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    SubjectRe: [PATCH] mm: remove broken 'kzalloc' mempool
    On Mon, 3 Aug 2009, Sage Weil wrote:
    > The kzalloc mempool zeros items when they are initially allocated, but
    > does not rezero used items that are returned to the pool. Consequently
    > mempool_alloc()s may return non-zeroed memory.
    >
    > Since there are/were only two in-tree users for mempool_create_kzalloc_pool(),
    > and 'fixing' this in a way that will re-zero used (but not new) items
    > before first use is non-trivial, just remove it.

    This should of course only be applied after the fixes for the two callers
    (dm multipath and ibmvscsi), whatever the protocol for order that may
    be...

    sage


    >
    > CC: <linux-mm@kvack.org>
    > Signed-off-by: Sage Weil <sage@newdream.net>
    > ---
    > include/linux/mempool.h | 10 ++--------
    > mm/mempool.c | 7 -------
    > 2 files changed, 2 insertions(+), 15 deletions(-)
    >
    > diff --git a/include/linux/mempool.h b/include/linux/mempool.h
    > index 9be484d..7c08052 100644
    > --- a/include/linux/mempool.h
    > +++ b/include/linux/mempool.h
    > @@ -47,22 +47,16 @@ mempool_create_slab_pool(int min_nr, struct kmem_cache *kc)
    > }
    >
    > /*
    > - * 2 mempool_alloc_t's and a mempool_free_t to kmalloc/kzalloc and kfree
    > - * the amount of memory specified by pool_data
    > + * a mempool_alloc_t and a mempool_free_t to kmalloc and kfree the
    > + * amount of memory specified by pool_data
    > */
    > void *mempool_kmalloc(gfp_t gfp_mask, void *pool_data);
    > -void *mempool_kzalloc(gfp_t gfp_mask, void *pool_data);
    > void mempool_kfree(void *element, void *pool_data);
    > static inline mempool_t *mempool_create_kmalloc_pool(int min_nr, size_t size)
    > {
    > return mempool_create(min_nr, mempool_kmalloc, mempool_kfree,
    > (void *) size);
    > }
    > -static inline mempool_t *mempool_create_kzalloc_pool(int min_nr, size_t size)
    > -{
    > - return mempool_create(min_nr, mempool_kzalloc, mempool_kfree,
    > - (void *) size);
    > -}
    >
    > /*
    > * A mempool_alloc_t and mempool_free_t for a simple page allocator that
    > diff --git a/mm/mempool.c b/mm/mempool.c
    > index a46eb1b..eea4f7d 100644
    > --- a/mm/mempool.c
    > +++ b/mm/mempool.c
    > @@ -308,13 +308,6 @@ void *mempool_kmalloc(gfp_t gfp_mask, void *pool_data)
    > }
    > EXPORT_SYMBOL(mempool_kmalloc);
    >
    > -void *mempool_kzalloc(gfp_t gfp_mask, void *pool_data)
    > -{
    > - size_t size = (size_t) pool_data;
    > - return kzalloc(size, gfp_mask);
    > -}
    > -EXPORT_SYMBOL(mempool_kzalloc);
    > -
    > void mempool_kfree(void *element, void *pool_data)
    > {
    > kfree(element);
    > --
    > 1.5.6.5
    >
    >


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