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-rw-r--r--fs/splice.c199
1 files changed, 125 insertions, 74 deletions
diff --git a/fs/splice.c b/fs/splice.c
index 98412721f056..f2400ce7d528 100644
--- a/fs/splice.c
+++ b/fs/splice.c
@@ -185,6 +185,9 @@ ssize_t splice_to_pipe(struct pipe_inode_info *pipe,
struct splice_pipe_desc *spd)
{
unsigned int spd_pages = spd->nr_pages;
+ unsigned int tail = pipe->tail;
+ unsigned int head = pipe->head;
+ unsigned int mask = pipe->ring_size - 1;
int ret = 0, page_nr = 0;
if (!spd_pages)
@@ -196,9 +199,8 @@ ssize_t splice_to_pipe(struct pipe_inode_info *pipe,
goto out;
}
- while (pipe->nrbufs < pipe->buffers) {
- int newbuf = (pipe->curbuf + pipe->nrbufs) & (pipe->buffers - 1);
- struct pipe_buffer *buf = pipe->bufs + newbuf;
+ while (!pipe_full(head, tail, pipe->max_usage)) {
+ struct pipe_buffer *buf = &pipe->bufs[head & mask];
buf->page = spd->pages[page_nr];
buf->offset = spd->partial[page_nr].offset;
@@ -207,7 +209,8 @@ ssize_t splice_to_pipe(struct pipe_inode_info *pipe,
buf->ops = spd->ops;
buf->flags = 0;
- pipe->nrbufs++;
+ head++;
+ pipe->head = head;
page_nr++;
ret += buf->len;
@@ -228,17 +231,19 @@ EXPORT_SYMBOL_GPL(splice_to_pipe);
ssize_t add_to_pipe(struct pipe_inode_info *pipe, struct pipe_buffer *buf)
{
+ unsigned int head = pipe->head;
+ unsigned int tail = pipe->tail;
+ unsigned int mask = pipe->ring_size - 1;
int ret;
if (unlikely(!pipe->readers)) {
send_sig(SIGPIPE, current, 0);
ret = -EPIPE;
- } else if (pipe->nrbufs == pipe->buffers) {
+ } else if (pipe_full(head, tail, pipe->max_usage)) {
ret = -EAGAIN;
} else {
- int newbuf = (pipe->curbuf + pipe->nrbufs) & (pipe->buffers - 1);
- pipe->bufs[newbuf] = *buf;
- pipe->nrbufs++;
+ pipe->bufs[head & mask] = *buf;
+ pipe->head = head + 1;
return buf->len;
}
pipe_buf_release(pipe, buf);
@@ -252,14 +257,14 @@ EXPORT_SYMBOL(add_to_pipe);
*/
int splice_grow_spd(const struct pipe_inode_info *pipe, struct splice_pipe_desc *spd)
{
- unsigned int buffers = READ_ONCE(pipe->buffers);
+ unsigned int max_usage = READ_ONCE(pipe->max_usage);
- spd->nr_pages_max = buffers;
- if (buffers <= PIPE_DEF_BUFFERS)
+ spd->nr_pages_max = max_usage;
+ if (max_usage <= PIPE_DEF_BUFFERS)
return 0;
- spd->pages = kmalloc_array(buffers, sizeof(struct page *), GFP_KERNEL);
- spd->partial = kmalloc_array(buffers, sizeof(struct partial_page),
+ spd->pages = kmalloc_array(max_usage, sizeof(struct page *), GFP_KERNEL);
+ spd->partial = kmalloc_array(max_usage, sizeof(struct partial_page),
GFP_KERNEL);
if (spd->pages && spd->partial)
@@ -298,10 +303,11 @@ ssize_t generic_file_splice_read(struct file *in, loff_t *ppos,
{
struct iov_iter to;
struct kiocb kiocb;
- int idx, ret;
+ unsigned int i_head;
+ int ret;
iov_iter_pipe(&to, READ, pipe, len);
- idx = to.idx;
+ i_head = to.head;
init_sync_kiocb(&kiocb, in);
