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authorLinus Torvalds <torvalds@linux-foundation.org>2013-11-21 21:32:38 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2013-11-21 21:32:38 -0800
commita5d6e63323fe7799eb0e6fd0a41fbfad10fca258 (patch)
treeca52285fc4ac7fa25a8e1621782a5a51130ac08b
parent78dc53c422172a317adb0776dfb687057ffa28b7 (diff)
parent7aa555bf26763b86332c7a3689701c999834b87a (diff)
downloadlinux-a5d6e63323fe7799eb0e6fd0a41fbfad10fca258.tar.gz
Merge branch 'akpm' (fixes from Andrew)
Merge patches from Andrew Morton: "13 fixes" * emailed patches from Andrew Morton <akpm@linux-foundation.org>: mm: place page->pmd_huge_pte to right union MAINTAINERS: add keyboard driver to Hyper-V file list x86, mm: do not leak page->ptl for pmd page tables ipc,shm: correct error return value in shmctl (SHM_UNLOCK) mm, mempolicy: silence gcc warning block/partitions/efi.c: fix bound check ARM: drivers/rtc/rtc-at91rm9200.c: disable interrupts at shutdown mm: hugetlbfs: fix hugetlbfs optimization kernel: remove CONFIG_USE_GENERIC_SMP_HELPERS cleanly ipc,shm: fix shm_file deletion races mm: thp: give transparent hugepage code a separate copy_page checkpatch: fix "Use of uninitialized value" warnings configfs: fix race between dentry put and lookup
-rw-r--r--Documentation/vm/split_page_table_lock6
-rw-r--r--MAINTAINERS1
-rw-r--r--arch/x86/mm/pgtable.c4
-rw-r--r--block/partitions/efi.c5
-rw-r--r--drivers/block/null_blk.c8
-rw-r--r--drivers/rtc/rtc-at91rm9200.c9
-rw-r--r--fs/configfs/dir.c16
-rw-r--r--include/linux/hugetlb.h10
-rw-r--r--include/linux/mm_types.h6
-rw-r--r--ipc/shm.c37
-rw-r--r--mm/hugetlb.c51
-rw-r--r--mm/mempolicy.c2
-rw-r--r--mm/migrate.c48
-rw-r--r--mm/swap.c143
-rw-r--r--net/Kconfig4
-rwxr-xr-xscripts/checkpatch.pl1
16 files changed, 227 insertions, 124 deletions
diff --git a/Documentation/vm/split_page_table_lock b/Documentation/vm/split_page_table_lock
index 7521d367f21..6dea4fd5c96 100644
--- a/Documentation/vm/split_page_table_lock
+++ b/Documentation/vm/split_page_table_lock
@@ -63,9 +63,9 @@ levels.
PMD split lock enabling requires pgtable_pmd_page_ctor() call on PMD table
allocation and pgtable_pmd_page_dtor() on freeing.
-Allocation usually happens in pmd_alloc_one(), freeing in pmd_free(), but
-make sure you cover all PMD table allocation / freeing paths: i.e X86_PAE
-preallocate few PMDs on pgd_alloc().
+Allocation usually happens in pmd_alloc_one(), freeing in pmd_free() and
+pmd_free_tlb(), but make sure you cover all PMD table allocation / freeing
+paths: i.e X86_PAE preallocate few PMDs on pgd_alloc().
