voron

experimental ARM OS
git clone git://git.2f30.org/voron.git
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commit ff92885350650362cd408a6ba613898c461641d5
parent 263d36a92c39d879c9288b572353d4f7a3fff9ce
Author: oblique <psyberbits@gmail.com>
Date:   Tue Jul 23 15:37:19 +0300

Restructure the code of krealloc() and add one feature in it.

Feature added:
    If the new rounded size of krealloc() is smaller than the current
    one, then allocate a smaller memory region.

Diffstat:
kernel/alloc.c | 50++++++++++++++++++++++++--------------------------
1 file changed, 24 insertions(+), 26 deletions(-)
diff --git a/kernel/alloc.c b/kernel/alloc.c @@ -131,46 +131,44 @@ krealloc(void *addr, size_t size) { void *p; struct list_head *pos; - struct mem_chunk *memc; + struct mem_chunk *memc = NULL; if (!size && addr) { kfree(addr); return NULL; } - if (addr) { - /* Lookup for the old base pointer `addr' if it is part of a - * previous allocation */ - spinlock_lock(&alloclist_lock); - list_for_each(pos, &alloclist) { - memc = list_entry(pos, struct mem_chunk, list); - if (addr == memc->start) - goto found; - } - spinlock_unlock(&alloclist_lock); - } - - /* Allocate new space at a different base address */ - p = kmalloc(size); - if (!p) - return NULL; + /* If addr is NULL, allocate new space */ + if (!addr) + return kmalloc(size); - return p; -found: - /* Are we shrinking the space? If so just return the old `addr' */ - if (size <= memc->size) { - spinlock_unlock(&alloclist_lock); - return addr; + /* Lookup for the old base pointer `addr' if it is part of a + * previous allocation */ + spinlock_lock(&alloclist_lock); + list_for_each(pos, &alloclist) { + memc = list_entry(pos, struct mem_chunk, list); + if (addr == memc->start) { + /* Is the new rounded size the same of the current one? + * If so just return the old `addr' */ + if (roundup(size) == memc->size) { + spinlock_unlock(&alloclist_lock); + return addr; + } + break; + } } spinlock_unlock(&alloclist_lock); - /* Allocate some space, copy over the old contents at `addr' and - * free that space */ + /* Allocate some space, copy over the old contents and then + * free them */ p = kmalloc(size); if (!p) return NULL; - memcpy(p, addr, memc->size); + if (memc->size < size) + memcpy(p, addr, memc->size); + else + memcpy(p, addr, size); kfree(addr); return p;