From 08ece5bb2312b4510b161a6ef6682f37f4eac8a1 Mon Sep 17 00:00:00 2001 From: Zoltan Kiss Date: Thu, 23 Jan 2014 21:23:44 +0000 Subject: xen/grant-table: Avoid m2p_override during mapping The grant mapping API does m2p_override unnecessarily: only gntdev needs it, for blkback and future netback patches it just cause a lock contention, as those pages never go to userspace. Therefore this series does the following: - the original functions were renamed to __gnttab_[un]map_refs, with a new parameter m2p_override - based on m2p_override either they follow the original behaviour, or just set the private flag and call set_phys_to_machine - gnttab_[un]map_refs are now a wrapper to call __gnttab_[un]map_refs with m2p_override false - a new function gnttab_[un]map_refs_userspace provides the old behaviour It also removes a stray space from page.h and change ret to 0 if XENFEAT_auto_translated_physmap, as that is the only possible return value there. v2: - move the storing of the old mfn in page->index to gnttab_map_refs - move the function header update to a separate patch v3: - a new approach to retain old behaviour where it needed - squash the patches into one v4: - move out the common bits from m2p* functions, and pass pfn/mfn as parameter - clear page->private before doing anything with the page, so m2p_find_override won't race with this v5: - change return value handling in __gnttab_[un]map_refs - remove a stray space in page.h - add detail why ret = 0 now at some places v6: - don't pass pfn to m2p* functions, just get it locally Signed-off-by: Zoltan Kiss Suggested-by: David Vrabel Acked-by: David Vrabel Acked-by: Stefano Stabellini Signed-off-by: Konrad Rzeszutek Wilk --- arch/x86/include/asm/xen/page.h | 5 +++-- arch/x86/xen/p2m.c | 17 ++--------------- 2 files changed, 5 insertions(+), 17 deletions(-) (limited to 'arch/x86') diff --git a/arch/x86/include/asm/xen/page.h b/arch/x86/include/asm/xen/page.h index 3e276eb23d1b..787e1bb5aafc 100644 --- a/arch/x86/include/asm/xen/page.h +++ b/arch/x86/include/asm/xen/page.h @@ -52,7 +52,8 @@ extern unsigned long set_phys_range_identity(unsigned long pfn_s, extern int m2p_add_override(unsigned long mfn, struct page *page, struct gnttab_map_grant_ref *kmap_op); extern int m2p_remove_override(struct page *page, - struct gnttab_map_grant_ref *kmap_op); + struct gnttab_map_grant_ref *kmap_op, + unsigned long mfn); extern struct page *m2p_find_override(unsigned long mfn); extern unsigned long m2p_find_override_pfn(unsigned long mfn, unsigned long pfn); @@ -121,7 +122,7 @@ static inline unsigned long mfn_to_pfn(unsigned long mfn) pfn = m2p_find_override_pfn(mfn, ~0); } - /* + /* * pfn is ~0 if there are no entries in the m2p for mfn or if the * entry doesn't map back to the mfn and m2p_override doesn't have a * valid entry for it. diff --git a/arch/x86/xen/p2m.c b/arch/x86/xen/p2m.c index 696c694986d0..8009acbe41e4 100644 --- a/arch/x86/xen/p2m.c +++ b/arch/x86/xen/p2m.c @@ -899,13 +899,6 @@ int m2p_add_override(unsigned long mfn, struct page *page, "m2p_add_override: pfn %lx not mapped", pfn)) return -EINVAL; } - WARN_ON(PagePrivate(page)); - SetPagePrivate(page); - set_page_private(page, mfn); - page->index = pfn_to_mfn(pfn); - - if (unlikely(!set_phys_to_machine(pfn, FOREIGN_FRAME(mfn)))) - return -ENOMEM; if (kmap_op != NULL) { if (!PageHighMem(page)) { @@ -944,19 +937,16 @@ int m2p_add_override(unsigned long mfn, struct page *page, } EXPORT_SYMBOL_GPL(m2p_add_override); int m2p_remove_override(struct page *page, - struct gnttab_map_grant_ref *kmap_op) + struct gnttab_map_grant_ref *kmap_op, + unsigned long mfn) { unsigned long flags; - unsigned long mfn; unsigned long pfn; unsigned long uninitialized_var(address); unsigned level; pte_t *ptep = NULL; pfn = page_to_pfn(page); - mfn = get_phys_to_machine(pfn); - if (mfn == INVALID_P2M_ENTRY || !(mfn & FOREIGN_FRAME_BIT)) - return -EINVAL; if (!PageHighMem(page)) { address = (unsigned long)__va(pfn << PAGE_SHIFT); @@ -970,10 +960,7 @@ int m2p_remove_override(struct page *page, spin_lock_irqsave(&m2p_override_lock, flags); list_del(&page->lru); spin_unlock_irqrestore(&m2p_override_lock, flags); - WARN_ON(!PagePrivate(page)); - ClearPagePrivate(page); - set_phys_to_machine(pfn, page->index); if (kmap_op != NULL) { if (!PageHighMem(page)) { struct multicall_space mcs; -- cgit v1.2.3 From f93576e1ac34fd7a93d6f3432e71295bbe6a27ce Mon Sep 17 00:00:00 2001 From: Dave Jones Date: Mon, 27 Jan 2014 10:56:09 -0500 Subject: xen/pvh: Fix misplaced kfree from xlated_setup_gnttab_pages Passing a freed 'pages' to free_xenballooned_pages will end badly on kernels with slub debug enabled. This looks out of place between the rc assign and the check, but we do want to kfree pages regardless of which path we take. Signed-off-by: Dave Jones Signed-off-by: Konrad Rzeszutek Wilk --- arch/x86/xen/grant-table.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'arch/x86') diff --git a/arch/x86/xen/grant-table.c b/arch/x86/xen/grant-table.c index 103c93f874b2..c98583588580 100644 --- a/arch/x86/xen/grant-table.c +++ b/arch/x86/xen/grant-table.c @@ -162,14 +162,15 @@ static int __init xlated_setup_gnttab_pages(void) rc = arch_gnttab_map_shared(pfns, nr_grant_frames, nr_grant_frames, &xen_auto_xlat_grant_frames.vaddr); - kfree(pages); if (rc) { pr_warn("%s Couldn't map %ld pfns rc:%d\n", __func__, nr_grant_frames, rc); free_xenballooned_pages(nr_grant_frames, pages); + kfree(pages); kfree(pfns); return rc; } + kfree(pages); xen_auto_xlat_grant_frames.pfn = pfns; xen_auto_xlat_grant_frames.count = nr_grant_frames; -- cgit v1.2.3