support splice reads on seq_file based procfs files

support splice reads on seq_file based procfs files

[Christoph Hellwig]

Hi Al,

Greg reported a problem due to the fact that Android tests use procfs
files to test splice, which stopped working with 5.10-rc1.  This series
adds read_iter support for seq_file, and uses those for all proc files
using seq_file to restore splice read support.

[PATCH 1/3] seq_file: add seq_read_iter

[Christoph Hellwig]

iov_iter based variant for reading a seq_file.  seq_read is
reimplemented on top of the iter variant.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 fs/seq_file.c            | 45 ++++++++++++++++++++++++++++------------
 include/linux/seq_file.h |  1 +
 2 files changed, 33 insertions(+), 13 deletions(-)

diff --git a/fs/seq_file.c b/fs/seq_file.c
index 31219c1db17de3..3b20e21604e74a 100644
--- a/fs/seq_file.c
+++ b/fs/seq_file.c
@@ -18,6 +18,7 @@
 #include <linux/mm.h>
 #include <linux/printk.h>
 #include <linux/string_helpers.h>
+#include <linux/uio.h>
 
 #include <linux/uaccess.h>
 #include <asm/page.h>
@@ -146,7 +147,28 @@ static int traverse(struct seq_file *m, loff_t offset)
  */
 ssize_t seq_read(struct file *file, char __user *buf, size_t size, loff_t *ppos)
 {
-	struct seq_file *m = file->private_data;
+	struct iovec iov = { .iov_base = buf, .iov_len = size};
+	struct kiocb kiocb;
+	struct iov_iter iter;
+	ssize_t ret;
+
+	init_sync_kiocb(&kiocb, file);
+	iov_iter_init(&iter, READ, &iov, 1, size);
+
+	kiocb.ki_pos = *ppos;
+	ret = seq_read_iter(&kiocb, &iter);
+	*ppos = kiocb.ki_pos;
+	return ret;
+}
+EXPORT_SYMBOL(seq_read);
+
+/*
+ * Ready-made ->f_op->read_iter()
+ */
+ssize_t seq_read_iter(struct kiocb *iocb, struct iov_iter *iter)
+{
+	struct seq_file *m = iocb->ki_filp->private_data;
+	size_t size = iov_iter_count(iter);
 	size_t copied = 0;
 	size_t n;
 	void *p;
@@ -158,14 +180,14 @@ ssize_t seq_read(struct file *file, char __user *buf, size_t size, loff_t *ppos)
 	 * if request is to read from zero offset, reset iterator to first
 	 * record as it might have been already advanced by previous requests
 	 */
-	if (*ppos == 0) {
+	if (iocb->ki_pos == 0) {
 		m->index = 0;
 		m->count = 0;
 	}
 
-	/* Don't assume *ppos is where we left it */
-	if (unlikely(*ppos != m->read_pos)) {
-		while ((err = traverse(m, *ppos)) == -EAGAIN)
+	/* Don't assume ki_pos is where we left it */
+	if (unlikely(iocb->ki_pos != m->read_pos)) {
+		while ((err = traverse(m, iocb->ki_pos)) == -EAGAIN)
 			;
 		if (err) {
 			/* With prejudice... */
@@ -174,7 +196,7 @@ ssize_t seq_read(struct file *file, char __user *buf, size_t size, loff_t *ppos)
 			m->count = 0;
 			goto Done;
 		} else {
-			m->read_pos = *ppos;
+			m->read_pos = iocb->ki_pos;
 		}
 	}
 
@@ -187,13 +209,11 @@ ssize_t seq_read(struct file *file, char __user *buf, size_t size, loff_t *ppos)
 	/* if not empty - flush it first */
 	if (m->count) {
 		n = min(m->count, size);
-		err = copy_to_user(buf, m->buf + m->from, n);
-		if (err)
+		if (copy_to_iter(m->buf + m->from, n, iter) != n)
 			goto Efault;
 		m->count -= n;
 		m->from += n;
 		size -= n;
-		buf += n;
 		copied += n;
 		if (!size)
 			goto Done;
@@ -254,8 +274,7 @@ ssize_t seq_read(struct file *file, char __user *buf, size_t size, loff_t *ppos)
 	}
 	m->op->stop(m, p);
 	n = min(m->count, size);
-	err = copy_to_user(buf, m->buf, n);
-	if (err)
+	if (copy_to_iter(m->buf, n, iter) != n)
 		goto Efault;
 	copied += n;
 	m->count -= n;
@@ -264,7 +283,7 @@ ssize_t seq_read(struct file *file, char __user *buf, size_t size, loff_t *ppos)
 	if (!copied)
 		copied = err;
 	else {
-		*ppos += copied;
+		iocb->ki_pos += copied;
 		m->read_pos += copied;
 	}
 	mutex_unlock(&m->lock);
@@ -276,7 +295,7 @@ ssize_t seq_read(struct file *file, char __user *buf, size_t size, loff_t *ppos)
 	err = -EFAULT;
 	goto Done;
 }
-EXPORT_SYMBOL(seq_read);
+EXPORT_SYMBOL(seq_read_iter);
 
 /**
  *	seq_lseek -	->llseek() method for sequential files.
diff --git a/include/linux/seq_file.h b/include/linux/seq_file.h
index 813614d4b71fbc..b83b3ae3c877f3 100644
--- a/include/linux/seq_file.h
+++ b/include/linux/seq_file.h
@@ -107,6 +107,7 @@ void seq_pad(struct seq_file *m, char c);
 char *mangle_path(char *s, const char *p, const char *esc);
 int seq_open(struct file *, const struct seq_operations *);
 ssize_t seq_read(struct file *, char __user *, size_t, loff_t *);
+ssize_t seq_read_iter(struct kiocb *iocb, struct iov_iter *iter);
 loff_t seq_lseek(struct file *, loff_t, int);
 int seq_release(struct inode *, struct file *);
 int seq_write(struct seq_file *seq, const void *data, size_t len);
-- 
2.28.0

Re: [PATCH 1/3] seq_file: add seq_read_iter

[Greg KH]

On Thu, Oct 29, 2020 at 11:09:48AM +0100, Christoph Hellwig wrote:
> iov_iter based variant for reading a seq_file.  seq_read is
> reimplemented on top of the iter variant.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
>  fs/seq_file.c            | 45 ++++++++++++++++++++++++++++------------
>  include/linux/seq_file.h |  1 +
>  2 files changed, 33 insertions(+), 13 deletions(-)

Tested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

[PATCH 2/3] proc: wire up generic_file_splice_read for iter ops

[Christoph Hellwig]

Wire up generic_file_splice_read for the iter based proxy ops, so
that splice reads from them work.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 fs/proc/inode.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/fs/proc/inode.c b/fs/proc/inode.c
index 58c075e2a452d6..bde6b6f69852d2 100644
--- a/fs/proc/inode.c
+++ b/fs/proc/inode.c
@@ -597,6 +597,7 @@ static const struct file_operations proc_iter_file_ops = {
 	.llseek		= proc_reg_llseek,
 	.read_iter	= proc_reg_read_iter,
 	.write		= proc_reg_write,
+	.splice_read	= generic_file_splice_read,
 	.poll		= proc_reg_poll,
 	.unlocked_ioctl	= proc_reg_unlocked_ioctl,
 	.mmap		= proc_reg_mmap,
@@ -622,6 +623,7 @@ static const struct file_operations proc_reg_file_ops_compat = {
 static const struct file_operations proc_iter_file_ops_compat = {
 	.llseek		= proc_reg_llseek,
 	.read_iter	= proc_reg_read_iter,
+	.splice_read	= generic_file_splice_read,
 	.write		= proc_reg_write,
 	.poll		= proc_reg_poll,
 	.unlocked_ioctl	= proc_reg_unlocked_ioctl,
-- 
2.28.0

Re: [PATCH 2/3] proc: wire up generic_file_splice_read for iter ops

[Greg KH]

On Thu, Oct 29, 2020 at 11:09:49AM +0100, Christoph Hellwig wrote:
> Wire up generic_file_splice_read for the iter based proxy ops, so
> that splice reads from them work.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
>  fs/proc/inode.c | 2 ++
>  1 file changed, 2 insertions(+)

Tested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

[PATCH 3/3] proc: switch over direct seq_read method calls to seq_read_iter

[Christoph Hellwig]

Switch over all instances used directly as methods using these sed
expressions:

sed -i -e 's/\.proc_read\(\s*=\s*\)seq_read/\.proc_read_iter\1seq_read_iter/g'

This fixes a problem with the Android bionic test suite using /proc/cpuinfo
and /proc/version for its splice based tests.

