[PATCH 02/25] iov_iter: Use accessor function [ver #2]

From: David Howells
Date: Tue Oct 23 2018 - 19:58:02 EST

Use accessor functions to access an iterator's type and direction. This
allows for the possibility of using some other method of determining the
type of iterator than if-chains with bitwise-AND conditions.

Signed-off-by: David Howells <dhowells@xxxxxxxxxx>
---

block/bio.c | 2 +-
fs/block_dev.c | 2 +-
fs/ceph/file.c | 2 +-
fs/cifs/file.c | 4 ++--
fs/cifs/misc.c | 2 +-
fs/cifs/smbdirect.c | 17 +++++++++++----
fs/direct-io.c | 2 +-
fs/fuse/file.c | 2 +-
fs/iomap.c | 2 +-
include/linux/uio.h | 48 +++++++++++++++++++++++++++++-------------
lib/iov_iter.c | 56 +++++++++++++++++++++++++------------------------
mm/filemap.c | 2 +-
net/9p/trans_virtio.c | 2 +-
net/tls/tls_sw.c | 4 ++--
14 files changed, 87 insertions(+), 60 deletions(-)

diff --git a/block/bio.c b/block/bio.c
index 0093bed81c0e..c55f36bbe12a 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -1255,7 +1255,7 @@ struct bio *bio_copy_user_iov(struct request_queue *q,
/*
* success
*/
- if (((iter->type & WRITE) && (!map_data || !map_data->null_mapped)) ||
+ if ((iov_iter_rw(iter) == WRITE && (!map_data || !map_data->null_mapped)) ||
(map_data && map_data->from_user)) {
ret = bio_copy_from_iter(bio, iter);
if (ret)
diff --git a/fs/block_dev.c b/fs/block_dev.c
index 38b8ce05cbc7..a80b4f0ee7c4 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -349,7 +349,7 @@ __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter, int nr_pages)

dio->size = 0;
dio->multi_bio = false;
- dio->should_dirty = is_read && (iter->type == ITER_IOVEC);
+ dio->should_dirty = is_read && iter_is_iovec(iter);

blk_start_plug(&plug);
for (;;) {
diff --git a/fs/ceph/file.c b/fs/ceph/file.c
index 92ab20433682..524ecc95b04d 100644
--- a/fs/ceph/file.c
+++ b/fs/ceph/file.c
@@ -658,7 +658,7 @@ static ssize_t ceph_sync_read(struct kiocb *iocb, struct iov_iter *to,
if (ret < 0)
return ret;

- if (unlikely(to->type & ITER_PIPE)) {
+ if (unlikely(iov_iter_is_pipe(to))) {
size_t page_off;
ret = iov_iter_get_pages_alloc(to, &pages, len,
&page_off);
diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index 8d41ca7bfcf1..dcdbcb6f09f8 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -2990,7 +2990,7 @@ cifs_readdata_to_iov(struct cifs_readdata *rdata, struct iov_iter *iter)
size_t copy = min_t(size_t, remaining, PAGE_SIZE);
size_t written;

- if (unlikely(iter->type & ITER_PIPE)) {
+ if (unlikely(iov_iter_is_pipe(iter))) {
void *addr = kmap_atomic(page);

written = copy_to_iter(addr, copy, iter);
@@ -3302,7 +3302,7 @@ ssize_t cifs_user_readv(struct kiocb *iocb, struct iov_iter *to)
if (!is_sync_kiocb(iocb))
ctx->iocb = iocb;

- if (to->type == ITER_IOVEC)
+ if (iter_is_iovec(to))
ctx->should_dirty = true;

rc = setup_aio_ctx_iter(ctx, to, READ);
diff --git a/fs/cifs/misc.c b/fs/cifs/misc.c
index 6926685e513c..7b5b960a04b8 100644
--- a/fs/cifs/misc.c
+++ b/fs/cifs/misc.c
@@ -786,7 +786,7 @@ setup_aio_ctx_iter(struct cifs_aio_ctx *ctx, struct iov_iter *iter, int rw)
struct page **pages = NULL;
struct bio_vec *bv = NULL;

