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-rw-r--r--fs/open.c5
-rw-r--r--fs/read_write.c113
2 files changed, 70 insertions, 48 deletions
diff --git a/fs/open.c b/fs/open.c
index a00350018a47..9c7d724a6f67 100644
--- a/fs/open.c
+++ b/fs/open.c
@@ -1219,8 +1219,9 @@ EXPORT_SYMBOL(nonseekable_open);
/*
* stream_open is used by subsystems that want stream-like file descriptors.
* Such file descriptors are not seekable and don't have notion of position
- * (file.f_pos is always 0). Contrary to file descriptors of other regular
- * files, .read() and .write() can run simultaneously.
+ * (file.f_pos is always 0 and ppos passed to .read()/.write() is always NULL).
+ * Contrary to file descriptors of other regular files, .read() and .write()
+ * can run simultaneously.
*
* stream_open never fails and is marked to return int so that it could be
* directly used as file_operations.open .
diff --git a/fs/read_write.c b/fs/read_write.c
index 61b43ad7608e..c543d965e288 100644
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -365,29 +365,37 @@ out_putf:
int rw_verify_area(int read_write, struct file *file, const loff_t *ppos, size_t count)
{
struct inode *inode;
- loff_t pos;
int retval = -EINVAL;
inode = file_inode(file);
if (unlikely((ssize_t) count < 0))
return retval;
- pos = *ppos;
- if (unlikely(pos < 0)) {
- if (!unsigned_offsets(file))
- return retval;
- if (count >= -pos) /* both values are in 0..LLONG_MAX */
- return -EOVERFLOW;
- } else if (unlikely((loff_t) (pos + count) < 0)) {
- if (!unsigned_offsets(file))
- return retval;
- }
- if (unlikely(inode->i_flctx && mandatory_lock(inode))) {
- retval = locks_mandatory_area(inode, file, pos, pos + count - 1,
- read_write == READ ? F_RDLCK : F_WRLCK);
- if (retval < 0)
- return retval;
+ /*
+ * ranged mandatory locking does not apply to streams - it makes sense
+ * only for files where position has a meaning.
+ */
+ if (ppos) {
+ loff_t pos = *ppos;
+
+ if (unlikely(pos < 0)) {
+ if (!unsigned_offsets(file))
+ return retval;
+ if (count >= -pos) /* both values are in 0..LLONG_MAX */
+ return -EOVERFLOW;
+ } else if (unlikely((loff_t) (pos + count) < 0)) {
+ if (!unsigned_offsets(file))
+ return retval;
+ }
+
+ if (unlikely(inode->i_flctx && mandatory_lock(inode))) {
+ retval = locks_mandatory_area(inode, file, pos, pos + count - 1,
+ read_write == READ ? F_RDLCK : F_WRLCK);
+ if (retval < 0)
+ return retval;
+ }
}
+
return security_file_permission(file,
read_write == READ ? MAY_READ : MAY_WRITE);
}
@@ -400,12 +408,13 @@ static ssize_t new_sync_read(struct file *filp, char __user *buf, size_t len, lo
ssize_t ret;
init_sync_kiocb(&kiocb, filp);
- kiocb.ki_pos = *ppos;
+ kiocb.ki_pos = (ppos ? *ppos : 0);
iov_iter_init(&iter, READ, &iov, 1, len);
ret = call_read_iter(filp, &kiocb, &iter);
BUG_ON(ret == -EIOCBQUEUED);
- *ppos = kiocb.ki_pos;
+ if (ppos)
+ *ppos = kiocb.ki_pos;
return ret;
}
@@ -468,12 +477,12 @@ static ssize_t new_sync_write(struct file *filp, const char __user *buf, size_t
ssize_t ret;
init_sync_kiocb(&kiocb, filp);
- kiocb.ki_pos = *ppos;
+ kiocb.ki_pos = (ppos ? *ppos : 0);
iov_iter_init(&iter, WRITE, &iov, 1, len);