Fixes: 36e2c7421f02 ("fs: don't allow splice read/write without explicit ops")
Reported-by: Greg KH <gregkh@linuxfoundation.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 arch/alpha/kernel/srm_env.c                        |  2 +-
 arch/arm/mm/alignment.c                            |  2 +-
 arch/powerpc/kernel/rtas-proc.c                    | 10 +++++-----
 arch/powerpc/platforms/pseries/lpar.c              |  4 ++--
 arch/powerpc/platforms/pseries/lparcfg.c           |  2 +-
 arch/sh/mm/alignment.c                             |  2 +-
 arch/sparc/kernel/led.c                            |  2 +-
 arch/um/kernel/exitcode.c                          |  2 +-
 arch/um/kernel/process.c                           |  2 +-
 arch/x86/kernel/cpu/mtrr/if.c                      |  2 +-
 drivers/acpi/proc.c                                |  2 +-
 drivers/hwmon/dell-smm-hwmon.c                     |  2 +-
 drivers/ide/ide-proc.c                             |  2 +-
 drivers/input/input.c                              |  4 ++--
 drivers/macintosh/via-pmu.c                        |  2 +-
 drivers/md/md.c                                    |  2 +-
 drivers/misc/sgi-gru/gruprocfs.c                   |  6 +++---
 drivers/net/wireless/intel/ipw2x00/libipw_module.c |  2 +-
 .../net/wireless/intersil/hostap/hostap_download.c |  2 +-
 drivers/parisc/led.c                               |  2 +-
 drivers/platform/x86/thinkpad_acpi.c               |  2 +-
 drivers/platform/x86/toshiba_acpi.c                |  8 ++++----
 drivers/pnp/pnpbios/proc.c                         |  2 +-
 drivers/s390/block/dasd_proc.c                     |  2 +-
 drivers/s390/cio/blacklist.c                       |  2 +-
 drivers/scsi/scsi_devinfo.c                        |  2 +-
 drivers/scsi/scsi_proc.c                           |  4 ++--
 drivers/scsi/sg.c                                  |  4 ++--
 .../staging/rtl8192u/ieee80211/ieee80211_module.c  |  2 +-
 drivers/usb/gadget/function/rndis.c                |  2 +-
 drivers/video/fbdev/via/viafbdev.c                 | 14 +++++++-------
 fs/cifs/cifs_debug.c                               | 14 +++++++-------
 fs/cifs/dfs_cache.c                                |  2 +-
 fs/fscache/object-list.c                           |  2 +-
 fs/jbd2/journal.c                                  |  2 +-
 fs/jfs/jfs_debug.c                                 |  2 +-
 fs/nfsd/nfsctl.c                                   |  2 +-
 fs/nfsd/stats.c                                    |  2 +-
 fs/proc/cpuinfo.c                                  |  2 +-
 fs/proc/generic.c                                  |  4 ++--
 fs/proc/proc_net.c                                 |  4 ++--
 fs/proc/stat.c                                     |  2 +-
 include/linux/seq_file.h                           |  2 +-
 ipc/util.c                                         |  2 +-
 kernel/irq/proc.c                                  |  6 +++---
 kernel/kallsyms.c                                  |  2 +-
 kernel/latencytop.c                                |  2 +-
 kernel/locking/lockdep_proc.c                      |  2 +-
 kernel/module.c                                    |  2 +-
 kernel/profile.c                                   |  2 +-
 kernel/sched/psi.c                                 |  6 +++---
 lib/dynamic_debug.c                                |  2 +-
 mm/slab_common.c                                   |  2 +-
 mm/swapfile.c                                      |  2 +-
 net/atm/mpoa_proc.c                                |  2 +-
 net/core/pktgen.c                                  |  6 +++---
 net/ipv4/netfilter/ipt_CLUSTERIP.c                 |  2 +-
 net/ipv4/route.c                                   |  4 ++--
 net/netfilter/xt_recent.c                          |  2 +-
 net/sunrpc/cache.c                                 |  2 +-
 net/sunrpc/stats.c                                 |  2 +-
 sound/core/info.c                                  |  2 +-
 62 files changed, 96 insertions(+), 96 deletions(-)

diff --git a/arch/alpha/kernel/srm_env.c b/arch/alpha/kernel/srm_env.c
index 528d2be5818298..8ad9c100ef7612 100644
--- a/arch/alpha/kernel/srm_env.c
+++ b/arch/alpha/kernel/srm_env.c
@@ -121,7 +121,7 @@ static ssize_t srm_env_proc_write(struct file *file, const char __user *buffer,
 
 static const struct proc_ops srm_env_proc_ops = {
 	.proc_open	= srm_env_proc_open,
-	.proc_read	= seq_read,
+	.proc_read_iter	= seq_read_iter,
 	.proc_lseek	= seq_lseek,
 	.proc_release	= single_release,
 	.proc_write	= srm_env_proc_write,
diff --git a/arch/arm/mm/alignment.c b/arch/arm/mm/alignment.c
index ea81e89e77400e..f189a7bfcd6553 100644
--- a/arch/arm/mm/alignment.c
+++ b/arch/arm/mm/alignment.c
@@ -164,7 +164,7 @@ static ssize_t alignment_proc_write(struct file *file, const char __user *buffer
 
 static const struct proc_ops alignment_proc_ops = {
 	.proc_open	= alignment_proc_open,
-	.proc_read	= seq_read,
+	.proc_read_iter	= seq_read_iter,
 	.proc_lseek	= seq_lseek,
 	.proc_release	= single_release,
 	.proc_write	= alignment_proc_write,
diff --git a/arch/powerpc/kernel/rtas-proc.c b/arch/powerpc/kernel/rtas-proc.c
index 2d33f342a29307..3aace56aacc1df 100644
--- a/arch/powerpc/kernel/rtas-proc.c
+++ b/arch/powerpc/kernel/rtas-proc.c
@@ -161,7 +161,7 @@ static int poweron_open(struct inode *inode, struct file *file)
 
 static const struct proc_ops ppc_rtas_poweron_proc_ops = {
 	.proc_open	= poweron_open,
-	.proc_read	= seq_read,
+	.proc_read_iter	= seq_read_iter,
 	.proc_lseek	= seq_lseek,
 	.proc_write	= ppc_rtas_poweron_write,
 	.proc_release	= single_release,
@@ -174,7 +174,7 @@ static int progress_open(struct inode *inode, struct file *file)
 
 static const struct proc_ops ppc_rtas_progress_proc_ops = {
 	.proc_open	= progress_open,
-	.proc_read	= seq_read,
+	.proc_read_iter	= seq_read_iter,
 	.proc_lseek	= seq_lseek,
 	.proc_write	= ppc_rtas_progress_write,
 	.proc_release	= single_release,
@@ -187,7 +187,7 @@ static int clock_open(struct inode *inode, struct file *file)
 
 static const struct proc_ops ppc_rtas_clock_proc_ops = {
 	.proc_open	= clock_open,
-	.proc_read	= seq_read,
+	.proc_read_iter	= seq_read_iter,
 	.proc_lseek	= seq_lseek,
 	.proc_write	= ppc_rtas_clock_write,
 	.proc_release	= single_release,
@@ -200,7 +200,7 @@ static int tone_freq_open(struct inode *inode, struct file *file)
 
 static const struct proc_ops ppc_rtas_tone_freq_proc_ops = {
 	.proc_open	= tone_freq_open,
-	.proc_read	= seq_read,
+	.proc_read_iter	= seq_read_iter,
 	.proc_lseek	= seq_lseek,
 	.proc_write	= ppc_rtas_tone_freq_write,
 	.proc_release	= single_release,
@@ -213,7 +213,7 @@ static int tone_volume_open(struct inode *inode, struct file *file)
 
 static const struct proc_ops ppc_rtas_tone_volume_proc_ops = {
 	.proc_open	= tone_volume_open,
-	.proc_read	= seq_read,
+	.proc_read_iter	= seq_read_iter,
 	.proc_lseek	= seq_lseek,
 	.proc_write	= ppc_rtas_tone_volume_write,
 	.proc_release	= single_release,
diff --git a/arch/powerpc/platforms/pseries/lpar.c b/arch/powerpc/platforms/pseries/lpar.c
index 764170fdb0f74a..9053a98bd1a5bc 100644
--- a/arch/powerpc/platforms/pseries/lpar.c
+++ b/arch/powerpc/platforms/pseries/lpar.c
@@ -585,7 +585,7 @@ static int vcpudispatch_stats_open(struct inode *inode, struct file *file)
 
 static const struct proc_ops vcpudispatch_stats_proc_ops = {
 	.proc_open	= vcpudispatch_stats_open,
-	.proc_read	= seq_read,
+	.proc_read_iter	= seq_read_iter,
 	.proc_write	= vcpudispatch_stats_write,
 	.proc_lseek	= seq_lseek,
 	.proc_release	= single_release,
@@ -629,7 +629,7 @@ static int vcpudispatch_stats_freq_open(struct inode *inode, struct file *file)
 
 static const struct proc_ops vcpudispatch_stats_freq_proc_ops = {
 	.proc_open	= vcpudispatch_stats_freq_open,
-	.proc_read	= seq_read,
+	.proc_read_iter	= seq_read_iter,
 	.proc_write	= vcpudispatch_stats_freq_write,
 	.proc_lseek	= seq_lseek,
 	.proc_release	= single_release,
diff --git a/arch/powerpc/platforms/pseries/lparcfg.c b/arch/powerpc/platforms/pseries/lparcfg.c
index e278390ab28d14..6e980f9850ce52 100644
--- a/arch/powerpc/platforms/pseries/lparcfg.c
+++ b/arch/powerpc/platforms/pseries/lparcfg.c
@@ -734,7 +734,7 @@ static int lparcfg_open(struct inode *inode, struct file *file)
 }
 