- if (iter->type & ITER_KVEC) {
+ if (iov_iter_is_kvec(iter)) {
memcpy(&ctx->iter, iter, sizeof(struct iov_iter));
ctx->len = count;
iov_iter_advance(iter, count);
diff --git a/fs/cifs/smbdirect.c b/fs/cifs/smbdirect.c
index 5fdb9a509a97..5b05bf255268 100644
--- a/fs/cifs/smbdirect.c
+++ b/fs/cifs/smbdirect.c
@@ -2054,14 +2054,22 @@ int smbd_recv(struct smbd_connection *info, struct msghdr *msg)

info->smbd_recv_pending++;

- switch (msg->msg_iter.type) {
- case READ | ITER_KVEC:
+ if (iov_iter_rw(&msg->msg_iter) == WRITE) {
+ /* It's a bug in upper layer to get there */
+ cifs_dbg(VFS, "CIFS: invalid msg iter dir %u\n",
+ iov_iter_rw(&msg->msg_iter));
+ rc = -EINVAL;
+ goto out;
+ }
+
+ switch (iov_iter_type(&msg->msg_iter)) {
+ case ITER_KVEC:
buf = msg->msg_iter.kvec->iov_base;
to_read = msg->msg_iter.kvec->iov_len;
rc = smbd_recv_buf(info, buf, to_read);
break;

- case READ | ITER_BVEC:
+ case ITER_BVEC:
page = msg->msg_iter.bvec->bv_page;
page_offset = msg->msg_iter.bvec->bv_offset;
to_read = msg->msg_iter.bvec->bv_len;
@@ -2071,10 +2079,11 @@ int smbd_recv(struct smbd_connection *info, struct msghdr *msg)
default:
/* It's a bug in upper layer to get there */
cifs_dbg(VFS, "CIFS: invalid msg type %d\n",
- msg->msg_iter.type);
+ iov_iter_type(&msg->msg_iter));
rc = -EINVAL;
}

+out:
info->smbd_recv_pending--;
wake_up(&info->wait_smbd_recv_pending);

diff --git a/fs/direct-io.c b/fs/direct-io.c
index 093fb54cd316..722d17c88edb 100644
--- a/fs/direct-io.c
+++ b/fs/direct-io.c
@@ -1313,7 +1313,7 @@ do_blockdev_direct_IO(struct kiocb *iocb, struct inode *inode,
spin_lock_init(&dio->bio_lock);
dio->refcount = 1;

- dio->should_dirty = (iter->type == ITER_IOVEC);
+ dio->should_dirty = iter_is_iovec(iter) && iov_iter_rw(iter) == READ;
sdio.iter = iter;
sdio.final_block_in_request = end >> blkbits;

diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index 32d0b883e74f..c9ccd45156dc 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -1271,7 +1271,7 @@ static int fuse_get_user_pages(struct fuse_req *req, struct iov_iter *ii,
ssize_t ret = 0;

/* Special case for kernel I/O: can copy directly into the buffer */
- if (ii->type & ITER_KVEC) {
+ if (iov_iter_is_kvec(ii)) {
unsigned long user_addr = fuse_get_user_addr(ii);
size_t frag_size = fuse_get_frag_size(ii, *nbytesp);

diff --git a/fs/iomap.c b/fs/iomap.c
index ec15cf2ec696..2c53400aa802 100644
--- a/fs/iomap.c
+++ b/fs/iomap.c
@@ -1795,7 +1795,7 @@ iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
if (pos >= dio->i_size)
goto out_free_dio;

- if (iter->type == ITER_IOVEC)
+ if (iter_is_iovec(iter) && iov_iter_rw(iter) == READ)
dio->flags |= IOMAP_DIO_DIRTY;
} else {
flags |= IOMAP_WRITE;
diff --git a/include/linux/uio.h b/include/linux/uio.h
index 422b1c01ee0d..fcabc959c794 100644
--- a/include/linux/uio.h
+++ b/include/linux/uio.h
@@ -21,7 +21,7 @@ struct kvec {
size_t iov_len;
};

