> + }
>> + }
>> +
>> + if (!list_empty(&rinfo->grants)) {
>> + struct grant *gnt_list_entry, *n;
>> + list_for_each_entry_safe(gnt_list_entry, n,
>> + &rinfo->grants, node) {
>> + list_del(&gnt_list_entry->node);
>> + if (rinfo->dinfo->feature_persistent)
>> + __free_page(pfn_to_page(gnt_list_entry->pfn));
>> + kfree(gnt_list_entry);
>> + }
>> + }
>> +}
>> +
>> static int blkfront_setup_indirect(struct blkfront_ring_info *rinfo)
>> {
>> unsigned int segs;
>> @@ -1783,28 +1880,14 @@ static int blkfront_setup_indirect(struct blkfront_ring_info *rinfo)
>> return 0;
>>
>> out_of_memory:
>> - for (i = 0; i < BLK_RING_SIZE(dinfo); i++) {
>> - kfree(rinfo->shadow[i].grants_used);
>> - rinfo->shadow[i].grants_used = NULL;
>> - kfree(rinfo->shadow[i].sg);
>> - rinfo->shadow[i].sg = NULL;
>> - kfree(rinfo->shadow[i].indirect_grants);
>> - rinfo->shadow[i].indirect_grants = NULL;
>> - }
>> - if (!list_empty(&rinfo->indirect_pages)) {
>> - struct page *indirect_page, *n;
>> - list_for_each_entry_safe(indirect_page, n, &rinfo->indirect_pages, lru) {
>> - list_del(&indirect_page->lru);
>> - __free_page(indirect_page);
>> - }
>> - }
>> + blkfront_clean_ring(rinfo);
>> return -ENOMEM;
>> }
>>
>> /*
>> * Gather all backend feature-*
>> */
>> -static int blkfront_gather_backend_features(struct blkfront_dev_info *dinfo)
>> +static void __blkfront_gather_backend_features(struct blkfront_dev_info *dinfo)
>> {
>> int err;
>> int barrier, flush, discard, persistent;
>> @@ -1859,8 +1942,25 @@ static int blkfront_gather_backend_features(struct blkfront_dev_info *dinfo)
>> else
>> dinfo->max_indirect_segments = min(indirect_segments,
>> xen_blkif_max_segments);
>> +}
>> +
>> +static int blkfront_gather_backend_features(struct blkfront_dev_info *dinfo)
>> +{
>> + int err, i;
>> +
>> + __blkfront_gather_backend_features(dinfo);
>
> IMHO, there's no need to introduce __blkfront_gather_backend_features,
> just add the chunk below to the existing blkfront_gather_backend_features.
>
Will update.
>> - return blkfront_setup_indirect(&dinfo->rinfo);
>> + for (i = 0; i < dinfo->nr_rings; i++) {
>> + err = blkfront_setup_indirect(&dinfo->rinfo[i]);
>> + if (err)
>> + goto out;
>> + }
>> + return 0;
>> +
>> +out:
>> + while (--i >= 0)
>> + blkfront_clean_ring(&dinfo->rinfo[i]);
>> + return err;
>> }
>>
>> /*
>> @@ -1873,8 +1973,8 @@ static void blkfront_connect(struct blkfront_dev_info *dinfo)
>> unsigned long sector_size;
>> unsigned int physical_sector_size;
>> unsigned int binfo;
>> - int err;
>> - struct blkfront_ring_info *rinfo = &dinfo->rinfo;
>> + int err, i;
>> + struct blkfront_ring_info *rinfo;
>>
>> switch (dinfo->connected) {
>> case BLKIF_STATE_CONNECTED:
>> @@ -1951,7 +2051,10 @@ static void blkfront_connect(struct blkfront_dev_info *dinfo)
>> /* Kick pending requests. */
>> spin_lock_irq(&dinfo->io_lock);
>> dinfo->connected = BLKIF_STATE_CONNECTED;
>> - kick_pending_request_queues(rinfo);
>> + for (i = 0; i < dinfo->nr_rings; i++) {
>> + rinfo = &dinfo->rinfo[i];
>
> If rinfo is only going to be used in the for loop you can declare it inside:
>
Will update.
Thank you for your patient for these big patches.
> struct blkfront_ring_info *rinfo = &dinfo->rinfo[i];
>
>> + kick_pending_request_queues(rinfo);
>> + }
>> spin_unlock_irq(&dinfo->io_lock);
>>
>> add_disk(dinfo->gd);
>>
>
--
Regards,
-Bob
--
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