 static const struct proc_ops lparcfg_proc_ops = {
-	.proc_read	= seq_read,
+	.proc_read_iter	= seq_read_iter,
 	.proc_write	= lparcfg_write,
 	.proc_open	= lparcfg_open,
 	.proc_release	= single_release,
diff --git a/arch/sh/mm/alignment.c b/arch/sh/mm/alignment.c
index fb517b82a87b10..66115241ad93a4 100644
--- a/arch/sh/mm/alignment.c
+++ b/arch/sh/mm/alignment.c
@@ -154,7 +154,7 @@ static ssize_t alignment_proc_write(struct file *file,
 
 static const struct proc_ops alignment_proc_ops = {
 	.proc_open	= alignment_proc_open,
-	.proc_read	= seq_read,
+	.proc_read_iter	= seq_read_iter,
 	.proc_lseek	= seq_lseek,
 	.proc_release	= single_release,
 	.proc_write	= alignment_proc_write,
diff --git a/arch/sparc/kernel/led.c b/arch/sparc/kernel/led.c
index bd48575172c323..a0b893d216c443 100644
--- a/arch/sparc/kernel/led.c
+++ b/arch/sparc/kernel/led.c
@@ -106,7 +106,7 @@ static ssize_t led_proc_write(struct file *file, const char __user *buffer,
 
 static const struct proc_ops led_proc_ops = {
 	.proc_open	= led_proc_open,
-	.proc_read	= seq_read,
+	.proc_read_iter	= seq_read_iter,
 	.proc_lseek	= seq_lseek,
 	.proc_release	= single_release,
 	.proc_write	= led_proc_write,
diff --git a/arch/um/kernel/exitcode.c b/arch/um/kernel/exitcode.c
index 43edc2aa57e4fb..95184d271a47cf 100644
--- a/arch/um/kernel/exitcode.c
+++ b/arch/um/kernel/exitcode.c
@@ -57,7 +57,7 @@ static ssize_t exitcode_proc_write(struct file *file,
 
 static const struct proc_ops exitcode_proc_ops = {
 	.proc_open	= exitcode_proc_open,
-	.proc_read	= seq_read,
+	.proc_read_iter	= seq_read_iter,
 	.proc_lseek	= seq_lseek,
 	.proc_release	= single_release,
 	.proc_write	= exitcode_proc_write,
diff --git a/arch/um/kernel/process.c b/arch/um/kernel/process.c
index 3bed09538dd951..da35249c37139b 100644
--- a/arch/um/kernel/process.c
+++ b/arch/um/kernel/process.c
@@ -312,7 +312,7 @@ static ssize_t sysemu_proc_write(struct file *file, const char __user *buf,
 
 static const struct proc_ops sysemu_proc_ops = {
 	.proc_open	= sysemu_proc_open,
-	.proc_read	= seq_read,
+	.proc_read_iter	= seq_read_iter,
 	.proc_lseek	= seq_lseek,
 	.proc_release	= single_release,
 	.proc_write	= sysemu_proc_write,
diff --git a/arch/x86/kernel/cpu/mtrr/if.c b/arch/x86/kernel/cpu/mtrr/if.c
index a5c506f6da7fa1..f5743b5ecaf232 100644
--- a/arch/x86/kernel/cpu/mtrr/if.c
+++ b/arch/x86/kernel/cpu/mtrr/if.c
@@ -398,7 +398,7 @@ static int mtrr_open(struct inode *inode, struct file *file)
 
 static const struct proc_ops mtrr_proc_ops = {
 	.proc_open		= mtrr_open,
-	.proc_read		= seq_read,
+	.proc_read_iter		= seq_read_iter,
 	.proc_lseek		= seq_lseek,
 	.proc_write		= mtrr_write,
 	.proc_ioctl		= mtrr_ioctl,
diff --git a/drivers/acpi/proc.c b/drivers/acpi/proc.c
index 0cca7991f18643..6b827eb76038d2 100644
--- a/drivers/acpi/proc.c
+++ b/drivers/acpi/proc.c
@@ -132,7 +132,7 @@ acpi_system_wakeup_device_open_fs(struct inode *inode, struct file *file)
 
 static const struct proc_ops acpi_system_wakeup_device_proc_ops = {
 	.proc_open	= acpi_system_wakeup_device_open_fs,
-	.proc_read	= seq_read,
+	.proc_read_iter	= seq_read_iter,
 	.proc_write	= acpi_system_write_wakeup_device,
 	.proc_lseek	= seq_lseek,
 	.proc_release	= single_release,
diff --git a/drivers/hwmon/dell-smm-hwmon.c b/drivers/hwmon/dell-smm-hwmon.c
index ec448f5f2dc330..976acbbe8ce91a 100644
--- a/drivers/hwmon/dell-smm-hwmon.c
+++ b/drivers/hwmon/dell-smm-hwmon.c
@@ -597,7 +597,7 @@ static int i8k_open_fs(struct inode *inode, struct file *file)
 
 static const struct proc_ops i8k_proc_ops = {
 	.proc_open	= i8k_open_fs,
-	.proc_read	= seq_read,
+	.proc_read_iter	= seq_read_iter,
 	.proc_lseek	= seq_lseek,
 	.proc_release	= single_release,
 	.proc_ioctl	= i8k_ioctl,
diff --git a/drivers/ide/ide-proc.c b/drivers/ide/ide-proc.c
index 15c17f3781ee91..7021976d3ad529 100644
--- a/drivers/ide/ide-proc.c
+++ b/drivers/ide/ide-proc.c
@@ -383,7 +383,7 @@ static ssize_t ide_settings_proc_write(struct file *file, const char __user *buf
 
 static const struct proc_ops ide_settings_proc_ops = {
 	.proc_open	= ide_settings_proc_open,
-	.proc_read	= seq_read,
+	.proc_read_iter	= seq_read_iter,
 	.proc_lseek	= seq_lseek,
 	.proc_release	= single_release,
 	.proc_write	= ide_settings_proc_write,
diff --git a/drivers/input/input.c b/drivers/input/input.c
index 3cfd2c18eebd9d..c8180d7f92d576 100644
--- a/drivers/input/input.c
+++ b/drivers/input/input.c
@@ -1220,7 +1220,7 @@ static int input_proc_devices_open(struct inode *inode, struct file *file)
 static const struct proc_ops input_devices_proc_ops = {
 	.proc_open	= input_proc_devices_open,
 	.proc_poll	= input_proc_devices_poll,
-	.proc_read	= seq_read,
+	.proc_read_iter	= seq_read_iter,
 	.proc_lseek	= seq_lseek,
 	.proc_release	= seq_release,
 };
@@ -1282,7 +1282,7 @@ static int input_proc_handlers_open(struct inode *inode, struct file *file)
 
 static const struct proc_ops input_handlers_proc_ops = {
 	.proc_open	= input_proc_handlers_open,
-	.proc_read	= seq_read,
+	.proc_read_iter	= seq_read_iter,
 	.proc_lseek	= seq_lseek,
 	.proc_release	= seq_release,
 };
diff --git a/drivers/macintosh/via-pmu.c b/drivers/macintosh/via-pmu.c
index 73e6ae88fafd4e..9415eddb419402 100644
--- a/drivers/macintosh/via-pmu.c
+++ b/drivers/macintosh/via-pmu.c
@@ -973,7 +973,7 @@ static ssize_t pmu_options_proc_write(struct file *file,
 
 static const struct proc_ops pmu_options_proc_ops = {
 	.proc_open	= pmu_options_proc_open,
-	.proc_read	= seq_read,
+	.proc_read_iter	= seq_read_iter,
 	.proc_lseek	= seq_lseek,
 	.proc_release	= single_release,
 	.proc_write	= pmu_options_proc_write,
diff --git a/drivers/md/md.c b/drivers/md/md.c
index 98bac4f304ae26..11c0dc3fa2298a 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -8355,7 +8355,7 @@ static __poll_t mdstat_poll(struct file *filp, poll_table *wait)
 
 static const struct proc_ops mdstat_proc_ops = {
 	.proc_open	= md_seq_open,
-	.proc_read	= seq_read,
+	.proc_read_iter	= seq_read_iter,
 	.proc_lseek	= seq_lseek,
 	.proc_release	= seq_release,
 	.proc_poll	= mdstat_poll,
diff --git a/drivers/misc/sgi-gru/gruprocfs.c b/drivers/misc/sgi-gru/gruprocfs.c
index 97b8b38ab47dfd..fc9498ec797762 100644
--- a/drivers/misc/sgi-gru/gruprocfs.c
+++ b/drivers/misc/sgi-gru/gruprocfs.c
@@ -257,7 +257,7 @@ static int options_open(struct inode *inode, struct file *file)
 /* *INDENT-OFF* */
 static const struct proc_ops statistics_proc_ops = {
 	.proc_open	= statistics_open,
-	.proc_read	= seq_read,
+	.proc_read_iter	= seq_read_iter,
 	.proc_write	= statistics_write,
 	.proc_lseek	= seq_lseek,
 	.proc_release	= single_release,
@@ -265,7 +265,7 @@ static const struct proc_ops statistics_proc_ops = {
 