With everything in place you can set CONFIG_ARCH_ENABLE_SPLIT_PMD_PTLOCK.
diff --git a/MAINTAINERS b/MAINTAINERS
index 8d98e54f2bf..d9c97dce663 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -4065,6 +4065,7 @@ F: arch/x86/include/uapi/asm/hyperv.h
F: arch/x86/kernel/cpu/mshyperv.c
F: drivers/hid/hid-hyperv.c
F: drivers/hv/
+F: drivers/input/serio/hyperv-keyboard.c
F: drivers/net/hyperv/
F: drivers/scsi/storvsc_drv.c
F: drivers/video/hyperv_fb.c
diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c
index 36aa999b263..c96314abd14 100644
--- a/arch/x86/mm/pgtable.c
+++ b/arch/x86/mm/pgtable.c
@@ -61,6 +61,7 @@ void ___pte_free_tlb(struct mmu_gather *tlb, struct page *pte)
#if PAGETABLE_LEVELS > 2
void ___pmd_free_tlb(struct mmu_gather *tlb, pmd_t *pmd)
{
+ struct page *page = virt_to_page(pmd);
paravirt_release_pmd(__pa(pmd) >> PAGE_SHIFT);
/*
* NOTE! For PAE, any changes to the top page-directory-pointer-table
@@ -69,7 +70,8 @@ void ___pmd_free_tlb(struct mmu_gather *tlb, pmd_t *pmd)
#ifdef CONFIG_X86_PAE
tlb->need_flush_all = 1;
#endif
- tlb_remove_page(tlb, virt_to_page(pmd));
+ pgtable_pmd_page_dtor(page);
+ tlb_remove_page(tlb, page);
}
#if PAGETABLE_LEVELS > 3
diff --git a/block/partitions/efi.c b/block/partitions/efi.c
index a8287b49d06..dc51f467a56 100644
--- a/block/partitions/efi.c
+++ b/block/partitions/efi.c
@@ -96,6 +96,7 @@
* - Code works, detects all the partitions.
*
************************************************************/
+#include <linux/kernel.h>
#include <linux/crc32.h>
#include <linux/ctype.h>
#include <linux/math64.h>
@@ -715,8 +716,8 @@ int efi_partition(struct parsed_partitions *state)
efi_guid_unparse(&ptes[i].unique_partition_guid, info->uuid);
/* Naively convert UTF16-LE to 7 bits. */
- label_max = min(sizeof(info->volname) - 1,
- sizeof(ptes[i].partition_name));
+ label_max = min(ARRAY_SIZE(info->volname) - 1,
+ ARRAY_SIZE(ptes[i].partition_name));
info->volname[label_max] = 0;
while (label_count < label_max) {
u8 c = ptes[i].partition_name[label_count] & 0xff;
diff --git a/drivers/block/null_blk.c b/drivers/block/null_blk.c
index b5d842370cc..ea192ec029c 100644
--- a/drivers/block/null_blk.c
+++ b/drivers/block/null_blk.c
@@ -223,7 +223,7 @@ static void null_softirq_done_fn(struct request *rq)
blk_end_request_all(rq, 0);
}
-#if defined(CONFIG_SMP) && defined(CONFIG_USE_GENERIC_SMP_HELPERS)
+#ifdef CONFIG_SMP
static void null_ipi_cmd_end_io(void *data)
{
@@ -260,7 +260,7 @@ static void null_cmd_end_ipi(struct nullb_cmd *cmd)
put_cpu();
}
-#endif /* CONFIG_SMP && CONFIG_USE_GENERIC_SMP_HELPERS */
+#endif /* CONFIG_SMP */
static inline void null_handle_cmd(struct nullb_cmd *cmd)
{
@@ -270,7 +270,7 @@ static inline void null_handle_cmd(struct nullb_cmd *cmd)
end_cmd(cmd);
break;
case NULL_IRQ_SOFTIRQ:
-#if defined(CONFIG_SMP) && defined(CONFIG_USE_GENERIC_SMP_HELPERS)
+#ifdef CONFIG_SMP
null_cmd_end_ipi(cmd);
#else
end_cmd(cmd);
@@ -571,7 +571,7 @@ static int __init null_init(void)
{
unsigned int i;
-#if !defined(CONFIG_SMP) || !defined(CONFIG_USE_GENERIC_SMP_HELPERS)
+#if !defined(CONFIG_SMP)
if (irqmode == NULL_IRQ_SOFTIRQ) {
pr_warn("null_blk: softirq completions not available.\n");
pr_warn("null_blk: using direct completions.\n");
diff --git a/drivers/rtc/rtc-at91rm9200.c b/drivers/rtc/rtc-at91rm9200.c
index 8b2cd8a5a2f..c0da95e9570 100644
--- a/drivers/rtc/rtc-at91rm9200.c
+++ b/drivers/rtc/rtc-at91rm9200.c
@@ -428,6 +428,14 @@ static int __exit at91_rtc_remove(struct platform_device *pdev)
return 0;
}
+static void at91_rtc_shutdown(struct platform_device *pdev)
