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[PATCH] eCryptfs: convert kmap() to kmap_atomic()
Replace kmap() with kmap_atomic(). Reduce the amount of time that mappings are held. Signed-off-by: Michael Halcrow <mhalcrow@us.ibm.com> Signed-off-by: Trevor Highland <tshighla@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Michael Halcrow
Linus Torvalds
parent
70456600f4
commit
9d8b8ce556
@ -429,10 +429,10 @@ static int ecryptfs_read_in_page(struct ecryptfs_page_crypt_context *ctx,
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goto out;
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}
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} else {
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rc = ecryptfs_grab_and_map_lower_page(lower_page, NULL,
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lower_inode,
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lower_page_idx);
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if (rc) {
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*lower_page = grab_cache_page(lower_inode->i_mapping,
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lower_page_idx);
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if (!(*lower_page)) {
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rc = -EINVAL;
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ecryptfs_printk(
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KERN_ERR, "Error attempting to grab and map "
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"lower page with index [0x%.16x]; rc = [%d]\n",
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@ -514,10 +514,6 @@ int ecryptfs_copy_page_to_lower(struct page *page, struct inode *lower_inode,
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struct file *lower_file);
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int ecryptfs_do_readpage(struct file *file, struct page *page,
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pgoff_t lower_page_index);
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int ecryptfs_grab_and_map_lower_page(struct page **lower_page,
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char **lower_virt,
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struct inode *lower_inode,
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unsigned long lower_page_index);
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int ecryptfs_writepage_and_release_lower_page(struct page *lower_page,
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struct inode *lower_inode,
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struct writeback_control *wbc);
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@ -234,22 +234,11 @@ int ecryptfs_do_readpage(struct file *file, struct page *page,
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goto out;
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}
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wait_on_page_locked(lower_page);
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page_data = (char *)kmap(page);
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if (!page_data) {
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rc = -ENOMEM;
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ecryptfs_printk(KERN_ERR, "Error mapping page\n");
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goto out;
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}
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lower_page_data = (char *)kmap(lower_page);
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if (!lower_page_data) {
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rc = -ENOMEM;
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ecryptfs_printk(KERN_ERR, "Error mapping page\n");
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kunmap(page);
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goto out;
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}
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page_data = kmap_atomic(page, KM_USER0);
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lower_page_data = kmap_atomic(lower_page, KM_USER1);
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memcpy(page_data, lower_page_data, PAGE_CACHE_SIZE);
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kunmap(lower_page);
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kunmap(page);
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kunmap_atomic(lower_page_data, KM_USER1);
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kunmap_atomic(page_data, KM_USER0);
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rc = 0;
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out:
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if (likely(lower_page))
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@ -325,19 +314,14 @@ static int ecryptfs_readpage(struct file *file, struct page *page)
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if (page->index < num_pages_in_header_region) {
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char *page_virt;
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page_virt = (char *)kmap(page);
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if (!page_virt) {
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rc = -ENOMEM;
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printk(KERN_ERR "Error mapping page\n");
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goto out;
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}
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page_virt = kmap_atomic(page, KM_USER0);
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memset(page_virt, 0, PAGE_CACHE_SIZE);
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if (page->index == 0) {
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rc = ecryptfs_read_xattr_region(
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page_virt, file->f_path.dentry);
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set_header_info(page_virt, crypt_stat);
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}
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kunmap(page);
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kunmap_atomic(page_virt, KM_USER0);
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if (rc) {
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printk(KERN_ERR "Error reading xattr "
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"region\n");
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@ -387,26 +371,19 @@ static int fill_zeros_to_end_of_page(struct page *page, unsigned int to)
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{
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struct inode *inode = page->mapping->host;
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int end_byte_in_page;
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int rc = 0;
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char *page_virt;
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if ((i_size_read(inode) / PAGE_CACHE_SIZE) == page->index) {
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end_byte_in_page = i_size_read(inode) % PAGE_CACHE_SIZE;
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if (to > end_byte_in_page)
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end_byte_in_page = to;
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page_virt = kmap(page);
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if (!page_virt) {
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rc = -ENOMEM;
