14  * struct iova_bitmap_map - A bitmap representing an IOVA range
16  * Main data structure for tracking mapped user pages of bitmap data.
24  * The user does not need to exact location of the bits in the bitmap.
26  * records the IOVA *range* in the bitmap by setting the corresponding
29  * The bitmap is an array of u64 whereas each bit represents an IOVA of
30  * range of (1 << pgshift). Thus formula for the bitmap data to be set is:
47 	/* pinned pages representing the bitmap data */
52  * struct iova_bitmap - The IOVA bitmap object
54  * Main data structure for iterating over the bitmap data.
57  * It uses a windowing scheme and pins the bitmap in relatively
60  * The bitmap object uses one base page to store all the pinned pages
61  * pointers related to the bitmap. For sizeof(struct page*) == 8 it stores
63  * 2M of bitmap data is pinned at a time. If the iova_bitmap page size is
72  * An example of the APIs on how to use/iterate over the IOVA bitmap:
74  *   bitmap = iova_bitmap_alloc(iova, length, page_size, data);
75  *   if (IS_ERR(bitmap))
76  *       return PTR_ERR(bitmap);
78  *   ret = iova_bitmap_for_each(bitmap, arg, dirty_reporter_fn);
80  *   iova_bitmap_free(bitmap);
87  *   iova_bitmap_set(bitmap, iova, iova_length);
90  * which u64 word of the bitmap is mapped, up to @mapped_total_index.
94  * The IOVA bitmap is usually located on what tracks DMA mapped ranges or
96  * bitmap.
99 	/* IOVA range representing the currently mapped bitmap data */
102 	/* userspace address of the bitmap */
103 	u8 __user *bitmap;  member
111 	/* base IOVA of the whole bitmap */
114 	/* length of the IOVA range for the whole bitmap */
119  * Converts a relative IOVA to a bitmap index.
120  * This function provides the index into the u64 array (bitmap::bitmap)
122  * Relative IOVA means relative to the bitmap::mapped base IOVA
127 static unsigned long iova_bitmap_offset_to_index(struct iova_bitmap *bitmap,  in iova_bitmap_offset_to_index()  argument
130 	unsigned long pgsize = 1UL << bitmap->mapped.pgshift;  in iova_bitmap_offset_to_index()
132 	return iova / (BITS_PER_TYPE(*bitmap->bitmap) * pgsize);  in iova_bitmap_offset_to_index()
136  * Converts a bitmap index to a *relative* IOVA.
138 static unsigned long iova_bitmap_index_to_offset(struct iova_bitmap *bitmap,  in iova_bitmap_index_to_offset()  argument
141 	unsigned long pgshift = bitmap->mapped.pgshift;  in iova_bitmap_index_to_offset()
143 	return (index * BITS_PER_TYPE(*bitmap->bitmap)) << pgshift;  in iova_bitmap_index_to_offset()
149 static unsigned long iova_bitmap_mapped_iova(struct iova_bitmap *bitmap)  in iova_bitmap_mapped_iova()  argument
151 	unsigned long skip = bitmap->mapped_base_index;  in iova_bitmap_mapped_iova()
153 	return bitmap->iova + iova_bitmap_index_to_offset(bitmap, skip);  in iova_bitmap_mapped_iova()
157  * Pins the bitmap user pages for the current range window.
158  * This is internal to IOVA bitmap and called when advancing the
159  * index (@mapped_base_index) or allocating the bitmap.
161 static int iova_bitmap_get(struct iova_bitmap *bitmap)  in iova_bitmap_get()  argument
163 	struct iova_bitmap_map *mapped = &bitmap->mapped;  in iova_bitmap_get()
174 	npages = DIV_ROUND_UP((bitmap->mapped_total_index -  in iova_bitmap_get()
175 			       bitmap->mapped_base_index) *  in iova_bitmap_get()
176 			       sizeof(*bitmap->bitmap), PAGE_SIZE);  in iova_bitmap_get()
179 	 * Bitmap address to be pinned is calculated via pointer arithmetic  in iova_bitmap_get()
180 	 * with bitmap u64 word index.  in iova_bitmap_get()
182 	addr = bitmap->bitmap + bitmap->mapped_base_index;  in iova_bitmap_get()
186 	 * This is, for example, on x86 means 2M of bitmap data max.  in iova_bitmap_get()
198 	mapped->iova = iova_bitmap_mapped_iova(bitmap);  in iova_bitmap_get()
202 	 * This handles the case where the bitmap is not PAGE_SIZE  in iova_bitmap_get()
210  * Unpins the bitmap user pages and clears @npages
212  * the index or freeing the bitmap.
