* [PATCH 1/5] fuse: Rename FUSE_DIO_CUSE
2020-11-19 14:16 [PATCH 0/5] [RFC] MUSE: Userspace backed MTD Richard Weinberger
@ 2020-11-19 14:16 ` Richard Weinberger
2020-11-19 14:16 ` [PATCH 2/5] fuse: Export fuse_simple_request Richard Weinberger
` (4 subsequent siblings)
5 siblings, 0 replies; 7+ messages in thread
From: Richard Weinberger @ 2020-11-19 14:16 UTC (permalink / raw)
To: miklos
Cc: miquel.raynal, vigneshr, linux-fsdevel, linux-kernel, linux-mtd,
Richard Weinberger
MUSE needs to use this flag too, rename it to
FUSE_DIO_NOFS to denote that the DIO operation has no FUSE backed
inode.
Signed-off-by: Richard Weinberger <richard@nod.at>
---
fs/fuse/cuse.c | 4 ++--
fs/fuse/file.c | 4 ++--
fs/fuse/fuse_i.h | 4 ++--
3 files changed, 6 insertions(+), 6 deletions(-)
diff --git a/fs/fuse/cuse.c b/fs/fuse/cuse.c
index 45082269e698..55744430b0f0 100644
--- a/fs/fuse/cuse.c
+++ b/fs/fuse/cuse.c
@@ -96,7 +96,7 @@ static ssize_t cuse_read_iter(struct kiocb *kiocb, struct iov_iter *to)
struct fuse_io_priv io = FUSE_IO_PRIV_SYNC(kiocb);
loff_t pos = 0;
- return fuse_direct_io(&io, to, &pos, FUSE_DIO_CUSE);
+ return fuse_direct_io(&io, to, &pos, FUSE_DIO_NOFS);
}
static ssize_t cuse_write_iter(struct kiocb *kiocb, struct iov_iter *from)
@@ -108,7 +108,7 @@ static ssize_t cuse_write_iter(struct kiocb *kiocb, struct iov_iter *from)
* responsible for locking and sanity checks.
*/
return fuse_direct_io(&io, from, &pos,
- FUSE_DIO_WRITE | FUSE_DIO_CUSE);
+ FUSE_DIO_WRITE | FUSE_DIO_NOFS);
}
static int cuse_open(struct inode *inode, struct file *file)
diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index c03034e8c152..697e79032c73 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -1409,7 +1409,7 @@ ssize_t fuse_direct_io(struct fuse_io_priv *io, struct iov_iter *iter,
loff_t *ppos, int flags)
{
int write = flags & FUSE_DIO_WRITE;
- int cuse = flags & FUSE_DIO_CUSE;
+ int nofs = flags & FUSE_DIO_NOFS;
struct file *file = io->iocb->ki_filp;
struct inode *inode = file->f_mapping->host;
struct fuse_file *ff = file->private_data;
@@ -1430,7 +1430,7 @@ ssize_t fuse_direct_io(struct fuse_io_priv *io, struct iov_iter *iter,
return -ENOMEM;
ia->io = io;
- if (!cuse && fuse_range_is_writeback(inode, idx_from, idx_to)) {
+ if (!nofs && fuse_range_is_writeback(inode, idx_from, idx_to)) {
if (!write)
inode_lock(inode);
fuse_sync_writes(inode);
diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h
index d51598017d13..637caddff2a8 100644
--- a/fs/fuse/fuse_i.h
+++ b/fs/fuse/fuse_i.h
@@ -1140,8 +1140,8 @@ int fuse_do_open(struct fuse_mount *fm, u64 nodeid, struct file *file,
/** If set, it is WRITE; otherwise - READ */
#define FUSE_DIO_WRITE (1 << 0)
-/** CUSE pass fuse_direct_io() a file which f_mapping->host is not from FUSE */
-#define FUSE_DIO_CUSE (1 << 1)
+/** CUSE and MUSE pass fuse_direct_io() a file which f_mapping->host is not from FUSE */
+#define FUSE_DIO_NOFS (1 << 1)
ssize_t fuse_direct_io(struct fuse_io_priv *io, struct iov_iter *iter,
loff_t *ppos, int flags);
--
2.26.2
^ permalink raw reply related [flat|nested] 7+ messages in thread* [PATCH 2/5] fuse: Export fuse_simple_request
2020-11-19 14:16 [PATCH 0/5] [RFC] MUSE: Userspace backed MTD Richard Weinberger
2020-11-19 14:16 ` [PATCH 1/5] fuse: Rename FUSE_DIO_CUSE Richard Weinberger
@ 2020-11-19 14:16 ` Richard Weinberger
2020-11-19 14:16 ` [PATCH 3/5] fuse: Make cuse_parse_one a common helper Richard Weinberger
` (3 subsequent siblings)
5 siblings, 0 replies; 7+ messages in thread
From: Richard Weinberger @ 2020-11-19 14:16 UTC (permalink / raw)
To: miklos
Cc: miquel.raynal, vigneshr, linux-fsdevel, linux-kernel, linux-mtd,
Richard Weinberger
MUSE will use this function to issue requests,
so export it.
