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-rw-r--r--fs/pipe.c141
-rw-r--r--fs/splice.c4
-rw-r--r--include/linux/pipe_fs_i.h11
3 files changed, 126 insertions, 30 deletions
diff --git a/fs/pipe.c b/fs/pipe.c
index d9644fd9cc0..3941a7f78b5 100644
--- a/fs/pipe.c
+++ b/fs/pipe.c
@@ -55,7 +55,8 @@ void pipe_wait(struct pipe_inode_info *pipe)
}
static int
-pipe_iov_copy_from_user(void *to, struct iovec *iov, unsigned long len)
+pipe_iov_copy_from_user(void *to, struct iovec *iov, unsigned long len,
+ int atomic)
{
unsigned long copy;
@@ -64,8 +65,13 @@ pipe_iov_copy_from_user(void *to, struct iovec *iov, unsigned long len)
iov++;
copy = min_t(unsigned long, len, iov->iov_len);
- if (copy_from_user(to, iov->iov_base, copy))
- return -EFAULT;
+ if (atomic) {
+ if (__copy_from_user_inatomic(to, iov->iov_base, copy))
+ return -EFAULT;
+ } else {
+ if (copy_from_user(to, iov->iov_base, copy))
+ return -EFAULT;
+ }
to += copy;
len -= copy;
iov->iov_base += copy;
@@ -75,7 +81,8 @@ pipe_iov_copy_from_user(void *to, struct iovec *iov, unsigned long len)
}
static int
-pipe_iov_copy_to_user(struct iovec *iov, const void *from, unsigned long len)
+pipe_iov_copy_to_user(struct iovec *iov, const void *from, unsigned long len,
+ int atomic)
{
unsigned long copy;
@@ -84,8 +91,13 @@ pipe_iov_copy_to_user(struct iovec *iov, const void *from, unsigned long len)
iov++;
copy = min_t(unsigned long, len, iov->iov_len);
- if (copy_to_user(iov->iov_base, from, copy))
- return -EFAULT;
+ if (atomic) {
+ if (__copy_to_user_inatomic(iov->iov_base, from, copy))
+ return -EFAULT;
+ } else {
+ if (copy_to_user(iov->iov_base, from, copy))
+ return -EFAULT;
+ }
from += copy;
len -= copy;
iov->iov_base += copy;
@@ -94,6 +106,47 @@ pipe_iov_copy_to_user(struct iovec *iov, const void *from, unsigned long len)
return 0;
}
+/*
+ * Attempt to pre-fault in the user memory, so we can use atomic copies.
+ * Returns the number of bytes not faulted in.
+ */
+static int iov_fault_in_pages_write(struct iovec *iov, unsigned long len)
+{
+ while (!iov->iov_len)
+ iov++;
+
+ while (len > 0) {
+ unsigned long this_len;
+
+ this_len = min_t(unsigned long, len, iov->iov_len);
+ if (fault_in_pages_writeable(iov->iov_base, this_len))
+ break;
+
+ len -= this_len;
+ iov++;
+ }
+
+ return len;
+}
+
+/*
+ * Pre-fault in the user memory, so we can use atomic copies.
+ */
+static void iov_fault_in_pages_read(struct iovec *iov, unsigned long len)
+{
+ while (!iov->iov_len)
+ iov++;
+
+ while (len > 0) {
+ unsigned long this_len;
+
+ this_len = min_t(unsigned long, len, iov->iov_len);
+ fault_in_pages_readable(iov->iov_base, this_len);
+ len -= this_len;
+ iov++;
+ }
+}
+
static void anon_pipe_buf_release(struct pipe_inode_info *pipe,
struct pipe_buffer *buf)
{
@@ -111,15 +164,24 @@ static void anon_pipe_buf_release(struct pipe_inode_info *pipe,
}
void *generic_pipe_buf_map(struct pipe_inode_info *pipe,
- struct pipe_buffer *buf)
+ struct pipe_buffer *buf, int atomic)
{
+ if (atomic) {
+ buf->flags |= PIPE_BUF_FLAG_ATOMIC;
+ return kmap_atomic(buf->page, KM_USER0);
+ }
+
return kmap(buf->page);
}
void generic_pipe_buf_unmap(struct pipe_inode_info *pipe,
- struct pipe_buffer *buf)
+ struct pipe_buffer *buf, void *map_data)
{
- kunmap(buf->page);
+ if (buf->flags & PIPE_BUF_FLAG_ATOMIC) {
+ buf->flags &= ~PIPE_BUF_FLAG_ATOMIC;
+ kunmap_atomic(map_data, KM_USER0);
+ } else
+ kunmap(buf->page);
}
static int anon_pipe_buf_steal(struct pipe_inode_info *pipe,
@@ -183,7 +245,7 @@ pipe_readv(struct file *filp, const struct iovec *_iov,
struct pipe_buf_operations *ops = buf->ops;
void *addr;
size_t chars = buf->len;
- int error;
+ int error, atomic;
if (chars > total_len)
chars = total_len;
@@ -195,12 +257,21 @@ pipe_readv(struct file *filp, const struct iovec *_iov,
break;
}
- addr = ops->map(pipe, buf);
- error = pipe_iov_copy_to_user(iov, addr + buf->offset, chars);
- ops->unmap(pipe, buf);
+ atomic = !iov_fault_in_pages_write(iov, chars);
+redo:
+ addr = ops->map(pipe, buf, atomic);
+ error = pipe_iov_copy_to_user(iov, addr + buf->offset, chars, atomic);
+ ops->unmap(pipe, buf, addr);
if (unlikely(error)) {
+ /*
+ * Just retry with the slow path if we failed.
