replace checking for ->read/->aio_read presence with check in ->f_mode

Since we are about to introduce new methods (read_iter/write_iter), the
tests in a bunch of places would have to grow inconveniently.  Check
once (at open() time) and store results in ->f_mode as FMODE_CAN_READ
and FMODE_CAN_WRITE resp.  It might end up being a temporary measure -
once everything switches from ->aio_{read,write} to ->{read,write}_iter
it might make sense to return to open-coded checks.  We'll see...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

diff --git a/drivers/mtd/nand/nandsim.c b/drivers/mtd/nand/nandsim.c
index 42e8a77..4f0d836 100644 (file)
--- a/drivers/mtd/nand/nandsim.c
+++ b/drivers/mtd/nand/nandsim.c
@@ -575,12 +575,12 @@ 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->read && !cfile->f_op->aio_read) {
+               if (!(cfile->f_mode & FMODE_CAN_READ)) {
                        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 (!(cfile->f_mode & FMODE_CAN_WRITE)) {
                        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 ec20a1f..a8898df 100644 (file)
--- a/drivers/usb/gadget/storage_common.c
+++ b/drivers/usb/gadget/storage_common.c
@@ -220,11 +220,11 @@ 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 (!(filp->f_mode & FMODE_CAN_READ)) {
                LINFO(curlun, "file not readable: %s\n", filename);
                goto out;
        }
-       if (!(filp->f_op->write || filp->f_op->aio_write))
+       if (!(filp->f_mode & FMODE_CAN_WRITE))
                ro = 1;
 
        size = i_size_read(inode->i_mapping->host);

diff --git a/fs/file_table.c b/fs/file_table.c
index a374f50..be73cbc 100644 (file)
--- a/fs/file_table.c
+++ b/fs/file_table.c
@@ -175,6 +175,10 @@ struct file *alloc_file(struct path *path, fmode_t mode,
        file->f_path = *path;
        file->f_inode = path->dentry->d_inode;
        file->f_mapping = path->dentry->d_inode->i_mapping;
+       if ((mode & FMODE_READ) && likely(fop->read || fop->aio_read))
+               mode |= FMODE_CAN_READ;
+       if ((mode & FMODE_WRITE) && likely(fop->write || fop->aio_write))
+               mode |= FMODE_CAN_WRITE;
        file->f_mode = mode;
        file->f_op = fop;
        if ((mode & (FMODE_READ | FMODE_WRITE)) == FMODE_READ)

diff --git a/fs/open.c b/fs/open.c
index 9d64679..39d3d04 100644 (file)
--- a/fs/open.c
+++ b/fs/open.c
@@ -725,6 +725,10 @@ static int do_dentry_open(struct file *f,
        }
        if ((f->f_mode & (FMODE_READ | FMODE_WRITE)) == FMODE_READ)
                i_readcount_inc(inode);
+       if ((f->f_mode & FMODE_READ) && likely(f->f_op->read || f->f_op->aio_read))
+               f->f_mode |= FMODE_CAN_READ;
+       if ((f->f_mode & FMODE_WRITE) && likely(f->f_op->write || f->f_op->aio_write))
+               f->f_mode |= FMODE_CAN_WRITE;
 
        f->f_flags &= ~(O_CREAT | O_EXCL | O_NOCTTY | O_TRUNC);
 

diff --git a/fs/read_write.c b/fs/read_write.c
index 31c6efa..d29d2a3 100644 (file)
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -396,7 +396,7 @@ 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->read && !file->f_op->aio_read)
+       if (!(file->f_mode & FMODE_CAN_READ))
                return -EINVAL;
        if (unlikely(!access_ok(VERIFY_WRITE, buf, count)))
                return -EFAULT;
@@ -445,7 +445,7 @@ 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->write && !file->f_op->aio_write)
+       if (!(file->f_mode & FMODE_CAN_WRITE))
                return -EINVAL;
 
        old_fs = get_fs();
@@ -472,7 +472,7 @@ 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->write && !file->f_op->aio_write)
+       if (!(file->f_mode & FMODE_CAN_WRITE))
                return -EINVAL;
        if (unlikely(!access_ok(VERIFY_READ, buf, count)))
                return -EFAULT;
@@ -785,7 +785,7 @@ ssize_t vfs_readv(struct file *file, const struct iovec __user *vec,
 {
        if (!(file->f_mode & FMODE_READ))
                return -EBADF;
-       if (!file->f_op->aio_read && !file->f_op->read)
+       if (!(file->f_mode & FMODE_CAN_READ))
                return -EINVAL;
 
        return do_readv_writev(READ, file, vec, vlen, pos);
@@ -798,7 +798,7 @@ ssize_t vfs_writev(struct file *file, const struct iovec __user *vec,
 {
        if (!(file->f_mode & FMODE_WRITE))
                return -EBADF;
-       if (!file->f_op->aio_write && !file->f_op->write)
+       if (!(file->f_mode & FMODE_CAN_WRITE))
                return -EINVAL;
 
        return do_readv_writev(WRITE, file, vec, vlen, pos);
@@ -964,7 +964,7 @@ static size_t compat_readv(struct file *file,
                goto out;
 
        ret = -EINVAL;
-       if (!file->f_op->aio_read && !file->f_op->read)
+       if (!(file->f_mode & FMODE_CAN_READ))
                goto out;
 
        ret = compat_do_readv_writev(READ, file, vec, vlen, pos);
@@ -1041,7 +1041,7 @@ static size_t compat_writev(struct file *file,
                goto out;
 
        ret = -EINVAL;
-       if (!file->f_op->aio_write && !file->f_op->write)
+       if (!(file->f_mode & FMODE_CAN_WRITE))
                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 8153396..75eb713 100644 (file)
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -128,6 +128,10 @@ typedef void (dio_iodone_t)(struct kiocb *iocb, loff_t offset,
 #define FMODE_ATOMIC_POS       ((__force fmode_t)0x8000)
 /* Write access to underlying fs */
 #define FMODE_WRITER           ((__force fmode_t)0x10000)
+/* Has read method(s) */
+#define FMODE_CAN_READ          ((__force fmode_t)0x20000)
+/* Has write method(s) */
+#define FMODE_CAN_WRITE         ((__force fmode_t)0x40000)
 
 /* File was opened by fanotify and shouldn't generate fanotify events */
 #define FMODE_NONOTIFY         ((__force fmode_t)0x1000000)