286 строки
6.8 KiB
C
286 строки
6.8 KiB
C
#include <linux/mm.h>
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#include <linux/slab.h>
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#include <linux/string.h>
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#include <linux/module.h>
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#include <linux/err.h>
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#include <linux/sched.h>
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#include <asm/uaccess.h>
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#define CREATE_TRACE_POINTS
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#include <trace/events/kmem.h>
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/**
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* kstrdup - allocate space for and copy an existing string
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* @s: the string to duplicate
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* @gfp: the GFP mask used in the kmalloc() call when allocating memory
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*/
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char *kstrdup(const char *s, gfp_t gfp)
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{
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size_t len;
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char *buf;
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if (!s)
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return NULL;
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len = strlen(s) + 1;
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buf = kmalloc_track_caller(len, gfp);
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if (buf)
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memcpy(buf, s, len);
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return buf;
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}
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EXPORT_SYMBOL(kstrdup);
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/**
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* kstrndup - allocate space for and copy an existing string
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* @s: the string to duplicate
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* @max: read at most @max chars from @s
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* @gfp: the GFP mask used in the kmalloc() call when allocating memory
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*/
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char *kstrndup(const char *s, size_t max, gfp_t gfp)
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{
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size_t len;
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char *buf;
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if (!s)
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return NULL;
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len = strnlen(s, max);
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buf = kmalloc_track_caller(len+1, gfp);
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if (buf) {
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memcpy(buf, s, len);
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buf[len] = '\0';
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}
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return buf;
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}
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EXPORT_SYMBOL(kstrndup);
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/**
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* kmemdup - duplicate region of memory
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*
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* @src: memory region to duplicate
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* @len: memory region length
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* @gfp: GFP mask to use
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*/
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void *kmemdup(const void *src, size_t len, gfp_t gfp)
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{
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void *p;
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p = kmalloc_track_caller(len, gfp);
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if (p)
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memcpy(p, src, len);
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return p;
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}
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EXPORT_SYMBOL(kmemdup);
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/**
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* memdup_user - duplicate memory region from user space
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*
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* @src: source address in user space
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* @len: number of bytes to copy
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*
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* Returns an ERR_PTR() on failure.
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*/
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void *memdup_user(const void __user *src, size_t len)
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{
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void *p;
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/*
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* Always use GFP_KERNEL, since copy_from_user() can sleep and
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* cause pagefault, which makes it pointless to use GFP_NOFS
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* or GFP_ATOMIC.
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*/
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p = kmalloc_track_caller(len, GFP_KERNEL);
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if (!p)
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return ERR_PTR(-ENOMEM);
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if (copy_from_user(p, src, len)) {
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kfree(p);
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return ERR_PTR(-EFAULT);
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}
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return p;
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}
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EXPORT_SYMBOL(memdup_user);
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/**
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* __krealloc - like krealloc() but don't free @p.
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* @p: object to reallocate memory for.
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* @new_size: how many bytes of memory are required.
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* @flags: the type of memory to allocate.
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*
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* This function is like krealloc() except it never frees the originally
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* allocated buffer. Use this if you don't want to free the buffer immediately
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* like, for example, with RCU.
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*/
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void *__krealloc(const void *p, size_t new_size, gfp_t flags)
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{
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void *ret;
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size_t ks = 0;
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if (unlikely(!new_size))
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return ZERO_SIZE_PTR;
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if (p)
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ks = ksize(p);
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if (ks >= new_size)
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return (void *)p;
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ret = kmalloc_track_caller(new_size, flags);
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if (ret && p)
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memcpy(ret, p, ks);
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return ret;
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}
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EXPORT_SYMBOL(__krealloc);
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/**
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* krealloc - reallocate memory. The contents will remain unchanged.
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* @p: object to reallocate memory for.
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* @new_size: how many bytes of memory are required.
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* @flags: the type of memory to allocate.
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*
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* The contents of the object pointed to are preserved up to the
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* lesser of the new and old sizes. If @p is %NULL, krealloc()
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* behaves exactly like kmalloc(). If @size is 0 and @p is not a
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* %NULL pointer, the object pointed to is freed.
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*/
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void *krealloc(const void *p, size_t new_size, gfp_t flags)
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{
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void *ret;
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if (unlikely(!new_size)) {
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kfree(p);
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return ZERO_SIZE_PTR;
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}
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ret = __krealloc(p, new_size, flags);
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if (ret && p != ret)
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kfree(p);
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return ret;
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}
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EXPORT_SYMBOL(krealloc);
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/**
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* kzfree - like kfree but zero memory
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* @p: object to free memory of
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*
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* The memory of the object @p points to is zeroed before freed.