-enum {
+enum iter_type {
ITER_IOVEC = 0,
ITER_KVEC = 2,
ITER_BVEC = 4,
@@ -47,6 +47,36 @@ struct iov_iter {
};
};

+static inline enum iter_type iov_iter_type(const struct iov_iter *i)
+{
+ return i->type & ~(READ | WRITE);
+}
+
+static inline bool iter_is_iovec(const struct iov_iter *i)
+{
+ return iov_iter_type(i) == ITER_IOVEC;
+}
+
+static inline bool iov_iter_is_kvec(const struct iov_iter *i)
+{
+ return iov_iter_type(i) == ITER_KVEC;
+}
+
+static inline bool iov_iter_is_bvec(const struct iov_iter *i)
+{
+ return iov_iter_type(i) == ITER_BVEC;
+}
+
+static inline bool iov_iter_is_pipe(const struct iov_iter *i)
+{
+ return iov_iter_type(i) == ITER_PIPE;
+}
+
+static inline unsigned char iov_iter_rw(const struct iov_iter *i)
+{
+ return i->type & (READ | WRITE);
+}
+
/*
* Total number of bytes covered by an iovec.
*
@@ -74,7 +104,8 @@ static inline struct iovec iov_iter_iovec(const struct iov_iter *iter)
}

#define iov_for_each(iov, iter, start) \
- if (!((start).type & (ITER_BVEC | ITER_PIPE))) \
+ if (iov_iter_type(start) == ITER_IOVEC || \
+ iov_iter_type(start) == ITER_KVEC) \
for (iter = (start); \
(iter).count && \
((iov = iov_iter_iovec(&(iter))), 1); \
@@ -202,19 +233,6 @@ static inline size_t iov_iter_count(const struct iov_iter *i)
return i->count;
}

-static inline bool iter_is_iovec(const struct iov_iter *i)
-{
- return !(i->type & (ITER_BVEC | ITER_KVEC | ITER_PIPE));
-}
-
-/*
- * Get one of READ or WRITE out of iter->type without any other flags OR'd in
- * with it.
- *
- * The ?: is just for type safety.
- */
-#define iov_iter_rw(i) ((0 ? (struct iov_iter *)0 : (i))->type & (READ | WRITE))
-
/*
* Cap the iov_iter by given limit; note that the second argument is
* *not* the new size - it's upper limit for such. Passing it a value
diff --git a/lib/iov_iter.c b/lib/iov_iter.c
index 8be175df3075..42d39116a556 100644
--- a/lib/iov_iter.c
+++ b/lib/iov_iter.c
@@ -558,7 +558,7 @@ static size_t copy_pipe_to_iter(const void *addr, size_t bytes,
size_t _copy_to_iter(const void *addr, size_t bytes, struct iov_iter *i)
{
const char *from = addr;
- if (unlikely(i->type & ITER_PIPE))
+ if (unlikely(iov_iter_is_pipe(i)))
return copy_pipe_to_iter(addr, bytes, i);
if (iter_is_iovec(i))
might_fault();
@@ -658,7 +658,7 @@ size_t _copy_to_iter_mcsafe(const void *addr, size_t bytes, struct iov_iter *i)
const char *from = addr;
unsigned long rem, curr_addr, s_addr = (unsigned long) addr;

