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:
50 	/* pinned pages representing the bitmap data */
55  * struct iova_bitmap - The IOVA bitmap object
57  * Main data structure for iterating over the bitmap data.
60  * It uses a windowing scheme and pins the bitmap in relatively
63  * The bitmap object uses one base page to store all the pinned pages
64  * pointers related to the bitmap. For sizeof(struct page*) == 8 it stores
66  * 2M of bitmap data is pinned at a time. If the iova_bitmap page size is
75  * An example of the APIs on how to use/iterate over the IOVA bitmap:
77  *   bitmap = iova_bitmap_alloc(iova, length, page_size, data);
78  *   if (IS_ERR(bitmap))
79  *       return PTR_ERR(bitmap);
81  *   ret = iova_bitmap_for_each(bitmap, arg, dirty_reporter_fn);
83  *   iova_bitmap_free(bitmap);
90  *   iova_bitmap_set(bitmap, iova, iova_length);
93  * which u64 word of the bitmap is mapped, up to @mapped_total_index.
97  * The IOVA bitmap is usually located on what tracks DMA mapped ranges or
99  * bitmap.
102 	/* IOVA range representing the currently mapped bitmap data */
105 	/* userspace address of the bitmap */
106 	u8 __user *bitmap;  member
114 	/* base IOVA of the whole bitmap */
117 	/* length of the IOVA range for the whole bitmap */
122  * Converts a relative IOVA to a bitmap index.
123  * This function provides the index into the u64 array (bitmap::bitmap)
125  * Relative IOVA means relative to the bitmap::mapped base IOVA
130 static unsigned long iova_bitmap_offset_to_index(struct iova_bitmap *bitmap,  in iova_bitmap_offset_to_index()  argument
133 	unsigned long pgsize = 1 << bitmap->mapped.pgshift;  in iova_bitmap_offset_to_index()
135 	return iova / (BITS_PER_TYPE(*bitmap->bitmap) * pgsize);  in iova_bitmap_offset_to_index()
139  * Converts a bitmap index to a *relative* IOVA.
141 static unsigned long iova_bitmap_index_to_offset(struct iova_bitmap *bitmap,  in iova_bitmap_index_to_offset()  argument
144 	unsigned long pgshift = bitmap->mapped.pgshift;  in iova_bitmap_index_to_offset()
146 	return (index * BITS_PER_TYPE(*bitmap->bitmap)) << pgshift;  in iova_bitmap_index_to_offset()
152 static unsigned long iova_bitmap_mapped_iova(struct iova_bitmap *bitmap)  in iova_bitmap_mapped_iova()  argument
154 	unsigned long skip = bitmap->mapped_base_index;  in iova_bitmap_mapped_iova()
156 	return bitmap->iova + iova_bitmap_index_to_offset(bitmap, skip);  in iova_bitmap_mapped_iova()
159 static unsigned long iova_bitmap_mapped_length(struct iova_bitmap *bitmap);
162  * Pins the bitmap user pages for the current range window.
163  * This is internal to IOVA bitmap and called when advancing the
164  * index (@mapped_base_index) or allocating the bitmap.
166 static int iova_bitmap_get(struct iova_bitmap *bitmap)  in iova_bitmap_get()  argument
168 	struct iova_bitmap_map *mapped = &bitmap->mapped;  in iova_bitmap_get()
179 	npages = DIV_ROUND_UP((bitmap->mapped_total_index -  in iova_bitmap_get()
180 			       bitmap->mapped_base_index) *  in iova_bitmap_get()
181 			       sizeof(*bitmap->bitmap), PAGE_SIZE);  in iova_bitmap_get()
184 	 * Bitmap address to be pinned is calculated via pointer arithmetic  in iova_bitmap_get()
185 	 * with bitmap u64 word index.  in iova_bitmap_get()
187 	addr = bitmap->bitmap + bitmap->mapped_base_index;  in iova_bitmap_get()
191 	 * This is, for example, on x86 means 2M of bitmap data max.  in iova_bitmap_get()
203 	mapped->iova = iova_bitmap_mapped_iova(bitmap);  in iova_bitmap_get()
207 	 * This handles the case where the bitmap is not PAGE_SIZE  in iova_bitmap_get()
211 	mapped->length = iova_bitmap_mapped_length(bitmap);  in iova_bitmap_get()
216  * Unpins the bitmap user pages and clears @npages
218  * the index or freeing the bitmap.
