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Date: Wed, 3 Jun 2015 13:40:01 +0800
From: Bob Liu <bob.liu@...cle.com>
To: xen-devel@...ts.xen.org
Cc: david.vrabel@...rix.com, justing@...ctralogic.com,
konrad.wilk@...cle.com, roger.pau@...rix.com,
paul.durrant@...rix.com, julien.grall@...rix.com,
linux-kernel@...r.kernel.org, Bob Liu <bob.liu@...cle.com>
Subject: [PATCH 1/3] drivers: xen-blkback: delay pending_req allocation to connect_ring
This is a pre-patch for multi-page ring feature.
In connect_ring, we can know exactly how many pages are used for the shared
ring, delay pending_req allocation here so that we won't waste too much memory.
Signed-off-by: Bob Liu <bob.liu@...cle.com>
---
drivers/block/xen-blkback/common.h | 2 +-
drivers/block/xen-blkback/xenbus.c | 82 +++++++++++++++++-------------------
2 files changed, 39 insertions(+), 45 deletions(-)
diff --git a/drivers/block/xen-blkback/common.h b/drivers/block/xen-blkback/common.h
index f620b5d..043f13b 100644
--- a/drivers/block/xen-blkback/common.h
+++ b/drivers/block/xen-blkback/common.h
@@ -248,7 +248,7 @@ struct backend_info;
#define PERSISTENT_GNT_WAS_ACTIVE 1
/* Number of requests that we can fit in a ring */
-#define XEN_BLKIF_REQS 32
+#define XEN_BLKIF_REQS_PER_PAGE 32
struct persistent_gnt {
struct page *page;
diff --git a/drivers/block/xen-blkback/xenbus.c b/drivers/block/xen-blkback/xenbus.c
index 6ab69ad..c212d41 100644
--- a/drivers/block/xen-blkback/xenbus.c
+++ b/drivers/block/xen-blkback/xenbus.c
@@ -124,8 +124,6 @@ static void xen_update_blkif_status(struct xen_blkif *blkif)
static struct xen_blkif *xen_blkif_alloc(domid_t domid)
{
struct xen_blkif *blkif;
- struct pending_req *req, *n;
- int i, j;
BUILD_BUG_ON(MAX_INDIRECT_PAGES > BLKIF_MAX_INDIRECT_PAGES_PER_REQUEST);
@@ -151,51 +149,11 @@ static struct xen_blkif *xen_blkif_alloc(domid_t domid)
INIT_LIST_HEAD(&blkif->pending_free);
INIT_WORK(&blkif->free_work, xen_blkif_deferred_free);
-
- for (i = 0; i < XEN_BLKIF_REQS; i++) {
- req = kzalloc(sizeof(*req), GFP_KERNEL);
- if (!req)
- goto fail;
- list_add_tail(&req->free_list,
- &blkif->pending_free);
- for (j = 0; j < MAX_INDIRECT_SEGMENTS; j++) {
- req->segments[j] = kzalloc(sizeof(*req->segments[0]),
- GFP_KERNEL);
- if (!req->segments[j])
- goto fail;
- }
- for (j = 0; j < MAX_INDIRECT_PAGES; j++) {
- req->indirect_pages[j] = kzalloc(sizeof(*req->indirect_pages[0]),
- GFP_KERNEL);
- if (!req->indirect_pages[j])
- goto fail;
- }
- }
spin_lock_init(&blkif->pending_free_lock);
init_waitqueue_head(&blkif->pending_free_wq);
init_waitqueue_head(&blkif->shutdown_wq);
return blkif;
-
-fail:
- list_for_each_entry_safe(req, n, &blkif->pending_free, free_list) {
- list_del(&req->free_list);
- for (j = 0; j < MAX_INDIRECT_SEGMENTS; j++) {
- if (!req->segments[j])
- break;
- kfree(req->segments[j]);
- }
- for (j = 0; j < MAX_INDIRECT_PAGES; j++) {
- if (!req->indirect_pages[j])
- break;
- kfree(req->indirect_pages[j]);
- }
- kfree(req);
- }
-
- kmem_cache_free(xen_blkif_cachep, blkif);
-
- return ERR_PTR(-ENOMEM);
}
static int xen_blkif_map(struct xen_blkif *blkif, grant_ref_t gref,
@@ -312,7 +270,7 @@ static void xen_blkif_free(struct xen_blkif *blkif)
i++;
}
- WARN_ON(i != XEN_BLKIF_REQS);
+ WARN_ON(i != XEN_BLKIF_REQS_PER_PAGE);
kmem_cache_free(xen_blkif_cachep, blkif);
}
@@ -864,7 +822,8 @@ static int connect_ring(struct backend_info *be)
unsigned int evtchn;
unsigned int pers_grants;
char protocol[64] = "";
- int err;
+ struct pending_req *req, *n;
+ int err, i, j;
pr_debug("%s %s\n", __func__, dev->otherend);
@@ -905,6 +864,24 @@ static int connect_ring(struct backend_info *be)
ring_ref, evtchn, be->blkif->blk_protocol, protocol,
pers_grants ? "persistent grants" : "");
+ for (i = 0; i < XEN_BLKIF_REQS_PER_PAGE; i++) {
+ req = kzalloc(sizeof(*req), GFP_KERNEL);
+ if (!req)
+ goto fail;
+ list_add_tail(&req->free_list, &be->blkif->pending_free);
+ for (j = 0; j < MAX_INDIRECT_SEGMENTS; j++) {
+ req->segments[j] = kzalloc(sizeof(*req->segments[0]), GFP_KERNEL);
+ if (!req->segments[j])
+ goto fail;
+ }
+ for (j = 0; j < MAX_INDIRECT_PAGES; j++) {
+ req->indirect_pages[j] = kzalloc(sizeof(*req->indirect_pages[0]),
+ GFP_KERNEL);
+ if (!req->indirect_pages[j])
+ goto fail;
+ }
+ }
+
/* Map the shared frame, irq etc. */
err = xen_blkif_map(be->blkif, ring_ref, evtchn);
if (err) {
@@ -914,6 +891,23 @@ static int connect_ring(struct backend_info *be)
}
return 0;
+
+fail:
+ list_for_each_entry_safe(req, n, &be->blkif->pending_free, free_list) {
+ list_del(&req->free_list);
+ for (j = 0; j < MAX_INDIRECT_SEGMENTS; j++) {
+ if (!req->segments[j])
+ break;
+ kfree(req->segments[j]);
+ }
+ for (j = 0; j < MAX_INDIRECT_PAGES; j++) {
+ if (!req->indirect_pages[j])
+ break;
+ kfree(req->indirect_pages[j]);
+ }
+ kfree(req);
+ }
+ return -ENOMEM;
}
static const struct xenbus_device_id xen_blkbk_ids[] = {
--
1.7.10.4
--
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