- if (unlikely(i->type & ITER_PIPE))
+ if (unlikely(iov_iter_is_pipe(i)))
return copy_pipe_to_iter_mcsafe(addr, bytes, i);
if (iter_is_iovec(i))
might_fault();
@@ -692,7 +692,7 @@ EXPORT_SYMBOL_GPL(_copy_to_iter_mcsafe);
size_t _copy_from_iter(void *addr, size_t bytes, struct iov_iter *i)
{
char *to = addr;
- if (unlikely(i->type & ITER_PIPE)) {
+ if (unlikely(iov_iter_is_pipe(i))) {
WARN_ON(1);
return 0;
}
@@ -712,7 +712,7 @@ EXPORT_SYMBOL(_copy_from_iter);
bool _copy_from_iter_full(void *addr, size_t bytes, struct iov_iter *i)
{
char *to = addr;
- if (unlikely(i->type & ITER_PIPE)) {
+ if (unlikely(iov_iter_is_pipe(i))) {
WARN_ON(1);
return false;
}
@@ -739,7 +739,7 @@ EXPORT_SYMBOL(_copy_from_iter_full);
size_t _copy_from_iter_nocache(void *addr, size_t bytes, struct iov_iter *i)
{
char *to = addr;
- if (unlikely(i->type & ITER_PIPE)) {
+ if (unlikely(iov_iter_is_pipe(i))) {
WARN_ON(1);
return 0;
}
@@ -773,7 +773,7 @@ EXPORT_SYMBOL(_copy_from_iter_nocache);
size_t _copy_from_iter_flushcache(void *addr, size_t bytes, struct iov_iter *i)
{
char *to = addr;
- if (unlikely(i->type & ITER_PIPE)) {
+ if (unlikely(iov_iter_is_pipe(i))) {
WARN_ON(1);
return 0;
}
@@ -794,7 +794,7 @@ EXPORT_SYMBOL_GPL(_copy_from_iter_flushcache);
bool _copy_from_iter_full_nocache(void *addr, size_t bytes, struct iov_iter *i)
{
char *to = addr;
- if (unlikely(i->type & ITER_PIPE)) {
+ if (unlikely(iov_iter_is_pipe(i))) {
WARN_ON(1);
return false;
}
@@ -836,7 +836,7 @@ size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes,
size_t wanted = copy_to_iter(kaddr + offset, bytes, i);
kunmap_atomic(kaddr);
return wanted;
- } else if (likely(!(i->type & ITER_PIPE)))
+ } else if (likely(!iov_iter_is_pipe(i)))
return copy_page_to_iter_iovec(page, offset, bytes, i);
else
return copy_page_to_iter_pipe(page, offset, bytes, i);
@@ -848,7 +848,7 @@ size_t copy_page_from_iter(struct page *page, size_t offset, size_t bytes,
{
if (unlikely(!page_copy_sane(page, offset, bytes)))
return 0;
- if (unlikely(i->type & ITER_PIPE)) {
+ if (unlikely(iov_iter_is_pipe(i))) {
WARN_ON(1);
return 0;
}
@@ -888,7 +888,7 @@ static size_t pipe_zero(size_t bytes, struct iov_iter *i)

size_t iov_iter_zero(size_t bytes, struct iov_iter *i)
{
- if (unlikely(i->type & ITER_PIPE))
+ if (unlikely(iov_iter_is_pipe(i)))
return pipe_zero(bytes, i);
iterate_and_advance(i, bytes, v,
clear_user(v.iov_base, v.iov_len),
@@ -908,7 +908,7 @@ size_t iov_iter_copy_from_user_atomic(struct page *page,
kunmap_atomic(kaddr);
return 0;
}
- if (unlikely(i->type & ITER_PIPE)) {
+ if (unlikely(iov_iter_is_pipe(i))) {
kunmap_atomic(kaddr);
WARN_ON(1);
return 0;
@@ -972,7 +972,7 @@ static void pipe_advance(struct iov_iter *i, size_t size)

