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| author | Peter Zijlstra <peterz@infradead.org> | 2018-12-03 20:03:50 +0300 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2018-12-17 20:54:27 +0300 |
| commit | 83b4e39146aa70913580966e0f2b78b7c3492760 (patch) | |
| tree | 9e05cc0576a9bfb239380d40c48abfb281bd1e59 /arch/x86/mm/pageattr.c | |
| parent | 935f5839827ef54b53406e80906f7c355eb73c1b (diff) | |
| download | linux-83b4e39146aa70913580966e0f2b78b7c3492760.tar.xz | |
x86/mm/cpa: Make cpa_data::numpages invariant
Make sure __change_page_attr_set_clr() doesn't modify cpa->numpages.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tom.StDenis@amd.com
Cc: dave.hansen@intel.com
Link: http://lkml.kernel.org/r/20181203171043.493000228@infradead.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/mm/pageattr.c')
| -rw-r--r-- | arch/x86/mm/pageattr.c | 21 |
1 files changed, 13 insertions, 8 deletions
diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c index 351874259a71..12b69263e501 100644 --- a/arch/x86/mm/pageattr.c +++ b/arch/x86/mm/pageattr.c @@ -1625,14 +1625,15 @@ static int cpa_process_alias(struct cpa_data *cpa) static int __change_page_attr_set_clr(struct cpa_data *cpa, int checkalias) { unsigned long numpages = cpa->numpages; - int ret; + unsigned long rempages = numpages; + int ret = 0; - while (numpages) { + while (rempages) { /* * Store the remaining nr of pages for the large page * preservation check. */ - cpa->numpages = numpages; + cpa->numpages = rempages; /* for array changes, we can't use large page */ if (cpa->flags & (CPA_ARRAY | CPA_PAGES_ARRAY)) cpa->numpages = 1; @@ -1643,12 +1644,12 @@ static int __change_page_attr_set_clr(struct cpa_data *cpa, int checkalias) if (!debug_pagealloc_enabled()) spin_unlock(&cpa_lock); if (ret) - return ret; + goto out; if (checkalias) { ret = cpa_process_alias(cpa); if (ret) - return ret; + goto out; } /* @@ -1656,11 +1657,15 @@ static int __change_page_attr_set_clr(struct cpa_data *cpa, int checkalias) * CPA operation. Either a large page has been * preserved or a single page update happened. */ - BUG_ON(cpa->numpages > numpages || !cpa->numpages); - numpages -= cpa->numpages; + BUG_ON(cpa->numpages > rempages || !cpa->numpages); + rempages -= cpa->numpages; cpa->curpage += cpa->numpages; } - return 0; + +out: + /* Restore the original numpages */ + cpa->numpages = numpages; + return ret; } /* |