ret = call_write_iter(filp, &kiocb, &iter);
BUG_ON(ret == -EIOCBQUEUED);
- if (ret > 0)
+ if (ret > 0 && ppos)
*ppos = kiocb.ki_pos;
return ret;
}
@@ -558,15 +567,10 @@ ssize_t vfs_write(struct file *file, const char __user *buf, size_t count, loff_
return ret;
}
-static inline loff_t file_pos_read(struct file *file)
-{
- return file->f_mode & FMODE_STREAM ? 0 : file->f_pos;
-}
-
-static inline void file_pos_write(struct file *file, loff_t pos)
+/* file_ppos returns &file->f_pos or NULL if file is stream */
+static inline loff_t *file_ppos(struct file *file)
{
- if ((file->f_mode & FMODE_STREAM) == 0)
- file->f_pos = pos;
+ return file->f_mode & FMODE_STREAM ? NULL : &file->f_pos;
}
ssize_t ksys_read(unsigned int fd, char __user *buf, size_t count)
@@ -575,10 +579,14 @@ ssize_t ksys_read(unsigned int fd, char __user *buf, size_t count)
ssize_t ret = -EBADF;
if (f.file) {
- loff_t pos = file_pos_read(f.file);
- ret = vfs_read(f.file, buf, count, &pos);
- if (ret >= 0)
- file_pos_write(f.file, pos);
+ loff_t pos, *ppos = file_ppos(f.file);
+ if (ppos) {
+ pos = *ppos;
+ ppos = &pos;
+ }
+ ret = vfs_read(f.file, buf, count, ppos);
+ if (ret >= 0 && ppos)
+ f.file->f_pos = pos;
fdput_pos(f);
}
return ret;
@@ -595,10 +603,14 @@ ssize_t ksys_write(unsigned int fd, const char __user *buf, size_t count)
ssize_t ret = -EBADF;
if (f.file) {
- loff_t pos = file_pos_read(f.file);
- ret = vfs_write(f.file, buf, count, &pos);
- if (ret >= 0)
- file_pos_write(f.file, pos);
+ loff_t pos, *ppos = file_ppos(f.file);
+ if (ppos) {
+ pos = *ppos;
+ ppos = &pos;
+ }
+ ret = vfs_write(f.file, buf, count, ppos);
+ if (ret >= 0 && ppos)
+ f.file->f_pos = pos;
fdput_pos(f);
}
@@ -673,14 +685,15 @@ static ssize_t do_iter_readv_writev(struct file *filp, struct iov_iter *iter,
ret = kiocb_set_rw_flags(&kiocb, flags);
if (ret)
return ret;
- kiocb.ki_pos = *ppos;
+ kiocb.ki_pos = (ppos ? *ppos : 0);
if (type == READ)
ret = call_read_iter(filp, &kiocb, iter);
else
ret = call_write_iter(filp, &kiocb, iter);
BUG_ON(ret == -EIOCBQUEUED);
- *ppos = kiocb.ki_pos;
+ if (ppos)
+ *ppos = kiocb.ki_pos;
return ret;
}
@@ -1013,10 +1026,14 @@ static ssize_t do_readv(unsigned long fd, const struct iovec __user *vec,
ssize_t ret = -EBADF;
if (f.file) {
- loff_t pos = file_pos_read(f.file);
- ret = vfs_readv(f.file, vec, vlen, &pos, flags);
- if (ret >= 0)
- file_pos_write(f.file, pos);
+ loff_t pos, *ppos = file_ppos(f.file);
+ if (ppos) {
+ pos = *ppos;
+ ppos = &pos;
+ }
+ ret = vfs_readv(f.file, vec, vlen, ppos, flags);
+ if (ret >= 0 && ppos)
+ f.file->f_pos = pos;
fdput_pos(f);
}
@@ -1033,10 +1050,14 @@ static ssize_t do_writev(unsigned long fd, const struct iovec __user *vec,
ssize_t ret = -EBADF;
if (f.file) {
- loff_t pos = file_pos_read(f.file);
- ret = vfs_writev(f.file, vec, vlen, &pos, flags);
- if (ret >= 0)
- file_pos_write(f.file, pos);
+ loff_t pos, *ppos = file_ppos(f.file);
+ if (ppos) {
+ pos = *ppos;
+ ppos = &pos;
+ }
+ ret = vfs_writev(f.file, vec, vlen, ppos, flags);
+ if (ret >= 0 && ppos)
+ f.file->f_pos = pos;
fdput_pos(f);
}
generated by cgit v1.2.3 (git 2.39.0) at 2024-11-26 02:29:50 +0300