diff options
author | Zoltan Kiss <zoltan.kiss@citrix.com> | 2014-01-23 21:23:44 +0000 |
---|---|---|
committer | Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> | 2014-01-31 09:48:32 -0500 |
commit | 08ece5bb2312b4510b161a6ef6682f37f4eac8a1 (patch) | |
tree | d331f6b82ca8f0346afdf54bc793fb10c4bdaec8 /drivers | |
parent | 47c542050d306e50f09512eb6339dbf2fc02fddd (diff) | |
download | linux-08ece5bb2312b4510b161a6ef6682f37f4eac8a1.tar.bz2 |
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 <zoltan.kiss@citrix.com>
Suggested-by: David Vrabel <david.vrabel@citrix.com>
Acked-by: David Vrabel <david.vrabel@citrix.com>
Acked-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Diffstat (limited to 'drivers')
-rw-r--r-- | drivers/block/xen-blkback/blkback.c | 15 | ||||
-rw-r--r-- | drivers/xen/gntdev.c | 13 | ||||
-rw-r--r-- | drivers/xen/grant-table.c | 89 |
3 files changed, 90 insertions, 27 deletions
diff --git a/drivers/block/xen-blkback/blkback.c b/drivers/block/xen-blkback/blkback.c index 6620b73d0490..875025f299b6 100644 --- a/drivers/block/xen-blkback/blkback.c +++ b/drivers/block/xen-blkback/blkback.c @@ -285,8 +285,7 @@ static void free_persistent_gnts(struct xen_blkif *blkif, struct rb_root *root, if (++segs_to_unmap == BLKIF_MAX_SEGMENTS_PER_REQUEST || !rb_next(&persistent_gnt->node)) { - ret = gnttab_unmap_refs(unmap, NULL, pages, - segs_to_unmap); + ret = gnttab_unmap_refs(unmap, pages, segs_to_unmap); BUG_ON(ret); put_free_pages(blkif, pages, segs_to_unmap); segs_to_unmap = 0; @@ -321,8 +320,7 @@ static void unmap_purged_grants(struct work_struct *work) pages[segs_to_unmap] = persistent_gnt->page; if (++segs_to_unmap == BLKIF_MAX_SEGMENTS_PER_REQUEST) { - ret = gnttab_unmap_refs(unmap, NULL, pages, - segs_to_unmap); + ret = gnttab_unmap_refs(unmap, pages, segs_to_unmap); BUG_ON(ret); put_free_pages(blkif, pages, segs_to_unmap); segs_to_unmap = 0; @@ -330,7 +328,7 @@ static void unmap_purged_grants(struct work_struct *work) kfree(persistent_gnt); } if (segs_to_unmap > 0) { - ret = gnttab_unmap_refs(unmap, NULL, pages, segs_to_unmap); + ret = gnttab_unmap_refs(unmap, pages, segs_to_unmap); BUG_ON(ret); put_free_pages(blkif, pages, segs_to_unmap); } @@ -670,15 +668,14 @@ static void xen_blkbk_unmap(struct xen_blkif *blkif, GNTMAP_host_map, pages[i]->handle); pages[i]->handle = BLKBACK_INVALID_HANDLE; if (++invcount == BLKIF_MAX_SEGMENTS_PER_REQUEST) { - ret = gnttab_unmap_refs(unmap, NULL, unmap_pages, - invcount); + ret = gnttab_unmap_refs(unmap, unmap_pages, invcount); BUG_ON(ret); put_free_pages(blkif, unmap_pages, invcount); invcount = 0; } } if (invcount) { - ret = gnttab_unmap_refs(unmap, NULL, unmap_pages, invcount); + ret = gnttab_unmap_refs(unmap, unmap_pages, invcount); BUG_ON(ret); put_free_pages(blkif, unmap_pages, invcount); } @@ -740,7 +737,7 @@ again: } if (segs_to_map) { - ret = gnttab_map_refs(map, NULL, pages_to_gnt, segs_to_map); + ret = gnttab_map_refs(map, pages_to_gnt, segs_to_map); BUG_ON(ret); } diff --git a/drivers/xen/gntdev.c b/drivers/xen/gntdev.c index 073b4a19a8b0..34a2704fbc88 100644 --- a/drivers/xen/gntdev.c +++ b/drivers/xen/gntdev.c @@ -284,8 +284,10 @@ static int map_grant_pages(struct grant_map *map) } pr_debug("map %d+%d\n", map->index, map->count); - err = gnttab_map_refs(map->map_ops, use_ptemod ? map->kmap_ops : NULL, - map->pages, map->count); + err = gnttab_map_refs_userspace(map->map_ops, + use_ptemod ? map->kmap_ops : NULL, + map->pages, + map->count); if (err) return err; @@ -315,9 +317,10 @@ static int __unmap_grant_pages(struct grant_map *map, int offset, int pages) } } - err = gnttab_unmap_refs(map->unmap_ops + offset, - use_ptemod ? map->kmap_ops + offset : NULL, map->pages + offset, - pages); + err = gnttab_unmap_refs_userspace(map->unmap_ops + offset, + use_ptemod ? map->kmap_ops + offset : NULL, + map->pages + offset, + pages); if (err) return err; diff --git a/drivers/xen/grant-table.c b/drivers/xen/grant-table.c index b84e3ab839aa..8ee13e2e45e2 100644 --- a/drivers/xen/grant-table.c +++ b/drivers/xen/grant-table.c @@ -928,15 +928,17 @@ void gnttab_batch_copy(struct gnttab_copy *batch, unsigned count) } EXPORT_SYMBOL_GPL(gnttab_batch_copy); -int