+{
+ /* Disable all interrupts */
+ at91_rtc_write(AT91_RTC_IDR, AT91_RTC_ACKUPD | AT91_RTC_ALARM |
+ AT91_RTC_SECEV | AT91_RTC_TIMEV |
+ AT91_RTC_CALEV);
+}
+
#ifdef CONFIG_PM_SLEEP
/* AT91RM9200 RTC Power management control */
@@ -466,6 +474,7 @@ static SIMPLE_DEV_PM_OPS(at91_rtc_pm_ops, at91_rtc_suspend, at91_rtc_resume);
static struct platform_driver at91_rtc_driver = {
.remove = __exit_p(at91_rtc_remove),
+ .shutdown = at91_rtc_shutdown,
.driver = {
.name = "at91_rtc",
.owner = THIS_MODULE,
diff --git a/fs/configfs/dir.c b/fs/configfs/dir.c
index 4522e075577..e081acbac2e 100644
--- a/fs/configfs/dir.c
+++ b/fs/configfs/dir.c
@@ -56,10 +56,19 @@ static void configfs_d_iput(struct dentry * dentry,
struct configfs_dirent *sd = dentry->d_fsdata;
if (sd) {
- BUG_ON(sd->s_dentry != dentry);
/* Coordinate with configfs_readdir */
spin_lock(&configfs_dirent_lock);
- sd->s_dentry = NULL;
+ /* Coordinate with configfs_attach_attr where will increase
+ * sd->s_count and update sd->s_dentry to new allocated one.
+ * Only set sd->dentry to null when this dentry is the only
+ * sd owner.
+ * If not do so, configfs_d_iput may run just after
+ * configfs_attach_attr and set sd->s_dentry to null
+ * even it's still in use.
+ */
+ if (atomic_read(&sd->s_count) <= 2)
+ sd->s_dentry = NULL;
+
spin_unlock(&configfs_dirent_lock);
configfs_put(sd);
}
@@ -416,8 +425,11 @@ static int configfs_attach_attr(struct configfs_dirent * sd, struct dentry * den
struct configfs_attribute * attr = sd->s_element;
int error;
+ spin_lock(&configfs_dirent_lock);
dentry->d_fsdata = configfs_get(sd);
sd->s_dentry = dentry;
+ spin_unlock(&configfs_dirent_lock);
+
error = configfs_create(dentry, (attr->ca_mode & S_IALLUGO) | S_IFREG,
configfs_init_file);
if (error) {
diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index acd2010328f..9649ff0c63f 100644
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -31,6 +31,7 @@ struct hugepage_subpool *hugepage_new_subpool(long nr_blocks);
void hugepage_put_subpool(struct hugepage_subpool *spool);
int PageHuge(struct page *page);
+int PageHeadHuge(struct page *page_head);
void reset_vma_resv_huge_pages(struct vm_area_struct *vma);
int hugetlb_sysctl_handler(struct ctl_table *, int, void __user *, size_t *, loff_t *);
@@ -69,7 +70,6 @@ int dequeue_hwpoisoned_huge_page(struct page *page);
bool isolate_huge_page(struct page *page, struct list_head *list);
void putback_active_hugepage(struct page *page);
bool is_hugepage_active(struct page *page);
-void copy_huge_page(struct page *dst, struct page *src);
#ifdef CONFIG_ARCH_WANT_HUGE_PMD_SHARE
pte_t *huge_pmd_share(struct mm_struct *mm, unsigned long addr, pud_t *pud);
@@ -104,6 +104,11 @@ static inline int PageHuge(struct page *page)
return 0;
}
+static inline int PageHeadHuge(struct page *page_head)
+{
+ return 0;
+}
+
static inline void reset_vma_resv_huge_pages(struct vm_area_struct *vma)
{
}
@@ -140,9 +145,6 @@ static inline int dequeue_hwpoisoned_huge_page(struct page *page)
#define isolate_huge_page(p, l) false
#define putback_active_hugepage(p) do {} while (0)
#define is_hugepage_active(x) false
-static inline void copy_huge_page(struct page *dst, struct page *src)
-{
-}
static inline unsigned long hugetlb_change_protection(struct vm_area_struct *vma,
unsigned long address, unsigned long end, pgprot_t newprot)
diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index 10f5a7272b8..011eb85d7b0 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -65,9 +65,6 @@ struct page {
* this page is only used to
* free other pages.
