From 270752654eaa57d759044484095a77a568c7e0cc Mon Sep 17 00:00:00 2001
From: "Kristofer.Pettersson@naruto." <>
Date: Thu, 11 Jan 2007 09:40:17 +0100
Subject: [PATCH] Bug#24751 - Possible infinit loop in init_io_cache() when
 insufficient memory - When cache memory can't be allocated size is
 recaclulated using 3/4 of   the requested memory. This number is rounded up
 to the nearest   min_cache step.   However with the previous implementation
 the new cache size might   become bigger than requested because of this
 rounding and thus we get   an infinit loop. - This patch fixes this problem
 by ensuring that the new cache size   always will be smaller on the second
 and subsequent iterations until   we reach min_cache.

---
 mysys/mf_iocache.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/mysys/mf_iocache.c b/mysys/mf_iocache.c
index b17df3da260..a91002d3b4c 100644
--- a/mysys/mf_iocache.c
+++ b/mysys/mf_iocache.c
@@ -199,11 +199,11 @@ int init_io_cache(IO_CACHE *info, File file, uint cachesize,
   if (type != READ_NET && type != WRITE_NET)
   {
     /* Retry allocating memory in smaller blocks until we get one */
+    cachesize=(uint) ((ulong) (cachesize + min_cache-1) &
+			(ulong) ~(min_cache-1));
     for (;;)
     {
       uint buffer_block;
-      cachesize=(uint) ((ulong) (cachesize + min_cache-1) &
-			(ulong) ~(min_cache-1));
       if (cachesize < min_cache)
 	cachesize = min_cache;
       buffer_block = cachesize;
@@ -222,7 +222,8 @@ int init_io_cache(IO_CACHE *info, File file, uint cachesize,
       }
       if (cachesize == min_cache)
 	DBUG_RETURN(2);				/* Can't alloc cache */
-      cachesize= (uint) ((long) cachesize*3/4); /* Try with less memory */
+      /* Try with less memory */
+      cachesize= (uint) ((ulong) cachesize*3/4 & (ulong)~(min_cache-1));
     }
   }