i915/gt/shmem_utils.c

0001 // SPDX-License-Identifier: MIT
0002 /*
0003  * Copyright © 2020 Intel Corporation
0004  */
0005
0006 #include <linux/iosys-map.h>
0007 #include <linux/mm.h>
0008 #include <linux/pagemap.h>
0009 #include <linux/shmem_fs.h>
0010
0011 #include "gem/i915_gem_object.h"
0012 #include "gem/i915_gem_lmem.h"
0013 #include "shmem_utils.h"
0014
0015 struct file *shmem_create_from_data(const char *name, void *data, size_t len)
0016 {
0017     struct file *file;
0018     int err;
0019
0020     file = shmem_file_setup(name, PAGE_ALIGN(len), VM_NORESERVE);
0021     if (IS_ERR(file))
0022         return file;
0023
0024     err = shmem_write(file, 0, data, len);
0025     if (err) {
0026         fput(file);
0027         return ERR_PTR(err);
0028     }
0029
0030     return file;
0031 }
0032
0033 struct file *shmem_create_from_object(struct drm_i915_gem_object *obj)
0034 {
0035     struct file *file;
0036     void *ptr;
0037
0038     if (i915_gem_object_is_shmem(obj)) {
0039         file = obj->base.filp;
0040         atomic_long_inc(&file->f_count);
0041         return file;
0042     }
0043
0044     ptr = i915_gem_object_pin_map_unlocked(obj, i915_gem_object_is_lmem(obj) ?
0045                         I915_MAP_WC : I915_MAP_WB);
0046     if (IS_ERR(ptr))
0047         return ERR_CAST(ptr);
0048
0049     file = shmem_create_from_data("", ptr, obj->base.size);
0050     i915_gem_object_unpin_map(obj);
0051
0052     return file;
0053 }
0054
0055 void *shmem_pin_map(struct file *file)
0056 {
0057     struct page **pages;
0058     size_t n_pages, i;
0059     void *vaddr;
0060
0061     n_pages = file->f_mapping->host->i_size >> PAGE_SHIFT;
0062     pages = kvmalloc_array(n_pages, sizeof(*pages), GFP_KERNEL);
0063     if (!pages)
0064         return NULL;
0065
0066     for (i = 0; i < n_pages; i++) {
0067         pages[i] = shmem_read_mapping_page_gfp(file->f_mapping, i,
0068                                GFP_KERNEL);
0069         if (IS_ERR(pages[i]))
0070             goto err_page;
0071     }
0072
0073     vaddr = vmap(pages, n_pages, VM_MAP_PUT_PAGES, PAGE_KERNEL);
0074     if (!vaddr)
0075         goto err_page;
0076     mapping_set_unevictable(file->f_mapping);
0077     return vaddr;
0078 err_page:
0079     while (i--)
0080         put_page(pages[i]);
0081     kvfree(pages);
0082     return NULL;
0083 }
0084
0085 void shmem_unpin_map(struct file *file, void *ptr)
0086 {
0087     mapping_clear_unevictable(file->f_mapping);
0088     vfree(ptr);
0089 }
0090
0091 static int __shmem_rw(struct file *file, loff_t off,
0092               void *ptr, size_t len,
0093               bool write)
0094 {
0095     unsigned long pfn;
0096
0097     for (pfn = off >> PAGE_SHIFT; len; pfn++) {
0098         unsigned int this =
0099             min_t(size_t, PAGE_SIZE - offset_in_page(off), len);
0100         struct page *page;
0101         void *vaddr;
0102
0103         page = shmem_read_mapping_page_gfp(file->f_mapping, pfn,
0104                            GFP_KERNEL);
0105         if (IS_ERR(page))
0106             return PTR_ERR(page);
0107
0108         vaddr = kmap(page);
0109         if (write) {
0110             memcpy(vaddr + offset_in_page(off), ptr, this);
0111             set_page_dirty(page);
0112         } else {
0113             memcpy(ptr, vaddr + offset_in_page(off), this);
0114         }
0115         mark_page_accessed(page);
0116         kunmap(page);
0117         put_page(page);
0118
0119         len -= this;
0120         ptr += this;
0121         off = 0;
0122     }
0123
0124     return 0;
0125 }
0126
0127 int shmem_read_to_iosys_map(struct file *file, loff_t off,
0128                 struct iosys_map *map, size_t map_off, size_t len)
0129 {
0130     unsigned long pfn;
0131
0132     for (pfn = off >> PAGE_SHIFT; len; pfn++) {
0133         unsigned int this =
0134             min_t(size_t, PAGE_SIZE - offset_in_page(off), len);
0135         struct page *page;
0136         void *vaddr;
0137
0138         page = shmem_read_mapping_page_gfp(file->f_mapping, pfn,
0139                            GFP_KERNEL);
0140         if (IS_ERR(page))
0141             return PTR_ERR(page);
0142
0143         vaddr = kmap(page);
0144         iosys_map_memcpy_to(map, map_off, vaddr + offset_in_page(off),
0145                     this);
0146         mark_page_accessed(page);
0147         kunmap(page);
0148         put_page(page);
0149
0150         len -= this;
0151         map_off += this;
0152         off = 0;
0153     }
0154
0155     return 0;
0156 }
0157
0158 int shmem_read(struct file *file, loff_t off, void *dst, size_t len)
0159 {
0160     return __shmem_rw(file, off, dst, len, false);
0161 }
0162
0163 int shmem_write(struct file *file, loff_t off, void *src, size_t len)
0164 {
0165     return __shmem_rw(file, off, src, len, true);
0166 }
0167
0168 #if IS_ENABLED(CONFIG_DRM_I915_SELFTEST)
0169 #include "st_shmem_utils.c"
0170 #endif