Signed-off-by: Richard Weinberger <richard@nod.at>
---
fs/fuse/dev.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c
index 588f8d1240aa..8b7209537683 100644
--- a/fs/fuse/dev.c
+++ b/fs/fuse/dev.c
@@ -522,6 +522,7 @@ ssize_t fuse_simple_request(struct fuse_mount *fm, struct fuse_args *args)
return ret;
}
+EXPORT_SYMBOL_GPL(fuse_simple_request);
static bool fuse_request_queue_background(struct fuse_req *req)
{
--
2.26.2
^ permalink raw reply related [flat|nested] 7+ messages in thread* [PATCH 3/5] fuse: Make cuse_parse_one a common helper
2020-11-19 14:16 [PATCH 0/5] [RFC] MUSE: Userspace backed MTD Richard Weinberger
2020-11-19 14:16 ` [PATCH 1/5] fuse: Rename FUSE_DIO_CUSE Richard Weinberger
2020-11-19 14:16 ` [PATCH 2/5] fuse: Export fuse_simple_request Richard Weinberger
@ 2020-11-19 14:16 ` Richard Weinberger
2020-11-19 14:16 ` [PATCH 4/5] mtd: Add MTD_MUSE flag Richard Weinberger
` (2 subsequent siblings)
5 siblings, 0 replies; 7+ messages in thread
From: Richard Weinberger @ 2020-11-19 14:16 UTC (permalink / raw)
To: miklos
Cc: miquel.raynal, vigneshr, linux-fsdevel, linux-kernel, linux-mtd,
Richard Weinberger
This function will be used by MUSE too, let's share it.
Signed-off-by: Richard Weinberger <richard@nod.at>
---
fs/fuse/Kconfig | 4 +++
fs/fuse/Makefile | 1 +
fs/fuse/cuse.c | 58 +----------------------------------------
fs/fuse/fuse_i.h | 3 +++
fs/fuse/helper.c | 68 ++++++++++++++++++++++++++++++++++++++++++++++++
5 files changed, 77 insertions(+), 57 deletions(-)
create mode 100644 fs/fuse/helper.c
diff --git a/fs/fuse/Kconfig b/fs/fuse/Kconfig
index 40ce9a1c12e5..9c8cc1e7b3a5 100644
--- a/fs/fuse/Kconfig
+++ b/fs/fuse/Kconfig
@@ -18,9 +18,13 @@ config FUSE_FS
If you want to develop a userspace FS, or if you want to use
a filesystem based on FUSE, answer Y or M.
+config FUSE_HELPER
+ def_bool n
+
config CUSE
tristate "Character device in Userspace support"
depends on FUSE_FS
+ select FUSE_HELPER
help
This FUSE extension allows character devices to be
implemented in userspace.
diff --git a/fs/fuse/Makefile b/fs/fuse/Makefile
index 8c7021fb2cd4..7a5768cce6be 100644
--- a/fs/fuse/Makefile
+++ b/fs/fuse/Makefile
@@ -9,5 +9,6 @@ obj-$(CONFIG_VIRTIO_FS) += virtiofs.o
fuse-y := dev.o dir.o file.o inode.o control.o xattr.o acl.o readdir.o
fuse-$(CONFIG_FUSE_DAX) += dax.o
+fuse-$(CONFIG_FUSE_HELPER) += helper.o
virtiofs-y := virtio_fs.o
diff --git a/fs/fuse/cuse.c b/fs/fuse/cuse.c
index 55744430b0f0..24c015547130 100644
--- a/fs/fuse/cuse.c
+++ b/fs/fuse/cuse.c
@@ -199,62 +199,6 @@ struct cuse_devinfo {
const char *name;
};
-/**
- * cuse_parse_one - parse one key=value pair
- * @pp: i/o parameter for the current position
- * @end: points to one past the end of the packed string
- * @keyp: out parameter for key
- * @valp: out parameter for value
- *
- * *@pp points to packed strings - "key0=val0\0key1=val1\0" which ends
- * at @end - 1. This function parses one pair and set *@keyp to the
- * start of the key and *@valp to the start of the value. Note that
- * the original string is modified such that the key string is
- * terminated with '\0'. *@pp is updated to point to the next string.
- *
- * RETURNS:
- * 1 on successful parse, 0 on EOF, -errno on failure.
