fs: create file_readable() and file_writable() functions

Create functions to simplify if file_ops contain either a read
or aio_read op, or likewise write or aio_write. We will be adding
read_iter and write_iter and don't need to be complicating the code
in multiple places.

Signed-off-by: Dave Kleikamp <dave.kleikamp@oracle.com>

diff --git a/drivers/mtd/nand/nandsim.c b/drivers/mtd/nand/nandsim.c
index cb38f3d94218b2c977437062f8f402d07941fd6c..6a44ba63be1dfce21572933a71cdb09e26038f00 100644 (file)
--- a/drivers/mtd/nand/nandsim.c
+++ b/drivers/mtd/nand/nandsim.c
@@ -576,12 +576,12 @@ static int alloc_device(struct nandsim *ns)
                cfile = filp_open(cache_file, O_CREAT | O_RDWR | O_LARGEFILE, 0600);
                if (IS_ERR(cfile))
                        return PTR_ERR(cfile);
-               if (!cfile->f_op || (!cfile->f_op->read && !cfile->f_op->aio_read)) {
+               if (!file_readable(cfile)) {
                        NS_ERR("alloc_device: cache file not readable\n");
                        err = -EINVAL;
                        goto err_close;
                }
-               if (!cfile->f_op->write && !cfile->f_op->aio_write) {
+               if (!file_writable(cfile)) {
                        NS_ERR("alloc_device: cache file not writeable\n");
                        err = -EINVAL;
                        goto err_close;

diff --git a/drivers/usb/gadget/storage_common.c b/drivers/usb/gadget/storage_common.c
index dbce3a9074e6ebac353ec891ecc7c6726c5359b7..a801a005540e3c3e5958b577302f40ad07b2eb1e 100644 (file)
--- a/drivers/usb/gadget/storage_common.c
+++ b/drivers/usb/gadget/storage_common.c
@@ -450,11 +450,11 @@ static int fsg_lun_open(struct fsg_lun *curlun, const char *filename)
         * If we can't read the file, it's no good.
         * If we can't write the file, use it read-only.
         */
-       if (!(filp->f_op->read || filp->f_op->aio_read)) {
+       if (!file_readable(filp)) {
                LINFO(curlun, "file not readable: %s\n", filename);
                goto out;
        }
-       if (!(filp->f_op->write || filp->f_op->aio_write))
+       if (!file_writable(filp))
                ro = 1;
 
        size = i_size_read(inode->i_mapping->host);

diff --git a/fs/read_write.c b/fs/read_write.c
index 122a3846d9e14270a26952e92b25971257ebd82b..022929ceabd3064431e6e638122de71e23a2c48d 100644 (file)
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -385,7 +385,7 @@ ssize_t vfs_read(struct file *file, char __user *buf, size_t count, loff_t *pos)
 
        if (!(file->f_mode & FMODE_READ))
                return -EBADF;
-       if (!file->f_op || (!file->f_op->read && !file->f_op->aio_read))
+       if (!file_readable(file))
                return -EINVAL;
        if (unlikely(!access_ok(VERIFY_WRITE, buf, count)))
                return -EFAULT;
@@ -435,7 +435,7 @@ ssize_t __kernel_write(struct file *file, const char *buf, size_t count, loff_t
        const char __user *p;
        ssize_t ret;
 
-       if (!file->f_op || (!file->f_op->write && !file->f_op->aio_write))
+       if (!file_writable(file))
                return -EINVAL;
 
        old_fs = get_fs();
@@ -462,7 +462,7 @@ ssize_t vfs_write(struct file *file, const char __user *buf, size_t count, loff_
 
        if (!(file->f_mode & FMODE_WRITE))
                return -EBADF;
-       if (!file->f_op || (!file->f_op->write && !file->f_op->aio_write))
+       if (!file_writable(file))
                return -EINVAL;
        if (unlikely(!access_ok(VERIFY_READ, buf, count)))
                return -EFAULT;
@@ -781,7 +781,7 @@ ssize_t vfs_readv(struct file *file, const struct iovec __user *vec,
 {
        if (!(file->f_mode & FMODE_READ))
                return -EBADF;
-       if (!file->f_op || (!file->f_op->aio_read && !file->f_op->read))
+       if (!file_readable(file))
                return -EINVAL;
 
        return do_readv_writev(READ, file, vec, vlen, pos);
@@ -794,7 +794,7 @@ ssize_t vfs_writev(struct file *file, const struct iovec __user *vec,
 {
        if (!(file->f_mode & FMODE_WRITE))
                return -EBADF;
-       if (!file->f_op || (!file->f_op->aio_write && !file->f_op->write))
+       if (!file_writable(file))
                return -EINVAL;
 
        return do_readv_writev(WRITE, file, vec, vlen, pos);
@@ -968,7 +968,7 @@ static size_t compat_readv(struct file *file,
                goto out;
 
        ret = -EINVAL;
-       if (!file->f_op || (!file->f_op->aio_read && !file->f_op->read))
+       if (!file_readable(file))
                goto out;
 
        ret = compat_do_readv_writev(READ, file, vec, vlen, pos);
@@ -1035,7 +1035,7 @@ static size_t compat_writev(struct file *file,
                goto out;
 
        ret = -EINVAL;
-       if (!file->f_op || (!file->f_op->aio_write && !file->f_op->write))
+       if (!file_writable(file))
                goto out;
 
        ret = compat_do_readv_writev(WRITE, file, vec, vlen, pos);

diff --git a/include/linux/fs.h b/include/linux/fs.h
index d716a29ae9a43a83d965f80cec496ef719a0a34b..fc1e2a8cbf85e67021eeb8b46ec9a84ca9f341a3 100644 (file)
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1652,6 +1652,16 @@ struct file_operations {
        int (*show_fdinfo)(struct seq_file *m, struct file *f);
 };
 
+static inline int file_readable(struct file *filp)
+{
+       return filp && (filp->f_op->read || filp->f_op->aio_read);
+}
+
+static inline int file_writable(struct file *filp)
+{
+       return filp && (filp->f_op->write || filp->f_op->aio_write);
+}
+
 struct inode_operations {
        struct dentry * (*lookup) (struct inode *,struct dentry *, unsigned int);
        void * (*follow_link) (struct dentry *, struct nameidata *);