From ed978a811ec528dbe40243605c3afab55892f722 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Wed, 5 Mar 2014 22:53:04 -0500 Subject: [PATCH] new helper: generic_file_read_iter() iov_iter-using variant of generic_file_aio_read(). Some callers converted. Note that it's still not quite there for use as ->read_iter() - we depend on having zero iter->iov_offset in O_DIRECT case. Fortunately, that's true for all converted callers (and for generic_file_aio_read() itself). Signed-off-by: Al Viro --- fs/ceph/file.c | 15 +---------- fs/nfs/file.c | 2 +- include/linux/fs.h | 1 + mm/filemap.c | 67 +++++++++++++++++++++++----------------------- 4 files changed, 37 insertions(+), 48 deletions(-) diff --git a/fs/ceph/file.c b/fs/ceph/file.c index d8f383d59449..910a3022eb27 100644 --- a/fs/ceph/file.c +++ b/fs/ceph/file.c @@ -833,24 +833,11 @@ static ssize_t ceph_aio_read(struct kiocb *iocb, const struct iovec *iov, /* hmm, this isn't really async... */ ret = ceph_sync_read(iocb, &i, &checkeof); } else { - /* - * We can't modify the content of iov, - * so we only read from beginning. - * - * When we switch generic_file_aio_read() to iov_iter, the - * if () below will be removed -- AV - */ - if (read) { - iocb->ki_pos = pos; - len = iocb->ki_nbytes; - read = 0; - iov_iter_init(&i, iov, nr_segs, len, 0); - } dout("aio_read %p %llx.%llx %llu~%u got cap refs on %s\n", inode, ceph_vinop(inode), pos, (unsigned)len, ceph_cap_string(got)); - ret = generic_file_aio_read(iocb, iov, nr_segs, pos); + ret = generic_file_read_iter(iocb, &i); } dout("aio_read %p %llx.%llx dropping cap refs on %s = %d\n", inode, ceph_vinop(inode), ceph_cap_string(got), (int)ret); diff --git a/fs/nfs/file.c b/fs/nfs/file.c index 3d01b152894e..a352bc6d613f 100644 --- a/fs/nfs/file.c +++ b/fs/nfs/file.c @@ -184,7 +184,7 @@ nfs_file_read(struct kiocb *iocb, const struct iovec *iov, result = nfs_revalidate_mapping(inode, iocb->ki_filp->f_mapping); if (!result) { - result = generic_file_aio_read(iocb, iov, nr_segs, pos); + result = generic_file_read_iter(iocb, &to); if (result > 0) nfs_add_stats(inode, NFSIOS_NORMALREADBYTES, result); } diff --git a/include/linux/fs.h b/include/linux/fs.h index 946a9484844f..d096ebc7f348 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -2404,6 +2404,7 @@ extern int generic_file_remap_pages(struct vm_area_struct *, unsigned long addr, unsigned long size, pgoff_t pgoff); int generic_write_checks(struct file *file, loff_t *pos, size_t *count, int isblk); extern ssize_t generic_file_aio_read(struct kiocb *, const struct iovec *, unsigned long, loff_t); +extern ssize_t generic_file_read_iter(struct kiocb *, struct iov_iter *); extern ssize_t __generic_file_aio_write(struct kiocb *, const struct iovec *, unsigned long); extern ssize_t generic_file_aio_write(struct kiocb *, const struct iovec *, unsigned long, loff_t); extern ssize_t generic_file_direct_write(struct kiocb *, struct iov_iter *, diff --git a/mm/filemap.c b/mm/filemap.c index 866f4ae8223b..a7f79e90209c 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -1663,55 +1663,34 @@ static ssize_t do_generic_file_read(struct file *filp, loff_t *ppos, return written ? written : error; } -/** - * generic_file_aio_read - generic filesystem read routine - * @iocb: kernel I/O control block - * @iov: io vector request - * @nr_segs: number of segments in the iovec - * @pos: current file position - * - * This is the "read()" routine for all filesystems - * that can use the page cache directly. - */ ssize_t -generic_file_aio_read(struct kiocb *iocb, const struct iovec *iov, - unsigned long nr_segs, loff_t pos) +generic_file_read_iter(struct kiocb *iocb, struct iov_iter *iter) { - struct file *filp = iocb->ki_filp; + struct file *file = iocb->ki_filp; ssize_t retval = 0; - size_t count; loff_t *ppos = &iocb->ki_pos; - struct iov_iter i; - - count = iov_length(iov, nr_segs); - iov_iter_init(&i, iov, nr_segs, count, 0); + loff_t pos = *ppos; /* coalesce the iovecs and go direct-to-BIO for O_DIRECT */ - if (filp->f_flags & O_DIRECT) { + if (file->f_flags & O_DIRECT) { + struct address_space *mapping = file->f_mapping; + struct inode *inode = mapping->host; + size_t count = iov_iter_count(iter); loff_t size; - struct address_space *mapping; - struct inode *inode; - mapping = filp->f_mapping; - inode = mapping->host; if (!count) goto out; /* skip atime */ size = i_size_read(inode); retval = filemap_write_and_wait_range(mapping, pos, pos + count - 1); if (!retval) { - struct iov_iter data = i; + struct iov_iter data = *iter; retval = mapping->a_ops->direct_IO(READ, iocb, &data, pos); } if (retval > 0) { *ppos = pos + retval; - count -= retval; - /* - * If we did a short DIO read we need to skip the - * section of the iov that we've already read data into. - */ - iov_iter_advance(&i, retval); + iov_iter_advance(iter, retval); } /* @@ -1722,16 +1701,38 @@ generic_file_aio_read(struct kiocb *iocb, const struct iovec *iov, * and return. Otherwise fallthrough to buffered io for * the rest of the read. */ - if (retval < 0 || !count || *ppos >= size) { - file_accessed(filp); + if (retval < 0 || !iov_iter_count(iter) || *ppos >= size) { + file_accessed(file); goto out; } } - retval = do_generic_file_read(filp, ppos, &i, retval); + retval = do_generic_file_read(file, ppos, iter, retval); out: return retval; } +EXPORT_SYMBOL(generic_file_read_iter); + +/** + * generic_file_aio_read - generic filesystem read routine + * @iocb: kernel I/O control block + * @iov: io vector request + * @nr_segs: number of segments in the iovec + * @pos: current file position + * + * This is the "read()" routine for all filesystems + * that can use the page cache directly. + */ +ssize_t +generic_file_aio_read(struct kiocb *iocb, const struct iovec *iov, + unsigned long nr_segs, loff_t pos) +{ + size_t count = iov_length(iov, nr_segs); + struct iov_iter i; + + iov_iter_init(&i, iov, nr_segs, count, 0); + return generic_file_read_iter(iocb, &i); +} EXPORT_SYMBOL(generic_file_aio_read); #ifdef CONFIG_MMU -- GitLab