 static const struct proc_ops mcs_statistics_proc_ops = {
 	.proc_open	= mcs_statistics_open,
-	.proc_read	= seq_read,
+	.proc_read_iter	= seq_read_iter,
 	.proc_write	= mcs_statistics_write,
 	.proc_lseek	= seq_lseek,
 	.proc_release	= single_release,
@@ -273,7 +273,7 @@ static const struct proc_ops mcs_statistics_proc_ops = {
 
 static const struct proc_ops options_proc_ops = {
 	.proc_open	= options_open,
-	.proc_read	= seq_read,
+	.proc_read_iter	= seq_read_iter,
 	.proc_write	= options_write,
 	.proc_lseek	= seq_lseek,
 	.proc_release	= single_release,
diff --git a/drivers/net/wireless/intel/ipw2x00/libipw_module.c b/drivers/net/wireless/intel/ipw2x00/libipw_module.c
index 43bab92a4148f2..1929db6921d7e0 100644
--- a/drivers/net/wireless/intel/ipw2x00/libipw_module.c
+++ b/drivers/net/wireless/intel/ipw2x00/libipw_module.c
@@ -242,7 +242,7 @@ static ssize_t debug_level_proc_write(struct file *file,
 
 static const struct proc_ops debug_level_proc_ops = {
 	.proc_open	= debug_level_proc_open,
-	.proc_read	= seq_read,
+	.proc_read_iter	= seq_read_iter,
 	.proc_lseek	= seq_lseek,
 	.proc_release	= single_release,
 	.proc_write	= debug_level_proc_write,
diff --git a/drivers/net/wireless/intersil/hostap/hostap_download.c b/drivers/net/wireless/intersil/hostap/hostap_download.c
index 7c6a5a6d1d45d8..8980fd57b2eda4 100644
--- a/drivers/net/wireless/intersil/hostap/hostap_download.c
+++ b/drivers/net/wireless/intersil/hostap/hostap_download.c
@@ -234,7 +234,7 @@ static int prism2_download_aux_dump_proc_open(struct inode *inode, struct file *
 
 static const struct proc_ops prism2_download_aux_dump_proc_ops = {
 	.proc_open		= prism2_download_aux_dump_proc_open,
-	.proc_read		= seq_read,
+	.proc_read_iter		= seq_read_iter,
 	.proc_lseek		= seq_lseek,
 	.proc_release		= seq_release_private,
 };
diff --git a/drivers/parisc/led.c b/drivers/parisc/led.c
index 36c6613f7a36b7..d75df3977926b3 100644
--- a/drivers/parisc/led.c
+++ b/drivers/parisc/led.c
@@ -232,7 +232,7 @@ static ssize_t led_proc_write(struct file *file, const char __user *buf,
 
 static const struct proc_ops led_proc_ops = {
 	.proc_open	= led_proc_open,
-	.proc_read	= seq_read,
+	.proc_read_iter	= seq_read_iter,
 	.proc_lseek	= seq_lseek,
 	.proc_release	= single_release,
 	.proc_write	= led_proc_write,
diff --git a/drivers/platform/x86/thinkpad_acpi.c b/drivers/platform/x86/thinkpad_acpi.c
index e3810675090ac9..aa784b2b0d5ec5 100644
--- a/drivers/platform/x86/thinkpad_acpi.c
+++ b/drivers/platform/x86/thinkpad_acpi.c
@@ -909,7 +909,7 @@ static ssize_t dispatch_proc_write(struct file *file,
 
 static const struct proc_ops dispatch_proc_ops = {
 	.proc_open	= dispatch_proc_open,
-	.proc_read	= seq_read,
+	.proc_read_iter	= seq_read_iter,
 	.proc_lseek	= seq_lseek,
 	.proc_release	= single_release,
 	.proc_write	= dispatch_proc_write,
diff --git a/drivers/platform/x86/toshiba_acpi.c b/drivers/platform/x86/toshiba_acpi.c
index e557d757c64708..ba425abdaa6e3c 100644
--- a/drivers/platform/x86/toshiba_acpi.c
+++ b/drivers/platform/x86/toshiba_acpi.c
@@ -1428,7 +1428,7 @@ static ssize_t lcd_proc_write(struct file *file, const char __user *buf,
 
 static const struct proc_ops lcd_proc_ops = {
 	.proc_open	= lcd_proc_open,
-	.proc_read	= seq_read,
+	.proc_read_iter	= seq_read_iter,
 	.proc_lseek	= seq_lseek,
 	.proc_release	= single_release,
 	.proc_write	= lcd_proc_write,
@@ -1534,7 +1534,7 @@ static ssize_t video_proc_write(struct file *file, const char __user *buf,
 
 static const struct proc_ops video_proc_ops = {
 	.proc_open	= video_proc_open,
-	.proc_read	= seq_read,
+	.proc_read_iter	= seq_read_iter,
 	.proc_lseek	= seq_lseek,
 	.proc_release	= single_release,
 	.proc_write	= video_proc_write,
@@ -1611,7 +1611,7 @@ static ssize_t fan_proc_write(struct file *file, const char __user *buf,
 
 static const struct proc_ops fan_proc_ops = {
 	.proc_open	= fan_proc_open,
-	.proc_read	= seq_read,
+	.proc_read_iter	= seq_read_iter,
 	.proc_lseek	= seq_lseek,
 	.proc_release	= single_release,
 	.proc_write	= fan_proc_write,
@@ -1655,7 +1655,7 @@ static ssize_t keys_proc_write(struct file *file, const char __user *buf,
 
 static const struct proc_ops keys_proc_ops = {
 	.proc_open	= keys_proc_open,
-	.proc_read	= seq_read,
+	.proc_read_iter	= seq_read_iter,
 	.proc_lseek	= seq_lseek,
 	.proc_release	= single_release,
 	.proc_write	= keys_proc_write,
diff --git a/drivers/pnp/pnpbios/proc.c b/drivers/pnp/pnpbios/proc.c
index a806830e3a407f..10d0181c4430ab 100644
--- a/drivers/pnp/pnpbios/proc.c
+++ b/drivers/pnp/pnpbios/proc.c
@@ -212,7 +212,7 @@ static ssize_t pnpbios_proc_write(struct file *file, const char __user *buf,
 
 static const struct proc_ops pnpbios_proc_ops = {
 	.proc_open	= pnpbios_proc_open,
-	.proc_read	= seq_read,
+	.proc_read_iter	= seq_read_iter,
 	.proc_lseek	= seq_lseek,
 	.proc_release	= single_release,
 	.proc_write	= pnpbios_proc_write,
diff --git a/drivers/s390/block/dasd_proc.c b/drivers/s390/block/dasd_proc.c
index 62a859ea67f893..278f0dccc85ff1 100644
--- a/drivers/s390/block/dasd_proc.c
+++ b/drivers/s390/block/dasd_proc.c
@@ -322,7 +322,7 @@ static ssize_t dasd_stats_proc_write(struct file *file,
 
 static const struct proc_ops dasd_stats_proc_ops = {
 	.proc_open	= dasd_stats_proc_open,
-	.proc_read	= seq_read,
+	.proc_read_iter	= seq_read_iter,
 	.proc_lseek	= seq_lseek,
 	.proc_release	= single_release,
 	.proc_write	= dasd_stats_proc_write,
diff --git a/drivers/s390/cio/blacklist.c b/drivers/s390/cio/blacklist.c
index 4dd2eb63485699..05f58c453b060c 100644
--- a/drivers/s390/cio/blacklist.c
+++ b/drivers/s390/cio/blacklist.c
@@ -401,7 +401,7 @@ cio_ignore_proc_open(struct inode *inode, struct file *file)
 
 static const struct proc_ops cio_ignore_proc_ops = {
 	.proc_open	= cio_ignore_proc_open,
-	.proc_read	= seq_read,
+	.proc_read_iter	= seq_read_iter,
 	.proc_lseek	= seq_lseek,
 	.proc_release	= seq_release_private,
 	.proc_write	= cio_ignore_write,
diff --git a/drivers/scsi/scsi_devinfo.c b/drivers/scsi/scsi_devinfo.c
index ba84244c1b4f65..f2e42862e27f25 100644
--- a/drivers/scsi/scsi_devinfo.c
+++ b/drivers/scsi/scsi_devinfo.c
@@ -739,7 +739,7 @@ static ssize_t proc_scsi_devinfo_write(struct file *file,
 
 static const struct proc_ops scsi_devinfo_proc_ops = {
 	.proc_open	= proc_scsi_devinfo_open,
-	.proc_read	= seq_read,
+	.proc_read_iter	= seq_read_iter,
 	.proc_write	= proc_scsi_devinfo_write,
 	.proc_lseek	= seq_lseek,
 	.proc_release	= seq_release,
diff --git a/drivers/scsi/scsi_proc.c b/drivers/scsi/scsi_proc.c
index d6982d3557396b..81601a9e79c4db 100644
--- a/drivers/scsi/scsi_proc.c
+++ b/drivers/scsi/scsi_proc.c
@@ -86,7 +86,7 @@ static int proc_scsi_host_open(struct inode *inode, struct file *file)
 static const struct proc_ops proc_scsi_ops = {
 	.proc_open	= proc_scsi_host_open,
 	.proc_release	= single_release,
-	.proc_read	= seq_read,
+	.proc_read_iter	= seq_read_iter,
 	.proc_lseek	= seq_lseek,
 	.proc_write	= proc_scsi_host_write
 };
@@ -438,7 +438,7 @@ static int proc_scsi_open(struct inode *inode, struct file *file)
 