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* If @p is %NULL, kzfree() does nothing.
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*
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* Note: this function zeroes the whole allocated buffer which can be a good
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* deal bigger than the requested buffer size passed to kmalloc(). So be
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* careful when using this function in performance sensitive code.
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*/
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void kzfree(const void *p)
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{
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size_t ks;
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void *mem = (void *)p;
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if (unlikely(ZERO_OR_NULL_PTR(mem)))
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return;
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ks = ksize(mem);
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memset(mem, 0, ks);
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kfree(mem);
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}
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EXPORT_SYMBOL(kzfree);
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/*
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* strndup_user - duplicate an existing string from user space
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* @s: The string to duplicate
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* @n: Maximum number of bytes to copy, including the trailing NUL.
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*/
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char *strndup_user(const char __user *s, long n)
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{
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char *p;
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long length;
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length = strnlen_user(s, n);
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if (!length)
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return ERR_PTR(-EFAULT);
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if (length > n)
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return ERR_PTR(-EINVAL);
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p = memdup_user(s, length);
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if (IS_ERR(p))
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return p;
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p[length - 1] = '\0';
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return p;
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}
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EXPORT_SYMBOL(strndup_user);
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#if defined(CONFIG_MMU) && !defined(HAVE_ARCH_PICK_MMAP_LAYOUT)
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void arch_pick_mmap_layout(struct mm_struct *mm)
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{
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mm->mmap_base = TASK_UNMAPPED_BASE;
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mm->get_unmapped_area = arch_get_unmapped_area;
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mm->unmap_area = arch_unmap_area;
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}
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#endif
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/*
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* Like get_user_pages_fast() except its IRQ-safe in that it won't fall
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* back to the regular GUP.
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* If the architecture not support this function, simply return with no
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* page pinned
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*/
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int __attribute__((weak)) __get_user_pages_fast(unsigned long start,
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int nr_pages, int write, struct page **pages)
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{
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return 0;
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}
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EXPORT_SYMBOL_GPL(__get_user_pages_fast);
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/**
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* get_user_pages_fast() - pin user pages in memory
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* @start: starting user address
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* @nr_pages: number of pages from start to pin
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* @write: whether pages will be written to
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* @pages: array that receives pointers to the pages pinned.
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* Should be at least nr_pages long.
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*
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* Returns number of pages pinned. This may be fewer than the number
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* requested. If nr_pages is 0 or negative, returns 0. If no pages
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* were pinned, returns -errno.
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*
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* get_user_pages_fast provides equivalent functionality to get_user_pages,
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* operating on current and current->mm, with force=0 and vma=NULL. However
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* unlike get_user_pages, it must be called without mmap_sem held.
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*
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* get_user_pages_fast may take mmap_sem and page table locks, so no
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* assumptions can be made about lack of locking. get_user_pages_fast is to be
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* implemented in a way that is advantageous (vs get_user_pages()) when the
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* user memory area is already faulted in and present in ptes. However if the
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* pages have to be faulted in, it may turn out to be slightly slower so
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* callers need to carefully consider what to use. On many architectures,
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* get_user_pages_fast simply falls back to get_user_pages.
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*/
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int __attribute__((weak)) get_user_pages_fast(unsigned long start,
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int nr_pages, int write, struct page **pages)
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{
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struct mm_struct *mm = current->mm;
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int ret;
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down_read(&mm->mmap_sem);
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ret = get_user_pages(current, mm, start, nr_pages,
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write, 0, pages, NULL);
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up_read(&mm->mmap_sem);
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return ret;
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}
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EXPORT_SYMBOL_GPL(get_user_pages_fast);
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/* Tracepoints definitions. */
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EXPORT_TRACEPOINT_SYMBOL(kmalloc);
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EXPORT_TRACEPOINT_SYMBOL(kmem_cache_alloc);
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EXPORT_TRACEPOINT_SYMBOL(kmalloc_node);
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EXPORT_TRACEPOINT_SYMBOL(kmem_cache_alloc_node);
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EXPORT_TRACEPOINT_SYMBOL(kfree);
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EXPORT_TRACEPOINT_SYMBOL(kmem_cache_free);
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