[PATCH 338/437] powerpc/kvm: convert to read/write iterators

[Jens Axboe]

Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
---
 arch/powerpc/kvm/book3s_64_mmu_hv.c    | 25 ++++++++++++-------------
 arch/powerpc/kvm/book3s_64_mmu_radix.c | 19 ++++++++-----------
 arch/powerpc/kvm/book3s_hv.c           | 26 +++++++++++---------------
 arch/powerpc/kvm/timing.c              | 14 +++++++-------
 4 files changed, 38 insertions(+), 46 deletions(-)

diff --git a/arch/powerpc/kvm/book3s_64_mmu_hv.c b/arch/powerpc/kvm/book3s_64_mmu_hv.c
index 2b1f0cdd8c18..254a267cac6f 100644
--- a/arch/powerpc/kvm/book3s_64_mmu_hv.c
+++ b/arch/powerpc/kvm/book3s_64_mmu_hv.c
@@ -1820,6 +1820,7 @@ static ssize_t kvm_htab_read(struct file *file, char __user *buf,
 
 	return nb;
 }
+FOPS_READ_ITER_HELPER(kvm_htab_read);
 
 static ssize_t kvm_htab_write(struct file *file, const char __user *buf,
 			      size_t count, loff_t *ppos)
@@ -1943,6 +1944,7 @@ static ssize_t kvm_htab_write(struct file *file, const char __user *buf,
 		return err;
 	return nb;
 }
+FOPS_WRITE_ITER_HELPER(kvm_htab_write);
 
 static int kvm_htab_release(struct inode *inode, struct file *filp)
 {
@@ -1957,8 +1959,8 @@ static int kvm_htab_release(struct inode *inode, struct file *filp)
 }
 
 static const struct file_operations kvm_htab_fops = {
-	.read		= kvm_htab_read,
-	.write		= kvm_htab_write,
+	.read_iter	= kvm_htab_read_iter,
+	.write_iter	= kvm_htab_write_iter,
 	.llseek		= default_llseek,
 	.release	= kvm_htab_release,
 };
@@ -2035,10 +2037,10 @@ static int debugfs_htab_release(struct inode *inode, struct file *file)
 	return 0;
 }
 
-static ssize_t debugfs_htab_read(struct file *file, char __user *buf,
-				 size_t len, loff_t *ppos)
+static ssize_t debugfs_htab_read(struct kiocb *iocb, struct iov_iter *to)
 {
-	struct debugfs_htab_state *p = file->private_data;
+	struct debugfs_htab_state *p = iocb->ki_filp->private_data;
+	size_t len = iov_iter_count(to);
 	ssize_t ret, r;
 	unsigned long i, n;
 	unsigned long v, hr, gr;
@@ -2057,11 +2059,10 @@ static ssize_t debugfs_htab_read(struct file *file, char __user *buf,
 		n = p->chars_left;
 		if (n > len)
 			n = len;
-		r = copy_to_user(buf, p->buf + p->buf_index, n);
+		r = copy_to_iter(p->buf + p->buf_index, n, to);
 		n -= r;
 		p->chars_left -= n;
 		p->buf_index += n;
-		buf += n;
 		len -= n;
 		ret = n;
 		if (r) {
@@ -2097,11 +2098,10 @@ static ssize_t debugfs_htab_read(struct file *file, char __user *buf,
 		p->chars_left = n;
 		if (n > len)
 			n = len;
-		r = copy_to_user(buf, p->buf, n);
+		r = copy_to_iter(p->buf, n, to);
 		n -= r;
 		p->chars_left -= n;
 		p->buf_index = n;
-		buf += n;
 		len -= n;
 		ret += n;
 		if (r) {
@@ -2117,8 +2117,7 @@ static ssize_t debugfs_htab_read(struct file *file, char __user *buf,
 	return ret;
 }
 
