diff options
Diffstat (limited to 'mm/mempolicy.c')
| -rw-r--r-- | mm/mempolicy.c | 35 |
1 files changed, 22 insertions, 13 deletions
diff --git a/mm/mempolicy.c b/mm/mempolicy.c index da858f794eb6..cfd26d7e61a1 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -797,16 +797,19 @@ static void get_policy_nodemask(struct mempolicy *p, nodemask_t *nodes) } } -static int lookup_node(unsigned long addr) +static int lookup_node(struct mm_struct *mm, unsigned long addr) { struct page *p; int err; - err = get_user_pages(addr & PAGE_MASK, 1, 0, &p, NULL); + int locked = 1; + err = get_user_pages_locked(addr & PAGE_MASK, 1, 0, &p, &locked); if (err >= 0) { err = page_to_nid(p); put_page(p); } + if (locked) + up_read(&mm->mmap_sem); return err; } @@ -817,7 +820,7 @@ static long do_get_mempolicy(int *policy, nodemask_t *nmask, int err; struct mm_struct *mm = current->mm; struct vm_area_struct *vma = NULL; - struct mempolicy *pol = current->mempolicy; + struct mempolicy *pol = current->mempolicy, *pol_refcount = NULL; if (flags & ~(unsigned long)(MPOL_F_NODE|MPOL_F_ADDR|MPOL_F_MEMS_ALLOWED)) @@ -857,7 +860,16 @@ static long do_get_mempolicy(int *policy, nodemask_t *nmask, if (flags & MPOL_F_NODE) { if (flags & MPOL_F_ADDR) { - err = lookup_node(addr); + /* + * Take a refcount on the mpol, lookup_node() + * wil drop the mmap_sem, so after calling + * lookup_node() only "pol" remains valid, "vma" + * is stale. + */ + pol_refcount = pol; + vma = NULL; + mpol_get(pol); + err = lookup_node(mm, addr); if (err < 0) goto out; *policy = err; @@ -892,7 +904,9 @@ static long do_get_mempolicy(int *policy, nodemask_t *nmask, out: mpol_cond_put(pol); if (vma) - up_read(¤t->mm->mmap_sem); + up_read(&mm->mmap_sem); + if (pol_refcount) + mpol_put(pol_refcount); return err; } @@ -2697,12 +2711,11 @@ static const char * const policy_modes[] = int mpol_parse_str(char *str, struct mempolicy **mpol) { struct mempolicy *new = NULL; - unsigned short mode; unsigned short mode_flags; nodemask_t nodes; char *nodelist = strchr(str, ':'); char *flags = strchr(str, '='); - int err = 1; + int err = 1, mode; if (nodelist) { /* NUL-terminate mode or flags string */ @@ -2717,12 +2730,8 @@ int mpol_parse_str(char *str, struct mempolicy **mpol) if (flags) *flags++ = '\0'; /* terminate mode string */ - for (mode = 0; mode < MPOL_MAX; mode++) { - if (!strcmp(str, policy_modes[mode])) { - break; - } - } - if (mode >= MPOL_MAX) + mode = match_string(policy_modes, MPOL_MAX, str); + if (mode < 0) goto out; switch (mode) { |