void iov_iter_advance(struct iov_iter *i, size_t size)
{
- if (unlikely(i->type & ITER_PIPE)) {
+ if (unlikely(iov_iter_is_pipe(i))) {
pipe_advance(i, size);
return;
}
@@ -987,7 +987,7 @@ void iov_iter_revert(struct iov_iter *i, size_t unroll)
if (WARN_ON(unroll > MAX_RW_COUNT))
return;
i->count += unroll;
- if (unlikely(i->type & ITER_PIPE)) {
+ if (unlikely(iov_iter_is_pipe(i))) {
struct pipe_inode_info *pipe = i->pipe;
int idx = i->idx;
size_t off = i->iov_offset;
@@ -1016,7 +1016,7 @@ void iov_iter_revert(struct iov_iter *i, size_t unroll)
return;
}
unroll -= i->iov_offset;
- if (i->type & ITER_BVEC) {
+ if (iov_iter_is_bvec(i)) {
const struct bio_vec *bvec = i->bvec;
while (1) {
size_t n = (--bvec)->bv_len;
@@ -1049,11 +1049,11 @@ EXPORT_SYMBOL(iov_iter_revert);
*/
size_t iov_iter_single_seg_count(const struct iov_iter *i)
{
- if (unlikely(i->type & ITER_PIPE))
+ if (unlikely(iov_iter_is_pipe(i)))
return i->count; // it is a silly place, anyway
if (i->nr_segs == 1)
return i->count;
- else if (i->type & ITER_BVEC)
+ else if (iov_iter_is_bvec(i))
return min(i->count, i->bvec->bv_len - i->iov_offset);
else
return min(i->count, i->iov->iov_len - i->iov_offset);
@@ -1106,7 +1106,7 @@ unsigned long iov_iter_alignment(const struct iov_iter *i)
unsigned long res = 0;
size_t size = i->count;

- if (unlikely(i->type & ITER_PIPE)) {
+ if (unlikely(iov_iter_is_pipe(i))) {
if (size && i->iov_offset && allocated(&i->pipe->bufs[i->idx]))
return size | i->iov_offset;
return size;
@@ -1125,7 +1125,7 @@ unsigned long iov_iter_gap_alignment(const struct iov_iter *i)
unsigned long res = 0;
size_t size = i->count;

- if (unlikely(i->type & ITER_PIPE)) {
+ if (unlikely(iov_iter_is_pipe(i))) {
WARN_ON(1);
return ~0U;
}
@@ -1193,7 +1193,7 @@ ssize_t iov_iter_get_pages(struct iov_iter *i,
if (maxsize > i->count)
maxsize = i->count;

- if (unlikely(i->type & ITER_PIPE))
+ if (unlikely(iov_iter_is_pipe(i)))
return pipe_get_pages(i, pages, maxsize, maxpages, start);
iterate_all_kinds(i, maxsize, v, ({
unsigned long addr = (unsigned long)v.iov_base;
@@ -1205,7 +1205,7 @@ ssize_t iov_iter_get_pages(struct iov_iter *i,
len = maxpages * PAGE_SIZE;
addr &= ~(PAGE_SIZE - 1);
n = DIV_ROUND_UP(len, PAGE_SIZE);
- res = get_user_pages_fast(addr, n, (i->type & WRITE) != WRITE, pages);
+ res = get_user_pages_fast(addr, n, iov_iter_rw(i) != WRITE, pages);
if (unlikely(res < 0))
return res;
return (res == n ? len : res * PAGE_SIZE) - *start;
@@ -1270,7 +1270,7 @@ ssize_t iov_iter_get_pages_alloc(struct iov_iter *i,
if (maxsize > i->count)
maxsize = i->count;

- if (unlikely(i->type & ITER_PIPE))
+ if (unlikely(iov_iter_is_pipe(i)))
return pipe_get_pages_alloc(i, pages, maxsize, start);
iterate_all_kinds(i, maxsize, v, ({
unsigned long addr = (unsigned long)v.iov_base;
@@ -1283,7 +1283,7 @@ ssize_t iov_iter_get_pages_alloc(struct iov_iter *i,
p = get_pages_array(n);
if (!p)
return -ENOMEM;
- res = get_user_pages_fast(addr, n, (i->type & WRITE) != WRITE, p);
+ res = get_user_pages_fast(addr, n, iov_iter_rw(i) != WRITE, p);
if (unlikely(res < 0)) {
kvfree(p);
return res;
@@ -1313,7 +1313,7 @@ size_t csum_and_copy_from_iter(void *addr, size_t bytes, __wsum *csum,
__wsum sum, next;
size_t off = 0;
sum = *csum;
- if (unlikely(i->type & ITER_PIPE)) {
+ if (unlikely(iov_iter_is_pipe(i))) {
WARN_ON(1);
return 0;
}
@@ -1355,7 +1355,7 @@ bool csum_and_copy_from_iter_full(void *addr, size_t bytes, __wsum *csum,
__wsum sum, next;
size_t off = 0;
sum = *csum;
- if (unlikely(i->type & ITER_PIPE)) {
+ if (unlikely(iov_iter_is_pipe(i))) {
WARN_ON(1);
return false;
}
@@ -1400,7 +1400,7 @@ size_t csum_and_copy_to_iter(const void *addr, size_t bytes, __wsum *csum,
__wsum sum, next;
size_t off = 0;
sum = *csum;
- if (unlikely(i->type & ITER_PIPE)) {
+ if (unlikely(iov_iter_is_pipe(i))) {
WARN_ON(1); /* for now */
return 0;
}
@@ -1443,7 +1443,7 @@ int iov_iter_npages(const struct iov_iter *i, int maxpages)
if (!size)
return 0;

