linux-kernel - [PATCH v3 21/21] xen/xenbus: eliminate xenbus_grant

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Date:   Thu,  5 May 2022 10:16:40 +0200
From:   Juergen Gross <jgross@...e.com>
To:     xen-devel@...ts.xenproject.org, linux-kernel@...r.kernel.org
Cc:     Juergen Gross <jgross@...e.com>,
        Boris Ostrovsky <boris.ostrovsky@...cle.com>,
        Stefano Stabellini <sstabellini@...nel.org>,
        Oleksandr Tyshchenko <oleksandr_tyshchenko@...m.com>
Subject: [PATCH v3 21/21] xen/xenbus: eliminate xenbus_grant_ring()

There is no external user of xenbus_grant_ring() left, so merge it into
the only caller xenbus_setup_ring().

Signed-off-by: Juergen Gross <jgross@...e.com>
Reviewed-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@...m.com>
---
V2:
- make error message more precise (Andrew Cooper)
---
 drivers/xen/xenbus/xenbus_client.c | 65 +++++++++---------------------
 include/xen/xenbus.h               |  2 -
 2 files changed, 19 insertions(+), 48 deletions(-)

diff --git a/drivers/xen/xenbus/xenbus_client.c b/drivers/xen/xenbus/xenbus_client.c
index 1a2e0d94ccd1..d6fdd2d209d3 100644
--- a/drivers/xen/xenbus/xenbus_client.c
+++ b/drivers/xen/xenbus/xenbus_client.c
@@ -363,50 +363,6 @@ static void xenbus_switch_fatal(struct xenbus_device *dev, int depth, int err,
 		__xenbus_switch_state(dev, XenbusStateClosing, 1);
 }
 
-/**
- * xenbus_grant_ring
- * @dev: xenbus device
- * @vaddr: starting virtual address of the ring
- * @nr_pages: number of pages to be granted
- * @grefs: grant reference array to be filled in
- *
- * Grant access to the given @vaddr to the peer of the given device.
- * Then fill in @grefs with grant references.  Return 0 on success, or
- * -errno on error.  On error, the device will switch to
- * XenbusStateClosing, and the error will be saved in the store.
- */
-int xenbus_grant_ring(struct xenbus_device *dev, void *vaddr,
-		      unsigned int nr_pages, grant_ref_t *grefs)
-{
-	int err;
-	unsigned int i;
-	grant_ref_t gref_head;
-
-	err = gnttab_alloc_grant_references(nr_pages, &gref_head);
-	if (err) {
-		xenbus_dev_fatal(dev, err, "granting access to ring page");
-		return err;
-	}
-
-	for (i = 0; i < nr_pages; i++) {
-		unsigned long gfn;
-
-		if (is_vmalloc_addr(vaddr))
-			gfn = pfn_to_gfn(vmalloc_to_pfn(vaddr));
-		else
-			gfn = virt_to_gfn(vaddr);
-
-		grefs[i] = gnttab_claim_grant_reference(&gref_head);
-		gnttab_grant_foreign_access_ref(grefs[i], dev->otherend_id,
-						gfn, 0);
-
-		vaddr = vaddr + XEN_PAGE_SIZE;
-	}
-
-	return 0;
-}
-EXPORT_SYMBOL_GPL(xenbus_grant_ring);
-
 /*
  * xenbus_setup_ring
  * @dev: xenbus device
@@ -424,6 +380,7 @@ int xenbus_setup_ring(struct xenbus_device *dev, gfp_t gfp, void **vaddr,
 		      unsigned int nr_pages, grant_ref_t *grefs)
 {
 	unsigned long ring_size = nr_pages * XEN_PAGE_SIZE;
+	grant_ref_t gref_head;
 	unsigned int i;
 	int ret;
 
@@ -433,9 +390,25 @@ int xenbus_setup_ring(struct xenbus_device *dev, gfp_t gfp, void **vaddr,
 		goto err;
 	}
 
-	ret = xenbus_grant_ring(dev, *vaddr, nr_pages, grefs);
-	if (ret)
+	ret = gnttab_alloc_grant_references(nr_pages, &gref_head);
+	if (ret) {
+		xenbus_dev_fatal(dev, ret, "granting access to %u ring pages",
+				 nr_pages);
 		goto err;
+	}
+
+	for (i = 0; i < nr_pages; i++) {
+		unsigned long gfn;
+
+		if (is_vmalloc_addr(*vaddr))
+			gfn = pfn_to_gfn(vmalloc_to_pfn(vaddr[i]));
+		else
+			gfn = virt_to_gfn(vaddr[i]);
+
+		grefs[i] = gnttab_claim_grant_reference(&gref_head);
+		gnttab_grant_foreign_access_ref(grefs[i], dev->otherend_id,
+						gfn, 0);
+	}
 
 	return 0;
 
diff --git a/include/xen/xenbus.h b/include/xen/xenbus.h
index b533b4adc835..eaa932b99d8a 100644
--- a/include/xen/xenbus.h
+++ b/include/xen/xenbus.h
@@ -224,8 +224,6 @@ int xenbus_watch_pathfmt(struct xenbus_device *dev, struct xenbus_watch *watch,
 			 const char *pathfmt, ...);
 
 int xenbus_switch_state(struct xenbus_device *dev, enum xenbus_state new_state);
-int xenbus_grant_ring(struct xenbus_device *dev, void *vaddr,
-		      unsigned int nr_pages, grant_ref_t *grefs);
 int xenbus_setup_ring(struct xenbus_device *dev, gfp_t gfp, void **vaddr,
 		      unsigned int nr_pages, grant_ref_t *grefs);
 void xenbus_teardown_ring(void **vaddr, unsigned int nr_pages,
-- 
2.35.3