From 72676bb53f33fd0ef3a1484fc1ecfd306dc6ff40 Mon Sep 17 00:00:00 2001 From: Vitaly Kuznetsov Date: Tue, 2 Feb 2016 16:57:18 -0800 Subject: lib/test-string_helpers.c: fix and improve string_get_size() tests Recently added commit 564b026fbd0d ("string_helpers: fix precision loss for some inputs") fixed precision issues for string_get_size() and broke tests. Fix and improve them: test both STRING_UNITS_2 and STRING_UNITS_10 at a time, better failure reporting, test small an huge values. Fixes: 564b026fbd0d28e9 ("string_helpers: fix precision loss for some inputs") Signed-off-by: Vitaly Kuznetsov Cc: Andy Shevchenko Cc: Rasmus Villemoes Cc: James Bottomley Cc: James Bottomley Cc: "James E.J. Bottomley" Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- lib/test-string_helpers.c | 67 ++++++++++++++++++++++++++++++++++------------- 1 file changed, 49 insertions(+), 18 deletions(-) (limited to 'lib') diff --git a/lib/test-string_helpers.c b/lib/test-string_helpers.c index 98866a770770..25b5cbfb7615 100644 --- a/lib/test-string_helpers.c +++ b/lib/test-string_helpers.c @@ -327,36 +327,67 @@ out: } #define string_get_size_maxbuf 16 -#define test_string_get_size_one(size, blk_size, units, exp_result) \ +#define test_string_get_size_one(size, blk_size, exp_result10, exp_result2) \ do { \ - BUILD_BUG_ON(sizeof(exp_result) >= string_get_size_maxbuf); \ - __test_string_get_size((size), (blk_size), (units), \ - (exp_result)); \ + BUILD_BUG_ON(sizeof(exp_result10) >= string_get_size_maxbuf); \ + BUILD_BUG_ON(sizeof(exp_result2) >= string_get_size_maxbuf); \ + __test_string_get_size((size), (blk_size), (exp_result10), \ + (exp_result2)); \ } while (0) -static __init void __test_string_get_size(const u64 size, const u64 blk_size, - const enum string_size_units units, - const char *exp_result) +static __init void test_string_get_size_check(const char *units, + const char *exp, + char *res, + const u64 size, + const u64 blk_size) { - char buf[string_get_size_maxbuf]; - - string_get_size(size, blk_size, units, buf, sizeof(buf)); - if (!memcmp(buf, exp_result, strlen(exp_result) + 1)) + if (!memcmp(res, exp, strlen(exp) + 1)) return; - buf[sizeof(buf) - 1] = '\0'; - pr_warn("Test 'test_string_get_size_one' failed!\n"); - pr_warn("string_get_size(size = %llu, blk_size = %llu, units = %d\n", + res[string_get_size_maxbuf - 1] = '\0'; + + pr_warn("Test 'test_string_get_size' failed!\n"); + pr_warn("string_get_size(size = %llu, blk_size = %llu, units = %s)\n", size, blk_size, units); - pr_warn("expected: '%s', got '%s'\n", exp_result, buf); + pr_warn("expected: '%s', got '%s'\n", exp, res); +} + +static __init void __test_string_get_size(const u64 size, const u64 blk_size, + const char *exp_result10, + const char *exp_result2) +{ + char buf10[string_get_size_maxbuf]; + char buf2[string_get_size_maxbuf]; + + string_get_size(size, blk_size, STRING_UNITS_10, buf10, sizeof(buf10)); + string_get_size(size, blk_size, STRING_UNITS_2, buf2, sizeof(buf2)); + + test_string_get_size_check("STRING_UNITS_10", exp_result10, buf10, + size, blk_size); + + test_string_get_size_check("STRING_UNITS_2", exp_result2, buf2, + size, blk_size); } static __init void test_string_get_size(void) { - test_string_get_size_one(16384, 512, STRING_UNITS_2, "8.00 MiB"); - test_string_get_size_one(8192, 4096, STRING_UNITS_10, "32.7 MB"); - test_string_get_size_one(1, 512, STRING_UNITS_10, "512 B"); + /* small values */ + test_string_get_size_one(0, 512, "0 B", "0 B"); + test_string_get_size_one(1, 512, "512 B", "512 B"); + test_string_get_size_one(1100, 1, "1.10 kB", "1.07 