- */
-static int cuse_parse_one(char **pp, char *end, char **keyp, char **valp)
-{
- char *p = *pp;
- char *key, *val;
-
- while (p < end && *p == '\0')
- p++;
- if (p == end)
- return 0;
-
- if (end[-1] != '\0') {
- pr_err("info not properly terminated\n");
- return -EINVAL;
- }
-
- key = val = p;
- p += strlen(p);
-
- if (valp) {
- strsep(&val, "=");
- if (!val)
- val = key + strlen(key);
- key = strstrip(key);
- val = strstrip(val);
- } else
- key = strstrip(key);
-
- if (!strlen(key)) {
- pr_err("zero length info key specified\n");
- return -EINVAL;
- }
-
- *pp = p;
- *keyp = key;
- if (valp)
- *valp = val;
-
- return 1;
-}
-
/**
* cuse_parse_dev_info - parse device info
* @p: device info string
@@ -275,7 +219,7 @@ static int cuse_parse_devinfo(char *p, size_t len, struct cuse_devinfo *devinfo)
int rc;
while (true) {
- rc = cuse_parse_one(&p, end, &key, &val);
+ rc = fuse_kv_parse_one(&p, end, &key, &val);
if (rc < 0)
return rc;
if (!rc)
diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h
index 637caddff2a8..d36c71568a80 100644
--- a/fs/fuse/fuse_i.h
+++ b/fs/fuse/fuse_i.h
@@ -1210,4 +1210,7 @@ void fuse_dax_inode_cleanup(struct inode *inode);
bool fuse_dax_check_alignment(struct fuse_conn *fc, unsigned int map_alignment);
void fuse_dax_cancel_work(struct fuse_conn *fc);
+/* helper.c */
+int fuse_kv_parse_one(char **pp, char *end, char **keyp, char **valp);
+
#endif /* _FS_FUSE_I_H */
diff --git a/fs/fuse/helper.c b/fs/fuse/helper.c
new file mode 100644
index 000000000000..35d37338445e
--- /dev/null
+++ b/fs/fuse/helper.c
@@ -0,0 +1,68 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Helper functions used by CUSE and MUSE
+ *
+ * Copyright (C) 2008-2009 SUSE Linux Products GmbH
+ * Copyright (C) 2008-2009 Tejun Heo <tj@kernel.org>
+ *
+ */
+
+#include <linux/string.h>
+#include <linux/module.h>
+
+/**
+ * fuse_kv_parse_one - parse one key=value pair
+ * @pp: i/o parameter for the current position
+ * @end: points to one past the end of the packed string
+ * @keyp: out parameter for key
+ * @valp: out parameter for value
+ *
+ * *@pp points to packed strings - "key0=val0\0key1=val1\0" which ends
+ * at @end - 1. This function parses one pair and set *@keyp to the
+ * start of the key and *@valp to the start of the value. Note that
+ * the original string is modified such that the key string is
+ * terminated with '\0'. *@pp is updated to point to the next string.
+ *
+ * RETURNS:
+ * 1 on successful parse, 0 on EOF, -errno on failure.
+ */
+int fuse_kv_parse_one(char **pp, char *end, char **keyp, char **valp)
+{
+ char *p = *pp;
+ char *key, *val;
+
+ while (p < end && *p == '\0')
+ p++;
+ if (p == end)
+ return 0;
+
+ if (end[-1] != '\0') {
+ pr_err("info not properly terminated\n");
+ return -EINVAL;
+ }
+
+ key = val = p;
+ p += strlen(p);
+
+ if (valp) {
+ strsep(&val, "=");
+ if (!val)
+ val = key + strlen(key);
+ key = strstrip(key);
+ val = strstrip(val);
+ } else
+ key = strstrip(key);
+
+ if (!strlen(key)) {
+ pr_err("zero length info key specified\n");
+ return -EINVAL;
+ }
+
+ *pp = p;
+ *keyp = key;
+ if (valp)
+ *valp = val;
+
+ return 1;
+}
+EXPORT_SYMBOL_GPL(fuse_kv_parse_one);
--
2.26.2
^ permalink raw reply related [flat|nested] 7+ messages in thread* [PATCH 4/5] mtd: Add MTD_MUSE flag
2020-11-19 14:16 [PATCH 0/5] [RFC] MUSE: Userspace backed MTD Richard Weinberger
` (2 preceding siblings ...)
2020-11-19 14:16 ` [PATCH 3/5] fuse: Make cuse_parse_one a common helper Richard Weinberger
@ 2020-11-19 14:16 ` Richard Weinberger
2020-11-19 14:16 ` [PATCH 5/5] fuse: Implement MUSE: MTD in userspace Richard Weinberger
2020-11-25 23:13 ` [PATCH 0/5] [RFC] MUSE: Userspace backed MTD Richard Weinberger
5 siblings, 0 replies; 7+ messages in thread
From: Richard Weinberger @ 2020-11-19 14:16 UTC (permalink / raw)
To: miklos
Cc: miquel.raynal, vigneshr, linux-fsdevel, linux-kernel, linux-mtd,
Richard Weinberger
This flag will get set if an MTD is implemeted in userspace
using MUSE.