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ecryptfs_printk(KERN_WARNING,
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"Could not map page\n");
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goto out;
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}
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memset((page_virt + end_byte_in_page), 0,
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(PAGE_CACHE_SIZE - end_byte_in_page));
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kunmap(page);
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}
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if ((i_size_read(inode) / PAGE_CACHE_SIZE) != page->index)
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goto out;
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end_byte_in_page = i_size_read(inode) % PAGE_CACHE_SIZE;
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if (to > end_byte_in_page)
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end_byte_in_page = to;
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page_virt = kmap_atomic(page, KM_USER0);
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memset((page_virt + end_byte_in_page), 0,
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(PAGE_CACHE_SIZE - end_byte_in_page));
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kunmap_atomic(page_virt, KM_USER0);
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out:
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return rc;
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return 0;
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}
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static int ecryptfs_prepare_write(struct file *file, struct page *page,
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@ -414,7 +391,6 @@ static int ecryptfs_prepare_write(struct file *file, struct page *page,
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{
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int rc = 0;
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kmap(page);
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if (from == 0 && to == PAGE_CACHE_SIZE)
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goto out; /* If we are writing a full page, it will be
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up to date. */
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@ -424,30 +400,6 @@ out:
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return rc;
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}
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int ecryptfs_grab_and_map_lower_page(struct page **lower_page,
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char **lower_virt,
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struct inode *lower_inode,
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unsigned long lower_page_index)
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{
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int rc = 0;
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(*lower_page) = grab_cache_page(lower_inode->i_mapping,
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lower_page_index);
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if (!(*lower_page)) {
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ecryptfs_printk(KERN_ERR, "grab_cache_page for "
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"lower_page_index = [0x%.16x] failed\n",
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lower_page_index);
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rc = -EINVAL;
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goto out;
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}
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if (lower_virt)
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(*lower_virt) = kmap((*lower_page));
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else
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kmap((*lower_page));
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out:
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return rc;
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}
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int ecryptfs_writepage_and_release_lower_page(struct page *lower_page,
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struct inode *lower_inode,
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struct writeback_control *wbc)
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@ -466,11 +418,8 @@ out:
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return rc;
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}
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static void ecryptfs_unmap_and_release_lower_page(struct page *lower_page)
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static void ecryptfs_release_lower_page(struct page *lower_page)
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{
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kunmap(lower_page);
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ecryptfs_printk(KERN_DEBUG, "Unlocking lower page with index = "
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"[0x%.16x]\n", lower_page->index);
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unlock_page(lower_page);
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page_cache_release(lower_page);
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}
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@ -492,11 +441,11 @@ static int ecryptfs_write_inode_size_to_header(struct file *lower_file,
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const struct address_space_operations *lower_a_ops;
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u64 file_size;
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rc = ecryptfs_grab_and_map_lower_page(&header_page, &header_virt,
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lower_inode, 0);
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if (rc) {
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ecryptfs_printk(KERN_ERR, "grab_cache_page for header page "
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"failed\n");
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header_page = grab_cache_page(lower_inode->i_mapping, 0);
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if (!header_page) {
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ecryptfs_printk(KERN_ERR, "grab_cache_page for "
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"lower_page_index 0 failed\n");
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rc = -EINVAL;
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goto out;
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}
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lower_a_ops = lower_inode->i_mapping->a_ops;
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@ -504,12 +453,14 @@ static int ecryptfs_write_inode_size_to_header(struct file *lower_file,
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file_size = (u64)i_size_read(inode);
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ecryptfs_printk(KERN_DEBUG, "Writing size: [0x%.16x]\n", file_size);
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file_size = cpu_to_be64(file_size);
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header_virt = kmap_atomic(header_page, KM_USER0);
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memcpy(header_virt, &file_size, sizeof(u64));