 static const struct proc_ops scsi_scsi_proc_ops = {
 	.proc_open	= proc_scsi_open,
-	.proc_read	= seq_read,
+	.proc_read_iter	= seq_read_iter,
 	.proc_write	= proc_scsi_write,
 	.proc_lseek	= seq_lseek,
 	.proc_release	= seq_release,
diff --git a/drivers/scsi/sg.c b/drivers/scsi/sg.c
index bfa8d77322d732..90810ae56afa4e 100644
--- a/drivers/scsi/sg.c
+++ b/drivers/scsi/sg.c
@@ -2321,7 +2321,7 @@ static ssize_t sg_proc_write_adio(struct file *filp, const char __user *buffer,
 			          size_t count, loff_t *off);
 static const struct proc_ops adio_proc_ops = {
 	.proc_open	= sg_proc_single_open_adio,
-	.proc_read	= seq_read,
+	.proc_read_iter	= seq_read_iter,
 	.proc_lseek	= seq_lseek,
 	.proc_write	= sg_proc_write_adio,
 	.proc_release	= single_release,
@@ -2332,7 +2332,7 @@ static ssize_t sg_proc_write_dressz(struct file *filp,
 		const char __user *buffer, size_t count, loff_t *off);
 static const struct proc_ops dressz_proc_ops = {
 	.proc_open	= sg_proc_single_open_dressz,
-	.proc_read	= seq_read,
+	.proc_read_iter	= seq_read_iter,
 	.proc_lseek	= seq_lseek,
 	.proc_write	= sg_proc_write_dressz,
 	.proc_release	= single_release,
diff --git a/drivers/staging/rtl8192u/ieee80211/ieee80211_module.c b/drivers/staging/rtl8192u/ieee80211/ieee80211_module.c
index c52540b734fd48..a47d32a2166f41 100644
--- a/drivers/staging/rtl8192u/ieee80211/ieee80211_module.c
+++ b/drivers/staging/rtl8192u/ieee80211/ieee80211_module.c
@@ -249,7 +249,7 @@ static int open_debug_level(struct inode *inode, struct file *file)
 
 static const struct proc_ops debug_level_proc_ops = {
 	.proc_open	= open_debug_level,
-	.proc_read	= seq_read,
+	.proc_read_iter	= seq_read_iter,
 	.proc_lseek	= seq_lseek,
 	.proc_write	= write_debug_level,
 	.proc_release	= single_release,
diff --git a/drivers/usb/gadget/function/rndis.c b/drivers/usb/gadget/function/rndis.c
index 64de9f1b874c55..562781b95101d3 100644
--- a/drivers/usb/gadget/function/rndis.c
+++ b/drivers/usb/gadget/function/rndis.c
@@ -1166,7 +1166,7 @@ static int rndis_proc_open(struct inode *inode, struct file *file)
 
 static const struct proc_ops rndis_proc_ops = {
 	.proc_open	= rndis_proc_open,
-	.proc_read	= seq_read,
+	.proc_read_iter	= seq_read_iter,
 	.proc_lseek	= seq_lseek,
 	.proc_release	= single_release,
 	.proc_write	= rndis_proc_write,
diff --git a/drivers/video/fbdev/via/viafbdev.c b/drivers/video/fbdev/via/viafbdev.c
index 22deb340a0484f..6cf91191de7f15 100644
--- a/drivers/video/fbdev/via/viafbdev.c
+++ b/drivers/video/fbdev/via/viafbdev.c
@@ -1175,7 +1175,7 @@ static ssize_t viafb_dvp0_proc_write(struct file *file,
 
 static const struct proc_ops viafb_dvp0_proc_ops = {
 	.proc_open	= viafb_dvp0_proc_open,
-	.proc_read	= seq_read,
+	.proc_read_iter	= seq_read_iter,
 	.proc_lseek	= seq_lseek,
 	.proc_release	= single_release,
 	.proc_write	= viafb_dvp0_proc_write,
@@ -1239,7 +1239,7 @@ static ssize_t viafb_dvp1_proc_write(struct file *file,
 
 static const struct proc_ops viafb_dvp1_proc_ops = {
 	.proc_open	= viafb_dvp1_proc_open,
-	.proc_read	= seq_read,
+	.proc_read_iter	= seq_read_iter,
 	.proc_lseek	= seq_lseek,
 	.proc_release	= single_release,
 	.proc_write	= viafb_dvp1_proc_write,
@@ -1273,7 +1273,7 @@ static ssize_t viafb_dfph_proc_write(struct file *file,
 
 static const struct proc_ops viafb_dfph_proc_ops = {
 	.proc_open	= viafb_dfph_proc_open,
-	.proc_read	= seq_read,
+	.proc_read_iter	= seq_read_iter,
 	.proc_lseek	= seq_lseek,
 	.proc_release	= single_release,
 	.proc_write	= viafb_dfph_proc_write,
@@ -1307,7 +1307,7 @@ static ssize_t viafb_dfpl_proc_write(struct file *file,
 
 static const struct proc_ops viafb_dfpl_proc_ops = {
 	.proc_open	= viafb_dfpl_proc_open,
-	.proc_read	= seq_read,
+	.proc_read_iter	= seq_read_iter,
 	.proc_lseek	= seq_lseek,
 	.proc_release	= single_release,
 	.proc_write	= viafb_dfpl_proc_write,
@@ -1442,7 +1442,7 @@ static ssize_t viafb_vt1636_proc_write(struct file *file,
 
 static const struct proc_ops viafb_vt1636_proc_ops = {
 	.proc_open	= viafb_vt1636_proc_open,
-	.proc_read	= seq_read,
+	.proc_read_iter	= seq_read_iter,
 	.proc_lseek	= seq_lseek,
 	.proc_release	= single_release,
 	.proc_write	= viafb_vt1636_proc_write,
@@ -1519,7 +1519,7 @@ static ssize_t viafb_iga1_odev_proc_write(struct file *file,
 
 static const struct proc_ops viafb_iga1_odev_proc_ops = {
 	.proc_open	= viafb_iga1_odev_proc_open,
-	.proc_read	= seq_read,
+	.proc_read_iter	= seq_read_iter,
 	.proc_lseek	= seq_lseek,
 	.proc_release	= single_release,
 	.proc_write	= viafb_iga1_odev_proc_write,
@@ -1558,7 +1558,7 @@ static ssize_t viafb_iga2_odev_proc_write(struct file *file,
 
 static const struct proc_ops viafb_iga2_odev_proc_ops = {
 	.proc_open	= viafb_iga2_odev_proc_open,
-	.proc_read	= seq_read,
+	.proc_read_iter	= seq_read_iter,
 	.proc_lseek	= seq_lseek,
 	.proc_release	= single_release,
 	.proc_write	= viafb_iga2_odev_proc_write,
diff --git a/fs/cifs/cifs_debug.c b/fs/cifs/cifs_debug.c
index 53588d7517b4d0..877763996fa987 100644
--- a/fs/cifs/cifs_debug.c
+++ b/fs/cifs/cifs_debug.c
@@ -619,7 +619,7 @@ static int cifs_stats_proc_open(struct inode *inode, struct file *file)
 
 static const struct proc_ops cifs_stats_proc_ops = {
 	.proc_open	= cifs_stats_proc_open,
-	.proc_read	= seq_read,
+	.proc_read_iter	= seq_read_iter,
 	.proc_lseek	= seq_lseek,
 	.proc_release	= single_release,
 	.proc_write	= cifs_stats_proc_write,
@@ -648,7 +648,7 @@ static int name##_open(struct inode *inode, struct file *file) \
 \
 static const struct proc_ops cifs_##name##_proc_fops = { \
 	.proc_open	= name##_open, \
-	.proc_read	= seq_read, \
+	.proc_read_iter	= seq_read_iter, \
 	.proc_lseek	= seq_lseek, \
 	.proc_release	= single_release, \
 	.proc_write	= name##_write, \
@@ -782,7 +782,7 @@ static ssize_t cifsFYI_proc_write(struct file *file, const char __user *buffer,
 
 static const struct proc_ops cifsFYI_proc_ops = {
 	.proc_open	= cifsFYI_proc_open,
-	.proc_read	= seq_read,
+	.proc_read_iter	= seq_read_iter,
 	.proc_lseek	= seq_lseek,
 	.proc_release	= single_release,
 	.proc_write	= cifsFYI_proc_write,
@@ -813,7 +813,7 @@ static ssize_t cifs_linux_ext_proc_write(struct file *file,
 
 static const struct proc_ops cifs_linux_ext_proc_ops = {
 	.proc_open	= cifs_linux_ext_proc_open,
-	.proc_read	= seq_read,
+	.proc_read_iter	= seq_read_iter,
 	.proc_lseek	= seq_lseek,
 	.proc_release	= single_release,
 	.proc_write	= cifs_linux_ext_proc_write,
@@ -844,7 +844,7 @@ static ssize_t cifs_lookup_cache_proc_write(struct file *file,
 