Signed-off-by: Richard Weinberger <richard@nod.at>
---
include/uapi/mtd/mtd-abi.h | 1 +
1 file changed, 1 insertion(+)
diff --git a/include/uapi/mtd/mtd-abi.h b/include/uapi/mtd/mtd-abi.h
index 65b9db936557..2ad2217e3a96 100644
--- a/include/uapi/mtd/mtd-abi.h
+++ b/include/uapi/mtd/mtd-abi.h
@@ -105,6 +105,7 @@ struct mtd_write_req {
#define MTD_NO_ERASE 0x1000 /* No erase necessary */
#define MTD_POWERUP_LOCK 0x2000 /* Always locked after reset */
#define MTD_SLC_ON_MLC_EMULATION 0x4000 /* Emulate SLC behavior on MLC NANDs */
+#define MTD_MUSE 0x8000 /* This MTD is implemented in userspace */
/* Some common devices / combinations of capabilities */
#define MTD_CAP_ROM 0
--
2.26.2
^ permalink raw reply related [flat|nested] 7+ messages in thread* [PATCH 5/5] fuse: Implement MUSE: MTD in userspace
2020-11-19 14:16 [PATCH 0/5] [RFC] MUSE: Userspace backed MTD Richard Weinberger
` (3 preceding siblings ...)
2020-11-19 14:16 ` [PATCH 4/5] mtd: Add MTD_MUSE flag Richard Weinberger
@ 2020-11-19 14:16 ` Richard Weinberger
2020-11-25 23:13 ` [PATCH 0/5] [RFC] MUSE: Userspace backed MTD Richard Weinberger
5 siblings, 0 replies; 7+ messages in thread
From: Richard Weinberger @ 2020-11-19 14:16 UTC (permalink / raw)
To: miklos
Cc: miquel.raynal, vigneshr, linux-fsdevel, linux-kernel, linux-mtd,
Richard Weinberger
MUSE allows implementing a MTD in userspace.
So far userspace has control over mtd_read, mtd_write, mtd_erase,
and mtd_sync.
It can also set the following MTD parameters:
name, flags, site, writesize and erasesize.
That way advanced simulators for many type of flashes
can be implemented in userspace.
Signed-off-by: Richard Weinberger <richard@nod.at>
---
fs/fuse/Kconfig | 11 +
fs/fuse/Makefile | 1 +
fs/fuse/muse.c | 450 ++++++++++++++++++++++++++++++++++++++
include/uapi/linux/fuse.h | 25 ++-
4 files changed, 486 insertions(+), 1 deletion(-)
create mode 100644 fs/fuse/muse.c
diff --git a/fs/fuse/Kconfig b/fs/fuse/Kconfig
index 9c8cc1e7b3a5..2fc63dc18a53 100644
--- a/fs/fuse/Kconfig
+++ b/fs/fuse/Kconfig
@@ -56,3 +56,14 @@ config FUSE_DAX
If you want to allow mounting a Virtio Filesystem with the "dax"
option, answer Y.
+
+config MUSE
+ tristate "Memory Technology Device (MTD) in Userspace support"
+ depends on FUSE_FS
+ select FUSE_HELPER
+ select MTD
+ help
+ This FUSE extension allows an MTD to be implemented in userspace.
+
+ If you want to develop or use a userspace MTD based on MUSE,
+ answer Y or M.