214 static void iova_bitmap_put(struct iova_bitmap *bitmap)  in iova_bitmap_put()  argument
216 	struct iova_bitmap_map *mapped = &bitmap->mapped;  in iova_bitmap_put()
225  * iova_bitmap_alloc() - Allocates an IOVA bitmap object
228  * @page_size: Page size of the IOVA bitmap. It defines what each bit
230  * @data: Userspace address of the bitmap
242 	struct iova_bitmap *bitmap;  in iova_bitmap_alloc()  local
245 	bitmap = kzalloc(sizeof(*bitmap), GFP_KERNEL);  in iova_bitmap_alloc()
246 	if (!bitmap)  in iova_bitmap_alloc()
249 	mapped = &bitmap->mapped;  in iova_bitmap_alloc()
251 	bitmap->bitmap = (u8 __user *)data;  in iova_bitmap_alloc()
252 	bitmap->mapped_total_index =  in iova_bitmap_alloc()
253 		iova_bitmap_offset_to_index(bitmap, length - 1) + 1;  in iova_bitmap_alloc()
254 	bitmap->iova = iova;  in iova_bitmap_alloc()
255 	bitmap->length = length;  in iova_bitmap_alloc()
263 	rc = iova_bitmap_get(bitmap);  in iova_bitmap_alloc()
266 	return bitmap;  in iova_bitmap_alloc()
269 	iova_bitmap_free(bitmap);  in iova_bitmap_alloc()
274  * iova_bitmap_free() - Frees an IOVA bitmap object
275  * @bitmap: IOVA bitmap to free
280 void iova_bitmap_free(struct iova_bitmap *bitmap)  in iova_bitmap_free()  argument
282 	struct iova_bitmap_map *mapped = &bitmap->mapped;  in iova_bitmap_free()
284 	iova_bitmap_put(bitmap);  in iova_bitmap_free()
291 	kfree(bitmap);  in iova_bitmap_free()
295  * Returns the remaining bitmap indexes from mapped_total_index to process for
296  * the currently pinned bitmap pages.
298 static unsigned long iova_bitmap_mapped_remaining(struct iova_bitmap *bitmap)  in iova_bitmap_mapped_remaining()  argument
302 	bytes = (bitmap->mapped.npages << PAGE_SHIFT) - bitmap->mapped.pgoff;  in iova_bitmap_mapped_remaining()
304 	remaining = bitmap->mapped_total_index - bitmap->mapped_base_index;  in iova_bitmap_mapped_remaining()
306 			  DIV_ROUND_UP(bytes, sizeof(*bitmap->bitmap)));  in iova_bitmap_mapped_remaining()
314 static unsigned long iova_bitmap_mapped_length(struct iova_bitmap *bitmap)  in iova_bitmap_mapped_length()  argument
316 	unsigned long max_iova = bitmap->iova + bitmap->length - 1;  in iova_bitmap_mapped_length()
317 	unsigned long iova = iova_bitmap_mapped_iova(bitmap);  in iova_bitmap_mapped_length()
322 	 * when converted to IOVA gives us a max length that the bitmap  in iova_bitmap_mapped_length()
324 	 * only cover the IOVA range in @bitmap::iova .. @bitmap::length.  in iova_bitmap_mapped_length()
326 	remaining = iova_bitmap_index_to_offset(bitmap,  in iova_bitmap_mapped_length()
327 			iova_bitmap_mapped_remaining(bitmap));  in iova_bitmap_mapped_length()
338 static bool iova_bitmap_done(struct iova_bitmap *bitmap)  in iova_bitmap_done()  argument
340 	return bitmap->mapped_base_index >= bitmap->mapped_total_index;  in iova_bitmap_done()
345  * pages and pins the next set of bitmap pages.
348 static int iova_bitmap_advance(struct iova_bitmap *bitmap)  in iova_bitmap_advance()  argument
350 	unsigned long iova = iova_bitmap_mapped_length(bitmap) - 1;  in iova_bitmap_advance()
351 	unsigned long count = iova_bitmap_offset_to_index(bitmap, iova) + 1;  in iova_bitmap_advance()
353 	bitmap->mapped_base_index += count;  in iova_bitmap_advance()
355 	iova_bitmap_put(bitmap);  in iova_bitmap_advance()
356 	if (iova_bitmap_done(bitmap))  in iova_bitmap_advance()
359 	/* When advancing the index we pin the next set of bitmap pages */  in iova_bitmap_advance()
360 	return iova_bitmap_get(bitmap);  in iova_bitmap_advance()
364  * iova_bitmap_for_each() - Iterates over the bitmap
365  * @bitmap: IOVA bitmap to iterate
369  * Helper function to iterate over bitmap data representing a portion of IOVA
371  * mapped bitmap user pages into IOVA ranges to process.
376 int iova_bitmap_for_each(struct iova_bitmap *bitmap, void *opaque,  in iova_bitmap_for_each()  argument
381 	for (; !iova_bitmap_done(bitmap) && !ret;  in iova_bitmap_for_each()
382 	     ret = iova_bitmap_advance(bitmap)) {  in iova_bitmap_for_each()
383 		ret = fn(bitmap, iova_bitmap_mapped_iova(bitmap),  in iova_bitmap_for_each()
384 			 iova_bitmap_mapped_length(bitmap), opaque);  in iova_bitmap_for_each()
393  * iova_bitmap_set() - Records an IOVA range in bitmap
394  * @bitmap: IOVA bitmap
399  * the user bitmap.
402 void iova_bitmap_set(struct iova_bitmap *bitmap,  in iova_bitmap_set()  argument
405 	struct iova_bitmap_map *mapped = &bitmap->mapped;  in iova_bitmap_set()