mem-pool: Restructure mem-pool behaviour

This commit changes mem-pool behaviour to return a directly usable
address by performing the required adjustment on the address
being returned.

This is different from the previous behaviour where we're trying to fit
into the requested size, the list_head*2 also. This is not efficient
enough in terms of space but hopefully works better than not having any
mem-pool at all. Besides, I am not comfortable with mem-pool meta-data
and caller-useable memory area being the same because of the potential for
mem-pool's data structure corruption.

PS:
Please do read the comments in the code for more info during review.

Signed-off-by: Anand V. Avati <avati@amp.gluster.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/libglusterfs/src/mem-pool.h b/libglusterfs/src/mem-pool.h
index 492e868bc83..627945e1fe6 100644
--- a/libglusterfs/src/mem-pool.h
+++ b/libglusterfs/src/mem-pool.h
@@ -41,6 +41,7 @@ struct mem_pool {
 	unsigned long     padded_sizeof_type;
 	void             *pool;
 	void             *pool_end;
+        int               real_sizeof_type;
 };
 
 struct mem_pool *