diff --git a/fs/fuse/Makefile b/fs/fuse/Makefile
index 7a5768cce6be..67a7af3fb047 100644
--- a/fs/fuse/Makefile
+++ b/fs/fuse/Makefile
@@ -6,6 +6,7 @@
obj-$(CONFIG_FUSE_FS) += fuse.o
obj-$(CONFIG_CUSE) += cuse.o
obj-$(CONFIG_VIRTIO_FS) += virtiofs.o
+obj-$(CONFIG_MUSE) += muse.o
fuse-y := dev.o dir.o file.o inode.o control.o xattr.o acl.o readdir.o
fuse-$(CONFIG_FUSE_DAX) += dax.o
diff --git a/fs/fuse/muse.c b/fs/fuse/muse.c
new file mode 100644
index 000000000000..249907be9d98
--- /dev/null
+++ b/fs/fuse/muse.c
@@ -0,0 +1,450 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * MUSE: MTD in userspace
+ * Copyright (C) 2020 sigma star gmbh
+ * Author: Richard Weinberger <richard@nod.at>
+ */
+
+#define pr_fmt(fmt) "MUSE: " fmt
+
+#include <linux/anon_inodes.h>
+#include <linux/fuse.h>
+#include <linux/miscdevice.h>
+#include <linux/module.h>
+#include <linux/mtd/mtd.h>
+#include <linux/slab.h>
+
+#include "fuse_i.h"
+
+static struct file_operations muse_ctrl_fops;
+
+struct muse_conn {
+ struct fuse_mount fm;
+ struct fuse_conn fc;
+ struct fuse_file *ff;
+ struct mtd_info mtd;
+ struct file *dummy_file;
+ bool init_done;
+};
+
+struct muse_init_args {
+ struct fuse_args_pages ap;
+ struct muse_init_in in;
+ struct muse_init_out out;
+ struct page *page;
+ struct fuse_page_desc desc;
+};
+
+static int dummy_file_open(struct inode *inode, struct file *filp)
+{
+ WARN_ON_ONCE(1);
+ return -EIO;
+}
+
+static const struct file_operations dummy_file_ops = {
+ .open = dummy_file_open,
+};
+
+static void muse_fc_release(struct fuse_conn *fc)
+{
+ struct muse_conn *mc = container_of(fc, struct muse_conn, fc);
+
+ fput(mc->dummy_file);
+ kfree_rcu(mc, fc.rcu);
+}
+
+static int muse_mtd_erase(struct mtd_info *mtd, struct erase_info *instr)
+{
+ struct muse_conn *mc = mtd->priv;
+ struct fuse_mount *fm = &mc->fm;
+ struct muse_erase_in inarg;
+ FUSE_ARGS(args);
+
+ inarg.addr = instr->addr;
+ inarg.len = instr->len;
+
+ args.opcode = MUSE_ERASE;
+ args.nodeid = mc->ff->nodeid;
+ args.in_numargs = 1;
+ args.in_args[0].size = sizeof(inarg);
+ args.in_args[0].value = &inarg;
+
+ return fuse_simple_request(fm, &args);
+}
+
+static void muse_mtd_sync(struct mtd_info *mtd)
+{
+ struct muse_conn *mc = mtd->priv;
+ struct fuse_mount *fm = &mc->fm;
+ struct fuse_fsync_in inarg;
+ FUSE_ARGS(args);
+
+ memset(&inarg, 0, sizeof(inarg));
+ inarg.fh = mc->ff->fh;
+ inarg.fsync_flags = 0;
+
+ /*
+ * We reuse FUSE_FSYNC to sync the whole MTD.
+ */
+ args.opcode = FUSE_FSYNC;
+ args.nodeid = mc->ff->nodeid;
+ args.in_numargs = 1;
+ args.in_args[0].size = sizeof(inarg);
+ args.in_args[0].value = &inarg;
+
+ fuse_simple_request(fm, &args);
+}
+
+static int do_dio(struct kiocb *kiocb, struct iov_iter *iter, loff_t *pos, int flags)
+{
+ struct fuse_io_priv io = FUSE_IO_PRIV_SYNC(kiocb);
+
+ return fuse_direct_io(&io, iter, pos, flags);
+}
+
+static int muse_mtd_read(struct mtd_info *mtd, loff_t from, size_t len,
+ size_t *retlen, u_char *buf)
+{
+ struct kvec iov = { .iov_base = buf, .iov_len = len };
+ struct muse_conn *mc = mtd->priv;
+ struct kiocb kiocb;
+ struct iov_iter to;
+ loff_t pos = from;
+ int ret;
+
+ iov_iter_kvec(&to, READ, &iov, 1, len);
+ init_sync_kiocb(&kiocb, mc->dummy_file);
+
+ ret = do_dio(&kiocb, &to, &pos, FUSE_DIO_NOFS);
+
+ *retlen = len;
+ return len;
+}
+
+static int muse_mtd_write(struct mtd_info *mtd, loff_t to, size_t len,
+ size_t *retlen, const u_char *buf)
+{
+ struct kvec iov = { .iov_base = (u_char *)buf, .iov_len = len };
