+#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/module.h>
#include <linux/err.h>
+#include <linux/sched.h>
#include <asm/uaccess.h>
+#define CREATE_TRACE_POINTS
+#include <trace/events/kmem.h>
+
/**
* kstrdup - allocate space for and copy an existing string
* @s: the string to duplicate
EXPORT_SYMBOL(kmemdup);
/**
- * krealloc - reallocate memory. The contents will remain unchanged.
+ * memdup_user - duplicate memory region from user space
+ *
+ * @src: source address in user space
+ * @len: number of bytes to copy
+ *
+ * Returns an ERR_PTR() on failure.
+ */
+void *memdup_user(const void __user *src, size_t len)
+{
+ void *p;
+
+ /*
+ * Always use GFP_KERNEL, since copy_from_user() can sleep and
+ * cause pagefault, which makes it pointless to use GFP_NOFS
+ * or GFP_ATOMIC.
+ */
+ p = kmalloc_track_caller(len, GFP_KERNEL);
+ if (!p)
+ return ERR_PTR(-ENOMEM);
+
+ if (copy_from_user(p, src, len)) {
+ kfree(p);
+ return ERR_PTR(-EFAULT);
+ }
+
+ return p;
+}
+EXPORT_SYMBOL(memdup_user);
+
+/**
+ * __krealloc - like krealloc() but don't free @p.
* @p: object to reallocate memory for.
* @new_size: how many bytes of memory are required.
* @flags: the type of memory to allocate.
*
- * The contents of the object pointed to are preserved up to the
- * lesser of the new and old sizes. If @p is %NULL, krealloc()
- * behaves exactly like kmalloc(). If @size is 0 and @p is not a
- * %NULL pointer, the object pointed to is freed.
+ * This function is like krealloc() except it never frees the originally
+ * allocated buffer. Use this if you don't want to free the buffer immediately
+ * like, for example, with RCU.
*/
-void *krealloc(const void *p, size_t new_size, gfp_t flags)
+void *__krealloc(const void *p, size_t new_size, gfp_t flags)
{
void *ret;
size_t ks = 0;
- if (unlikely(!new_size)) {
- kfree(p);
+ if (unlikely(!new_size))
return ZERO_SIZE_PTR;
- }
if (p)
ks = ksize(p);
return (void *)p;
ret = kmalloc_track_caller(new_size, flags);
- if (ret) {
- memcpy(ret, p, min(new_size, ks));
+ if (ret && p)
+ memcpy(ret, p, ks);
+
+ return ret;
+}
+EXPORT_SYMBOL(__krealloc);
+
+/**
+ * krealloc - reallocate memory. The contents will remain unchanged.
+ * @p: object to reallocate memory for.
+ * @new_size: how many bytes of memory are required.
+ * @flags: the type of memory to allocate.
+ *
+ * The contents of the object pointed to are preserved up to the
+ * lesser of the new and old sizes. If @p is %NULL, krealloc()
+ * behaves exactly like kmalloc(). If @size is 0 and @p is not a
+ * %NULL pointer, the object pointed to is freed.
+ */
+void *krealloc(const void *p, size_t new_size, gfp_t flags)
+{
+ void *ret;
+
+ if (unlikely(!new_size)) {
kfree(p);
+ return ZERO_SIZE_PTR;
}
+
+ ret = __krealloc(p, new_size, flags);
+ if (ret && p != ret)
+ kfree(p);
+
return ret;
}
EXPORT_SYMBOL(krealloc);
+/**
+ * kzfree - like kfree but zero memory
+ * @p: object to free memory of
+ *
+ * The memory of the object @p points to is zeroed before freed.
+ * If @p is %NULL, kzfree() does nothing.
+ *
+ * Note: this function zeroes the whole allocated buffer which can be a good
+ * deal bigger than the requested buffer size passed to kmalloc(). So be
+ * careful when using this function in performance sensitive code.
+ */
+void kzfree(const void *p)
+{
+ size_t ks;
+ void *mem = (void *)p;
+
+ if (unlikely(ZERO_OR_NULL_PTR(mem)))
+ return;
+ ks = ksize(mem);
+ memset(mem, 0, ks);
+ kfree(mem);
+}
+EXPORT_SYMBOL(kzfree);
+
/*
* strndup_user - duplicate an existing string from user space
* @s: The string to duplicate
return p;
}
EXPORT_SYMBOL(strndup_user);
+
+#if defined(CONFIG_MMU) && !defined(HAVE_ARCH_PICK_MMAP_LAYOUT)
+void arch_pick_mmap_layout(struct mm_struct *mm)
+{
+ mm->mmap_base = TASK_UNMAPPED_BASE;
+ mm->get_unmapped_area = arch_get_unmapped_area;
+ mm->unmap_area = arch_unmap_area;
+}
+#endif
+
+/**
+ * get_user_pages_fast() - pin user pages in memory
+ * @start: starting user address
+ * @nr_pages: number of pages from start to pin
+ * @write: whether pages will be written to
+ * @pages: array that receives pointers to the pages pinned.
+ * Should be at least nr_pages long.
+ *
+ * Returns number of pages pinned. This may be fewer than the number
+ * requested. If nr_pages is 0 or negative, returns 0. If no pages
+ * were pinned, returns -errno.
+ *
+ * get_user_pages_fast provides equivalent functionality to get_user_pages,
+ * operating on current and current->mm, with force=0 and vma=NULL. However
+ * unlike get_user_pages, it must be called without mmap_sem held.
+ *
+ * get_user_pages_fast may take mmap_sem and page table locks, so no
+ * assumptions can be made about lack of locking. get_user_pages_fast is to be
+ * implemented in a way that is advantageous (vs get_user_pages()) when the
+ * user memory area is already faulted in and present in ptes. However if the
+ * pages have to be faulted in, it may turn out to be slightly slower so
+ * callers need to carefully consider what to use. On many architectures,
+ * get_user_pages_fast simply falls back to get_user_pages.
+ */
+int __attribute__((weak)) get_user_pages_fast(unsigned long start,
+ int nr_pages, int write, struct page **pages)
+{
+ struct mm_struct *mm = current->mm;
+ int ret;
+
+ down_read(&mm->mmap_sem);
+ ret = get_user_pages(current, mm, start, nr_pages,
+ write, 0, pages, NULL);
+ up_read(&mm->mmap_sem);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(get_user_pages_fast);
+
+/* Tracepoints definitions. */
+EXPORT_TRACEPOINT_SYMBOL(kmalloc);
+EXPORT_TRACEPOINT_SYMBOL(kmem_cache_alloc);
+EXPORT_TRACEPOINT_SYMBOL(kmalloc_node);
+EXPORT_TRACEPOINT_SYMBOL(kmem_cache_alloc_node);
+EXPORT_TRACEPOINT_SYMBOL(kfree);
+EXPORT_TRACEPOINT_SYMBOL(kmem_cache_free);
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff