From ae976416464b741913a13eea62eb6953ee065733 Mon Sep 17 00:00:00 2001 From: Hugh Dickins Date: Mon, 4 Jun 2007 10:00:39 +0200 Subject: [PATCH] shmem: convert to using splice instead of sendfile() Remove shmem_file_sendfile and resurrect shmem_readpage, as used by tmpfs to support loop and sendfile in 2.4 and 2.5. Now tmpfs can support splice, loop and sendfile in the simplest way, using generic_file_splice_read and generic_file_splice_write (with the aid of shmem_prepare_write). We could make some efficiency tweaks later, if there's a real need; but this is stable and works well as is. Signed-off-by: Hugh Dickins Signed-off-by: Jens Axboe --- mm/shmem.c | 42 +++++++++++++++++------------------------- 1 file changed, 17 insertions(+), 25 deletions(-) diff --git a/mm/shmem.c b/mm/shmem.c index b6aae2b3339..0493e4d0bca 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -1100,9 +1100,9 @@ static int shmem_getpage(struct inode *inode, unsigned long idx, * Normally, filepage is NULL on entry, and either found * uptodate immediately, or allocated and zeroed, or read * in under swappage, which is then assigned to filepage. - * But shmem_prepare_write passes in a locked filepage, - * which may be found not uptodate by other callers too, - * and may need to be copied from the swappage read in. + * But shmem_readpage and shmem_prepare_write pass in a locked + * filepage, which may be found not uptodate by other callers + * too, and may need to be copied from the swappage read in. */ repeat: if (!filepage) @@ -1485,9 +1485,18 @@ static const struct inode_operations shmem_symlink_inode_operations; static const struct inode_operations shmem_symlink_inline_operations; /* - * Normally tmpfs makes no use of shmem_prepare_write, but it - * lets a tmpfs file be used read-write below the loop driver. + * Normally tmpfs avoids the use of shmem_readpage and shmem_prepare_write; + * but providing them allows a tmpfs file to be used for splice, sendfile, and + * below the loop driver, in the generic fashion that many filesystems support. */ +static int shmem_readpage(struct file *file, struct page *page) +{ + struct inode *inode = page->mapping->host; + int error = shmem_getpage(inode, page->index, &page, SGP_CACHE, NULL); + unlock_page(page); + return error; +} + static int shmem_prepare_write(struct file *file, struct page *page, unsigned offset, unsigned to) { @@ -1711,25 +1720,6 @@ static ssize_t shmem_file_read(struct file *filp, char __user *buf, size_t count return desc.error; } -static ssize_t shmem_file_sendfile(struct file *in_file, loff_t *ppos, - size_t count, read_actor_t actor, void *target) -{ - read_descriptor_t desc; - - if (!count) - return 0; - - desc.written = 0; - desc.count = count; - desc.arg.data = target; - desc.error = 0; - - do_shmem_file_read(in_file, ppos, &desc, actor); - if (desc.written) - return desc.written; - return desc.error; -} - static int shmem_statfs(struct dentry *dentry, struct kstatfs *buf) { struct shmem_sb_info *sbinfo = SHMEM_SB(dentry->d_sb); @@ -2386,6 +2376,7 @@ static const struct address_space_operations shmem_aops = { .writepage = shmem_writepage, .set_page_dirty = __set_page_dirty_no_writeback, #ifdef CONFIG_TMPFS + .readpage = shmem_readpage, .prepare_write = shmem_prepare_write, .commit_write = simple_commit_write, #endif @@ -2399,7 +2390,8 @@ static const struct file_operations shmem_file_operations = { .read = shmem_file_read, .write = shmem_file_write, .fsync = simple_sync_file, - .sendfile = shmem_file_sendfile, + .splice_read = generic_file_splice_read, + .splice_write = generic_file_splice_write, #endif }; -- 2.41.1