*/
-#if defined(CONFIG_TRANSPARENT_HUGEPAGE) && USE_SPLIT_PMD_PTLOCKS
- pgtable_t pmd_huge_pte; /* protected by page->ptl */
-#endif
};
union {
@@ -135,6 +132,9 @@ struct page {
struct list_head list; /* slobs list of pages */
struct slab *slab_page; /* slab fields */
+#if defined(CONFIG_TRANSPARENT_HUGEPAGE) && USE_SPLIT_PMD_PTLOCKS
+ pgtable_t pmd_huge_pte; /* protected by page->ptl */
+#endif
};
/* Remainder is not double word aligned */
diff --git a/ipc/shm.c b/ipc/shm.c
index d69739610fd..7a51443a51d 100644
--- a/ipc/shm.c
+++ b/ipc/shm.c
@@ -208,15 +208,18 @@ static void shm_open(struct vm_area_struct *vma)
*/
static void shm_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp)
{
+ struct file *shm_file;
+
+ shm_file = shp->shm_file;
+ shp->shm_file = NULL;
ns->shm_tot -= (shp->shm_segsz + PAGE_SIZE - 1) >> PAGE_SHIFT;
shm_rmid(ns, shp);
shm_unlock(shp);
- if (!is_file_hugepages(shp->shm_file))
- shmem_lock(shp->shm_file, 0, shp->mlock_user);
+ if (!is_file_hugepages(shm_file))
+ shmem_lock(shm_file, 0, shp->mlock_user);
else if (shp->mlock_user)
- user_shm_unlock(file_inode(shp->shm_file)->i_size,
- shp->mlock_user);
- fput (shp->shm_file);
+ user_shm_unlock(file_inode(shm_file)->i_size, shp->mlock_user);
+ fput(shm_file);
ipc_rcu_putref(shp, shm_rcu_free);
}
@@ -974,15 +977,25 @@ SYSCALL_DEFINE3(shmctl, int, shmid, int, cmd, struct shmid_ds __user *, buf)
ipc_lock_object(&shp->shm_perm);
if (!ns_capable(ns->user_ns, CAP_IPC_LOCK)) {
kuid_t euid = current_euid();
- err = -EPERM;
if (!uid_eq(euid, shp->shm_perm.uid) &&
- !uid_eq(euid, shp->shm_perm.cuid))
+ !uid_eq(euid, shp->shm_perm.cuid)) {
+ err = -EPERM;
goto out_unlock0;
- if (cmd == SHM_LOCK && !rlimit(RLIMIT_MEMLOCK))
+ }
+ if (cmd == SHM_LOCK && !rlimit(RLIMIT_MEMLOCK)) {
+ err = -EPERM;
goto out_unlock0;
+ }
}
shm_file = shp->shm_file;
+
+ /* check if shm_destroy() is tearing down shp */
+ if (shm_file == NULL) {
+ err = -EIDRM;
+ goto out_unlock0;
+ }
+
if (is_file_hugepages(shm_file))
goto out_unlock0;
@@ -1101,6 +1114,14 @@ long do_shmat(int shmid, char __user *shmaddr, int shmflg, ulong *raddr,
goto out_unlock;
ipc_lock_object(&shp->shm_perm);
+
+ /* check if shm_destroy() is tearing down shp */
+ if (shp->shm_file == NULL) {
+ ipc_unlock_object(&shp->shm_perm);
+ err = -EIDRM;
+ goto out_unlock;
+ }
+
path = shp->shm_file->f_path;
path_get(&path);
shp->shm_nattch++;
