kernel/lib/flex_array.c, branch linux-2.6.34.y

flex_array: fix the panic when calling flex_array_alloc() without __GFP_ZERO

2010-04-24T18:31:24Z

memset() is called with the wrong address and the kernel panics. Signed-off-by: Changli Gao Cc: Patrick McHardy Acked-by: David Rientjes Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

flex_array: add missing kerneldoc annotations

2009-09-22T14:17:47Z

Add kerneldoc annotations for function formals of type struct flex_array and gfp_t which are currently lacking. Signed-off-by: David Rientjes Cc: Dave Hansen Cc: Randy Dunlap Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

flex_array: introduce DEFINE_FLEX_ARRAY

2009-09-22T14:17:47Z

FLEX_ARRAY_INIT(element_size, total_nr_elements) cannot determine if either parameter is valid, so flex arrays which are statically allocated with this interface can easily become corrupted or reference beyond its allocated memory. This removes FLEX_ARRAY_INIT() as a struct flex_array initializer since no initializer may perform the required checking. Instead, the array is now defined with a new interface: DEFINE_FLEX_ARRAY(name, element_size, total_nr_elements) This may be prefixed with `static' for file scope. This interface includes compile-time checking of the parameters to ensure they are valid. Since the validity of both element_size and total_nr_elements depend on FLEX_ARRAY_BASE_SIZE and FLEX_ARRAY_PART_SIZE, the kernel build will fail if either of these predefined values changes such that the array parameters are no longer valid. Since BUILD_BUG_ON() requires compile time constants, several of the static inline functions that were once local to lib/flex_array.c had to be moved to include/linux/flex_array.h. Signed-off-by: David Rientjes Acked-by: Dave Hansen Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

flex_array: add flex_array_shrink function

2009-09-22T14:17:47Z

Add a new function to the flex_array API: int flex_array_shrink(struct flex_array *fa) This function will free all unused second-level pages. Since elements are now poisoned if they are not allocated with __GFP_ZERO, it's possible to identify parts that consist solely of unused elements. flex_array_shrink() returns the number of pages freed. Signed-off-by: David Rientjes Cc: Dave Hansen Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

flex_array: poison free elements

2009-09-22T14:17:47Z

Newly initialized flex_array's and/or flex_array_part's are now poisoned with a new poison value, FLEX_ARRAY_FREE. It's value is similar to POISON_FREE used in the various slab allocators, but is different to distinguish between flex array's poisoned kmem and slab allocator poisoned kmem. This will allow us to identify flex_array_part's that only contain free elements (and free them with an addition to the flex_array API). This could also be extended in the future to identify `get' uses on elements that have not been `put'. If __GFP_ZERO is passed for a part's gfp mask, the poisoning is avoided. These elements are considered to be in-use since they have been initialized. Signed-off-by: David Rientjes Cc: Dave Hansen Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

flex_array: add flex_array_clear function

2009-09-22T14:17:47Z

Add a new function to the flex_array API: int flex_array_clear(struct flex_array *fa, unsigned int element_nr) This function will zero the element at element_nr in the flex_array. Although this is equivalent to using flex_array_put() and passing a pointer to zero'd memory, flex_array_clear() does not require such a pointer to memory that would most likely need to be allocated on the caller's stack which could be significantly large depending on element_size. Signed-off-by: David Rientjes Cc: Dave Hansen Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

flex_array: convert element_nr formals to unsigned

2009-08-27T03:06:52Z

It's problematic to allow signed element_nr's or total's to be passed as part of the flex array API. flex_array_alloc() allows total_nr_elements to be set to a negative quantity, which is obviously erroneous. flex_array_get() and flex_array_put() allows negative array indices in dereferencing an array part, which could address memory mapped before struct flex_array. The fix is to convert all existing element_nr formals to be qualified as unsigned. Existing checks to compare it to total_nr_elements or the max array size based on element_size need not be changed. Signed-off-by: David Rientjes Cc: Dave Hansen Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

flex_array: fix flex_array_free_parts comment

2009-08-27T03:06:52Z

flex_array_free_parts() does not take `src' or `element_nr' formals, so remove their respective comments. Signed-off-by: David Rientjes Acked-by: Dave Hansen Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

flex_array: fix get function for elements in base starting at non-zero

2009-08-27T03:06:52Z

If all array elements fit into the base structure and data is copied using flex_array_put() starting at a non-zero index, flex_array_get() will fail to return the data. This fixes the bug by only checking for NULL parts when all elements do not fit in the base structure when flex_array_get() is used. Otherwise, fa_element_to_part_nr() will always be 0 since there are no parts structures needed and such element may never have been put. Thus, it will remain NULL due to the kzalloc() of the base. Additionally, flex_array_put() now only checks for a NULL part when all elements do not fit in the base structure. This is otherwise unnecessary since the base structure is guaranteed to exist (or we would have already hit a NULL pointer). Signed-off-by: David Rientjes Acked-by: Dave Hansen Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

flex_array: remove unneeded index calculation

2009-08-04T22:33:46Z

flex_array_get() calculates an index value, then drops it on the floor; simply remove it. Signed-off-by: Jonathan Corbet Acked-by: Dave Hansen Signed-off-by: Linus Torvalds