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iov_iter: add iter_iov_addr() and iter_iov_len() helpers

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These just return the address and length of the current iovec segment
in the iterator. Convert existing iov_iter_iovec() users to use them
instead of getting a copy of the current vec.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Jens Axboe 2023-03-29 09:16:45 -06:00
parent e4d3202c18
commit 95e49cf837
4 changed files with 24 additions and 25 deletions
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11
fs/read_write.c
View File

@ -749,15 +749,14 @@ static ssize_t do_loop_readv_writev(struct file *filp, struct iov_iter *iter,
return -EOPNOTSUPP;
while (iov_iter_count(iter)) {
struct iovec iovec = iov_iter_iovec(iter);
ssize_t nr;
if (type == READ) {
nr = filp->f_op->read(filp, iovec.iov_base,
iovec.iov_len, ppos);
nr = filp->f_op->read(filp, iter_iov_addr(iter),
iter_iov_len(iter), ppos);
} else {
nr = filp->f_op->write(filp, iovec.iov_base,
iovec.iov_len, ppos);
nr = filp->f_op->write(filp, iter_iov_addr(iter),
iter_iov_len(iter), ppos);
}
if (nr < 0) {
@ -766,7 +765,7 @@ static ssize_t do_loop_readv_writev(struct file *filp, struct iov_iter *iter,
break;
}
ret += nr;
if (nr != iovec.iov_len)
if (nr != iter_iov_len(iter))
break;
iov_iter_advance(iter, nr);
}

2
include/linux/uio.h
View File

@ -70,6 +70,8 @@ struct iov_iter {
};
#define iter_iov(iter) (iter)->__iov
#define iter_iov_addr(iter) (iter_iov(iter)->iov_base + (iter)->iov_offset)
#define iter_iov_len(iter) (iter_iov(iter)->iov_len - (iter)->iov_offset)
static inline enum iter_type iov_iter_type(const struct iov_iter *i)
{

27
io_uring/rw.c
View File

@ -447,26 +447,25 @@ static ssize_t loop_rw_iter(int ddir, struct io_rw *rw, struct iov_iter *iter)
ppos = io_kiocb_ppos(kiocb);
while (iov_iter_count(iter)) {
struct iovec iovec;
void __user *addr;
size_t len;
ssize_t nr;
if (iter_is_ubuf(iter)) {
iovec.iov_base = iter->ubuf + iter->iov_offset;
iovec.iov_len = iov_iter_count(iter);
addr = iter->ubuf + iter->iov_offset;
len = iov_iter_count(iter);
} else if (!iov_iter_is_bvec(iter)) {
iovec = iov_iter_iovec(iter);
addr = iter_iov_addr(iter);
len = iter_iov_len(iter);
} else {
iovec.iov_base = u64_to_user_ptr(rw->addr);
iovec.iov_len = rw->len;
addr = u64_to_user_ptr(rw->addr);
len = rw->len;
}
if (ddir == READ) {
nr = file->f_op->read(file, iovec.iov_base,
iovec.iov_len, ppos);
} else {
nr = file->f_op->write(file, iovec.iov_base,
iovec.iov_len, ppos);
}
if (ddir == READ)
nr = file->f_op->read(file, addr, len, ppos);
else
nr = file->f_op->write(file, addr, len, ppos);
if (nr < 0) {
if (!ret)
@ -482,7 +481,7 @@ static ssize_t loop_rw_iter(int ddir, struct io_rw *rw, struct iov_iter *iter)
if (!rw->len)
break;
}
if (nr != iovec.iov_len)
if (nr != len)
break;
}

9
mm/madvise.c
View File

@ -1456,7 +1456,7 @@ SYSCALL_DEFINE5(process_madvise, int, pidfd, const struct iovec __user *, vec,
size_t, vlen, int, behavior, unsigned int, flags)
{
ssize_t ret;
struct iovec iovstack[UIO_FASTIOV], iovec;
struct iovec iovstack[UIO_FASTIOV];
struct iovec *iov = iovstack;
struct iov_iter iter;
struct task_struct *task;
@ -1503,12 +1503,11 @@ SYSCALL_DEFINE5(process_madvise, int, pidfd, const struct iovec __user *, vec,
total_len = iov_iter_count(&iter);
while (iov_iter_count(&iter)) {
iovec = iov_iter_iovec(&iter);
ret = do_madvise(mm, (unsigned long)iovec.iov_base,
iovec.iov_len, behavior);
ret = do_madvise(mm, (unsigned long)iter_iov_addr(&iter),
iter_iov_len(&iter), behavior);
if (ret < 0)
break;
iov_iter_advance(&iter, iovec.iov_len);
iov_iter_advance(&iter, iter_iov_len(&iter));
}
ret = (total_len - iov_iter_count(&iter)) ? : ret;