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| author | David Rientjes <rientjes@google.com> | 2009-09-21 17:04:30 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2009-09-22 07:17:47 -0700 |
| commit | e6de3988aa52debb25a427d085061f3bf1181d54 (patch) | |
| tree | 4a5dd6acac3e73049918c646bd977894335e5560 | |
| parent | 2f30b1f9e1b612cdd1a17daeecf514229e8d6a5f (diff) | |
| download | lwn-e6de3988aa52debb25a427d085061f3bf1181d54.tar.gz lwn-e6de3988aa52debb25a427d085061f3bf1181d54.zip | |
flex_array: add flex_array_clear function
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 <rientjes@google.com>
Cc: Dave Hansen <dave@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | include/linux/flex_array.h | 1 | ||||
| -rw-r--r-- | lib/flex_array.c | 26 |
2 files changed, 27 insertions, 0 deletions
diff --git a/include/linux/flex_array.h b/include/linux/flex_array.h index 45ff18491514..3887b21f883f 100644 --- a/include/linux/flex_array.h +++ b/include/linux/flex_array.h @@ -44,6 +44,7 @@ void flex_array_free(struct flex_array *fa); void flex_array_free_parts(struct flex_array *fa); int flex_array_put(struct flex_array *fa, unsigned int element_nr, void *src, gfp_t flags); +int flex_array_clear(struct flex_array *fa, unsigned int element_nr); void *flex_array_get(struct flex_array *fa, unsigned int element_nr); #endif /* _FLEX_ARRAY_H */ diff --git a/lib/flex_array.c b/lib/flex_array.c index 7baed2fc3bc8..b68f99be4080 100644 --- a/lib/flex_array.c +++ b/lib/flex_array.c @@ -207,6 +207,32 @@ int flex_array_put(struct flex_array *fa, unsigned int element_nr, void *src, } /** + * flex_array_clear - clear element in array at @element_nr + * @element_nr: index of the position to clear. + * + * Locking must be provided by the caller. + */ +int flex_array_clear(struct flex_array *fa, unsigned int element_nr) +{ + int part_nr = fa_element_to_part_nr(fa, element_nr); + struct flex_array_part *part; + void *dst; + + if (element_nr >= fa->total_nr_elements) + return -ENOSPC; + if (elements_fit_in_base(fa)) + part = (struct flex_array_part *)&fa->parts[0]; + else { + part = fa->parts[part_nr]; + if (!part) + return -EINVAL; + } + dst = &part->elements[index_inside_part(fa, element_nr)]; + memset(dst, 0, fa->element_size); + return 0; +} + +/** * flex_array_prealloc - guarantee that array space exists * @start: index of first array element for which space is allocated * @end: index of last (inclusive) element for which space is allocated |