+ struct muse_conn *mc = mtd->priv;
+ struct iov_iter from;
+ struct kiocb kiocb;
+ loff_t pos = to;
+ int ret;
+
+ iov_iter_kvec(&from, WRITE, &iov, 1, len);
+ init_sync_kiocb(&kiocb, mc->dummy_file);
+
+ ret = do_dio(&kiocb, &from, &pos, FUSE_DIO_WRITE | FUSE_DIO_NOFS);
+
+ *retlen = len;
+ return 0;
+}
+
+static int muse_mtd_get_device(struct mtd_info *mtd)
+{
+ struct muse_conn *mc = mtd->priv;
+
+ fuse_conn_get(&mc->fc);
+
+ return 0;
+}
+
+static void muse_mtd_put_device(struct mtd_info *mtd)
+{
+ struct muse_conn *mc = mtd->priv;
+
+ fuse_conn_put(&mc->fc);
+}
+
+struct mtdreq {
+ const char *name;
+ struct mtd_info_user mi;
+};
+
+static int muse_parse_mtdreq(char *p, size_t len, struct mtd_info *mtd)
+{
+ struct mtdreq req = {};
+ char *end = p + len;
+ char *key, *val;
+ int ret;
+
+ for (;;) {
+ ret = fuse_kv_parse_one(&p, end, &key, &val);
+ if (ret < 0)
+ goto out;
+ if (!ret)
+ break;
+
+ if (strcmp(key, "NAME") == 0) {
+ req.name = val;
+ } else if (strcmp(key, "TYPE") == 0) {
+ req.mi.type = (uint8_t)simple_strtoul(val, NULL, 10);
+ } else if (strcmp(key, "FLAGS") == 0) {
+ req.mi.flags = simple_strtoul(val, NULL, 10);
+ } else if (strcmp(key, "SIZE") == 0) {
+ req.mi.size = simple_strtoul(val, NULL, 10);
+ } else if (strcmp(key, "WRITESIZE") == 0) {
+ req.mi.writesize = simple_strtoul(val, NULL, 10);
+ } else if (strcmp(key, "ERASESIZE") == 0) {
+ req.mi.erasesize = simple_strtoul(val, NULL, 10);
+ } else {
+ pr_warn("Ignoring unknown MTD param \"%s\"\n", key);
+ }
+ }
+
+ ret = -EINVAL;
+
+ if (!req.name)
+ goto out;
+
+ if (!req.mi.size || !req.mi.writesize || !req.mi.erasesize)
+ goto out;
+
+ if (req.mi.size % req.mi.writesize)
+ goto out;
+
+ if (req.mi.size % req.mi.erasesize)
+ goto out;
+
+ if (req.mi.flags & ~(MTD_WRITEABLE | MTD_BIT_WRITEABLE | MTD_NO_ERASE))
+ goto out;
+
+ if (req.mi.type == MTD_ABSENT || req.mi.type == MTD_UBIVOLUME)
+ goto out;
+
+ mtd->name = kstrdup(req.name, GFP_KERNEL);
+ if (!mtd->name) {
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ mtd->size = req.mi.size;
+ mtd->erasesize = req.mi.erasesize;
+ mtd->writesize = req.mi.writesize;
+ mtd->writebufsize = mtd->writesize;
+ mtd->type = req.mi.type;
+ mtd->flags = MTD_MUSE | req.mi.flags;
+
+ ret = 0;
+out:
+ return ret;
+}
+
+static void muse_process_init_reply(struct fuse_mount *fm,
+ struct fuse_args *args, int error)
+{
+ struct fuse_conn *fc = fm->fc;
+ struct muse_init_args *ia = container_of(args, struct muse_init_args, ap.args);
+ struct muse_conn *mc = container_of(fc, struct muse_conn, fc);
+ struct fuse_args_pages *ap = &ia->ap;
+ struct muse_init_out *arg = &ia->out;
+ struct page *page = ap->pages[0];
+ int ret;
+
+ if (error || arg->fuse_major != FUSE_KERNEL_VERSION || arg->fuse_minor < 33) {
+ goto abort;
+ }
+
+ fc->minor = arg->fuse_minor;
+ fc->max_read = max_t(unsigned int, arg->max_read, 4096);
+ fc->max_write = max_t(unsigned int, arg->max_write, 4096);
+
+ ret = muse_parse_mtdreq(page_address(page), ap->args.out_args[1].size,
+ &mc->mtd);
+ if (ret)
+ goto abort;
+
+ mc->ff = fuse_file_alloc(fm);
+ if (!mc->ff)
+ goto abort;
+
+ /*
+ * HACK:
+ * fuse_direct_io() expects a file object.
+ */
+ mc->dummy_file = anon_inode_getfile("[muse]", &dummy_file_ops, NULL, O_RDWR);
+ if (!mc->dummy_file)
+ goto abort_free_ff;
+
+ mc->dummy_file->private_data = mc->ff;
+
+ mc->ff->fh = 0;
+ mc->ff->open_flags = FOPEN_DIRECT_IO;
+
+ /*
+ * With MUSE there are no files, so we use one fuse file for the mtd object
+ * with nodeid FUSE_ROOT_ID.