+ */
+ if (atomic) {
+ atomic = 0;
+ goto redo;
+ }
if (!ret)
- ret = -EFAULT;
+ ret = error;
break;
}
ret += chars;
@@ -304,21 +375,28 @@ pipe_writev(struct file *filp, const struct iovec *_iov,
int offset = buf->offset + buf->len;
if (ops->can_merge && offset + chars <= PAGE_SIZE) {
+ int error, atomic = 1;
void *addr;
- int error;
error = ops->pin(pipe, buf);
if (error)
goto out;
- addr = ops->map(pipe, buf);
+ iov_fault_in_pages_read(iov, chars);
+redo1:
+ addr = ops->map(pipe, buf, atomic);
error = pipe_iov_copy_from_user(offset + addr, iov,
- chars);
- ops->unmap(pipe, buf);
+ chars, atomic);
+ ops->unmap(pipe, buf, addr);
ret = error;
do_wakeup = 1;
- if (error)
+ if (error) {
+ if (atomic) {
+ atomic = 0;
+ goto redo1;
+ }
goto out;
+ }
buf->len += chars;
total_len -= chars;
ret = chars;
@@ -341,7 +419,8 @@ pipe_writev(struct file *filp, const struct iovec *_iov,
int newbuf = (pipe->curbuf + bufs) & (PIPE_BUFFERS-1);
struct pipe_buffer *buf = pipe->bufs + newbuf;
struct page *page = pipe->tmp_page;
- int error;
+ char *src;
+ int error, atomic = 1;
if (!page) {
page = alloc_page(GFP_HIGHUSER);
@@ -361,11 +440,27 @@ pipe_writev(struct file *filp, const struct iovec *_iov,
if (chars > total_len)
chars = total_len;
- error = pipe_iov_copy_from_user(kmap(page), iov, chars);
- kunmap(page);
+ iov_fault_in_pages_read(iov, chars);
+redo2:
+ if (atomic)
+ src = kmap_atomic(page, KM_USER0);
+ else
+ src = kmap(page);
+
+ error = pipe_iov_copy_from_user(src, iov, chars,
+ atomic);
+ if (atomic)
+ kunmap_atomic(src, KM_USER0);
+ else
+ kunmap(page);
+
if (unlikely(error)) {
+ if (atomic) {
+ atomic = 0;
+ goto redo2;
+ }
if (!ret)
- ret = -EFAULT;
+ ret = error;
break;
}
ret += chars;
diff --git a/fs/splice.c b/fs/splice.c
index 0a6916423e7..d4664a297ba 100644
--- a/fs/splice.c
+++ b/fs/splice.c
@@ -640,13 +640,13 @@ find_page:
/*
* Careful, ->map() uses KM_USER0!
*/
- char *src = buf->ops->map(info, buf);
+ char *src = buf->ops->map(info, buf, 1);
char *dst = kmap_atomic(page, KM_USER1);
memcpy(dst + offset, src + buf->offset, this_len);
flush_dcache_page(page);
kunmap_atomic(dst, KM_USER1);
- buf->ops->unmap(info, buf);
+ buf->ops->unmap(info, buf, src);
}
ret = mapping->a_ops->commit_write(file, page, offset, offset+this_len);
diff --git a/include/linux/pipe_fs_i.h b/include/linux/pipe_fs_i.h
index b8aae1fc518..4c054491e38 100644
--- a/include/linux/pipe_fs_i.h
+++ b/include/linux/pipe_fs_i.h
@@ -5,7 +5,8 @@
#define PIPE_BUFFERS (16)
-#define PIPE_BUF_FLAG_LRU 0x01
+#define PIPE_BUF_FLAG_LRU 0x01 /* page is on the LRU */
+#define PIPE_BUF_FLAG_ATOMIC 0x02 /* was atomically mapped */
struct pipe_buffer {
struct page *page;
@@ -28,8 +29,8 @@ struct pipe_buffer {
*/
struct pipe_buf_operations {
int can_merge;
- void * (*map)(struct pipe_inode_info *, struct pipe_buffer *);
- void (*unmap)(struct pipe_inode_info *, struct pipe_buffer *);
+ void * (*map)(struct pipe_inode_info *, struct pipe_buffer *, int);
+ void (*unmap)(struct pipe_inode_info *, struct pipe_buffer *, void *);
int (*pin)(struct pipe_inode_info *, struct pipe_buffer *);
void (*release)(struct pipe_inode_info *, struct pipe_buffer *);
int (*steal)(struct pipe_inode_info *, struct pipe_buffer *);
@@ -64,8 +65,8 @@ void free_pipe_info(struct inode * inode);
void __free_pipe_info(struct pipe_inode_info *);
/* Generic pipe buffer ops functions */
-void *generic_pipe_buf_map(struct pipe_inode_info *, struct pipe_buffer *);
-void generic_pipe_buf_unmap(struct pipe_inode_info *, struct pipe_buffer *);
+void *generic_pipe_buf_map(struct pipe_inode_info *, struct pipe_buffer *, int);
+void generic_pipe_buf_unmap(struct pipe_inode_info *, struct pipe_buffer *, void *);
void generic_pipe_buf_get(struct pipe_inode_info *, struct pipe_buffer *);
int generic_pipe_buf_pin(struct pipe_inode_info *, struct pipe_buffer *);
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2024-11-08 16:43:51 +0000