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 7d57af21f49..dee6cf4e6d3 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -476,40 +476,6 @@ static int vma_has_reserves(struct vm_area_struct *vma, long chg)
return 0;
}
-static void copy_gigantic_page(struct page *dst, struct page *src)
-{
- int i;
- struct hstate *h = page_hstate(src);
- struct page *dst_base = dst;
- struct page *src_base = src;
-
- for (i = 0; i < pages_per_huge_page(h); ) {
- cond_resched();
- copy_highpage(dst, src);
-
- i++;
- dst = mem_map_next(dst, dst_base, i);
- src = mem_map_next(src, src_base, i);
- }
-}
-
-void copy_huge_page(struct page *dst, struct page *src)
-{
- int i;
- struct hstate *h = page_hstate(src);
-
- if (unlikely(pages_per_huge_page(h) > MAX_ORDER_NR_PAGES)) {
- copy_gigantic_page(dst, src);
- return;
- }
-
- might_sleep();
- for (i = 0; i < pages_per_huge_page(h); i++) {
- cond_resched();
- copy_highpage(dst + i, src + i);
- }
-}
-
static void enqueue_huge_page(struct hstate *h, struct page *page)
{
int nid = page_to_nid(page);
@@ -736,6 +702,23 @@ int PageHuge(struct page *page)
}
EXPORT_SYMBOL_GPL(PageHuge);
+/*
+ * PageHeadHuge() only returns true for hugetlbfs head page, but not for
+ * normal or transparent huge pages.
+ */
+int PageHeadHuge(struct page *page_head)
+{
+ compound_page_dtor *dtor;
+
+ if (!PageHead(page_head))
+ return 0;
+
+ dtor = get_compound_page_dtor(page_head);
+
+ return dtor == free_huge_page;
+}
+EXPORT_SYMBOL_GPL(PageHeadHuge);
+
pgoff_t __basepage_index(struct page *page)
{
struct page *page_head = compound_head(page);
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index c4403cdf343..eca4a312912 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -2950,7 +2950,7 @@ void mpol_to_str(char *buffer, int maxlen, struct mempolicy *pol)
return;
}
- p += snprintf(p, maxlen, policy_modes[mode]);
+ p += snprintf(p, maxlen, "%s", policy_modes[mode]);
if (flags & MPOL_MODE_FLAGS) {
p += snprintf(p, buffer + maxlen - p, "=");
diff --git a/mm/migrate.c b/mm/migrate.c
index 316e720a202..bb940045fe8 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -442,6 +442,54 @@ int migrate_huge_page_move_mapping(struct address_space *mapping,
}
/*
+ * Gigantic pages are so large that we do not guarantee that page++ pointer
+ * arithmetic will work across the entire page. We need something more
+ * specialized.