220 static void iova_bitmap_put(struct iova_bitmap *bitmap)  in iova_bitmap_put()  argument
222 	struct iova_bitmap_map *mapped = &bitmap->mapped;  in iova_bitmap_put()
231  * iova_bitmap_alloc() - Allocates an IOVA bitmap object
234  * @page_size: Page size of the IOVA bitmap. It defines what each bit
236  * @data: Userspace address of the bitmap
248 	struct iova_bitmap *bitmap;  in iova_bitmap_alloc()  local
251 	bitmap = kzalloc(sizeof(*bitmap), GFP_KERNEL);  in iova_bitmap_alloc()
252 	if (!bitmap)  in iova_bitmap_alloc()
255 	mapped = &bitmap->mapped;  in iova_bitmap_alloc()
257 	bitmap->bitmap = (u8 __user *)data;  in iova_bitmap_alloc()
258 	bitmap->mapped_total_index =  in iova_bitmap_alloc()
259 		iova_bitmap_offset_to_index(bitmap, length - 1) + 1;  in iova_bitmap_alloc()
260 	bitmap->iova = iova;  in iova_bitmap_alloc()
261 	bitmap->length = length;  in iova_bitmap_alloc()
269 	return bitmap;  in iova_bitmap_alloc()
272 	iova_bitmap_free(bitmap);  in iova_bitmap_alloc()
278  * iova_bitmap_free() - Frees an IOVA bitmap object
279  * @bitmap: IOVA bitmap to free
284 void iova_bitmap_free(struct iova_bitmap *bitmap)  in iova_bitmap_free()  argument
286 	struct iova_bitmap_map *mapped = &bitmap->mapped;  in iova_bitmap_free()
288 	iova_bitmap_put(bitmap);  in iova_bitmap_free()
295 	kfree(bitmap);  in iova_bitmap_free()
300  * Returns the remaining bitmap indexes from mapped_total_index to process for
301  * the currently pinned bitmap pages.
303 static unsigned long iova_bitmap_mapped_remaining(struct iova_bitmap *bitmap)  in iova_bitmap_mapped_remaining()  argument
307 	bytes = (bitmap->mapped.npages << PAGE_SHIFT) - bitmap->mapped.pgoff;  in iova_bitmap_mapped_remaining()
309 	remaining = bitmap->mapped_total_index - bitmap->mapped_base_index;  in iova_bitmap_mapped_remaining()
311 			  DIV_ROUND_UP(bytes, sizeof(*bitmap->bitmap)));  in iova_bitmap_mapped_remaining()
319 static unsigned long iova_bitmap_mapped_length(struct iova_bitmap *bitmap)  in iova_bitmap_mapped_length()  argument
321 	unsigned long max_iova = bitmap->iova + bitmap->length - 1;  in iova_bitmap_mapped_length()
322 	unsigned long iova = iova_bitmap_mapped_iova(bitmap);  in iova_bitmap_mapped_length()
327 	 * when converted to IOVA gives us a max length that the bitmap  in iova_bitmap_mapped_length()
329 	 * only cover the IOVA range in @bitmap::iova .. @bitmap::length.  in iova_bitmap_mapped_length()
331 	remaining = iova_bitmap_index_to_offset(bitmap,  in iova_bitmap_mapped_length()
332 			iova_bitmap_mapped_remaining(bitmap));  in iova_bitmap_mapped_length()
353  * pages and pins the next set of bitmap pages.
356 static int iova_bitmap_advance_to(struct iova_bitmap *bitmap,  in iova_bitmap_advance_to()  argument
361 	index = iova_bitmap_offset_to_index(bitmap, iova - bitmap->iova);  in iova_bitmap_advance_to()
362 	if (index >= bitmap->mapped_total_index)  in iova_bitmap_advance_to()
364 	bitmap->mapped_base_index = index;  in iova_bitmap_advance_to()
366 	iova_bitmap_put(bitmap);  in iova_bitmap_advance_to()
368 	/* Pin the next set of bitmap pages */  in iova_bitmap_advance_to()
369 	return iova_bitmap_get(bitmap);  in iova_bitmap_advance_to()
373  * iova_bitmap_for_each() - Iterates over the bitmap
374  * @bitmap: IOVA bitmap to iterate
378  * Helper function to iterate over bitmap data representing a portion of IOVA
380  * mapped bitmap user pages into IOVA ranges to process.
385 int iova_bitmap_for_each(struct iova_bitmap *bitmap, void *opaque,  in iova_bitmap_for_each()  argument
388 	return fn(bitmap, bitmap->iova, bitmap->length, 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()
416 		if (iova_bitmap_advance_to(bitmap, iova))  in iova_bitmap_set()