kiocb.ki_pos = *ppos;
ret = call_read_iter(in, &kiocb, &to);
@@ -309,7 +315,7 @@ ssize_t generic_file_splice_read(struct file *in, loff_t *ppos,
*ppos = kiocb.ki_pos;
file_accessed(in);
} else if (ret < 0) {
- to.idx = idx;
+ to.head = i_head;
to.iov_offset = 0;
iov_iter_advance(&to, 0); /* to free what was emitted */
/*
@@ -370,11 +376,12 @@ static ssize_t default_file_splice_read(struct file *in, loff_t *ppos,
struct iov_iter to;
struct page **pages;
unsigned int nr_pages;
+ unsigned int mask;
size_t offset, base, copied = 0;
ssize_t res;
int i;
- if (pipe->nrbufs == pipe->buffers)
+ if (pipe_full(pipe->head, pipe->tail, pipe->max_usage))
return -EAGAIN;
/*
@@ -400,8 +407,9 @@ static ssize_t default_file_splice_read(struct file *in, loff_t *ppos,
}
}
- pipe->bufs[to.idx].offset = offset;
- pipe->bufs[to.idx].len -= offset;
+ mask = pipe->ring_size - 1;
+ pipe->bufs[to.head & mask].offset = offset;
+ pipe->bufs[to.head & mask].len -= offset;
for (i = 0; i < nr_pages; i++) {
size_t this_len = min_t(size_t, len, PAGE_SIZE - offset);
@@ -443,7 +451,8 @@ static int pipe_to_sendpage(struct pipe_inode_info *pipe,
more = (sd->flags & SPLICE_F_MORE) ? MSG_MORE : 0;
- if (sd->len < sd->total_len && pipe->nrbufs > 1)
+ if (sd->len < sd->total_len &&
+ pipe_occupancy(pipe->head, pipe->tail) > 1)
more |= MSG_SENDPAGE_NOTLAST;
return file->f_op->sendpage(file, buf->page, buf->offset,
@@ -481,10 +490,13 @@ static void wakeup_pipe_writers(struct pipe_inode_info *pipe)
static int splice_from_pipe_feed(struct pipe_inode_info *pipe, struct splice_desc *sd,
splice_actor *actor)
{
+ unsigned int head = pipe->head;
+ unsigned int tail = pipe->tail;
+ unsigned int mask = pipe->ring_size - 1;
int ret;
- while (pipe->nrbufs) {
- struct pipe_buffer *buf = pipe->bufs + pipe->curbuf;
+ while (!pipe_empty(tail, head)) {
+ struct pipe_buffer *buf = &pipe->bufs[tail & mask];
sd->len = buf->len;
if (sd->len > sd->total_len)
@@ -511,8 +523,8 @@ static int splice_from_pipe_feed(struct pipe_inode_info *pipe, struct splice_des
if (!buf->len) {
pipe_buf_release(pipe, buf);
- pipe->curbuf = (pipe->curbuf + 1) & (pipe->buffers - 1);
- pipe->nrbufs--;
+ tail++;
+ pipe->tail = tail;
if (pipe->files)
sd->need_wakeup = true;
}
@@ -543,7 +555,7 @@ static int splice_from_pipe_next(struct pipe_inode_info *pipe, struct splice_des
if (signal_pending(current))
return -ERESTARTSYS;
- while (!pipe->nrbufs) {
+ while (pipe_empty(pipe->head, pipe->tail)) {
if (!pipe->writers)
return 0;
@@ -686,7 +698,7 @@ iter_file_splice_write(struct pipe_inode_info *pipe, struct file *out,
.pos = *ppos,
.u.file = out,
};
- int nbufs = pipe->buffers;
+ int nbufs = pipe->max_usage;
struct bio_vec *array = kcalloc(nbufs, sizeof(struct bio_vec),
GFP_KERNEL);
ssize_t ret;
@@ -699,16 +711,19 @@ iter_file_splice_write(struct pipe_inode_info *pipe, struct file *out,