+ */
+static void __copy_gigantic_page(struct page *dst, struct page *src,
+ int nr_pages)
+{
+ int i;
+ struct page *dst_base = dst;
+ struct page *src_base = src;
+
+ for (i = 0; i < nr_pages; ) {
+ cond_resched();
+ copy_highpage(dst, src);
+
+ i++;
+ dst = mem_map_next(dst, dst_base, i);
+ src = mem_map_next(src, src_base, i);
+ }
+}
+
+static void copy_huge_page(struct page *dst, struct page *src)
+{
+ int i;
+ int nr_pages;
+
+ if (PageHuge(src)) {
+ /* hugetlbfs page */
+ struct hstate *h = page_hstate(src);
+ nr_pages = pages_per_huge_page(h);
+
+ if (unlikely(nr_pages > MAX_ORDER_NR_PAGES)) {
+ __copy_gigantic_page(dst, src, nr_pages);
+ return;
+ }
+ } else {
+ /* thp page */
+ BUG_ON(!PageTransHuge(src));
+ nr_pages = hpage_nr_pages(src);
+ }
+
+ for (i = 0; i < nr_pages; i++) {
+ cond_resched();
+ copy_highpage(dst + i, src + i);
+ }
+}
+
+/*
* Copy the page to its new location
*/
void migrate_page_copy(struct page *newpage, struct page *page)
diff --git a/mm/swap.c b/mm/swap.c
index 7a9f80d451f..84b26aaabd0 100644
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -82,19 +82,6 @@ static void __put_compound_page(struct page *page)
static void put_compound_page(struct page *page)
{
- /*
- * hugetlbfs pages cannot be split from under us. If this is a
- * hugetlbfs page, check refcount on head page and release the page if
- * the refcount becomes zero.
- */
- if (PageHuge(page)) {
- page = compound_head(page);
- if (put_page_testzero(page))
- __put_compound_page(page);
-
- return;
- }
-
if (unlikely(PageTail(page))) {
/* __split_huge_page_refcount can run under us */
struct page *page_head = compound_trans_head(page);
@@ -111,14 +98,31 @@ static void put_compound_page(struct page *page)
* still hot on arches that do not support
* this_cpu_cmpxchg_double().
*/
- if (PageSlab(page_head)) {
- if (PageTail(page)) {
+ if (PageSlab(page_head) || PageHeadHuge(page_head)) {
+ if (likely(PageTail(page))) {
+ /*
+ * __split_huge_page_refcount
+ * cannot race here.
+ */
+ VM_BUG_ON(!PageHead(page_head));
+ atomic_dec(&page->_mapcount);
if (put_page_testzero(page_head))
VM_BUG_ON(1);
-
- atomic_dec(&page->_mapcount);
- goto skip_lock_tail;
+ if (put_page_testzero(page_head))
+ __put_compound_page(page_head);
+ return;
} else
+ /*
+ * __split_huge_page_refcount
+ * run before us, "page" was a
+ * THP tail. The split
+ * page_head has been freed
+ * and reallocated as slab or
+ * hugetlbfs page of smaller
+ * order (only possible if
+ * reallocated as slab on
+ * x86).
+ */
goto skip_lock;
}
/*
@@ -132,8 +136,27 @@ static void put_compound_page(struct page *page)
/* __split_huge_page_refcount run before us */
compound_unlock_irqrestore(page_head, flags);
skip_lock:
- if (put_page_testzero(page_head))
- __put_single_page(page_head);
+ if (put_page_testzero(page_head)) {
+ /*
+ * The head page may have been
+ * freed and reallocated as a
+ * compound page of smaller
+ * order and then freed again.
+ * All we know is that it
+ * cannot have become: a THP
+ * page, a compound page of
+ * higher order, a tail page.
+ * That is because we still
+ * hold the refcount of the
+ * split THP tail and
+ * page_head was the THP head
+ * before the split.
+ */
+ if (PageHead(page_head))
+ __put_compound_page(page_head);
+ else
+ __put_single_page(page_head);
+ }
out_put_single:
if (put_page_testzero(page))
__put_single_page(page);
@@ -155,7 +178,6 @@ out_put_single:
VM_BUG_ON(atomic_read(&page->_count) != 0);
compound_unlock_irqrestore(page_head, flags);
-skip_lock_tail:
if (put_page_testzero(page_head)) {
if (PageHead(page_head))
__put_compound_page(page_head);
@@ -198,51 +220,52 @@ bool __get_page_tail(struct page *page)
* proper PT lock that already serializes against
* split_huge_page().