+ */
+ mc->ff->nodeid = FUSE_ROOT_ID;
+
+ mc->mtd._erase = muse_mtd_erase;
+ mc->mtd._read = muse_mtd_read;
+ mc->mtd._sync = muse_mtd_sync;
+ mc->mtd._write = muse_mtd_write;
+ mc->mtd._get_device = muse_mtd_get_device;
+ mc->mtd._put_device = muse_mtd_put_device;
+ mc->mtd.priv = mc;
+ mc->mtd.owner = THIS_MODULE;
+
+ /*
+ * We want one READ/WRITE op per MTD io. So the MTD pagesize needs
+ * to fit into max_write/max_read:
+ */
+ if (fc->max_write < mc->mtd.writesize || fc->max_read < mc->mtd.writesize)
+ goto abort_put_file;
+
+ if (mtd_device_register(&mc->mtd, NULL, 0) != 0)
+ goto abort_put_file;
+
+ mc->init_done = true;
+
+ kfree(ia);
+ __free_page(page);
+ return;
+
+abort_put_file:
+ fput(mc->dummy_file);
+abort_free_ff:
+ fuse_file_free(mc->ff);
+abort:
+ fuse_abort_conn(fc);
+}
+
+static int muse_send_init(struct muse_conn *mc)
+{
+ struct fuse_mount *fm = &mc->fm;
+ struct fuse_args_pages *ap;
+ struct muse_init_args *ia;
+ struct page *page;
+ int ret = -ENOMEM;
+
+ BUILD_BUG_ON(MUSE_INIT_INFO_MAX > PAGE_SIZE);
+
+ page = alloc_page(GFP_KERNEL | __GFP_ZERO);
+ if (!page)
+ goto err;
+
+ ia = kzalloc(sizeof(*ia), GFP_KERNEL);
+ if (!ia)
+ goto err_page;
+
+ ap = &ia->ap;
+ ia->in.fuse_major = FUSE_KERNEL_VERSION;
+ ia->in.fuse_minor = FUSE_KERNEL_MINOR_VERSION;
+ ap->args.opcode = MUSE_INIT;
+ ap->args.in_numargs = 1;
+ ap->args.in_args[0].size = sizeof(ia->in);
+ ap->args.in_args[0].value = &ia->in;
+ ap->args.out_numargs = 2;
+ ap->args.out_args[0].size = sizeof(ia->out);
+ ap->args.out_args[0].value = &ia->out;
+ ap->args.out_args[1].size = MUSE_INIT_INFO_MAX;
+ ap->args.out_argvar = true;
+ ap->args.out_pages = true;
+ ap->num_pages = 1;
+ ap->pages = &ia->page;
+ ap->descs = &ia->desc;
+ ia->page = page;
+ ia->desc.length = ap->args.out_args[1].size;
+ ap->args.end = muse_process_init_reply;
+
+ ret = fuse_simple_background(fm, &ap->args, GFP_KERNEL);
+ if (ret)
+ goto err_ia;
+
+ return 0;
+
+err_ia:
+ kfree(ia);
+err_page:
+ __free_page(page);
+err:
+ return ret;
+}
+
+static int muse_ctrl_open(struct inode *inode, struct file *file)
+{
+ struct muse_conn *mc;
+ struct fuse_dev *fud;
+ int ret;
+
+ if (!capable(CAP_SYS_ADMIN)) {
+ ret = -EPERM;
+ goto err;
+ }
+
+ mc = kzalloc(sizeof(*mc), GFP_KERNEL);
+ if (!mc) {
+ ret = -ENOMEM;
+ goto err;
+ }
+
+ fuse_conn_init(&mc->fc, &mc->fm, get_user_ns(&init_user_ns),
+ &fuse_dev_fiq_ops, NULL);
+
+ fud = fuse_dev_alloc_install(&mc->fc);
+ if (!fud) {
+ ret = -ENOMEM;
+ goto err_free;
+ }
+
+ mc->fc.release = muse_fc_release;
+ mc->fc.initialized = 1;
+
+ ret = muse_send_init(mc);
+ if (ret)
+ goto err_dev;
+
+ file->private_data = fud;
+
+ return 0;
+
+err_dev:
+ fuse_dev_free(fud);
+ fuse_conn_put(&mc->fc);
+err_free:
+ kfree(mc);
+err:
+ return ret;
+}
+
+static int muse_ctrl_release(struct inode *inode, struct file *file)
+{
+ struct fuse_dev *fud = file->private_data;
+ struct muse_conn *mc = container_of(fud->fc, struct muse_conn, fc);
+
+ if (mc->init_done)
+ mtd_device_unregister(&mc->mtd);
+
+ fuse_conn_put(&mc->fc);
+
+ return fuse_dev_release(inode, file);
+}
+
+static struct miscdevice muse_ctrl_dev = {
+ .minor = MISC_DYNAMIC_MINOR,
+ .name = "muse",
+ .fops = &muse_ctrl_fops,
+};
+
+static int __init muse_init(void)
+{
+ muse_ctrl_fops = fuse_dev_operations;
+ muse_ctrl_fops.owner = THIS_MODULE;
+ muse_ctrl_fops.open = muse_ctrl_open;
+ muse_ctrl_fops.release = muse_ctrl_release;
+
+ return misc_register(&muse_ctrl_dev);
+}
+
+static void __exit muse_exit(void)
+{
+ misc_deregister(&muse_ctrl_dev);
+}
+
+module_init(muse_init);
+module_exit(muse_exit);
+
+MODULE_AUTHOR("Richard Weinberger <richard@nod.at>");
