From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Christoph Hellwig <hch@lst.de>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Sasha Levin <sashal@kernel.org>,
linux-fsdevel@vger.kernel.org
Subject: [PATCH AUTOSEL 5.9 53/55] seq_file: add seq_read_iter
Date: Mon, 9 Nov 2020 22:53:16 -0500 [thread overview]
Message-ID: <20201110035318.423757-53-sashal@kernel.org> (raw)
In-Reply-To: <20201110035318.423757-1-sashal@kernel.org>
From: Christoph Hellwig <hch@lst.de>
[ Upstream commit d4d50710a8b46082224376ef119a4dbb75b25c56 ]
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>
Tested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
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 31219c1db17de..3b20e21604e74 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 813614d4b71fb..b83b3ae3c877f 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);
--
2.27.0
next prev parent reply other threads:[~2020-11-10 3:54 UTC|newest]
Thread overview: 61+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-10 3:52 [PATCH AUTOSEL 5.9 01/55] ASoC: mediatek: mt8183-da7219: fix DAPM paths for rt1015 Sasha Levin
2020-11-10 3:52 ` [PATCH AUTOSEL 5.9 02/55] ASoC: qcom: sdm845: set driver name correctly Sasha Levin
2020-11-10 3:52 ` [PATCH AUTOSEL 5.9 03/55] ASoC: cs42l51: manage mclk shutdown delay Sasha Levin
2020-11-10 3:52 ` [PATCH AUTOSEL 5.9 04/55] ASoC: SOF: loader: handle all SOF_IPC_EXT types Sasha Levin
2020-11-10 3:52 ` [PATCH AUTOSEL 5.9 05/55] usb: dwc3: pci: add support for the Intel Alder Lake-S Sasha Levin
2020-11-10 3:52 ` [PATCH AUTOSEL 5.9 06/55] opp: Reduce the size of critical section in _opp_table_kref_release() Sasha Levin
2020-11-10 3:52 ` [PATCH AUTOSEL 5.9 07/55] usb: gadget: goku_udc: fix potential crashes in probe Sasha Levin
2020-11-10 3:52 ` [PATCH AUTOSEL 5.9 08/55] usb: raw-gadget: fix memory leak in gadget_setup Sasha Levin
2020-11-10 3:52 ` [PATCH AUTOSEL 5.9 09/55] selftests/ftrace: check for do_sys_openat2 in user-memory test Sasha Levin
2020-11-10 3:52 ` [PATCH AUTOSEL 5.9 10/55] selftests: pidfd: fix compilation errors due to wait.h Sasha Levin
2020-11-10 3:52 ` [PATCH AUTOSEL 5.9 11/55] ALSA: hda: Separate runtime and system suspend Sasha Levin
2020-11-10 3:52 ` [PATCH AUTOSEL 5.9 12/55] ALSA: hda: Reinstate runtime_allow() for all hda controllers Sasha Levin
2020-11-10 3:52 ` [PATCH AUTOSEL 5.9 13/55] x86/boot/compressed/64: Introduce sev_status Sasha Levin
2020-11-10 3:52 ` [PATCH AUTOSEL 5.9 14/55] gfs2: Free rd_bits later in gfs2_clear_rgrpd to fix use-after-free Sasha Levin
2020-11-10 3:52 ` [PATCH AUTOSEL 5.9 15/55] gfs2: Add missing truncate_inode_pages_final for sd_aspace Sasha Levin
2020-11-10 3:52 ` [PATCH AUTOSEL 5.9 16/55] gfs2: check for live vs. read-only file system in gfs2_fitrim Sasha Levin
2020-11-10 3:52 ` [PATCH AUTOSEL 5.9 17/55] scsi: hpsa: Fix memory leak in hpsa_init_one() Sasha Levin
2020-11-10 3:52 ` [PATCH AUTOSEL 5.9 18/55] drm/amdgpu: perform srbm soft reset always on SDMA resume Sasha Levin
2020-11-10 3:52 ` [PATCH AUTOSEL 5.9 19/55] drm/amd/pm: correct the baco reset sequence for CI ASICs Sasha Levin
2020-11-10 3:52 ` [PATCH AUTOSEL 5.9 20/55] drm/amd/pm: perform SMC reset on suspend/hibernation Sasha Levin
2020-11-10 3:52 ` [PATCH AUTOSEL 5.9 21/55] drm/amd/pm: do not use ixFEATURE_STATUS for checking smc running Sasha Levin
2020-11-10 3:52 ` [PATCH AUTOSEL 5.9 22/55] mac80211: fix use of skb payload instead of header Sasha Levin
2020-11-10 3:52 ` [PATCH AUTOSEL 5.9 23/55] cfg80211: initialize wdev data earlier Sasha Levin
