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Subject[PATCH 06/23] vfs: Teach read/write to use file_hotplug_read_lock
From: Eric W. Biederman <ebiederm@maxwell.arastra.com>

Signed-off-by: Eric W. Biederman <ebiederm@aristanetworks.com>
---
fs/compat.c | 16 +++++++++++-
fs/read_write.c | 70 +++++++++++++++++++++++++++++++++++++++++++++---------
2 files changed, 72 insertions(+), 14 deletions(-)

diff --git a/fs/compat.c b/fs/compat.c
index 25be41c..dad9957 100644
--- a/fs/compat.c
+++ b/fs/compat.c
@@ -1196,12 +1196,18 @@ static size_t compat_readv(struct file *file,
if (!(file->f_mode & FMODE_READ))
goto out;

+ ret = -EIO;
+ if (!file_hotplug_read_trylock(file))
+ goto out;
+
ret = -EINVAL;
if (!file->f_op || (!file->f_op->aio_read && !file->f_op->read))
- goto out;
+ goto out_unlock;

ret = compat_do_readv_writev(READ, file, vec, vlen, pos);

+out_unlock:
+ file_hotplug_read_unlock(file);
out:
if (ret > 0)
add_rchar(current, ret);
@@ -1253,12 +1259,18 @@ static size_t compat_writev(struct file *file,
if (!(file->f_mode & FMODE_WRITE))
goto out;

+ ret = -EIO;
+ if (!file_hotplug_read_trylock(file))
+ goto out;
+
ret = -EINVAL;
if (!file->f_op || (!file->f_op->aio_write && !file->f_op->write))
- goto out;
+ goto out_unlock;

ret = compat_do_readv_writev(WRITE, file, vec, vlen, pos);

+out_unlock:
+ file_hotplug_read_unlock(file);
out:
if (ret > 0)
add_wchar(current, ret);
diff --git a/fs/read_write.c b/fs/read_write.c
index c9511ce..718baea 100644
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -288,12 +288,18 @@ ssize_t vfs_read(struct file *file, char __user *buf, size_t count, loff_t *pos)
{
ssize_t ret;

+ ret = -EBADF;
if (!(file->f_mode & FMODE_READ))
- return -EBADF;
+ goto out;
+ ret = -EIO;
+ if (!file_hotplug_read_trylock(file))
+ goto out;
+ ret = -EINVAL;
if (!file->f_op || (!file->f_op->read && !file->f_op->aio_read))
- return -EINVAL;
+ goto out_unlock;
+ ret = -EFAULT;
if (unlikely(!access_ok(VERIFY_WRITE, buf, count)))
- return -EFAULT;
+ goto out_unlock;

ret = rw_verify_area(READ, file, pos, count);
if (ret >= 0) {
@@ -309,6 +315,9 @@ ssize_t vfs_read(struct file *file, char __user *buf, size_t count, loff_t *pos)
inc_syscr(current);
}

+out_unlock:
+ file_hotplug_read_unlock(file);
+out:
return ret;
}

@@ -343,12 +352,18 @@ ssize_t vfs_write(struct file *file, const char __user *buf, size_t count, loff_
{
ssize_t ret;

+ ret = -EBADF;
if (!(file->f_mode & FMODE_WRITE))
- return -EBADF;
+ goto out;
+ ret = -EIO;
+ if (!file_hotplug_read_trylock(file))
+ goto out;
+ ret = -EINVAL;
if (!file->f_op || (!file->f_op->write && !file->f_op->aio_write))
- return -EINVAL;
+ goto out_unlock;
+ ret = -EFAULT;
if (unlikely(!access_ok(VERIFY_READ, buf, count)))
- return -EFAULT;
+ goto out_unlock;

ret = rw_verify_area(WRITE, file, pos, count);
if (ret >= 0) {
@@ -364,6 +379,9 @@ ssize_t vfs_write(struct file *file, const char __user *buf, size_t count, loff_
inc_syscw(current);
}

+out_unlock:
+ file_hotplug_read_unlock(file);
+out:
return ret;
}

@@ -676,12 +694,26 @@ out:
ssize_t vfs_readv(struct file *file, const struct iovec __user *vec,
unsigned long vlen, loff_t *pos)
{
+ ssize_t ret;
+
+ ret = -EBADF;
if (!(file->f_mode & FMODE_READ))
- return -EBADF;
+ goto out;
+
+ ret = -EIO;
+ if (!file_hotplug_read_trylock(file))
+ goto out;
+
+ ret = -EINVAL;
if (!file->f_op || (!file->f_op->aio_read && !file->f_op->read))
- return -EINVAL;
+ goto out_unlock;
+
+ ret = do_readv_writev(READ, file, vec, vlen, pos);

- return do_readv_writev(READ, file, vec, vlen, pos);
+out_unlock:
+ file_hotplug_read_unlock(file);
+out:
+ return ret;
}

EXPORT_SYMBOL(vfs_readv);
@@ -689,12 +721,26 @@ EXPORT_SYMBOL(vfs_readv);
ssize_t vfs_writev(struct file *file, const struct iovec __user *vec,
unsigned long vlen, loff_t *pos)
{
+ ssize_t ret;
+
+ ret = -EBADF;
if (!(file->f_mode & FMODE_WRITE))
- return -EBADF;
+ goto out;
+
+ ret = -EIO;
+ if (!file_hotplug_read_trylock(file))
+ goto out;
+
+ ret = -EINVAL;
if (!file->f_op || (!file->f_op->aio_write && !file->f_op->write))
- return -EINVAL;
+ goto out_unlock;

- return do_readv_writev(WRITE, file, vec, vlen, pos);
+ ret = do_readv_writev(WRITE, file, vec, vlen, pos);
+
+out_unlock:
+ file_hotplug_read_unlock(file);
+out:
+ return ret;
}

EXPORT_SYMBOL(vfs_writev);
--
1.6.3.1.54.g99dd.dirty


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