From ad2a722f196d2b014f49e6c37e072df71eb3695f Mon Sep 17 00:00:00 2001 From: Boaz Harrosh Date: Tue, 12 Jan 2010 15:13:47 +0200 Subject: libfs: Open code simple_commit_write into only user * simple_commit_write was only called by simple_write_end. Open coding it makes it tiny bit less heavy on the arithmetic and much more readable. * While at it use zero_user() for clearing a partial page. * While at it add a docbook comment for simple_write_end. Signed-off-by: Boaz Harrosh Signed-off-by: Al Viro --- fs/libfs.c | 59 +++++++++++++++++++++++++++++++++++------------------------ 1 file changed, 35 insertions(+), 24 deletions(-) (limited to 'fs/libfs.c') diff --git a/fs/libfs.c b/fs/libfs.c index 6e8d17e1dc4c..cd88abdcb436 100644 --- a/fs/libfs.c +++ b/fs/libfs.c @@ -370,40 +370,51 @@ int simple_write_begin(struct file *file, struct address_space *mapping, return simple_prepare_write(file, page, from, from+len); } -static int simple_commit_write(struct file *file, struct page *page, - unsigned from, unsigned to) -{ - struct inode *inode = page->mapping->host; - loff_t pos = ((loff_t)page->index << PAGE_CACHE_SHIFT) + to; - - if (!PageUptodate(page)) - SetPageUptodate(page); - /* - * No need to use i_size_read() here, the i_size - * cannot change under us because we hold the i_mutex. - */ - if (pos > inode->i_size) - i_size_write(inode, pos); - set_page_dirty(page); - return 0; -} - +/** + * simple_write_end - .write_end helper for non-block-device FSes + * @available: See .write_end of address_space_operations + * @file: " + * @mapping: " + * @pos: " + * @len: " + * @copied: " + * @page: " + * @fsdata: " + * + * simple_write_end does the minimum needed for updating a page after writing is + * done. It has the same API signature as the .write_end of + * address_space_operations vector. So it can just be set onto .write_end for + * FSes that don't need any other processing. i_mutex is assumed to be held. + * Block based filesystems should use generic_write_end(). + * NOTE: Even though i_size might get updated by this function, mark_inode_dirty + * is not called, so a filesystem that actually does store data in .write_inode + * should extend on what's done here with a call to mark_inode_dirty() in the + * case that i_size has changed. + */ int simple_write_end(struct file *file, struct address_space *mapping, loff_t pos, unsigned len, unsigned copied, struct page *page, void *fsdata) { - unsigned from = pos & (PAGE_CACHE_SIZE - 1); + struct inode *inode = page->mapping->host; + loff_t last_pos = pos + copied; /* zero the stale part of the page if we did a short copy */ if (copied < len) { - void *kaddr = kmap_atomic(page, KM_USER0); - memset(kaddr + from + copied, 0, len - copied); - flush_dcache_page(page); - kunmap_atomic(kaddr, KM_USER0); + unsigned from = pos & (PAGE_CACHE_SIZE - 1); + + zero_user(page, from + copied, len - copied); } - simple_commit_write(file, page, from, from+copied); + if (!PageUptodate(page)) + SetPageUptodate(page); + /* + * No need to use i_size_read() here, the i_size + * cannot change under us because we hold the i_mutex. + */ + if (last_pos > inode->i_size) + i_size_write(inode, last_pos); + set_page_dirty(page); unlock_page(page); page_cache_release(page); -- cgit v1.2.3-59-g8ed1b From 193cf4b99113a4550598ba9e8343e591fc062e23 Mon Sep 17 00:00:00 2001 From: Boaz Harrosh Date: Tue, 12 Jan 2010 16:18:08 +0200 Subject: libfs: Unexport and kill simple_prepare_write Remove the EXPORT_UNUSED_SYMBOL of simple_prepare_write Collapse simple_prepare_write into it's only caller, though making it simpler and clearer to understand. Signed-off-by: Boaz Harrosh Signed-off-by: Al Viro --- fs/libfs.c | 22 ++++++---------------- include/linux/fs.h | 2 -- 2 files changed, 6 insertions(+), 18 deletions(-) (limited to 'fs/libfs.c') diff --git a/fs/libfs.c b/fs/libfs.c index cd88abdcb436..9e50bcf55857 100644 --- a/fs/libfs.c +++ b/fs/libfs.c @@ -338,28 +338,14 @@ int simple_readpage(struct file *file, struct page *page) return 0; } -int simple_prepare_write(struct file *file, struct page *page, - unsigned from, unsigned to) -{ - if (!PageUptodate(page)) { - if (to - from != PAGE_CACHE_SIZE) - zero_user_segments(page, - 0, from, - to, PAGE_CACHE_SIZE); - } - return 0; -} - int simple_write_begin(struct file *file, struct address_space *mapping, loff_t pos, unsigned len, unsigned flags, struct page **pagep, void **fsdata) { struct page *page; pgoff_t index; - unsigned from; index = pos >> PAGE_CACHE_SHIFT; - from = pos & (PAGE_CACHE_SIZE - 1); page = grab_cache_page_write_begin(mapping, index, flags); if (!page) @@ -367,7 +353,12 @@ int simple_write_begin(struct file *file, struct address_space *mapping, *pagep = page; - return simple_prepare_write(file, page, from, from+len); + if (!PageUptodate(page) && (len != PAGE_CACHE_SIZE)) { + unsigned from = pos & (PAGE_CACHE_SIZE - 1); + + zero_user_segments(page, 0, from, from + len, PAGE_CACHE_SIZE); + } + return 0; } /** @@ -864,7 +855,6 @@ EXPORT_SYMBOL(simple_getattr); EXPORT_SYMBOL(simple_link); EXPORT_SYMBOL(simple_lookup); EXPORT_SYMBOL(simple_pin_fs); -EXPORT_UNUSED_SYMBOL(simple_prepare_write); EXPORT_SYMBOL(simple_readpage); EXPORT_SYMBOL(simple_release_fs); EXPORT_SYMBOL(simple_rename); diff --git a/include/linux/fs.h b/include/linux/fs.h index ebb1cd5bc241..2b124c825e38 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -2340,8 +2340,6 @@ extern int simple_rename(struct inode *, struct dentry *, struct inode *, struct extern int simple_sync_file(struct file *, struct dentry *, int); extern int simple_empty(struct dentry *); extern int simple_readpage(struct file *file, struct page *page); -extern int simple_prepare_write(struct file *file, struct page *page, - unsigned offset, unsigned to); extern int simple_write_begin(struct file *file, struct address_space *mapping, loff_t pos, unsigned len, unsigned flags, struct page **pagep, void **fsdata); -- cgit v1.2.3-59-g8ed1b