splice_from_pipe_begin(&sd);
while (sd.total_len) {
struct iov_iter from;
+ unsigned int head = pipe->head;
+ unsigned int tail = pipe->tail;
+ unsigned int mask = pipe->ring_size - 1;
size_t left;
- int n, idx;
+ int n;
ret = splice_from_pipe_next(pipe, &sd);
if (ret <= 0)
break;
- if (unlikely(nbufs < pipe->buffers)) {
+ if (unlikely(nbufs < pipe->max_usage)) {
kfree(array);
- nbufs = pipe->buffers;
+ nbufs = pipe->max_usage;
array = kcalloc(nbufs, sizeof(struct bio_vec),
GFP_KERNEL);
if (!array) {
@@ -719,16 +734,13 @@ iter_file_splice_write(struct pipe_inode_info *pipe, struct file *out,
/* build the vector */
left = sd.total_len;
- for (n = 0, idx = pipe->curbuf; left && n < pipe->nrbufs; n++, idx++) {
- struct pipe_buffer *buf = pipe->bufs + idx;
+ for (n = 0; !pipe_empty(head, tail) && left && n < nbufs; tail++, n++) {
+ struct pipe_buffer *buf = &pipe->bufs[tail & mask];
size_t this_len = buf->len;
if (this_len > left)
this_len = left;
- if (idx == pipe->buffers - 1)
- idx = -1;
-
ret = pipe_buf_confirm(pipe, buf);
if (unlikely(ret)) {
if (ret == -ENODATA)
@@ -752,14 +764,15 @@ iter_file_splice_write(struct pipe_inode_info *pipe, struct file *out,
*ppos = sd.pos;
/* dismiss the fully eaten buffers, adjust the partial one */
+ tail = pipe->tail;
while (ret) {
- struct pipe_buffer *buf = pipe->bufs + pipe->curbuf;
+ struct pipe_buffer *buf = &pipe->bufs[tail & mask];
if (ret >= buf->len) {
ret -= buf->len;
buf->len = 0;
pipe_buf_release(pipe, buf);
- pipe->curbuf = (pipe->curbuf + 1) & (pipe->buffers - 1);
- pipe->nrbufs--;
+ tail++;
+ pipe->tail = tail;
if (pipe->files)
sd.need_wakeup = true;
} else {
@@ -942,15 +955,17 @@ ssize_t splice_direct_to_actor(struct file *in, struct splice_desc *sd,
sd->flags &= ~SPLICE_F_NONBLOCK;
more = sd->flags & SPLICE_F_MORE;
- WARN_ON_ONCE(pipe->nrbufs != 0);
+ WARN_ON_ONCE(!pipe_empty(pipe->head, pipe->tail));
while (len) {
+ unsigned int p_space;
size_t read_len;
loff_t pos = sd->pos, prev_pos = pos;
/* Don't try to read more the pipe has space for. */
- read_len = min_t(size_t, len,
- (pipe->buffers - pipe->nrbufs) << PAGE_SHIFT);
+ p_space = pipe->max_usage -
+ pipe_occupancy(pipe->head, pipe->tail);
+ read_len = min_t(size_t, len, p_space << PAGE_SHIFT);
ret = do_splice_to(in, &pos, pipe, read_len, flags);
if (unlikely(ret <= 0))
goto out_release;
@@ -989,7 +1004,7 @@ ssize_t splice_direct_to_actor(struct file *in, struct splice_desc *sd,
}
done:
- pipe->nrbufs = pipe->curbuf = 0;
+ pipe->tail = pipe->head = 0;
file_accessed(in);
return bytes;
@@ -998,8 +1013,8 @@ out_release:
* If we did an incomplete transfer we must release
* the pipe buffers in question:
*/
- for (i = 0; i < pipe->buffers; i++) {
- struct pipe_buffer *buf = pipe->bufs + i;
+ for (i = 0; i < pipe->ring_size; i++) {
+ struct pipe_buffer *buf = &pipe->bufs[i];
