From 293bc9822fa9b3c9d4b7893bcb241e085580771a Mon Sep 17 00:00:00 2001 From: Al Viro Date: Tue, 11 Feb 2014 18:37:41 -0500 Subject: new methods: ->read_iter() and ->write_iter() Beginning to introduce those. Just the callers for now, and it's clumsier than it'll eventually become; once we finish converting aio_read and aio_write instances, the things will get nicer. For now, these guys are in parallel to ->aio_read() and ->aio_write(); they take iocb and iov_iter, with everything in iov_iter already validated. File offset is passed in iocb->ki_pos, iov/nr_segs - in iov_iter. Main concerns in that series are stack footprint and ability to split the damn thing cleanly. [fix from Peter Ujfalusi folded] Signed-off-by: Al Viro --- fs/read_write.c | 90 +++++++++++++++++++++++++++++++++++++++++++++++++++++---- 1 file changed, 85 insertions(+), 5 deletions(-) (limited to 'fs/read_write.c') diff --git a/fs/read_write.c b/fs/read_write.c index d29d2a361d2c..fe2f9d5e3536 100644 --- a/fs/read_write.c +++ b/fs/read_write.c @@ -25,6 +25,7 @@ typedef ssize_t (*io_fn_t)(struct file *, char __user *, size_t, loff_t *); typedef ssize_t (*iov_fn_t)(struct kiocb *, const struct iovec *, unsigned long, loff_t); +typedef ssize_t (*iter_fn_t)(struct kiocb *, struct iov_iter *); const struct file_operations generic_ro_fops = { .llseek = generic_file_llseek, @@ -390,6 +391,27 @@ ssize_t do_sync_read(struct file *filp, char __user *buf, size_t len, loff_t *pp EXPORT_SYMBOL(do_sync_read); +ssize_t new_sync_read(struct file *filp, char __user *buf, size_t len, loff_t *ppos) +{ + struct iovec iov = { .iov_base = buf, .iov_len = len }; + struct kiocb kiocb; + struct iov_iter iter; + ssize_t ret; + + init_sync_kiocb(&kiocb, filp); + kiocb.ki_pos = *ppos; + kiocb.ki_nbytes = len; + iov_iter_init(&iter, READ, &iov, 1, len); + + ret = filp->f_op->read_iter(&kiocb, &iter); + if (-EIOCBQUEUED == ret) + ret = wait_on_sync_kiocb(&kiocb); + *ppos = kiocb.ki_pos; + return ret; +} + +EXPORT_SYMBOL(new_sync_read); + ssize_t vfs_read(struct file *file, char __user *buf, size_t count, loff_t *pos) { ssize_t ret; @@ -406,8 +428,10 @@ ssize_t vfs_read(struct file *file, char __user *buf, size_t count, loff_t *pos) count = ret; if (file->f_op->read) ret = file->f_op->read(file, buf, count, pos); - else + else if (file->f_op->aio_read) ret = do_sync_read(file, buf, count, pos); + else + ret = new_sync_read(file, buf, count, pos); if (ret > 0) { fsnotify_access(file); add_rchar(current, ret); @@ -439,6 +463,27 @@ ssize_t do_sync_write(struct file *filp, const char __user *buf, size_t len, lof EXPORT_SYMBOL(do_sync_write); +ssize_t new_sync_write(struct file *filp, const char __user *buf, size_t len, loff_t *ppos) +{ + struct iovec iov = { .iov_base = (void __user *)buf, .iov_len = len }; + struct kiocb kiocb; + struct iov_iter iter; + ssize_t ret; + + init_sync_kiocb(&kiocb, filp); + kiocb.ki_pos = *ppos; + kiocb.ki_nbytes = len; + iov_iter_init(&iter, WRITE, &iov, 1, len); + + ret = filp->f_op->write_iter(&kiocb, &iter); + if (-EIOCBQUEUED == ret) + ret = wait_on_sync_kiocb(&kiocb); + *ppos = kiocb.ki_pos; + return ret; +} + +EXPORT_SYMBOL(new_sync_write); + ssize_t __kernel_write(struct file *file, const char *buf, size_t count, loff_t *pos) { mm_segment_t old_fs; @@ -455,8 +500,10 @@ ssize_t __kernel_write(struct file *file, const char *buf, size_t count, loff_t count = MAX_RW_COUNT; if (file->f_op->write) ret = file->f_op->write(file, p, count, pos); - else + else if (file->f_op->aio_write) ret = do_sync_write(file, p, count, pos); + else + ret = new_sync_write(file, p, count, pos); set_fs(old_fs); if (ret > 0) { fsnotify_modify(file); @@ -483,8 +530,10 @@ ssize_t vfs_write(struct file *file, const char __user *buf, size_t count, loff_ file_start_write(file); if (file->f_op->write) ret = file->f_op->write(file, buf, count, pos); - else + else if (file->f_op->aio_write) ret = do_sync_write(file, buf, count, pos); + else + ret = new_sync_write(file, buf, count, pos); if (ret > 0) { fsnotify_modify(file); add_wchar(current, ret); @@ -601,6 +650,25 @@ unsigned long iov_shorten(struct iovec *iov, unsigned long nr_segs, size_t to) } EXPORT_SYMBOL(iov_shorten); +static ssize_t do_iter_readv_writev(struct file *filp, int rw, const struct iovec *iov, + unsigned long nr_segs, size_t len, loff_t *ppos, iter_fn_t fn) +{ + struct kiocb kiocb; + struct iov_iter iter; + ssize_t ret; + + init_sync_kiocb(&kiocb, filp); + kiocb.ki_pos = *ppos; + kiocb.ki_nbytes = len; + + iov_iter_init(&iter, rw, iov, nr_segs, len); + ret = fn(&kiocb, &iter); + if (ret == -EIOCBQUEUED) + ret = wait_on_sync_kiocb(&kiocb); + *ppos = kiocb.ki_pos; + return ret; +} + static ssize_t do_sync_readv_writev(struct file *filp, const struct iovec *iov, unsigned long nr_segs, size_t len, loff_t *ppos, iov_fn_t fn) { @@ -738,6 +806,7 @@ static ssize_t do_readv_writev(int type, struct file *file, ssize_t ret; io_fn_t fn; iov_fn_t fnv; + iter_fn_t iter_fn; ret = rw_copy_check_uvector(type, uvector, nr_segs, ARRAY_SIZE(iovstack), iovstack, &iov); @@ -753,13 +822,18 @@ static ssize_t do_readv_writev(int type, struct file *file, if (type == READ) { fn = file->f_op->read; fnv = file->f_op->aio_read; + iter_fn = file->f_op->read_iter; } else { fn = (io_fn_t)file->f_op->write; fnv = file->f_op->aio_write; + iter_fn = file->f_op->write_iter; file_start_write(file); } - if (fnv) + if (iter_fn) + ret = do_iter_readv_writev(file, type, iov, nr_segs, tot_len, + pos, iter_fn); + else if (fnv) ret = do_sync_readv_writev(file, iov, nr_segs, tot_len, pos, fnv); else @@ -912,6 +986,7 @@ static ssize_t compat_do_readv_writev(int type, struct file *file, ssize_t ret; io_fn_t fn; iov_fn_t fnv; + iter_fn_t iter_fn; ret = compat_rw_copy_check_uvector(type, uvector, nr_segs, UIO_FASTIOV, iovstack, &iov); @@ -927,13 +1002,18 @@ static ssize_t compat_do_readv_writev(int type, struct file *file, if (type == READ) { fn = file->f_op->read; fnv = file->f_op->aio_read; + iter_fn = file->f_op->read_iter; } else { fn = (io_fn_t)file->f_op->write; fnv = file->f_op->aio_write; + iter_fn = file->f_op->write_iter; file_start_write(file); } - if (fnv) + if (iter_fn) + ret = do_iter_readv_writev(file, type, iov, nr_segs, tot_len, + pos, iter_fn); + else if (fnv) ret = do_sync_readv_writev(file, iov, nr_segs, tot_len, pos, fnv); else -- cgit v1.2.3-59-g8ed1b