root/net/ceph/pagevec.c

DEFINITIONS

1. ceph_put_page_vector
2. ceph_release_page_vector
3. ceph_alloc_page_vector
4. ceph_copy_user_to_page_vector
5. ceph_copy_to_page_vector
6. ceph_copy_from_page_vector
7. ceph_zero_page_vector_range

   1 // SPDX-License-Identifier: GPL-2.0
   2 #include <linux/ceph/ceph_debug.h>
   3 
   4 #include <linux/module.h>
   5 #include <linux/sched.h>
   6 #include <linux/slab.h>
   7 #include <linux/file.h>
   8 #include <linux/namei.h>
   9 #include <linux/writeback.h>
  10 
  11 #include <linux/ceph/libceph.h>
  12 
  13 void ceph_put_page_vector(struct page **pages, int num_pages, bool dirty)
  14 {
  15         int i;
  16 
  17         for (i = 0; i < num_pages; i++) {
  18                 if (dirty)
  19                         set_page_dirty_lock(pages[i]);
  20                 put_page(pages[i]);
  21         }
  22         kvfree(pages);
  23 }
  24 EXPORT_SYMBOL(ceph_put_page_vector);
  25 
  26 void ceph_release_page_vector(struct page **pages, int num_pages)
  27 {
  28         int i;
  29 
  30         for (i = 0; i < num_pages; i++)
  31                 __free_pages(pages[i], 0);
  32         kfree(pages);
  33 }
  34 EXPORT_SYMBOL(ceph_release_page_vector);
  35 
  36 /*
  37  * allocate a vector new pages
  38  */
  39 struct page **ceph_alloc_page_vector(int num_pages, gfp_t flags)
  40 {
  41         struct page **pages;
  42         int i;
  43 
  44         pages = kmalloc_array(num_pages, sizeof(*pages), flags);
  45         if (!pages)
  46                 return ERR_PTR(-ENOMEM);
  47         for (i = 0; i < num_pages; i++) {
  48                 pages[i] = __page_cache_alloc(flags);
  49                 if (pages[i] == NULL) {
  50                         ceph_release_page_vector(pages, i);
  51                         return ERR_PTR(-ENOMEM);
  52                 }
  53         }
  54         return pages;
  55 }
  56 EXPORT_SYMBOL(ceph_alloc_page_vector);
  57 
  58 /*
  59  * copy user data into a page vector
  60  */
  61 int ceph_copy_user_to_page_vector(struct page **pages,
  62                                          const void __user *data,
  63                                          loff_t off, size_t len)
  64 {
  65         int i = 0;
  66         int po = off & ~PAGE_MASK;
  67         int left = len;
  68         int l, bad;
  69 
  70         while (left > 0) {
  71                 l = min_t(int, PAGE_SIZE-po, left);
  72                 bad = copy_from_user(page_address(pages[i]) + po, data, l);
  73                 if (bad == l)
  74                         return -EFAULT;
  75                 data += l - bad;
  76                 left -= l - bad;
  77                 po += l - bad;
  78                 if (po == PAGE_SIZE) {
  79                         po = 0;
  80                         i++;
  81                 }
  82         }
  83         return len;
  84 }
  85 EXPORT_SYMBOL(ceph_copy_user_to_page_vector);
  86 
  87 void ceph_copy_to_page_vector(struct page **pages,
  88                                     const void *data,
  89                                     loff_t off, size_t len)
  90 {
  91         int i = 0;
  92         size_t po = off & ~PAGE_MASK;
  93         size_t left = len;
  94 
  95         while (left > 0) {
  96                 size_t l = min_t(size_t, PAGE_SIZE-po, left);
  97 
  98                 memcpy(page_address(pages[i]) + po, data, l);
  99                 data += l;
 100                 left -= l;
 101                 po += l;
 102                 if (po == PAGE_SIZE) {
 103                         po = 0;
 104                         i++;
 105                 }
 106         }
 107 }
 108 EXPORT_SYMBOL(ceph_copy_to_page_vector);
 109 
 110 void ceph_copy_from_page_vector(struct page **pages,
 111                                     void *data,
 112                                     loff_t off, size_t len)
 113 {
 114         int i = 0;
 115         size_t po = off & ~PAGE_MASK;
 116         size_t left = len;
 117 
 118         while (left > 0) {
 119                 size_t l = min_t(size_t, PAGE_SIZE-po, left);
 120 
 121                 memcpy(data, page_address(pages[i]) + po, l);
 122                 data += l;
 123                 left -= l;
 124                 po += l;
 125                 if (po == PAGE_SIZE) {
 126                         po = 0;
 127                         i++;
 128                 }
 129         }
 130 }
 131 EXPORT_SYMBOL(ceph_copy_from_page_vector);
 132 
 133 /*
 134  * Zero an extent within a page vector.  Offset is relative to the
 135  * start of the first page.
 136  */
 137 void ceph_zero_page_vector_range(int off, int len, struct page **pages)
 138 {
 139         int i = off >> PAGE_SHIFT;
 140 
 141         off &= ~PAGE_MASK;
 142 
 143         dout("zero_page_vector_page %u~%u\n", off, len);
 144 
 145         /* leading partial page? */
 146         if (off) {
 147                 int end = min((int)PAGE_SIZE, off + len);
 148                 dout("zeroing %d %p head from %d\n", i, pages[i],
 149                      (int)off);
 150                 zero_user_segment(pages[i], off, end);
 151                 len -= (end - off);
 152                 i++;
 153         }
 154         while (len >= PAGE_SIZE) {
 155                 dout("zeroing %d %p len=%d\n", i, pages[i], len);
 156                 zero_user_segment(pages[i], 0, PAGE_SIZE);
 157                 len -= PAGE_SIZE;
 158                 i++;
 159         }
 160         /* trailing partial page? */
 161         if (len) {
 162                 dout("zeroing %d %p tail to %d\n", i, pages[i], (int)len);
 163                 zero_user_segment(pages[i], 0, len);
 164         }
 165 }
 166 EXPORT_SYMBOL(ceph_zero_page_vector_range);