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>
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2f30b1f9e1
Коммит
e6de3988aa
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@ -44,6 +44,7 @@ void flex_array_free(struct flex_array *fa);
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void flex_array_free_parts(struct flex_array *fa);
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int flex_array_put(struct flex_array *fa, unsigned int element_nr, void *src,
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gfp_t flags);
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int flex_array_clear(struct flex_array *fa, unsigned int element_nr);
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void *flex_array_get(struct flex_array *fa, unsigned int element_nr);
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#endif /* _FLEX_ARRAY_H */
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@ -206,6 +206,32 @@ int flex_array_put(struct flex_array *fa, unsigned int element_nr, void *src,
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return 0;
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}
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/**
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* flex_array_clear - clear element in array at @element_nr
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* @element_nr: index of the position to clear.
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*
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* Locking must be provided by the caller.
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*/
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int flex_array_clear(struct flex_array *fa, unsigned int element_nr)
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{
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int part_nr = fa_element_to_part_nr(fa, element_nr);
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struct flex_array_part *part;
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void *dst;
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if (element_nr >= fa->total_nr_elements)
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return -ENOSPC;
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if (elements_fit_in_base(fa))
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part = (struct flex_array_part *)&fa->parts[0];
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else {
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part = fa->parts[part_nr];
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if (!part)
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return -EINVAL;
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}
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dst = &part->elements[index_inside_part(fa, element_nr)];
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memset(dst, 0, fa->element_size);
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return 0;
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}
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/**
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* flex_array_prealloc - guarantee that array space exists
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* @start: index of first array element for which space is allocated
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