if (buf->ops)
pipe_buf_release(pipe, buf);
@@ -1075,7 +1090,7 @@ static int wait_for_space(struct pipe_inode_info *pipe, unsigned flags)
send_sig(SIGPIPE, current, 0);
return -EPIPE;
}
- if (pipe->nrbufs != pipe->buffers)
+ if (!pipe_full(pipe->head, pipe->tail, pipe->max_usage))
return 0;
if (flags & SPLICE_F_NONBLOCK)
return -EAGAIN;
@@ -1180,8 +1195,15 @@ static long do_splice(struct file *in, loff_t __user *off_in,
pipe_lock(opipe);
ret = wait_for_space(opipe, flags);
- if (!ret)
+ if (!ret) {
+ unsigned int p_space;
+
+ /* Don't try to read more the pipe has space for. */
+ p_space = opipe->max_usage - pipe_occupancy(opipe->head, opipe->tail);
+ len = min_t(size_t, len, p_space << PAGE_SHIFT);
+
ret = do_splice_to(in, &offset, opipe, len, flags);
+ }
pipe_unlock(opipe);
if (ret > 0)
wakeup_pipe_readers(opipe);
@@ -1442,16 +1464,16 @@ static int ipipe_prep(struct pipe_inode_info *pipe, unsigned int flags)
int ret;
/*
- * Check ->nrbufs without the inode lock first. This function
+ * Check the pipe occupancy without the inode lock first. This function
* is speculative anyways, so missing one is ok.
*/
- if (pipe->nrbufs)
+ if (!pipe_empty(pipe->head, pipe->tail))
return 0;
ret = 0;
pipe_lock(pipe);
- while (!pipe->nrbufs) {
+ while (pipe_empty(pipe->head, pipe->tail)) {
if (signal_pending(current)) {
ret = -ERESTARTSYS;
break;
@@ -1480,16 +1502,16 @@ static int opipe_prep(struct pipe_inode_info *pipe, unsigned int flags)
int ret;
/*
- * Check ->nrbufs without the inode lock first. This function
+ * Check pipe occupancy without the inode lock first. This function
* is speculative anyways, so missing one is ok.
*/
- if (pipe->nrbufs < pipe->buffers)
+ if (pipe_full(pipe->head, pipe->tail, pipe->max_usage))
return 0;
ret = 0;
pipe_lock(pipe);
- while (pipe->nrbufs >= pipe->buffers) {
+ while (pipe_full(pipe->head, pipe->tail, pipe->max_usage)) {
if (!pipe->readers) {
send_sig(SIGPIPE, current, 0);
ret = -EPIPE;
@@ -1520,7 +1542,10 @@ static int splice_pipe_to_pipe(struct pipe_inode_info *ipipe,
size_t len, unsigned int flags)
{
struct pipe_buffer *ibuf, *obuf;
- int ret = 0, nbuf;
+ unsigned int i_head, o_head;
+ unsigned int i_tail, o_tail;
+ unsigned int i_mask, o_mask;
+ int ret = 0;
bool input_wakeup = false;
@@ -1540,7 +1565,14 @@ retry:
*/
pipe_double_lock(ipipe, opipe);
+ i_tail = ipipe->tail;
+ i_mask = ipipe->ring_size - 1;
+ o_head = opipe->head;
+ o_mask = opipe->ring_size - 1;
+
do {
+ size_t o_len;
+
if (!opipe->readers) {
send_sig(SIGPIPE, current, 0);
if (!ret)
@@ -1548,14 +1580,18 @@ retry:
break;
}
- if (!ipipe->nrbufs && !ipipe->writers)
+ i_head = ipipe->head;
+ o_tail = opipe->tail;
+
+ if (pipe_empty(i_head, i_tail) && !ipipe->writers)
break;
/*
* Cannot make any progress, because either the input
* pipe is empty or the output pipe is full.
