From 30bede79400b0d1a24bde048fdec0a4abe4c4d76 Mon Sep 17 00:00:00 2001
From: dongjiuzhu1 <dongjiuzhu1@xiaomi.com>
Date: Fri, 16 Sep 2022 16:55:09 +0800
Subject: [PATCH] mm/mempool: fix bug about size mismatch and binary find

Signed-off-by: dongjiuzhu1 <dongjiuzhu1@xiaomi.com>
---
 mm/mempool/mempool.c          | 25 +++++++++++---------
 mm/mempool/mempool_multiple.c | 43 +++++++++++++++++++++--------------
 2 files changed, 40 insertions(+), 28 deletions(-)

diff --git a/mm/mempool/mempool.c b/mm/mempool/mempool.c
index 1c2bd0e743..8e6074d318 100644
--- a/mm/mempool/mempool.c
+++ b/mm/mempool/mempool.c
@@ -99,19 +99,22 @@ int mempool_init(FAR struct mempool_s *pool, FAR const char *name)
   sq_init(&pool->elist);
 
   count = pool->ninitial + pool->ninterrupt;
-  base = mempool_malloc(pool, sizeof(*base) +
-                        pool->bsize * count);
-  if (base == NULL)
+  if (count != 0)
     {
-      return -ENOMEM;
-    }
+      base = mempool_malloc(pool, sizeof(*base) +
+                            pool->bsize * count);
+      if (base == NULL)
+        {
+          return -ENOMEM;
+        }
 
-  sq_addfirst(base, &pool->elist);
-  mempool_add_list(&pool->ilist, base + 1,
-                   pool->ninterrupt, pool->bsize);
-  mempool_add_list(&pool->list, (FAR char *)(base + 1) +
-                   pool->ninterrupt * pool->bsize,
-                   pool->ninitial, pool->bsize);
+      sq_addfirst(base, &pool->elist);
+      mempool_add_list(&pool->ilist, base + 1,
+                       pool->ninterrupt, pool->bsize);
+      mempool_add_list(&pool->list, (FAR char *)(base + 1) +
+                       pool->ninterrupt * pool->bsize,
+                       pool->ninitial, pool->bsize);
+    }
 
   if (pool->wait && pool->nexpand == 0)
     {
diff --git a/mm/mempool/mempool_multiple.c b/mm/mempool/mempool_multiple.c
index 092b84f393..a71868c6c7 100644
--- a/mm/mempool/mempool_multiple.c
+++ b/mm/mempool/mempool_multiple.c
@@ -40,28 +40,29 @@
 static inline struct mempool_s *
 mempool_multiple_find(FAR struct mempool_multiple_s *mpool, size_t size)
 {
-  FAR struct mempool_s *low = mpool->pools;
-  FAR struct mempool_s *mid;
-  size_t n = mpool->npools;
+  size_t right = mpool->npools;
+  size_t left = 0;
+  size_t mid;
 
-  while (1)
+  while (left < right)
     {
-      n >>= 1;
-      mid = low + n;
-      if (size > mid->bsize)
+      mid = (left + right) >> 1;
+      if (mpool->pools[mid].bsize > size)
         {
-          if (n == 0)
-            {
-              return NULL;
-            }
-
-          low = ++mid;
+          right = mid;
         }
-      else if (size == mid->bsize || n == 0)
+      else
         {
-          return mid;
+          left = mid + 1;
         }
     }
+
+  if (left == mpool->npools)
+    {
+      return NULL;
+    }
+
+  return &mpool->pools[left];
 }
 
 /****************************************************************************
@@ -136,7 +137,11 @@ FAR void *mempool_multiple_alloc(FAR struct mempool_multiple_s *mpool,
   FAR struct mempool_s *pool;
 
   pool = mempool_multiple_find(mpool, size + SIZEOF_HEAD);
-  DEBUGASSERT(pool != NULL);
+  if (pool == NULL)
+    {
+      return NULL;
+    }
+
   do
     {
       FAR void *blk = mempool_alloc(pool);
@@ -266,7 +271,11 @@ FAR void *mempool_multiple_fixed_alloc(FAR struct mempool_multiple_s *mpool,
   FAR struct mempool_s *pool;
 
   pool = mempool_multiple_find(mpool, size);
-  DEBUGASSERT(pool != NULL);
+  if (pool == NULL)
+    {
+      return NULL;
+    }
+
   return mempool_alloc(pool);
 }