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Date: Mon, 13 Dec 2021 14:19:07 +0000
From: "Matthew Wilcox (Oracle)" <willy@...radead.org>
To: Baoquan He <bhe@...hat.com>, Vivek Goyal <vgoyal@...hat.com>,
Dave Young <dyoung@...hat.com>, kexec@...ts.infradead.org
Cc: "Matthew Wilcox (Oracle)" <willy@...radead.org>,
Tiezhu Yang <yangtiezhu@...ngson.cn>,
linux-kernel@...r.kernel.org,
Amit Daniel Kachhap <amit.kachhap@....com>,
Christoph Hellwig <hch@....de>, linux-fsdevel@...r.kernel.org
Subject: [PATCH v2 3/3] iov-kaddr
---
fs/9p/vfs_dir.c | 5 +----
fs/9p/xattr.c | 6 ++----
include/linux/uio.h | 9 +++++++++
lib/iov_iter.c | 32 ++++++++++++++++++++++++++++++++
4 files changed, 44 insertions(+), 8 deletions(-)
diff --git a/fs/9p/vfs_dir.c b/fs/9p/vfs_dir.c
index 8c854d8cb0cd..cad6c24f9f0d 100644
--- a/fs/9p/vfs_dir.c
+++ b/fs/9p/vfs_dir.c
@@ -90,7 +90,6 @@ static int v9fs_dir_readdir(struct file *file, struct dir_context *ctx)
struct p9_fid *fid;
int buflen;
struct p9_rdir *rdir;
- struct kvec kvec;
p9_debug(P9_DEBUG_VFS, "name %pD\n", file);
fid = file->private_data;
@@ -100,15 +99,13 @@ static int v9fs_dir_readdir(struct file *file, struct dir_context *ctx)
rdir = v9fs_alloc_rdir_buf(file, buflen);
if (!rdir)
return -ENOMEM;
- kvec.iov_base = rdir->buf;
- kvec.iov_len = buflen;
while (1) {
if (rdir->tail == rdir->head) {
struct iov_iter to;
int n;
- iov_iter_kvec(&to, READ, &kvec, 1, buflen);
+ iov_iter_kaddr(&to, READ, rdir->buf, buflen);
n = p9_client_read(file->private_data, ctx->pos, &to,
&err);
if (err)
diff --git a/fs/9p/xattr.c b/fs/9p/xattr.c
index a824441b95a2..6fb0e7640605 100644
--- a/fs/9p/xattr.c
+++ b/fs/9p/xattr.c
@@ -20,11 +20,10 @@ ssize_t v9fs_fid_xattr_get(struct p9_fid *fid, const char *name,
ssize_t retval;
u64 attr_size;
struct p9_fid *attr_fid;
- struct kvec kvec = {.iov_base = buffer, .iov_len = buffer_size};
struct iov_iter to;
int err;
- iov_iter_kvec(&to, READ, &kvec, 1, buffer_size);
+ iov_iter_kaddr(&to, READ, buffer, buffer_size);
attr_fid = p9_client_xattrwalk(fid, name, &attr_size);
if (IS_ERR(attr_fid)) {
@@ -105,11 +104,10 @@ int v9fs_xattr_set(struct dentry *dentry, const char *name,
int v9fs_fid_xattr_set(struct p9_fid *fid, const char *name,
const void *value, size_t value_len, int flags)
{
- struct kvec kvec = {.iov_base = (void *)value, .iov_len = value_len};
struct iov_iter from;
int retval, err;
- iov_iter_kvec(&from, WRITE, &kvec, 1, value_len);
+ iov_iter_kaddr(&from, WRITE, (void *)value, value_len);
p9_debug(P9_DEBUG_VFS, "name = %s value_len = %zu flags = %d\n",
name, value_len, flags);
diff --git a/include/linux/uio.h b/include/linux/uio.h
index 6350354f97e9..cedbc1ca5c15 100644
--- a/include/linux/uio.h
+++ b/include/linux/uio.h
@@ -23,6 +23,7 @@ enum iter_type {
ITER_KVEC,
ITER_BVEC,
ITER_PIPE,
+ ITER_KADDR,
ITER_XARRAY,
ITER_DISCARD,
};
@@ -43,6 +44,7 @@ struct iov_iter {
const struct iovec *iov;
const struct kvec *kvec;
const struct bio_vec *bvec;
+ void *kaddr;
struct xarray *xarray;
struct pipe_inode_info *pipe;
};
@@ -79,6 +81,11 @@ static inline bool iov_iter_is_kvec(const struct iov_iter *i)
return iov_iter_type(i) == ITER_KVEC;
}
+static inline bool iov_iter_is_kaddr(const struct iov_iter *i)
+{
+ return iov_iter_type(i) == ITER_KVEC;
+}
+
static inline bool iov_iter_is_bvec(const struct iov_iter *i)
{
return iov_iter_type(i) == ITER_BVEC;
@@ -236,6 +243,8 @@ void iov_iter_init(struct iov_iter *i, unsigned int direction, const struct iove
unsigned long nr_segs, size_t count);
void iov_iter_kvec(struct iov_iter *i, unsigned int direction, const struct kvec *kvec,
unsigned long nr_segs, size_t count);
+void iov_iter_kaddr(struct iov_iter *i, unsigned int direction, void *kaddr,
+ size_t count);
void iov_iter_bvec(struct iov_iter *i, unsigned int direction, const struct bio_vec *bvec,
unsigned long nr_segs, size_t count);
void iov_iter_pipe(struct iov_iter *i, unsigned int direction, struct pipe_inode_info *pipe,
diff --git a/lib/iov_iter.c b/lib/iov_iter.c
index 66a740e6e153..64e6bc33176a 100644
--- a/lib/iov_iter.c
+++ b/lib/iov_iter.c
@@ -38,6 +38,22 @@
n = off; \
}
+#define iterate_kaddr(i, n, base, len, off, STEP) { \
+ void *base; \
+ size_t len; \
+ size_t off = 0; \
+ size_t skip = i->iov_offset; \
+ len = min(n, i->count - skip); \
+ if (likely(len)) { \
+ base = i->kaddr + skip; \
+ len -= (STEP); \
+ off += len; \
+ skip += len; \
+ } \
+ i->iov_offset = skip; \
+ n = off; \
+}
+
#define iterate_bvec(i, n, base, len, off, p, STEP) { \
size_t off = 0; \
unsigned skip = i->iov_offset; \
@@ -136,6 +152,8 @@ __out: \
kvec, (K)) \
i->nr_segs -= kvec - i->kvec; \
i->kvec = kvec; \
+ } else if (iov_iter_is_kaddr(i)) { \
+ iterate_kaddr(i, n, base, len, off, (K)) \
} else if (iov_iter_is_xarray(i)) { \
void *base; \
size_t len; \
@@ -1185,6 +1203,20 @@ void iov_iter_kvec(struct iov_iter *i, unsigned int direction,
}
EXPORT_SYMBOL(iov_iter_kvec);
+void iov_iter_kaddr(struct iov_iter *i, unsigned int direction,
+ void *kaddr, size_t count)
+{
+ WARN_ON(direction & ~(READ | WRITE));
+ *i = (struct iov_iter){
+ .iter_type = ITER_KADDR,
+ .data_source = direction,
+ .kaddr = kaddr,
+ .iov_offset = 0,
+ .count = count
+ };
+}
+EXPORT_SYMBOL(iov_iter_kaddr);
+
void iov_iter_bvec(struct iov_iter *i, unsigned int direction,
const struct bio_vec *bvec, unsigned long nr_segs,
size_t count)
--
2.33.0
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