-static ssize_t debugfs_htab_write(struct file *file, const char __user *buf,
-			   size_t len, loff_t *ppos)
+static ssize_t debugfs_htab_write(struct kiocb *iocb, struct iov_iter *from)
 {
 	return -EACCES;
 }
@@ -2127,8 +2126,8 @@ static const struct file_operations debugfs_htab_fops = {
 	.owner	 = THIS_MODULE,
 	.open	 = debugfs_htab_open,
 	.release = debugfs_htab_release,
-	.read	 = debugfs_htab_read,
-	.write	 = debugfs_htab_write,
+	.read_iter  = debugfs_htab_read,
+	.write_iter = debugfs_htab_write,
 	.llseek	 = generic_file_llseek,
 };
 
diff --git a/arch/powerpc/kvm/book3s_64_mmu_radix.c b/arch/powerpc/kvm/book3s_64_mmu_radix.c
index 408d98f8a514..d33c92bbe6f2 100644
--- a/arch/powerpc/kvm/book3s_64_mmu_radix.c
+++ b/arch/powerpc/kvm/book3s_64_mmu_radix.c
@@ -1298,10 +1298,10 @@ static int debugfs_radix_release(struct inode *inode, struct file *file)
 	return 0;
 }
 
-static ssize_t debugfs_radix_read(struct file *file, char __user *buf,
-				 size_t len, loff_t *ppos)
+static ssize_t debugfs_radix_read(struct kiocb *iocb, struct iov_iter *to)
 {
-	struct debugfs_radix_state *p = file->private_data;
+	struct debugfs_radix_state *p = iocb->ki_filp->private_data;
+	size_t len = iov_iter_count(to);
 	ssize_t ret, r;
 	unsigned long n;
 	struct kvm *kvm;
@@ -1328,11 +1328,10 @@ static ssize_t debugfs_radix_read(struct file *file, char __user *buf,
 		n = p->chars_left;
 		if (n > len)
 			n = len;
-		r = copy_to_user(buf, p->buf + p->buf_index, n);
+		r = copy_to_iter(p->buf + p->buf_index, n, to);
 		n -= r;
 		p->chars_left -= n;
 		p->buf_index += n;
-		buf += n;
 		len -= n;
 		ret = n;
 		if (r) {
@@ -1428,11 +1427,10 @@ static ssize_t debugfs_radix_read(struct file *file, char __user *buf,
 		p->chars_left = n;
 		if (n > len)
 			n = len;
-		r = copy_to_user(buf, p->buf, n);
+		r = copy_to_iter(p->buf, n, to);
 		n -= r;
 		p->chars_left -= n;
 		p->buf_index = n;
-		buf += n;
 		len -= n;
 		ret += n;
 		if (r) {
@@ -1450,8 +1448,7 @@ static ssize_t debugfs_radix_read(struct file *file, char __user *buf,
 	return ret;
 }
 
-static ssize_t debugfs_radix_write(struct file *file, const char __user *buf,
-			   size_t len, loff_t *ppos)
+static ssize_t debugfs_radix_write(struct kiocb *iocb, struct iov_iter *from)
 {
 	return -EACCES;
 }
@@ -1460,8 +1457,8 @@ static const struct file_operations debugfs_radix_fops = {
 	.owner	 = THIS_MODULE,
 	.open	 = debugfs_radix_open,
 	.release = debugfs_radix_release,
-	.read	 = debugfs_radix_read,
-	.write	 = debugfs_radix_write,
+	.read_iter  = debugfs_radix_read,
+	.write_iter = debugfs_radix_write,
 	.llseek	 = generic_file_llseek,
 };
 
diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
index 8e86eb577eb8..33ccdf765395 100644
--- a/arch/powerpc/kvm/book3s_hv.c
+++ b/arch/powerpc/kvm/book3s_hv.c
@@ -2860,10 +2860,10 @@ static int debugfs_timings_release(struct inode *inode, struct file *file)
 	return 0;
 }
 
