linux/lib/flex_array.c, branch v2.6.39

flex_arrays: allow zero length flex arrays

2011-04-28T20:12:54Z

Just like kmalloc will allow one to allocate a 0 length segment of memory flex arrays should do the same thing. It should bomb if you try to use something, but it should at least allow the allocation. This is needed because when SELinux switched to using flex_arrays in 2.6.38 the inability to allocate a 0 length array resulted in SELinux policy load returning -ENOSPC when previously it worked. Based-on-patch-by: Steffen Klassert Signed-off-by: Eric Paris Tested-by: Chris Richards Cc: stable@kernel.org [2.6.38+]

flex_array: flex_array_prealloc takes a number of elements, not an end

2011-04-28T20:12:47Z

Change flex_array_prealloc to take the number of elements for which space should be allocated instead of the last (inclusive) element. Users and documentation are updated accordingly. flex_arrays got introduced before they had users. When folks started using it, they ended up needing a different API than was coded up originally. This swaps over to the API that folks apparently need. Based-on-patch-by: Steffen Klassert Signed-off-by: Eric Paris Tested-by: Chris Richards Acked-by: Dave Hansen Cc: stable@kernel.org [2.6.38+]

flex_array: export symbols to modules

2011-01-13T16:03:11Z

Alex said: I want to use flex_array to store a sparse array of ATM cell re-assembly buffers for my ATM over Ethernet driver. Using the per-vcc user_back structure causes problems when stacked with things like br2684. Add EXPORT_SYMBOL() for all publically accessible flex array functions and move to obj-y so that modules may use this library. Signed-off-by: David Rientjes Cc: Dave Hansen Cc: Paul Mundt Reported-by: Alex Bennee Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

flex_array: add helpers to get and put to make pointers easy to use

2010-08-10T03:45:09Z

Getting and putting arrays of pointers with flex arrays is a PITA. You have to remember to pass &ptr to the _put and you have to do weird and wacky casting to get the ptr back from the _get. Add two functions flex_array_get_ptr() and flex_array_put_ptr() to handle all of the magic. [akpm@linux-foundation.org: simplification suggested by Joe] Signed-off-by: Eric Paris Cc: David Rientjes Cc: Dave Hansen Cc: Joe Perches Cc: James Morris Cc: Joe Perches Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

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