gnttab_map_refs(struct gnttab_map_grant_ref *map_ops, +int __gnttab_map_refs(struct gnttab_map_grant_ref *map_ops, struct gnttab_map_grant_ref *kmap_ops, - struct page **pages, unsigned int count) + struct page **pages, unsigned int count, + bool m2p_override) { int i, ret; bool lazy = false; pte_t *pte; - unsigned long mfn; + unsigned long mfn, pfn; + BUG_ON(kmap_ops && !m2p_override); ret = HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, map_ops, count); if (ret) return ret; @@ -955,10 +957,12 @@ int gnttab_map_refs(struct gnttab_map_grant_ref *map_ops, set_phys_to_machine(map_ops[i].host_addr >> PAGE_SHIFT, map_ops[i].dev_bus_addr >> PAGE_SHIFT); } - return ret; + return 0; } - if (!in_interrupt() && paravirt_get_lazy_mode() == PARAVIRT_LAZY_NONE) { + if (m2p_override && + !in_interrupt() && + paravirt_get_lazy_mode() == PARAVIRT_LAZY_NONE) { arch_enter_lazy_mmu_mode(); lazy = true; } @@ -975,8 +979,20 @@ int gnttab_map_refs(struct gnttab_map_grant_ref *map_ops, } else { mfn = PFN_DOWN(map_ops[i].dev_bus_addr); } - ret = m2p_add_override(mfn, pages[i], kmap_ops ? - &kmap_ops[i] : NULL); + pfn = page_to_pfn(pages[i]); + + WARN_ON(PagePrivate(pages[i])); + SetPagePrivate(pages[i]); + set_page_private(pages[i], mfn); + + pages[i]->index = pfn_to_mfn(pfn); + if (unlikely(!set_phys_to_machine(pfn, FOREIGN_FRAME(mfn)))) { + ret = -ENOMEM; + goto out; + } + if (m2p_override) + ret = m2p_add_override(mfn, pages[i], kmap_ops ? + &kmap_ops[i] : NULL); if (ret) goto out; } @@ -987,15 +1003,32 @@ int gnttab_map_refs(struct gnttab_map_grant_ref *map_ops, return ret; } + +int gnttab_map_refs(struct gnttab_map_grant_ref *map_ops, + struct page **pages, unsigned int count) +{ + return __gnttab_map_refs(map_ops, NULL, pages, count, false); +} EXPORT_SYMBOL_GPL(gnttab_map_refs); -int gnttab_unmap_refs(struct gnttab_unmap_grant_ref *unmap_ops, +int gnttab_map_refs_userspace(struct gnttab_map_grant_ref *map_ops, + struct gnttab_map_grant_ref *kmap_ops, + struct page **pages, unsigned int count) +{ + return __gnttab_map_refs(map_ops, kmap_ops, pages, count, true); +} +EXPORT_SYMBOL_GPL(gnttab_map_refs_userspace); + +int __gnttab_unmap_refs(struct gnttab_unmap_grant_ref *unmap_ops, struct gnttab_map_grant_ref *kmap_ops, - struct page **pages, unsigned int count) + struct page **pages, unsigned int count, + bool m2p_override) { int i, ret; bool lazy = false; + unsigned long pfn, mfn; + BUG_ON(kmap_ops && !m2p_override); ret = HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, unmap_ops, count); if (ret) return ret; @@ -1006,17 +1039,33 @@ int gnttab_unmap_refs(struct gnttab_unmap_grant_ref *unmap_ops, set_phys_to_machine(unmap_ops[i].host_addr >> PAGE_SHIFT, INVALID_P2M_ENTRY); } - return ret; + return 0; } - if (!in_interrupt() && paravirt_get_lazy_mode() == PARAVIRT_LAZY_NONE) { + if (m2p_override && + !in_interrupt() && + paravirt_get_lazy_mode() == PARAVIRT_LAZY_NONE) { arch_enter_lazy_mmu_mode(); lazy = true; } for (i = 0; i < count; i++) { - ret = m2p_remove_override(pages[i], kmap_ops ? - &kmap_ops[i] : NULL); + pfn = page_to_pfn(pages[i]); + mfn = get_phys_to_machine(pfn); + if (mfn == INVALID_P2M_ENTRY || !(mfn & FOREIGN_FRAME_BIT)) { + ret = -EINVAL; + goto out; + } + + set_page_private(pages[i], INVALID_P2M_ENTRY); + WARN_ON(!PagePrivate(pages[i])); + ClearPagePrivate(pages[i]); + set_phys_to_machine(pfn, pages[i]->index); + if (m2p_override) + ret = m2p_remove_override(pages[i], + kmap_ops ? + &kmap_ops[i] : NULL, + mfn); if (ret) goto out; } @@ -1027,8 +1076,22 @@ int gnttab_unmap_refs(struct gnttab_unmap_grant_ref *unmap_ops, return ret; } + +int gnttab_unmap_refs(struct gnttab_unmap_grant_ref *map_ops, + struct page **pages, unsigned int count) +{ + return __gnttab_unmap_refs(map_ops, NULL, pages, count, false); +} EXPORT_SYMBOL_GPL(gnttab_unmap_refs); +int gnttab_unmap_refs_userspace(struct gnttab_unmap_grant_ref *map_ops, + struct gnttab_map_grant_ref *kmap_ops, + struct page **pages, unsigned int count) +{ + return __gnttab_unmap_refs(map_ops, kmap_ops, pages, count, true); +} +EXPORT_SYMBOL_GPL(gnttab_unmap_refs_userspace); + static unsigned nr_status_frames(unsigned nr_grant_frames) { BUG_ON(grefs_per_grant_frame == 0); |