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kunmap_atomic(header_virt, KM_USER0);
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rc = lower_a_ops->commit_write(lower_file, header_page, 0, 8);
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if (rc < 0)
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ecryptfs_printk(KERN_ERR, "Error commiting header page "
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"write\n");
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ecryptfs_unmap_and_release_lower_page(header_page);
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ecryptfs_release_lower_page(header_page);
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lower_inode->i_mtime = lower_inode->i_ctime = CURRENT_TIME;
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mark_inode_dirty_sync(inode);
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out:
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@ -597,10 +548,10 @@ int ecryptfs_get_lower_page(struct page **lower_page, struct inode *lower_inode,
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{
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int rc = 0;
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rc = ecryptfs_grab_and_map_lower_page(lower_page, NULL, lower_inode,
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lower_page_index);
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if (rc) {
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ecryptfs_printk(KERN_ERR, "Error attempting to grab and map "
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*lower_page = grab_cache_page(lower_inode->i_mapping, lower_page_index);
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if (!(*lower_page)) {
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rc = -EINVAL;
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ecryptfs_printk(KERN_ERR, "Error attempting to grab "
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"lower page with index [0x%.16x]\n",
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lower_page_index);
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goto out;
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@ -616,7 +567,7 @@ int ecryptfs_get_lower_page(struct page **lower_page, struct inode *lower_inode,
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}
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out:
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if (rc && (*lower_page)) {
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ecryptfs_unmap_and_release_lower_page(*lower_page);
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ecryptfs_release_lower_page(*lower_page);
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(*lower_page) = NULL;
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}
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return rc;
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@ -641,7 +592,7 @@ ecryptfs_commit_lower_page(struct page *lower_page, struct inode *lower_inode,
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"Error committing write; rc = [%d]\n", rc);
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} else
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rc = 0;
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ecryptfs_unmap_and_release_lower_page(lower_page);
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ecryptfs_release_lower_page(lower_page);
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return rc;
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}
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@ -747,7 +698,6 @@ static int ecryptfs_commit_write(struct file *file, struct page *page,
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lower_inode->i_mtime = lower_inode->i_ctime = CURRENT_TIME;
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mark_inode_dirty_sync(inode);
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out:
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kunmap(page); /* mapped in prior call (prepare_write) */
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if (rc < 0)
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ClearPageUptodate(page);
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else
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@ -772,6 +722,7 @@ int write_zeros(struct file *file, pgoff_t index, int start, int num_zeros)
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{
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int rc = 0;
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struct page *tmp_page;
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char *tmp_page_virt;
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tmp_page = ecryptfs_get1page(file, index);
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if (IS_ERR(tmp_page)) {
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@ -780,28 +731,26 @@ int write_zeros(struct file *file, pgoff_t index, int start, int num_zeros)
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rc = PTR_ERR(tmp_page);
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goto out;
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}
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kmap(tmp_page);
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rc = ecryptfs_prepare_write(file, tmp_page, start, start + num_zeros);
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if (rc) {
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ecryptfs_printk(KERN_ERR, "Error preparing to write zero's "
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"to remainder of page at index [0x%.16x]\n",
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index);
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kunmap(tmp_page);
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page_cache_release(tmp_page);
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goto out;
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}
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memset(((char *)page_address(tmp_page) + start), 0, num_zeros);
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tmp_page_virt = kmap_atomic(tmp_page, KM_USER0);
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memset(((char *)tmp_page_virt + start), 0, num_zeros);
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kunmap_atomic(tmp_page_virt, KM_USER0);
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rc = ecryptfs_commit_write(file, tmp_page, start, start + num_zeros);
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if (rc < 0) {
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ecryptfs_printk(KERN_ERR, "Error attempting to write zero's "
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"to remainder of page at index [0x%.16x]\n",
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index);
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kunmap(tmp_page);
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page_cache_release(tmp_page);
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goto out;
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}
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rc = 0;
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kunmap(tmp_page);
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page_cache_release(tmp_page);
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out:
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return rc;
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