diff options
Diffstat (limited to 'net/ceph/pagevec.c')
| -rw-r--r-- | net/ceph/pagevec.c | 223 |
1 files changed, 223 insertions, 0 deletions
diff --git a/net/ceph/pagevec.c b/net/ceph/pagevec.c new file mode 100644 index 00000000000..54caf068715 --- /dev/null +++ b/net/ceph/pagevec.c @@ -0,0 +1,223 @@ +#include <linux/ceph/ceph_debug.h> + +#include <linux/module.h> +#include <linux/sched.h> +#include <linux/slab.h> +#include <linux/file.h> +#include <linux/namei.h> +#include <linux/writeback.h> + +#include <linux/ceph/libceph.h> + +/* + * build a vector of user pages + */ +struct page **ceph_get_direct_page_vector(const char __user *data, + int num_pages, + loff_t off, size_t len) +{ + struct page **pages; + int rc; + + pages = kmalloc(sizeof(*pages) * num_pages, GFP_NOFS); + if (!pages) + return ERR_PTR(-ENOMEM); + + down_read(¤t->mm->mmap_sem); + rc = get_user_pages(current, current->mm, (unsigned long)data, + num_pages, 0, 0, pages, NULL); + up_read(¤t->mm->mmap_sem); + if (rc < 0) + goto fail; + return pages; + +fail: + kfree(pages); + return ERR_PTR(rc); +} +EXPORT_SYMBOL(ceph_get_direct_page_vector); + +void ceph_put_page_vector(struct page **pages, int num_pages) +{ + int i; + + for (i = 0; i < num_pages; i++) + put_page(pages[i]); + kfree(pages); +} +EXPORT_SYMBOL(ceph_put_page_vector); + +void ceph_release_page_vector(struct page **pages, int num_pages) +{ + int i; + + for (i = 0; i < num_pages; i++) + __free_pages(pages[i], 0); + kfree(pages); +} +EXPORT_SYMBOL(ceph_release_page_vector); + +/* + * allocate a vector new pages + */ +struct page **ceph_alloc_page_vector(int num_pages, gfp_t flags) +{ + struct page **pages; + int i; + + pages = kmalloc(sizeof(*pages) * num_pages, flags); + if (!pages) + return ERR_PTR(-ENOMEM); + for (i = 0; i < num_pages; i++) { + pages[i] = __page_cache_alloc(flags); + if (pages[i] == NULL) { + ceph_release_page_vector(pages, i); + return ERR_PTR(-ENOMEM); + } + } + return pages; +} +EXPORT_SYMBOL(ceph_alloc_page_vector); + +/* + * copy user data into a page vector + */ +int ceph_copy_user_to_page_vector(struct page **pages, + const char __user *data, + loff_t off, size_t len) +{ + int i = 0; + int po = off & ~PAGE_CACHE_MASK; + int left = len; + int l, bad; + + while (left > 0) { + l = min_t(int, PAGE_CACHE_SIZE-po, left); + bad = copy_from_user(page_address(pages[i]) + po, data, l); + if (bad == l) + return -EFAULT; + data += l - bad; + left -= l - bad; + po += l - bad; + if (po == PAGE_CACHE_SIZE) { + po = 0; + i++; + } + } + return len; +} +EXPORT_SYMBOL(ceph_copy_user_to_page_vector); + +int ceph_copy_to_page_vector(struct page **pages, + const char *data, + loff_t off, size_t len) +{ + int i = 0; + size_t po = off & ~PAGE_CACHE_MASK; + size_t left = len; + size_t l; + + while (left > 0) { + l = min_t(size_t, PAGE_CACHE_SIZE-po, left); + memcpy(page_address(pages[i]) + po, data, l); + data += l; + left -= l; + po += l; + if (po == PAGE_CACHE_SIZE) { + po = 0; + i++; + } + } + return len; +} +EXPORT_SYMBOL(ceph_copy_to_page_vector); + +int ceph_copy_from_page_vector(struct page **pages, + char *data, + loff_t off, size_t len) +{ + int i = 0; + size_t po = off & ~PAGE_CACHE_MASK; + size_t left = len; + size_t l; + + while (left > 0) { + l = min_t(size_t, PAGE_CACHE_SIZE-po, left); + memcpy(data, page_address(pages[i]) + po, l); + data += l; + left -= l; + po += l; + if (po == PAGE_CACHE_SIZE) { + po = 0; + i++; + } + } + return len; +} +EXPORT_SYMBOL(ceph_copy_from_page_vector); + +/* + * copy user data from a page vector into a user pointer + */ +int ceph_copy_page_vector_to_user(struct page **pages, + char __user *data, + loff_t off, size_t len) +{ + int i = 0; + int po = off & ~PAGE_CACHE_MASK; + int left = len; + int l, bad; + + while (left > 0) { + l = min_t(int, left, PAGE_CACHE_SIZE-po); + bad = copy_to_user(data, page_address(pages[i]) + po, l); + if (bad == l) + return -EFAULT; + data += l - bad; + left -= l - bad; + if (po) { + po += l - bad; + if (po == PAGE_CACHE_SIZE) + po = 0; + } + i++; + } + return len; +} +EXPORT_SYMBOL(ceph_copy_page_vector_to_user); + +/* + * Zero an extent within a page vector. Offset is relative to the + * start of the first page. + */ +void ceph_zero_page_vector_range(int off, int len, struct page **pages) +{ + int i = off >> PAGE_CACHE_SHIFT; + + off &= ~PAGE_CACHE_MASK; + + dout("zero_page_vector_page %u~%u\n", off, len); + + /* leading partial page? */ + if (off) { + int end = min((int)PAGE_CACHE_SIZE, off + len); + dout("zeroing %d %p head from %d\n", i, pages[i], + (int)off); + zero_user_segment(pages[i], off, end); + len -= (end - off); + i++; + } + while (len >= PAGE_CACHE_SIZE) { + dout("zeroing %d %p len=%d\n", i, pages[i], len); + zero_user_segment(pages[i], 0, PAGE_CACHE_SIZE); + len -= PAGE_CACHE_SIZE; + i++; + } + /* trailing partial page? */ + if (len) { + dout("zeroing %d %p tail to %d\n", i, pages[i], (int)len); + zero_user_segment(pages[i], 0, len); + } +} +EXPORT_SYMBOL(ceph_zero_page_vector_range); + |