Messages in this thread Patch in this message | | | Date | Fri, 3 Apr 2009 16:35:59 +0800 | From | Wu Fengguang <> | Subject | [PATCH v2] vfs: fix find_lock_page_retry() return value parsing |
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find_lock_page_retry() won't touch the *ppage value when returning VM_FAULT_RETRY. This is fine except for the case
if (VM_RandomReadHint()) goto no_cached_page;
where the 'page' could be undefined after calling find_lock_page_retry().
Fix it by checking the VM_FAULT_RETRY case first. Also do this for the other two find_lock_page_retry() invocations for the sake of consistency.
Cc: Ying Han <yinghan@google.com> Signed-off-by: Wu Fengguang <fengguang.wu@intel.com> --- mm/filemap.c | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-)
--- mm.orig/mm/filemap.c +++ mm/mm/filemap.c @@ -759,7 +759,7 @@ EXPORT_SYMBOL(find_lock_page); * @retry: 1 indicate caller tolerate a retry. * * If retry flag is on, and page is already locked by someone else, return - * a hint of retry. + * a hint of retry and leave *ppage untouched. * * Return *ppage==NULL if page is not in pagecache. Otherwise return *ppage * points to the page in the pagecache with ret=VM_FAULT_RETRY indicate a @@ -1575,10 +1575,10 @@ retry_find_nopage: vmf->pgoff, 1); retry_ret = find_lock_page_retry(mapping, vmf->pgoff, vma, &page, retry_flag); - if (!page) - goto no_cached_page; if (retry_ret == VM_FAULT_RETRY) return retry_ret; + if (!page) + goto no_cached_page; } if (PageReadahead(page)) { page_cache_async_readahead(mapping, ra, file, page, @@ -1617,10 +1617,10 @@ retry_find_nopage: } retry_ret = find_lock_page_retry(mapping, vmf->pgoff, vma, &page, retry_flag); - if (!page) - goto no_cached_page; if (retry_ret == VM_FAULT_RETRY) return retry_ret; + if (!page) + goto no_cached_page; } if (!did_readaround) @@ -1672,10 +1672,10 @@ no_cached_page: retry_ret = find_lock_page_retry(mapping, vmf->pgoff, vma, &page, retry_flag); + if (retry_ret == VM_FAULT_RETRY) + return retry_ret; if (!page) goto retry_find_nopage; - else if (retry_ret == VM_FAULT_RETRY) - return retry_ret; else goto retry_page_update; }
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