*/
+ unsigned long flags;
bool got = false;
- struct page *page_head;
-
- /*
- * If this is a hugetlbfs page it cannot be split under us. Simply
- * increment refcount for the head page.
- */
- if (PageHuge(page)) {
- page_head = compound_head(page);
- atomic_inc(&page_head->_count);
- got = true;
- } else {
- unsigned long flags;
+ struct page *page_head = compound_trans_head(page);
- page_head = compound_trans_head(page);
- if (likely(page != page_head &&
- get_page_unless_zero(page_head))) {
-
- /* Ref to put_compound_page() comment. */
- if (PageSlab(page_head)) {
- if (likely(PageTail(page))) {
- __get_page_tail_foll(page, false);
- return true;
- } else {
- put_page(page_head);
- return false;
- }
- }
-
- /*
- * page_head wasn't a dangling pointer but it
- * may not be a head page anymore by the time
- * we obtain the lock. That is ok as long as it
- * can't be freed from under us.
- */
- flags = compound_lock_irqsave(page_head);
- /* here __split_huge_page_refcount won't run anymore */
+ if (likely(page != page_head && get_page_unless_zero(page_head))) {
+ /* Ref to put_compound_page() comment. */
+ if (PageSlab(page_head) || PageHeadHuge(page_head)) {
if (likely(PageTail(page))) {
+ /*
+ * This is a hugetlbfs page or a slab
+ * page. __split_huge_page_refcount
+ * cannot race here.
+ */
+ VM_BUG_ON(!PageHead(page_head));
__get_page_tail_foll(page, false);
- got = true;
- }
- compound_unlock_irqrestore(page_head, flags);
- if (unlikely(!got))
+ return true;
+ } else {
+ /*
+ * __split_huge_page_refcount run
+ * before us, "page" was a THP
+ * tail. The split page_head has been
+ * freed and reallocated as slab or
+ * hugetlbfs page of smaller order
+ * (only possible if reallocated as
+ * slab on x86).
+ */
put_page(page_head);
+ return false;
+ }
+ }
+
+ /*
+ * page_head wasn't a dangling pointer but it
+ * may not be a head page anymore by the time
+ * we obtain the lock. That is ok as long as it
+ * can't be freed from under us.
+ */
+ flags = compound_lock_irqsave(page_head);
+ /* here __split_huge_page_refcount won't run anymore */
+ if (likely(PageTail(page))) {
+ __get_page_tail_foll(page, false);
+ got = true;
}
+ compound_unlock_irqrestore(page_head, flags);
+ if (unlikely(!got))
+ put_page(page_head);
}
return got;
}
diff --git a/net/Kconfig b/net/Kconfig
index 0715db64a5c..d334678c0bd 100644
--- a/net/Kconfig
+++ b/net/Kconfig
@@ -224,7 +224,7 @@ source "net/hsr/Kconfig"
config RPS
boolean
- depends on SMP && SYSFS && USE_GENERIC_SMP_HELPERS
+ depends on SMP && SYSFS
default y
config RFS_ACCEL
@@ -235,7 +235,7 @@ config RFS_ACCEL
config XPS
boolean
- depends on SMP && USE_GENERIC_SMP_HELPERS
+ depends on SMP
default y
config NETPRIO_CGROUP
diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index 61090e0ff61..9c981003037 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -3289,6 +3289,7 @@ sub process {
}
}
if (!defined $suppress_whiletrailers{$linenr} &&
+ defined($stat) && defined($cond) &&
$line =~ /\b(?:if|while|for)\s*\(/ && $line !~ /^.\s*#/) {
my ($s, $c) = ($stat, $cond);