 static const struct proc_ops cifs_lookup_cache_proc_ops = {
 	.proc_open	= cifs_lookup_cache_proc_open,
-	.proc_read	= seq_read,
+	.proc_read_iter	= seq_read_iter,
 	.proc_lseek	= seq_lseek,
 	.proc_release	= single_release,
 	.proc_write	= cifs_lookup_cache_proc_write,
@@ -875,7 +875,7 @@ static ssize_t traceSMB_proc_write(struct file *file, const char __user *buffer,
 
 static const struct proc_ops traceSMB_proc_ops = {
 	.proc_open	= traceSMB_proc_open,
-	.proc_read	= seq_read,
+	.proc_read_iter	= seq_read_iter,
 	.proc_lseek	= seq_lseek,
 	.proc_release	= single_release,
 	.proc_write	= traceSMB_proc_write,
@@ -986,7 +986,7 @@ static ssize_t cifs_security_flags_proc_write(struct file *file,
 
 static const struct proc_ops cifs_security_flags_proc_ops = {
 	.proc_open	= cifs_security_flags_proc_open,
-	.proc_read	= seq_read,
+	.proc_read_iter	= seq_read_iter,
 	.proc_lseek	= seq_lseek,
 	.proc_release	= single_release,
 	.proc_write	= cifs_security_flags_proc_write,
diff --git a/fs/cifs/dfs_cache.c b/fs/cifs/dfs_cache.c
index 6ee849698962d1..7f47c009900409 100644
--- a/fs/cifs/dfs_cache.c
+++ b/fs/cifs/dfs_cache.c
@@ -215,7 +215,7 @@ static int dfscache_proc_open(struct inode *inode, struct file *file)
 
 const struct proc_ops dfscache_proc_ops = {
 	.proc_open	= dfscache_proc_open,
-	.proc_read	= seq_read,
+	.proc_read_iter	= seq_read_iter,
 	.proc_lseek	= seq_lseek,
 	.proc_release	= single_release,
 	.proc_write	= dfscache_proc_write,
diff --git a/fs/fscache/object-list.c b/fs/fscache/object-list.c
index e106a1a1600d82..fab5a4197f50c3 100644
--- a/fs/fscache/object-list.c
+++ b/fs/fscache/object-list.c
@@ -408,7 +408,7 @@ static int fscache_objlist_release(struct inode *inode, struct file *file)
 
 const struct proc_ops fscache_objlist_proc_ops = {
 	.proc_open	= fscache_objlist_open,
-	.proc_read	= seq_read,
+	.proc_read_iter	= seq_read_iter,
 	.proc_lseek	= seq_lseek,
 	.proc_release	= fscache_objlist_release,
 };
diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
index 0c7c42bd530f5e..9e0a0c003d336b 100644
--- a/fs/jbd2/journal.c
+++ b/fs/jbd2/journal.c
@@ -1257,7 +1257,7 @@ static int jbd2_seq_info_release(struct inode *inode, struct file *file)
 
 static const struct proc_ops jbd2_info_proc_ops = {
 	.proc_open	= jbd2_seq_info_open,
-	.proc_read	= seq_read,
+	.proc_read_iter	= seq_read_iter,
 	.proc_lseek	= seq_lseek,
 	.proc_release	= jbd2_seq_info_release,
 };
diff --git a/fs/jfs/jfs_debug.c b/fs/jfs/jfs_debug.c
index 44b62b3c322e9a..235df6bac1d71a 100644
--- a/fs/jfs/jfs_debug.c
+++ b/fs/jfs/jfs_debug.c
@@ -45,7 +45,7 @@ static ssize_t jfs_loglevel_proc_write(struct file *file,
 
 static const struct proc_ops jfs_loglevel_proc_ops = {
 	.proc_open	= jfs_loglevel_proc_open,
-	.proc_read	= seq_read,
+	.proc_read_iter	= seq_read_iter,
 	.proc_lseek	= seq_lseek,
 	.proc_release	= single_release,
 	.proc_write	= jfs_loglevel_proc_write,
diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c
index f6d5d783f4a45b..1045786cb4d54a 100644
--- a/fs/nfsd/nfsctl.c
+++ b/fs/nfsd/nfsctl.c
@@ -159,7 +159,7 @@ static int exports_proc_open(struct inode *inode, struct file *file)
 
 static const struct proc_ops exports_proc_ops = {
 	.proc_open	= exports_proc_open,
-	.proc_read	= seq_read,
+	.proc_read_iter	= seq_read_iter,
 	.proc_lseek	= seq_lseek,
 	.proc_release	= seq_release,
 };
diff --git a/fs/nfsd/stats.c b/fs/nfsd/stats.c
index b1bc582b0493e4..1076f87715ad88 100644
--- a/fs/nfsd/stats.c
+++ b/fs/nfsd/stats.c
@@ -86,7 +86,7 @@ static int nfsd_proc_open(struct inode *inode, struct file *file)
 
 static const struct proc_ops nfsd_proc_ops = {
 	.proc_open	= nfsd_proc_open,
-	.proc_read	= seq_read,
+	.proc_read_iter	= seq_read_iter,
 	.proc_lseek	= seq_lseek,
 	.proc_release	= single_release,
 };
diff --git a/fs/proc/cpuinfo.c b/fs/proc/cpuinfo.c
index d0989a443c77df..419760fd77bdd8 100644
--- a/fs/proc/cpuinfo.c
+++ b/fs/proc/cpuinfo.c
@@ -19,7 +19,7 @@ static int cpuinfo_open(struct inode *inode, struct file *file)
 static const struct proc_ops cpuinfo_proc_ops = {
 	.proc_flags	= PROC_ENTRY_PERMANENT,
 	.proc_open	= cpuinfo_open,
-	.proc_read	= seq_read,
+	.proc_read_iter	= seq_read_iter,
 	.proc_lseek	= seq_lseek,
 	.proc_release	= seq_release,
 };
diff --git a/fs/proc/generic.c b/fs/proc/generic.c
index 2f9fa179194d72..4323b28db5643a 100644
--- a/fs/proc/generic.c
+++ b/fs/proc/generic.c
@@ -590,7 +590,7 @@ static int proc_seq_release(struct inode *inode, struct file *file)
 static const struct proc_ops proc_seq_ops = {
 	/* not permanent -- can call into arbitrary seq_operations */
 	.proc_open	= proc_seq_open,
-	.proc_read	= seq_read,
+	.proc_read_iter	= seq_read_iter,
 	.proc_lseek	= seq_lseek,
 	.proc_release	= proc_seq_release,
 };
@@ -621,7 +621,7 @@ static int proc_single_open(struct inode *inode, struct file *file)
 static const struct proc_ops proc_single_ops = {
 	/* not permanent -- can call into arbitrary ->single_show */
 	.proc_open	= proc_single_open,
-	.proc_read	= seq_read,
+	.proc_read_iter	= seq_read_iter,
 	.proc_lseek	= seq_lseek,
 	.proc_release	= single_release,
 };
diff --git a/fs/proc/proc_net.c b/fs/proc/proc_net.c
index ed8a6306990c43..fb0cd45fcc2682 100644
--- a/fs/proc/proc_net.c
+++ b/fs/proc/proc_net.c
@@ -92,7 +92,7 @@ static int seq_release_net(struct inode *ino, struct file *f)
 
 static const struct proc_ops proc_net_seq_ops = {
 	.proc_open	= seq_open_net,
-	.proc_read	= seq_read,
+	.proc_read_iter	= seq_read_iter,
 	.proc_write	= proc_simple_write,
 	.proc_lseek	= seq_lseek,
 	.proc_release	= seq_release_net,
@@ -204,7 +204,7 @@ static int single_release_net(struct inode *ino, struct file *f)
 
 static const struct proc_ops proc_net_single_ops = {
 	.proc_open	= single_open_net,
-	.proc_read	= seq_read,
+	.proc_read_iter	= seq_read_iter,
 	.proc_write	= proc_simple_write,
 	.proc_lseek	= seq_lseek,
 	.proc_release	= single_release_net,
diff --git a/fs/proc/stat.c b/fs/proc/stat.c
index 46b3293015fe61..4695b6de315129 100644
--- a/fs/proc/stat.c
+++ b/fs/proc/stat.c
@@ -226,7 +226,7 @@ static int stat_open(struct inode *inode, struct file *file)
 static const struct proc_ops stat_proc_ops = {
 	.proc_flags	= PROC_ENTRY_PERMANENT,
 	.proc_open	= stat_open,
-	.proc_read	= seq_read,
+	.proc_read_iter	= seq_read_iter,
 	.proc_lseek	= seq_lseek,
 	.proc_release	= single_release,
 };
diff --git a/include/linux/seq_file.h b/include/linux/seq_file.h
index b83b3ae3c877f3..9285d7da7b53a6 100644
--- a/include/linux/seq_file.h
+++ b/include/linux/seq_file.h
@@ -187,7 +187,7 @@ static int __name ## _open(struct inode *inode, struct file *file)	\
 									\
 static const struct proc_ops __name ## _proc_ops = {			\
 	.proc_open	= __name ## _open,				\
-	.proc_read	= seq_read,					\
+	.proc_read_iter	= seq_read_iter,					\
 	.proc_lseek	= seq_lseek,					\
 	.proc_release	= single_release,				\
 }
diff --git a/ipc/util.c b/ipc/util.c
index cfa0045e748d55..189c835108afc8 100644
--- a/ipc/util.c
+++ b/ipc/util.c
@@ -887,7 +887,7 @@ static int sysvipc_proc_release(struct inode *inode, struct file *file)
 static const struct proc_ops sysvipc_proc_ops = {
 	.proc_flags	= PROC_ENTRY_PERMANENT,
 	.proc_open	= sysvipc_proc_open,
-	.proc_read	= seq_read,
+	.proc_read_iter	= seq_read_iter,
 	.proc_lseek	= seq_lseek,
 	.proc_release	= sysvipc_proc_release,
 };
diff --git a/kernel/irq/proc.c b/kernel/irq/proc.c
index 72513ed2a5fc66..f6545d40e056cc 100644
--- a/kernel/irq/proc.c
+++ b/kernel/irq/proc.c
@@ -200,7 +200,7 @@ static int irq_affinity_list_proc_open(struct inode *inode, struct file *file)
 
