net/ceph/pagevec.c

   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 void ceph_copy_from_page_vector(struct page **pages,
  59                                     void *data,
  60                                     loff_t off, size_t len)
  61 {
  62         int i = 0;
  63         size_t po = off & ~PAGE_MASK;
  64         size_t left = len;
  65
  66         while (left > 0) {
  67                 size_t l = min_t(size_t, PAGE_SIZE-po, left);
  68
  69                 memcpy(data, page_address(pages[i]) + po, l);
  70                 data += l;
  71                 left -= l;
  72                 po += l;
  73                 if (po == PAGE_SIZE) {
  74                         po = 0;
  75                         i++;
  76                 }
  77         }
  78 }
  79 EXPORT_SYMBOL(ceph_copy_from_page_vector);
  80
  81 /*
  82  * Zero an extent within a page vector.  Offset is relative to the
  83  * start of the first page.
  84  */
  85 void ceph_zero_page_vector_range(int off, int len, struct page **pages)
  86 {
  87         int i = off >> PAGE_SHIFT;
  88
  89         off &= ~PAGE_MASK;
  90
  91         dout("zero_page_vector_page %u~%u\n", off, len);
  92
  93         /* leading partial page? */
  94         if (off) {
  95                 int end = min((int)PAGE_SIZE, off + len);
  96                 dout("zeroing %d %p head from %d\n", i, pages[i],
  97                      (int)off);
  98                 zero_user_segment(pages[i], off, end);
  99                 len -= (end - off);
 100                 i++;
 101         }
 102         while (len >= PAGE_SIZE) {
 103                 dout("zeroing %d %p len=%d\n", i, pages[i], len);
 104                 zero_user_segment(pages[i], 0, PAGE_SIZE);
 105                 len -= PAGE_SIZE;
 106                 i++;
 107         }
 108         /* trailing partial page? */
 109         if (len) {
 110                 dout("zeroing %d %p tail to %d\n", i, pages[i], (int)len);
 111                 zero_user_segment(pages[i], 0, len);
 112         }
 113 }
 114 EXPORT_SYMBOL(ceph_zero_page_vector_range);