linux-kernel - [PATCH 3/3] xen/privcmd: drop "pages" parameter from xen_remap

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Date:   Wed, 22 Sep 2021 12:18:25 +0200
From:   Jan Beulich <jbeulich@...e.com>
To:     Juergen Gross <jgross@...e.com>,
        Boris Ostrovsky <boris.ostrovsky@...cle.com>
Cc:     Stefano Stabellini <sstabellini@...nel.org>,
        "xen-devel@...ts.xenproject.org" <xen-devel@...ts.xenproject.org>,
        lkml <linux-kernel@...r.kernel.org>
Subject: [PATCH 3/3] xen/privcmd: drop "pages" parameter from xen_remap_pfn()

The function doesn't use it and all of its callers say in a comment that
their respective arguments are to be non-NULL only in auto-translated
mode. Since xen_remap_domain_mfn_array() isn't supposed to be used by
non-PV, drop the parameter there as well. It was bogusly passed as non-
NULL (PRIV_VMA_LOCKED) by its only caller anyway. For
xen_remap_domain_gfn_range(), otoh, it's not clear at all why this
wouldn't want / might not need to gain auto-translated support down the
road, so the parameter is retained there despite now remaining unused
(and the only caller passing NULL); correct a respective comment as
well.

Signed-off-by: Jan Beulich <jbeulich@...e.com>

--- a/arch/x86/xen/mmu_pv.c
+++ b/arch/x86/xen/mmu_pv.c
@@ -2398,7 +2398,7 @@ static int remap_area_pfn_pte_fn(pte_t *
 
 int xen_remap_pfn(struct vm_area_struct *vma, unsigned long addr,
 		  xen_pfn_t *pfn, int nr, int *err_ptr, pgprot_t prot,
-		  unsigned int domid, bool no_translate, struct page **pages)
+		  unsigned int domid, bool no_translate)
 {
 	int err = 0;
 	struct remap_data rmd;
--- a/drivers/xen/privcmd.c
+++ b/drivers/xen/privcmd.c
@@ -257,7 +257,7 @@ static long privcmd_ioctl_mmap(struct fi
 	LIST_HEAD(pagelist);
 	struct mmap_gfn_state state;
 
-	/* We only support privcmd_ioctl_mmap_batch for auto translated. */
+	/* We only support privcmd_ioctl_mmap_batch for non-auto-translated. */
 	if (xen_feature(XENFEAT_auto_translated_physmap))
 		return -ENOSYS;
 
@@ -810,8 +810,7 @@ static long privcmd_ioctl_mmap_resource(
 						 kdata.addr & PAGE_MASK,
 						 pfns, kdata.num, errs,
 						 vma->vm_page_prot,
-						 domid,
-						 vma->vm_private_data);
+						 domid);
 		if (num < 0)
 			rc = num;
 		else if (num != kdata.num) {
--- a/include/xen/xen-ops.h
+++ b/include/xen/xen-ops.h
@@ -64,12 +64,12 @@ static inline void xen_destroy_contiguou
 #if defined(CONFIG_XEN_PV)
 int xen_remap_pfn(struct vm_area_struct *vma, unsigned long addr,
 		  xen_pfn_t *pfn, int nr, int *err_ptr, pgprot_t prot,
-		  unsigned int domid, bool no_translate, struct page **pages);
+		  unsigned int domid, bool no_translate);
 #else
 static inline int xen_remap_pfn(struct vm_area_struct *vma, unsigned long addr,
 				xen_pfn_t *pfn, int nr, int *err_ptr,
 				pgprot_t prot,  unsigned int domid,
-				bool no_translate, struct page **pages)
+				bool no_translate)
 {
 	BUG();
 	return 0;
@@ -146,7 +146,7 @@ static inline int xen_remap_domain_gfn_a
 	 */
 	BUG_ON(err_ptr == NULL);
 	return xen_remap_pfn(vma, addr, gfn, nr, err_ptr, prot, domid,
-			     false, pages);
+			     false);
 }
 
 /*
@@ -158,7 +158,6 @@ static inline int xen_remap_domain_gfn_a
  * @err_ptr: Returns per-MFN error status.
  * @prot:    page protection mask
  * @domid:   Domain owning the pages
- * @pages:   Array of pages if this domain has an auto-translated physmap
  *
  * @mfn and @err_ptr may point to the same buffer, the MFNs will be
  * overwritten by the error codes after they are mapped.
@@ -169,14 +168,13 @@ static inline int xen_remap_domain_gfn_a
 static inline int xen_remap_domain_mfn_array(struct vm_area_struct *vma,
 					     unsigned long addr, xen_pfn_t *mfn,
 					     int nr, int *err_ptr,
-					     pgprot_t prot, unsigned int domid,
-					     struct page **pages)
+					     pgprot_t prot, unsigned int domid)
 {
 	if (xen_feature(XENFEAT_auto_translated_physmap))
 		return -EOPNOTSUPP;
 
 	return xen_remap_pfn(vma, addr, mfn, nr, err_ptr, prot, domid,
-			     true, pages);
+			     true);
 }
 
 /* xen_remap_domain_gfn_range() - map a range of foreign frames
@@ -200,8 +198,7 @@ static inline int xen_remap_domain_gfn_r
 	if (xen_feature(XENFEAT_auto_translated_physmap))
 		return -EOPNOTSUPP;
 
-	return xen_remap_pfn(vma, addr, &gfn, nr, NULL, prot, domid, false,
-			     pages);
+	return xen_remap_pfn(vma, addr, &gfn, nr, NULL, prot, domid, false);
 }
 
 int xen_unmap_domain_gfn_range(struct vm_area_struct *vma,