KiB"); + + /* normal values */ + test_string_get_size_one(16384, 512, "8.39 MB", "8.00 MiB"); + test_string_get_size_one(500118192, 512, "256 GB", "238 GiB"); + test_string_get_size_one(8192, 4096, "33.6 MB", "32.0 MiB"); + + /* weird block sizes */ + test_string_get_size_one(3000, 1900, "5.70 MB", "5.44 MiB"); + + /* huge values */ + test_string_get_size_one(U64_MAX, 4096, "75.6 ZB", "64.0 ZiB"); + test_string_get_size_one(4096, U64_MAX, "75.6 ZB", "64.0 ZiB"); } static int __init test_string_helpers_init(void) -- cgit v1.2.3 From 46437f9a554fbe3e110580ca08ab703b59f2f95a Mon Sep 17 00:00:00 2001 From: Matthew Wilcox Date: Tue, 2 Feb 2016 16:57:52 -0800 Subject: radix-tree: fix race in gang lookup If the indirect_ptr bit is set on a slot, that indicates we need to redo the lookup. Introduce a new function radix_tree_iter_retry() which forces the loop to retry the lookup by setting 'slot' to NULL and turning the iterator back to point at the problematic entry. This is a pretty rare problem to hit at the moment; the lookup has to race with a grow of the radix tree from a height of 0. The consequences of hitting this race are that gang lookup could return a pointer to a radix_tree_node instead of a pointer to whatever the user had inserted in the tree. Fixes: cebbd29e1c2f ("radix-tree: rewrite gang lookup using iterator") Signed-off-by: Matthew Wilcox Cc: Hugh Dickins Cc: Ohad Ben-Cohen Cc: Konstantin Khlebnikov Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/radix-tree.h | 16 ++++++++++++++++ lib/radix-tree.c | 12 ++++++++++-- 2 files changed, 26 insertions(+), 2 deletions(-) (limited to 'lib') diff --git a/include/linux/radix-tree.h b/include/linux/radix-tree.h index 7c88ad156a29..00b17c526c1f 100644 --- a/include/linux/radix-tree.h +++ b/include/linux/radix-tree.h @@ -378,6 +378,22 @@ radix_tree_iter_init(struct radix_tree_iter *iter, unsigned long start) void **radix_tree_next_chunk(struct radix_tree_root *root, struct radix_tree_iter *iter, unsigned flags); +/** + * radix_tree_iter_retry - retry this chunk of the iteration + * @iter: iterator state + * + * If we iterate over a tree protected only by the RCU lock, a race + * against deletion or creation may result in seeing a slot for which + * radix_tree_deref_retry() returns true. If so, call this function + * and continue the iteration. + */ +static inline __must_check +void **radix_tree_iter_retry(struct radix_tree_iter *iter) +{ + iter->next_index = iter->index; + return NULL; +} + /** * radix_tree_chunk_size - get current chunk size * diff --git a/lib/radix-tree.c b/lib/radix-tree.c index fcf5d98574ce..6b79e9026e24 100644 --- a/lib/radix-tree.c +++ b/lib/radix-tree.c @@ -1019,9 +1019,13 @@ radix_tree_gang_lookup(struct radix_tree_root *root, void **results, return 0; radix_tree_for_each_slot(slot, root, &iter, first_index) { - results[ret] = indirect_to_ptr(rcu_dereference_raw(*slot)); + results[ret] = rcu_dereference_raw(*slot); if (!results[ret]) continue; + if (radix_tree_is_indirect_ptr(results[ret])) { + slot = radix_tree_iter_retry(&iter); + continue; + } if (++ret == max_items) break; } @@ -1098,9 +1102,13 @@ radix_tree_gang_lookup_tag(struct radix_tree_root *root, void **results, return 0; radix_tree_for_each_tagged(slot, root, &iter, first_index, tag) { - results[ret] = indirect_to_ptr(rcu_dereference_raw(*slot)); + results[ret] = rcu_dereference_raw(*slot); if (!results[ret]) continue; + if (radix_tree_is_indirect_ptr(results[ret])) { + slot = radix_tree_iter_retry(&iter); + continue; + } if (++ret == max_items) break; } -- cgit v1.2.3