- if (unlikely(i->type & ITER_PIPE)) {
+ if (unlikely(iov_iter_is_pipe(i))) {
struct pipe_inode_info *pipe = i->pipe;
size_t off;
int idx;
@@ -1481,11 +1481,11 @@ EXPORT_SYMBOL(iov_iter_npages);
const void *dup_iter(struct iov_iter *new, struct iov_iter *old, gfp_t flags)
{
*new = *old;
- if (unlikely(new->type & ITER_PIPE)) {
+ if (unlikely(iov_iter_is_pipe(new))) {
WARN_ON(1);
return NULL;
}
- if (new->type & ITER_BVEC)
+ if (iov_iter_is_bvec(new))
return new->bvec = kmemdup(new->bvec,
new->nr_segs * sizeof(struct bio_vec),
flags);
diff --git a/mm/filemap.c b/mm/filemap.c
index 52517f28e6f4..bdeee0168ea7 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -2122,7 +2122,7 @@ static ssize_t generic_file_buffered_read(struct kiocb *iocb,
!mapping->a_ops->is_partially_uptodate)
goto page_not_up_to_date;
/* pipes can't handle partially uptodate pages */
- if (unlikely(iter->type & ITER_PIPE))
+ if (unlikely(iov_iter_is_pipe(iter)))
goto page_not_up_to_date;
if (!trylock_page(page))
goto page_not_up_to_date;
diff --git a/net/9p/trans_virtio.c b/net/9p/trans_virtio.c
index 7728b0acde09..4d7d2070e9c8 100644
--- a/net/9p/trans_virtio.c
+++ b/net/9p/trans_virtio.c
@@ -322,7 +322,7 @@ static int p9_get_mapped_pages(struct virtio_chan *chan,
if (!iov_iter_count(data))
return 0;

- if (!(data->type & ITER_KVEC)) {
+ if (iov_iter_is_kvec(data)) {
int n;
/*
* We allow only p9_max_pages pinned. We wait for the
diff --git a/net/tls/tls_sw.c b/net/tls/tls_sw.c
index a525fc4c2a4b..ad64b9c8b600 100644
--- a/net/tls/tls_sw.c
+++ b/net/tls/tls_sw.c
@@ -799,7 +799,7 @@ int tls_sw_sendmsg(struct sock *sk, struct msghdr *msg, size_t size)
struct crypto_tfm *tfm = crypto_aead_tfm(ctx->aead_send);
bool async_capable = tfm->__crt_alg->cra_flags & CRYPTO_ALG_ASYNC;
unsigned char record_type = TLS_RECORD_TYPE_DATA;
- bool is_kvec = msg->msg_iter.type & ITER_KVEC;
+ bool is_kvec = iov_iter_is_kvec(&msg->msg_iter);
bool eor = !(msg->msg_flags & MSG_MORE);
size_t try_to_copy, copied = 0;
struct sk_msg *msg_pl, *msg_en;
@@ -1457,7 +1457,7 @@ int tls_sw_recvmsg(struct sock *sk,
bool cmsg = false;
int target, err = 0;
long timeo;
- bool is_kvec = msg->msg_iter.type & ITER_KVEC;
+ bool is_kvec = iov_iter_is_kvec(&msg->msg_iter);
int num_async = 0;

flags |= nonblock;