2020-11-10 3:52 ` [PATCH AUTOSEL 5.9 24/55] mac80211: always wind down STA state Sasha Levin
2020-11-10 3:52 ` [PATCH AUTOSEL 5.9 25/55] cfg80211: regulatory: Fix inconsistent format argument Sasha Levin
2020-11-10 3:52 ` [PATCH AUTOSEL 5.9 26/55] wireguard: selftests: check that route_me_harder packets use the right sk Sasha Levin
2020-11-10 12:29 ` Jason A. Donenfeld
2020-11-10 17:21 ` Greg KH
2020-11-13 22:40 ` Jason A. Donenfeld
2020-11-10 3:52 ` [PATCH AUTOSEL 5.9 27/55] tracing: Fix the checking of stackidx in __ftrace_trace_stack Sasha Levin
2020-11-10 3:52 ` [PATCH AUTOSEL 5.9 28/55] Revert "nvme-pci: remove last_sq_tail" Sasha Levin
2020-11-10 3:52 ` [PATCH AUTOSEL 5.9 29/55] ARC: [plat-hsdk] Remap CCMs super early in asm boot trampoline Sasha Levin
2020-11-10 3:52 ` [PATCH AUTOSEL 5.9 30/55] scsi: scsi_dh_alua: Avoid crash during alua_bus_detach() Sasha Levin
2020-11-10 3:52 ` [PATCH AUTOSEL 5.9 31/55] scsi: mpt3sas: Fix timeouts observed while reenabling IRQ Sasha Levin
2020-11-10 3:52 ` [PATCH AUTOSEL 5.9 32/55] nvme: introduce nvme_sync_io_queues Sasha Levin
2020-11-10 3:52 ` [PATCH AUTOSEL 5.9 33/55] nvme-rdma: avoid race between time out and tear down Sasha Levin
2020-11-10 3:52 ` [PATCH AUTOSEL 5.9 34/55] nvme-tcp: " Sasha Levin
2020-11-10 3:52 ` [PATCH AUTOSEL 5.9 35/55] nvme-rdma: avoid repeated request completion Sasha Levin
2020-11-10 3:52 ` [PATCH AUTOSEL 5.9 36/55] nvme-tcp: " Sasha Levin
2020-11-10 3:53 ` [PATCH AUTOSEL 5.9 37/55] iommu/amd: Increase interrupt remapping table limit to 512 entries Sasha Levin
2020-11-10 3:53 ` [PATCH AUTOSEL 5.9 38/55] s390/smp: move rcu_cpu_starting() earlier Sasha Levin
2020-11-10 3:53 ` [PATCH AUTOSEL 5.9 39/55] vfio: platform: fix reference leak in vfio_platform_open Sasha Levin
2020-11-10 3:53 ` [PATCH AUTOSEL 5.9 40/55] vfio/pci: Bypass IGD init in case of -ENODEV Sasha Levin
2020-11-10 3:53 ` [PATCH AUTOSEL 5.9 41/55] i2c: mediatek: move dma reset before i2c reset Sasha Levin
2020-11-10 3:53 ` [PATCH AUTOSEL 5.9 42/55] net: usb: qmi_wwan: add Telit LE910Cx 0x1230 composition Sasha Levin
2020-11-10 3:53 ` [PATCH AUTOSEL 5.9 43/55] amd/amdgpu: Disable VCN DPG mode for Picasso Sasha Levin
2020-11-10 3:53 ` [PATCH AUTOSEL 5.9 44/55] kprobes: Tell lockdep about kprobe nesting Sasha Levin
2020-11-10 3:53 ` [PATCH AUTOSEL 5.9 45/55] iomap: clean up writeback state logic on writepage error Sasha Levin
2020-11-10 3:53 ` [PATCH AUTOSEL 5.9 46/55] selftests: proc: fix warning: _GNU_SOURCE redefined Sasha Levin
2020-11-10 3:53 ` [PATCH AUTOSEL 5.9 47/55] arm64: kexec_file: try more regions if loading segments fails Sasha Levin
2020-11-10 3:53 ` [PATCH AUTOSEL 5.9 48/55] riscv: Set text_offset correctly for M-Mode Sasha Levin
2020-11-10 3:53 ` [PATCH AUTOSEL 5.9 49/55] i2c: sh_mobile: implement atomic transfers Sasha Levin
2020-11-10 3:53 ` [PATCH AUTOSEL 5.9 50/55] i2c: designware: call i2c_dw_read_clear_intrbits_slave() once Sasha Levin
2020-11-10 3:53 ` [PATCH AUTOSEL 5.9 51/55] i2c: designware: slave should do WRITE_REQUESTED before WRITE_RECEIVED Sasha Levin
2020-11-10 3:53 ` [PATCH AUTOSEL 5.9 52/55] tpm_tis: Disable interrupts on ThinkPad T490s Sasha Levin
2020-11-10 3:53 ` Sasha Levin [this message]
2020-11-10 6:30 ` [PATCH AUTOSEL 5.9 53/55] seq_file: add seq_read_iter Greg Kroah-Hartman
2020-11-10 9:05 ` Christoph Hellwig
2020-11-10 17:35 ` Sasha Levin
2020-11-10 3:53 ` [PATCH AUTOSEL 5.9 54/55] vt: Disable KD_FONT_OP_COPY Sasha Levin
2020-11-10 3:53 ` [PATCH AUTOSEL 5.9 55/55] fork: fix copy_process(CLONE_PARENT) race with the exiting ->real_parent Sasha Levin
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