-static ssize_t debugfs_timings_read(struct file *file, char __user *buf,
-				    size_t len, loff_t *ppos)
+static ssize_t debugfs_timings_read(struct kiocb *iocb, struct iov_iter *to)
 {
-	struct debugfs_timings_state *p = file->private_data;
+	struct debugfs_timings_state *p = iocb->ki_filp->private_data;
+	size_t len = iov_iter_count(to);
 	struct kvm_vcpu *vcpu = p->vcpu;
 	char *s, *buf_end;
 	struct kvmhv_tb_accumulator tb;
@@ -2910,23 +2910,19 @@ static ssize_t debugfs_timings_read(struct file *file, char __user *buf,
 		p->buflen = s - p->buf;
 	}
 
-	pos = *ppos;
+	pos = iocb->ki_pos;
 	if (pos >= p->buflen)
 		return 0;
 	if (len > p->buflen - pos)
 		len = p->buflen - pos;
-	n = copy_to_user(buf, p->buf + pos, len);
-	if (n) {
-		if (n == len)
-			return -EFAULT;
-		len -= n;
-	}
-	*ppos = pos + len;
+	n = !copy_to_iter_full(p->buf + pos, len, to);
+	if (n)
+		return -EFAULT;
+	iocb->ki_pos = pos + len;
 	return len;
 }
 
-static ssize_t debugfs_timings_write(struct file *file, const char __user *buf,
-				     size_t len, loff_t *ppos)
+static ssize_t debugfs_timings_write(struct kiocb *iocb, struct iov_iter *from)
 {
 	return -EACCES;
 }
@@ -2935,8 +2931,8 @@ static const struct file_operations debugfs_timings_ops = {
 	.owner	 = THIS_MODULE,
 	.open	 = debugfs_timings_open,
 	.release = debugfs_timings_release,
-	.read	 = debugfs_timings_read,
-	.write	 = debugfs_timings_write,
+	.read_iter = debugfs_timings_read,
+	.write_iter = debugfs_timings_write,
 	.llseek	 = generic_file_llseek,
 };
 
diff --git a/arch/powerpc/kvm/timing.c b/arch/powerpc/kvm/timing.c
index 25071331f8c1..1281aaef2b44 100644
--- a/arch/powerpc/kvm/timing.c
+++ b/arch/powerpc/kvm/timing.c
@@ -158,10 +158,10 @@ static int kvmppc_exit_timing_show(struct seq_file *m, void *private)
 }
 
 /* Write 'c' to clear the timing statistics. */
-static ssize_t kvmppc_exit_timing_write(struct file *file,
-				       const char __user *user_buf,
-				       size_t count, loff_t *ppos)
+static ssize_t kvmppc_exit_timing_write(struct kiocb *iocb,
+					struct iov_iter *from)
 {
+	size_t count = iov_iter_count(from);
 	int err = -EINVAL;
 	char c;
 
@@ -169,13 +169,13 @@ static ssize_t kvmppc_exit_timing_write(struct file *file,
 		goto done;
 	}
 
-	if (get_user(c, user_buf)) {
+	if (get_iter(&c, from)) {
 		err = -EFAULT;
 		goto done;
 	}
 
 	if (c == 'c') {
-		struct seq_file *seqf = file->private_data;
+		struct seq_file *seqf = iocb->ki_filp->private_data;
 		struct kvm_vcpu *vcpu = seqf->private;
 		/* Write does not affect our buffers previously generated with
 		 * show. seq_file is locked here to prevent races of init with
@@ -198,8 +198,8 @@ static int kvmppc_exit_timing_open(struct inode *inode, struct file *file)
 static const struct file_operations kvmppc_exit_timing_fops = {
 	.owner   = THIS_MODULE,
 	.open    = kvmppc_exit_timing_open,
-	.read    = seq_read,
-	.write   = kvmppc_exit_timing_write,
+	.read_iter = seq_read_iter,
+	.write_iter = kvmppc_exit_timing_write,
 	.llseek  = seq_lseek,
 	.release = single_release,
 };
-- 
2.43.0