 static const struct proc_ops irq_affinity_proc_ops = {
 	.proc_open	= irq_affinity_proc_open,
-	.proc_read	= seq_read,
+	.proc_read_iter	= seq_read_iter,
 	.proc_lseek	= seq_lseek,
 	.proc_release	= single_release,
 	.proc_write	= irq_affinity_proc_write,
@@ -208,7 +208,7 @@ static const struct proc_ops irq_affinity_proc_ops = {
 
 static const struct proc_ops irq_affinity_list_proc_ops = {
 	.proc_open	= irq_affinity_list_proc_open,
-	.proc_read	= seq_read,
+	.proc_read_iter	= seq_read_iter,
 	.proc_lseek	= seq_lseek,
 	.proc_release	= single_release,
 	.proc_write	= irq_affinity_list_proc_write,
@@ -270,7 +270,7 @@ static int default_affinity_open(struct inode *inode, struct file *file)
 
 static const struct proc_ops default_affinity_proc_ops = {
 	.proc_open	= default_affinity_open,
-	.proc_read	= seq_read,
+	.proc_read_iter	= seq_read_iter,
 	.proc_lseek	= seq_lseek,
 	.proc_release	= single_release,
 	.proc_write	= default_affinity_write,
diff --git a/kernel/kallsyms.c b/kernel/kallsyms.c
index fe9de067771c34..9c85e881715dd4 100644
--- a/kernel/kallsyms.c
+++ b/kernel/kallsyms.c
@@ -738,7 +738,7 @@ const char *kdb_walk_kallsyms(loff_t *pos)
 
 static const struct proc_ops kallsyms_proc_ops = {
 	.proc_open	= kallsyms_open,
-	.proc_read	= seq_read,
+	.proc_read_iter	= seq_read_iter,
 	.proc_lseek	= seq_lseek,
 	.proc_release	= seq_release_private,
 };
diff --git a/kernel/latencytop.c b/kernel/latencytop.c
index 166d7bf49666b0..543c7f552c45ce 100644
--- a/kernel/latencytop.c
+++ b/kernel/latencytop.c
@@ -257,7 +257,7 @@ static int lstats_open(struct inode *inode, struct file *filp)
 
 static const struct proc_ops lstats_proc_ops = {
 	.proc_open	= lstats_open,
-	.proc_read	= seq_read,
+	.proc_read_iter	= seq_read_iter,
 	.proc_write	= lstats_write,
 	.proc_lseek	= seq_lseek,
 	.proc_release	= single_release,
diff --git a/kernel/locking/lockdep_proc.c b/kernel/locking/lockdep_proc.c
index 02ef87f50df29c..dc4dec091486b4 100644
--- a/kernel/locking/lockdep_proc.c
+++ b/kernel/locking/lockdep_proc.c
@@ -669,7 +669,7 @@ static int lock_stat_release(struct inode *inode, struct file *file)
 static const struct proc_ops lock_stat_proc_ops = {
 	.proc_open	= lock_stat_open,
 	.proc_write	= lock_stat_write,
-	.proc_read	= seq_read,
+	.proc_read_iter	= seq_read_iter,
 	.proc_lseek	= seq_lseek,
 	.proc_release	= lock_stat_release,
 };
diff --git a/kernel/module.c b/kernel/module.c
index a4fa44a652a757..0dae9d22120c52 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -4449,7 +4449,7 @@ static int modules_open(struct inode *inode, struct file *file)
 static const struct proc_ops modules_proc_ops = {
 	.proc_flags	= PROC_ENTRY_PERMANENT,
 	.proc_open	= modules_open,
-	.proc_read	= seq_read,
+	.proc_read_iter	= seq_read_iter,
 	.proc_lseek	= seq_lseek,
 	.proc_release	= seq_release,
 };
diff --git a/kernel/profile.c b/kernel/profile.c
index 6f69a4195d5630..101090397235ae 100644
--- a/kernel/profile.c
+++ b/kernel/profile.c
@@ -444,7 +444,7 @@ static ssize_t prof_cpu_mask_proc_write(struct file *file,
 
 static const struct proc_ops prof_cpu_mask_proc_ops = {
 	.proc_open	= prof_cpu_mask_proc_open,
-	.proc_read	= seq_read,
+	.proc_read_iter	= seq_read_iter,
 	.proc_lseek	= seq_lseek,
 	.proc_release	= single_release,
 	.proc_write	= prof_cpu_mask_proc_write,
diff --git a/kernel/sched/psi.c b/kernel/sched/psi.c
index 967732c0766c56..4c084d66746a73 100644
--- a/kernel/sched/psi.c
+++ b/kernel/sched/psi.c
@@ -1317,7 +1317,7 @@ static int psi_fop_release(struct inode *inode, struct file *file)
 
 static const struct proc_ops psi_io_proc_ops = {
 	.proc_open	= psi_io_open,
-	.proc_read	= seq_read,
+	.proc_read_iter	= seq_read_iter,
 	.proc_lseek	= seq_lseek,
 	.proc_write	= psi_io_write,
 	.proc_poll	= psi_fop_poll,
@@ -1326,7 +1326,7 @@ static const struct proc_ops psi_io_proc_ops = {
 
 static const struct proc_ops psi_memory_proc_ops = {
 	.proc_open	= psi_memory_open,
-	.proc_read	= seq_read,
+	.proc_read_iter	= seq_read_iter,
 	.proc_lseek	= seq_lseek,
 	.proc_write	= psi_memory_write,
 	.proc_poll	= psi_fop_poll,
@@ -1335,7 +1335,7 @@ static const struct proc_ops psi_memory_proc_ops = {
 
 static const struct proc_ops psi_cpu_proc_ops = {
 	.proc_open	= psi_cpu_open,
-	.proc_read	= seq_read,
+	.proc_read_iter	= seq_read_iter,
 	.proc_lseek	= seq_lseek,
 	.proc_write	= psi_cpu_write,
 	.proc_poll	= psi_fop_poll,
diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index bd7b3aaa93c380..7bb3a957664bd9 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -926,7 +926,7 @@ static const struct file_operations ddebug_proc_fops = {
 
 static const struct proc_ops proc_fops = {
 	.proc_open = ddebug_proc_open,
-	.proc_read = seq_read,
+	.proc_read_iter = seq_read_iter,
 	.proc_lseek = seq_lseek,
 	.proc_release = seq_release_private,
 	.proc_write = ddebug_proc_write
diff --git a/mm/slab_common.c b/mm/slab_common.c
index f9ccd5dc13f32a..bb341100a72bcd 100644
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -1049,7 +1049,7 @@ static int slabinfo_open(struct inode *inode, struct file *file)
 static const struct proc_ops slabinfo_proc_ops = {
 	.proc_flags	= PROC_ENTRY_PERMANENT,
 	.proc_open	= slabinfo_open,
-	.proc_read	= seq_read,
+	.proc_read_iter	= seq_read_iter,
 	.proc_write	= slabinfo_write,
 	.proc_lseek	= seq_lseek,
 	.proc_release	= seq_release,
diff --git a/mm/swapfile.c b/mm/swapfile.c
index c4a613688a175c..bb0d5cc00a2a54 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -2841,7 +2841,7 @@ static int swaps_open(struct inode *inode, struct file *file)
 static const struct proc_ops swaps_proc_ops = {
 	.proc_flags	= PROC_ENTRY_PERMANENT,
 	.proc_open	= swaps_open,
-	.proc_read	= seq_read,
+	.proc_read_iter	= seq_read_iter,
 	.proc_lseek	= seq_lseek,
 	.proc_release	= seq_release,
 	.proc_poll	= swaps_poll,
diff --git a/net/atm/mpoa_proc.c b/net/atm/mpoa_proc.c
index 829db9eba0cb95..fe8f822c7750a6 100644
--- a/net/atm/mpoa_proc.c
+++ b/net/atm/mpoa_proc.c
@@ -55,7 +55,7 @@ static int parse_qos(const char *buff);
 
 static const struct proc_ops mpc_proc_ops = {
 	.proc_open	= proc_mpc_open,
-	.proc_read	= seq_read,
+	.proc_read_iter	= seq_read_iter,
 	.proc_lseek	= seq_lseek,
 	.proc_write	= proc_mpc_write,
 	.proc_release	= seq_release,
diff --git a/net/core/pktgen.c b/net/core/pktgen.c
index 105978604ffdb3..8a60bbd76d1663 100644
--- a/net/core/pktgen.c
+++ b/net/core/pktgen.c
@@ -537,7 +537,7 @@ static int pgctrl_open(struct inode *inode, struct file *file)
 