*/
- if (!ipipe->nrbufs || opipe->nrbufs >= opipe->buffers) {
+ if (pipe_empty(i_head, i_tail) ||
+ pipe_full(o_head, o_tail, opipe->max_usage)) {
/* Already processed some buffers, break */
if (ret)
break;
@@ -1575,9 +1611,8 @@ retry:
goto retry;
}
- ibuf = ipipe->bufs + ipipe->curbuf;
- nbuf = (opipe->curbuf + opipe->nrbufs) & (opipe->buffers - 1);
- obuf = opipe->bufs + nbuf;
+ ibuf = &ipipe->bufs[i_tail & i_mask];
+ obuf = &opipe->bufs[o_head & o_mask];
if (len >= ibuf->len) {
/*
@@ -1585,10 +1620,12 @@ retry:
*/
*obuf = *ibuf;
ibuf->ops = NULL;
- opipe->nrbufs++;
- ipipe->curbuf = (ipipe->curbuf + 1) & (ipipe->buffers - 1);
- ipipe->nrbufs--;
+ i_tail++;
+ ipipe->tail = i_tail;
input_wakeup = true;
+ o_len = obuf->len;
+ o_head++;
+ opipe->head = o_head;
} else {
/*
* Get a reference to this pipe buffer,
@@ -1610,12 +1647,14 @@ retry:
pipe_buf_mark_unmergeable(obuf);
obuf->len = len;
- opipe->nrbufs++;
- ibuf->offset += obuf->len;
- ibuf->len -= obuf->len;
+ ibuf->offset += len;
+ ibuf->len -= len;
+ o_len = len;
+ o_head++;
+ opipe->head = o_head;
}
- ret += obuf->len;
- len -= obuf->len;
+ ret += o_len;
+ len -= o_len;
} while (len);
pipe_unlock(ipipe);
@@ -1641,7 +1680,10 @@ static int link_pipe(struct pipe_inode_info *ipipe,
size_t len, unsigned int flags)
{
struct pipe_buffer *ibuf, *obuf;
- int ret = 0, i = 0, nbuf;
+ unsigned int i_head, o_head;
+ unsigned int i_tail, o_tail;
+ unsigned int i_mask, o_mask;
+ int ret = 0;
/*
* Potential ABBA deadlock, work around it by ordering lock
@@ -1650,6 +1692,11 @@ static int link_pipe(struct pipe_inode_info *ipipe,
*/
pipe_double_lock(ipipe, opipe);
+ i_tail = ipipe->tail;
+ i_mask = ipipe->ring_size - 1;
+ o_head = opipe->head;
+ o_mask = opipe->ring_size - 1;
+
do {
if (!opipe->readers) {
send_sig(SIGPIPE, current, 0);
@@ -1658,15 +1705,19 @@ static int link_pipe(struct pipe_inode_info *ipipe,
break;
}
+ i_head = ipipe->head;
+ o_tail = opipe->tail;
+
/*
- * If we have iterated all input buffers or ran out of
+ * If we have iterated all input buffers or run out of
* output room, break.
*/
- if (i >= ipipe->nrbufs || opipe->nrbufs >= opipe->buffers)
+ if (pipe_empty(i_head, i_tail) ||
+ pipe_full(o_head, o_tail, opipe->max_usage))
break;
- ibuf = ipipe->bufs + ((ipipe->curbuf + i) & (ipipe->buffers-1));
- nbuf = (opipe->curbuf + opipe->nrbufs) & (opipe->buffers - 1);
+ ibuf = &ipipe->bufs[i_tail & i_mask];
+ obuf = &opipe->bufs[o_head & o_mask];
/*
* Get a reference to this pipe buffer,
@@ -1678,7 +1729,6 @@ static int link_pipe(struct pipe_inode_info *ipipe,
break;
}
- obuf = opipe->bufs + nbuf;
*obuf = *ibuf;
/*
@@ -1691,11 +1741,12 @@ static int link_pipe(struct pipe_inode_info *ipipe,
if (obuf->len > len)
obuf->len = len;
-
- opipe->nrbufs++;
ret += obuf->len;
len -= obuf->len;
- i++;
+
+ o_head++;
+ opipe->head = o_head;
+ i_tail++;
} while (len);
/*
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.