[RFC v2 1/5] Prepare for adding a new readv/writev with user flags.

From: Milosz Tanski
Date: Wed Sep 17 2014 - 18:22:27 EST


Plumbing the flags argument through the vfs code so they can be passed down to
__generic_file_(read/write)_iter function that do the acctual work.

Signed-off-by: Milosz Tanski <milosz@xxxxxxxxx>
---
drivers/target/target_core_file.c | 6 +++---
fs/nfsd/vfs.c | 4 ++--
fs/read_write.c | 28 ++++++++++++++++------------
fs/splice.c | 2 +-
include/linux/aio.h | 2 ++
include/linux/fs.h | 4 ++--
mm/filemap.c | 2 +-
7 files changed, 27 insertions(+), 21 deletions(-)

diff --git a/drivers/target/target_core_file.c b/drivers/target/target_core_file.c
index 7d6cdda..58d9a6d 100644
--- a/drivers/target/target_core_file.c
+++ b/drivers/target/target_core_file.c
@@ -350,9 +350,9 @@ static int fd_do_rw(struct se_cmd *cmd, struct scatterlist *sgl,
set_fs(get_ds());

if (is_write)
- ret = vfs_writev(fd, &iov[0], sgl_nents, &pos);
+ ret = vfs_writev(fd, &iov[0], sgl_nents, &pos, 0);
else
- ret = vfs_readv(fd, &iov[0], sgl_nents, &pos);
+ ret = vfs_readv(fd, &iov[0], sgl_nents, &pos, 0);

set_fs(old_fs);

@@ -528,7 +528,7 @@ fd_execute_write_same(struct se_cmd *cmd)

old_fs = get_fs();
set_fs(get_ds());
- rc = vfs_writev(f, &iov[0], iov_num, &pos);
+ rc = vfs_writev(f, &iov[0], iov_num, &pos, 0);
set_fs(old_fs);

vfree(iov);
diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
index f501a9b..db7a31d 100644
--- a/fs/nfsd/vfs.c
+++ b/fs/nfsd/vfs.c
@@ -855,7 +855,7 @@ __be32 nfsd_readv(struct file *file, loff_t offset, struct kvec *vec, int vlen,

oldfs = get_fs();
set_fs(KERNEL_DS);
- host_err = vfs_readv(file, (struct iovec __user *)vec, vlen, &offset);
+ host_err = vfs_readv(file, (struct iovec __user *)vec, vlen, &offset, 0);
set_fs(oldfs);
return nfsd_finish_read(file, count, host_err);
}
@@ -943,7 +943,7 @@ nfsd_vfs_write(struct svc_rqst *rqstp, struct svc_fh *fhp, struct file *file,

/* Write the data. */
oldfs = get_fs(); set_fs(KERNEL_DS);
- host_err = vfs_writev(file, (struct iovec __user *)vec, vlen, &pos);
+ host_err = vfs_writev(file, (struct iovec __user *)vec, vlen, &pos, 0);
set_fs(oldfs);
if (host_err < 0)
goto out_nfserr;
diff --git a/fs/read_write.c b/fs/read_write.c
index 009d854..9f6d13d 100644
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -651,7 +651,8 @@ 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)
+ unsigned long nr_segs, size_t len, loff_t *ppos, iter_fn_t fn,
+ int flags)
{
struct kiocb kiocb;
struct iov_iter iter;
@@ -660,6 +661,7 @@ static ssize_t do_iter_readv_writev(struct file *filp, int rw, const struct iove
init_sync_kiocb(&kiocb, filp);
kiocb.ki_pos = *ppos;
kiocb.ki_nbytes = len;
+ kiocb.ki_rwflags = flags;

iov_iter_init(&iter, rw, iov, nr_segs, len);
ret = fn(&kiocb, &iter);
@@ -798,7 +800,8 @@ out:

static ssize_t do_readv_writev(int type, struct file *file,
const struct iovec __user * uvector,
- unsigned long nr_segs, loff_t *pos)
+ unsigned long nr_segs, loff_t *pos,
+ int flags)
{
size_t tot_len;
struct iovec iovstack[UIO_FASTIOV];
@@ -832,7 +835,7 @@ static ssize_t do_readv_writev(int type, struct file *file,

if (iter_fn)
ret = do_iter_readv_writev(file, type, iov, nr_segs, tot_len,
- pos, iter_fn);
+ pos, iter_fn, flags);
else if (fnv)
ret = do_sync_readv_writev(file, iov, nr_segs, tot_len,
pos, fnv);
@@ -855,27 +858,27 @@ out:
}

ssize_t vfs_readv(struct file *file, const struct iovec __user *vec,
- unsigned long vlen, loff_t *pos)
+ unsigned long vlen, loff_t *pos, int flags)
{
if (!(file->f_mode & FMODE_READ))
return -EBADF;
if (!(file->f_mode & FMODE_CAN_READ))
return -EINVAL;

- return do_readv_writev(READ, file, vec, vlen, pos);
+ return do_readv_writev(READ, file, vec, vlen, pos, flags);
}