 static const struct proc_ops pktgen_proc_ops = {
 	.proc_open	= pgctrl_open,
-	.proc_read	= seq_read,
+	.proc_read_iter	= seq_read_iter,
 	.proc_lseek	= seq_lseek,
 	.proc_write	= pgctrl_write,
 	.proc_release	= single_release,
@@ -1709,7 +1709,7 @@ static int pktgen_if_open(struct inode *inode, struct file *file)
 
 static const struct proc_ops pktgen_if_proc_ops = {
 	.proc_open	= pktgen_if_open,
-	.proc_read	= seq_read,
+	.proc_read_iter	= seq_read_iter,
 	.proc_lseek	= seq_lseek,
 	.proc_write	= pktgen_if_write,
 	.proc_release	= single_release,
@@ -1846,7 +1846,7 @@ static int pktgen_thread_open(struct inode *inode, struct file *file)
 
 static const struct proc_ops pktgen_thread_proc_ops = {
 	.proc_open	= pktgen_thread_open,
-	.proc_read	= seq_read,
+	.proc_read_iter	= seq_read_iter,
 	.proc_lseek	= seq_lseek,
 	.proc_write	= pktgen_thread_write,
 	.proc_release	= single_release,
diff --git a/net/ipv4/netfilter/ipt_CLUSTERIP.c b/net/ipv4/netfilter/ipt_CLUSTERIP.c
index a8b980ad11d4e1..40af4bbf45197c 100644
--- a/net/ipv4/netfilter/ipt_CLUSTERIP.c
+++ b/net/ipv4/netfilter/ipt_CLUSTERIP.c
@@ -806,7 +806,7 @@ static ssize_t clusterip_proc_write(struct file *file, const char __user *input,
 
 static const struct proc_ops clusterip_proc_ops = {
 	.proc_open	= clusterip_proc_open,
-	.proc_read	= seq_read,
+	.proc_read_iter	= seq_read_iter,
 	.proc_write	= clusterip_proc_write,
 	.proc_lseek	= seq_lseek,
 	.proc_release	= clusterip_proc_release,
diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index dc2a399cd9f4fa..e09cb3a175529e 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -239,7 +239,7 @@ static int rt_cache_seq_open(struct inode *inode, struct file *file)
 
 static const struct proc_ops rt_cache_proc_ops = {
 	.proc_open	= rt_cache_seq_open,
-	.proc_read	= seq_read,
+	.proc_read_iter	= seq_read_iter,
 	.proc_lseek	= seq_lseek,
 	.proc_release	= seq_release,
 };
@@ -330,7 +330,7 @@ static int rt_cpu_seq_open(struct inode *inode, struct file *file)
 
 static const struct proc_ops rt_cpu_proc_ops = {
 	.proc_open	= rt_cpu_seq_open,
-	.proc_read	= seq_read,
+	.proc_read_iter	= seq_read_iter,
 	.proc_lseek	= seq_lseek,
 	.proc_release	= seq_release,
 };
diff --git a/net/netfilter/xt_recent.c b/net/netfilter/xt_recent.c
index 606411869698e0..19c17b02de8496 100644
--- a/net/netfilter/xt_recent.c
+++ b/net/netfilter/xt_recent.c
@@ -618,7 +618,7 @@ recent_mt_proc_write(struct file *file, const char __user *input,
 
 static const struct proc_ops recent_mt_proc_ops = {
 	.proc_open	= recent_seq_open,
-	.proc_read	= seq_read,
+	.proc_read_iter	= seq_read_iter,
 	.proc_write	= recent_mt_proc_write,
 	.proc_release	= seq_release_private,
 	.proc_lseek	= seq_lseek,
diff --git a/net/sunrpc/cache.c b/net/sunrpc/cache.c
index 20c93b68505e6d..4547fa18b6b7cb 100644
--- a/net/sunrpc/cache.c
+++ b/net/sunrpc/cache.c
@@ -1624,7 +1624,7 @@ static int content_release_procfs(struct inode *inode, struct file *filp)
 
 static const struct proc_ops content_proc_ops = {
 	.proc_open	= content_open_procfs,
-	.proc_read	= seq_read,
+	.proc_read_iter	= seq_read_iter,
 	.proc_lseek	= seq_lseek,
 	.proc_release	= content_release_procfs,
 };
diff --git a/net/sunrpc/stats.c b/net/sunrpc/stats.c
index c964b48eaabae4..95b56f0e5a01e8 100644
--- a/net/sunrpc/stats.c
+++ b/net/sunrpc/stats.c
@@ -71,7 +71,7 @@ static int rpc_proc_open(struct inode *inode, struct file *file)
 
 static const struct proc_ops rpc_proc_ops = {
 	.proc_open	= rpc_proc_open,
-	.proc_read	= seq_read,
+	.proc_read_iter	= seq_read_iter,
 	.proc_lseek	= seq_lseek,
 	.proc_release	= single_release,
 };
diff --git a/sound/core/info.c b/sound/core/info.c
index 9fec3070f8ba30..7bddc2b89a42fc 100644
--- a/sound/core/info.c
+++ b/sound/core/info.c
@@ -426,7 +426,7 @@ static const struct proc_ops snd_info_text_entry_ops =
 	.proc_release	= snd_info_text_entry_release,
 	.proc_write	= snd_info_text_entry_write,
 	.proc_lseek	= seq_lseek,
-	.proc_read	= seq_read,
+	.proc_read_iter	= seq_read_iter,
 };
 
 static struct snd_info_entry *create_subdir(struct module *mod,
-- 
2.28.0

Re: [PATCH 3/3] proc: switch over direct seq_read method calls to seq_read_iter

[Greg KH]

On Thu, Oct 29, 2020 at 11:09:50AM +0100, Christoph Hellwig wrote:
> Switch over all instances used directly as methods using these sed
> expressions:
> 
> sed -i -e 's/\.proc_read\(\s*=\s*\)seq_read/\.proc_read_iter\1seq_read_iter/g'
> 
> This fixes a problem with the Android bionic test suite using /proc/cpuinfo
> and /proc/version for its splice based tests.
> 
> Fixes: 36e2c7421f02 ("fs: don't allow splice read/write without explicit ops")
> Reported-by: Greg KH <gregkh@linuxfoundation.org>
> Signed-off-by: Christoph Hellwig <hch@lst.de>

I tested some of these files, so might as well add my "mark":

Tested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Re: support splice reads on seq_file based procfs files

[Christoph Hellwig]

ping?

On Thu, Oct 29, 2020 at 11:09:47AM +0100, Christoph Hellwig wrote:
> Hi Al,
> 
> Greg reported a problem due to the fact that Android tests use procfs
> files to test splice, which stopped working with 5.10-rc1.  This series
> adds read_iter support for seq_file, and uses those for all proc files
> using seq_file to restore splice read support.
---end quoted text---

Re: support splice reads on seq_file based procfs files

[Linus Torvalds]

On Tue, Nov 3, 2020 at 10:48 AM Christoph Hellwig <hch@lst.de> wrote:
>
> ping?

It looked fine by me, although honestly, I'd prefer that last patch to
be the minimum possible if we want this for 5.10.

Yeah, that might technically be just cpuinfo, but I'd be ok with the
other read-only core proc files (ie I would *not* add it to anything
that has a .proc_write operation like the ones in proc_net.c).

IOW, I'd start with just cpuinfo_proc_ops, proc_seq_ops,
proc_single_ops, and stat_proc_ops.

Because honestly, I'd rather restrict splice() as much as possible
than try to say "everything should be able to do splice".

Hmm?

               Linus

Re: support splice reads on seq_file based procfs files

[Christoph Hellwig]

On Tue, Nov 03, 2020 at 10:57:10AM -0800, Linus Torvalds wrote:
> On Tue, Nov 3, 2020 at 10:48 AM Christoph Hellwig <hch@lst.de> wrote:
> >
> > ping?
> 
> It looked fine by me, although honestly, I'd prefer that last patch to
> be the minimum possible if we want this for 5.10.
> 
> Yeah, that might technically be just cpuinfo, but I'd be ok with the
> other read-only core proc files (ie I would *not* add it to anything
> that has a .proc_write operation like the ones in proc_net.c).
> 
> IOW, I'd start with just cpuinfo_proc_ops, proc_seq_ops,
> proc_single_ops, and stat_proc_ops.

I think Greg reported another test case hitting /proc/version

> 
> Because honestly, I'd rather restrict splice() as much as possible
> than try to say "everything should be able to do splice".

sure.

Re: support splice reads on seq_file based procfs files

[Linus Torvalds]

On Tue, Nov 3, 2020 at 11:02 AM Christoph Hellwig <hch@lst.de> wrote:
>
> > IOW, I'd start with just cpuinfo_proc_ops, proc_seq_ops,
> > proc_single_ops, and stat_proc_ops.
>
> I think Greg reported another test case hitting /proc/version

Yeah, that would be covered by that proc_single_ops case.

Those four cases should really handle all of the normal /proc seq ops.
Anything else is going to be something very special.

               Linus