[PATCH] uml: hostfs - fix possible PAGE_CACHE_SHIFT overflows
Prevent page->index << PAGE_CACHE_SHIFT from overflowing. There is a casting there, but was added without care, so it's at the wrong place. Note the extra parens around the shift - "+" is higher precedence than "<<", leading to a GCC warning which saved all us. Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Signed-off-by: Linus Torvalds <torvalds@osdl.org>wifi-calibration
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3d0a07e331
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30f04a4efa
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@ -501,11 +501,16 @@ int hostfs_commit_write(struct file *file, struct page *page, unsigned from,
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long long start;
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long long start;
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int err = 0;
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int err = 0;
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start = (long long) (page->index << PAGE_CACHE_SHIFT) + from;
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start = (((long long) page->index) << PAGE_CACHE_SHIFT) + from;
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buffer = kmap(page);
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buffer = kmap(page);
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err = write_file(FILE_HOSTFS_I(file)->fd, &start, buffer + from,
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err = write_file(FILE_HOSTFS_I(file)->fd, &start, buffer + from,
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to - from);
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to - from);
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if(err > 0) err = 0;
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if(err > 0) err = 0;
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/* Actually, if !err, write_file has added to-from to start, so, despite
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* the appearance, we are comparing i_size against the _last_ written
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* location, as we should. */
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if(!err && (start > inode->i_size))
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if(!err && (start > inode->i_size))
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inode->i_size = start;
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inode->i_size = start;
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