+MODULE_DESCRIPTION("MTD in userspace");
+MODULE_LICENSE("GPLv2");
diff --git a/include/uapi/linux/fuse.h b/include/uapi/linux/fuse.h
index 7233502ea991..7862c6df7e63 100644
--- a/include/uapi/linux/fuse.h
+++ b/include/uapi/linux/fuse.h
@@ -210,7 +210,7 @@
#define FUSE_KERNEL_VERSION 7
/** Minor version number of this interface */
-#define FUSE_KERNEL_MINOR_VERSION 32
+#define FUSE_KERNEL_MINOR_VERSION 33
/** The node ID of the root inode */
#define FUSE_ROOT_ID 1
@@ -483,6 +483,10 @@ enum fuse_opcode {
/* CUSE specific operations */
CUSE_INIT = 4096,
+ /* MUSE specific operations */
+ MUSE_INIT = 8192,
+ MUSE_ERASE = 8193,
+
/* Reserved opcodes: helpful to detect structure endian-ness */
CUSE_INIT_BSWAP_RESERVED = 1048576, /* CUSE_INIT << 8 */
FUSE_INIT_BSWAP_RESERVED = 436207616, /* FUSE_INIT << 24 */
@@ -936,4 +940,23 @@ struct fuse_removemapping_one {
#define FUSE_REMOVEMAPPING_MAX_ENTRY \
(PAGE_SIZE / sizeof(struct fuse_removemapping_one))
+#define MUSE_INIT_INFO_MAX 4096
+
+struct muse_init_in {
+ uint32_t fuse_major;
+ uint32_t fuse_minor;
+};
+
+struct muse_init_out {
+ uint32_t fuse_major;
+ uint32_t fuse_minor;
+ uint32_t max_read;
+ uint32_t max_write;
+};
+
+struct muse_erase_in {
+ uint64_t addr;
+ uint64_t len;
+};
+
#endif /* _LINUX_FUSE_H */
--
2.26.2
^ permalink raw reply related [flat|nested] 7+ messages in thread* Re: [PATCH 0/5] [RFC] MUSE: Userspace backed MTD
2020-11-19 14:16 [PATCH 0/5] [RFC] MUSE: Userspace backed MTD Richard Weinberger
` (4 preceding siblings ...)
2020-11-19 14:16 ` [PATCH 5/5] fuse: Implement MUSE: MTD in userspace Richard Weinberger
@ 2020-11-25 23:13 ` Richard Weinberger
5 siblings, 0 replies; 7+ messages in thread
From: Richard Weinberger @ 2020-11-25 23:13 UTC (permalink / raw)
To: Miklos Szeredi
Cc: Miquel Raynal, Vignesh Raghavendra, linux-fsdevel, linux-kernel,
linux-mtd
----- Ursprüngliche Mail -----
> When working with flash devices a common task is emulating them to run various
> tests or inspect dumps from real hardware. To achieve that we have plenty of
> emulators in the mtd subsystem: mtdram, block2mtd, nandsim.
>
> Each of them implements a adhoc MTD and have various drawbacks.
> Over the last years some developers tried to extend them but these attempts
> often got rejected because they added just more adhoc feature instead of
> addressing overall problems.
>
> MUSE is a novel approach to address the need of advanced MTD emulators.
> Advanced means in this context supporting different (vendor specific) image
> formats, different ways for fault injection (fuzzing) and recoding/replaying
> IOs to emulate power cuts.
>
> The core goal of MUSE is having the complexity on the userspace side and
> only a small MTD driver in kernelspace.
> While playing with different approaches I realized that FUSE offers everything
> we need. So MUSE is a little like CUSE except that it does not implement a
> bare character device but an MTD.
>
> To get early feedback I'm sending this series as RFC, so don't consider it as
> ready to merge yet.
>
> Open issues are:
>
> 1. Dummy file object
> The logic around fuse_direct_io() expects a file object.
> Unlike FUSE or CUSE we don't have such an object in MUSE because usually an
> MTD is not opened by userspace. The kernel uses the MTD and makes it available
> to filesystems or other layers such as mtdblock, mtdchar or UBI.
> Currently a anon inode is (ab)used for that.
> Maybe there is a better way?
FYI, I'll send an updated series soon. I rewrote the MUSE IO path to not use fuse_direct_io()
which made things much simpler and all hacks go away.
Thanks,
//richard
^ permalink raw reply [flat|nested] 7+ messages in thread