EXPORT_SYMBOL(vfs_readv);

ssize_t vfs_writev(struct file *file, const struct iovec __user *vec,
- unsigned long vlen, loff_t *pos)
+ unsigned long vlen, loff_t *pos, int flags)
{
if (!(file->f_mode & FMODE_WRITE))
return -EBADF;
if (!(file->f_mode & FMODE_CAN_WRITE))
return -EINVAL;

- return do_readv_writev(WRITE, file, vec, vlen, pos);
+ return do_readv_writev(WRITE, file, vec, vlen, pos, flags);
}

EXPORT_SYMBOL(vfs_writev);
@@ -888,7 +891,7 @@ SYSCALL_DEFINE3(readv, unsigned long, fd, const struct iovec __user *, vec,

if (f.file) {
loff_t pos = file_pos_read(f.file);
- ret = vfs_readv(f.file, vec, vlen, &pos);
+ ret = vfs_readv(f.file, vec, vlen, &pos, 0);
if (ret >= 0)
file_pos_write(f.file, pos);
fdput_pos(f);
@@ -908,7 +911,7 @@ SYSCALL_DEFINE3(writev, unsigned long, fd, const struct iovec __user *, vec,

if (f.file) {
loff_t pos = file_pos_read(f.file);
- ret = vfs_writev(f.file, vec, vlen, &pos);
+ ret = vfs_writev(f.file, vec, vlen, &pos, 0);
if (ret >= 0)
file_pos_write(f.file, pos);
fdput_pos(f);
@@ -940,7 +943,7 @@ SYSCALL_DEFINE5(preadv, unsigned long, fd, const struct iovec __user *, vec,
if (f.file) {
ret = -ESPIPE;
if (f.file->f_mode & FMODE_PREAD)
- ret = vfs_readv(f.file, vec, vlen, &pos);
+ ret = vfs_readv(f.file, vec, vlen, &pos, 0);
fdput(f);
}

@@ -964,7 +967,7 @@ SYSCALL_DEFINE5(pwritev, unsigned long, fd, const struct iovec __user *, vec,
if (f.file) {
ret = -ESPIPE;
if (f.file->f_mode & FMODE_PWRITE)
- ret = vfs_writev(f.file, vec, vlen, &pos);
+ ret = vfs_writev(f.file, vec, vlen, &pos, 0);
fdput(f);
}

@@ -1012,7 +1015,7 @@ static ssize_t compat_do_readv_writev(int type, struct file *file,

if (iter_fn)
ret = do_iter_readv_writev(file, type, iov, nr_segs, tot_len,
- pos, iter_fn);
+ pos, iter_fn, 0);
else if (fnv)
ret = do_sync_readv_writev(file, iov, nr_segs, tot_len,
pos, fnv);
@@ -1111,6 +1114,7 @@ COMPAT_SYSCALL_DEFINE5(preadv, compat_ulong_t, fd,
return __compat_sys_preadv64(fd, vec, vlen, pos);
}

+
static size_t compat_writev(struct file *file,
const struct compat_iovec __user *vec,
unsigned long vlen, loff_t *pos)
diff --git a/fs/splice.c b/fs/splice.c
index f5cb9ba..9591b9f 100644
--- a/fs/splice.c
+++ b/fs/splice.c
@@ -576,7 +576,7 @@ static ssize_t kernel_readv(struct file *file, const struct iovec *vec,
old_fs = get_fs();
set_fs(get_ds());
/* The cast to a user pointer is valid due to the set_fs() */
- res = vfs_readv(file, (const struct iovec __user *)vec, vlen, &pos);
+ res = vfs_readv(file, (const struct iovec __user *)vec, vlen, &pos, 0);
set_fs(old_fs);

return res;
diff --git a/include/linux/aio.h b/include/linux/aio.h
index d9c92da..9c1d499 100644
--- a/include/linux/aio.h
+++ b/include/linux/aio.h
@@ -52,6 +52,8 @@ struct kiocb {
* this is the underlying eventfd context to deliver events to.
*/
struct eventfd_ctx *ki_eventfd;
+
+ int ki_rwflags;
};

static inline bool is_sync_kiocb(struct kiocb *kiocb)
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 9418772..e9bea52 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1556,9 +1556,9 @@ ssize_t rw_copy_check_uvector(int type, const struct iovec __user * uvector,
extern ssize_t vfs_read(struct file *, char __user *, size_t, loff_t *);
extern ssize_t vfs_write(struct file *, const char __user *, size_t, loff_t *);
extern ssize_t vfs_readv(struct file *, const struct iovec __user *,
- unsigned long, loff_t *);
+ unsigned long, loff_t *, int);
extern ssize_t vfs_writev(struct file *, const struct iovec __user *,
- unsigned long, loff_t *);
+ unsigned long, loff_t *, int);

struct super_operations {
struct inode *(*alloc_inode)(struct super_block *sb);
diff --git a/mm/filemap.c b/mm/filemap.c
index 90effcd..6e3ba07 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -1456,7 +1456,7 @@ static void shrink_readahead_size_eio(struct file *filp,
* of the logic when it comes to error handling etc.
*/
static ssize_t do_generic_file_read(struct file *filp, loff_t *ppos,
- struct iov_iter *iter, ssize_t written)
+ struct iov_iter *iter, ssize_t written, int flags)
{
struct address_space *mapping = filp->f_mapping;
struct inode *inode = mapping->host;
--
2.1.0

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