fs/backing-file: Convert to revert/override_creds_light()

As the credentials used by backing-file are long lived in relation to
the critical section (override_creds() -> revert_creds()) we can
replace them by their lighter alternatives.

Signed-off-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>

diff --git a/fs/backing-file.c b/fs/backing-file.c
index a38737592ec77b50fa4d417a98ca272ca5f89399..526ddb4d6f764e8d3b0566ec51c5efa90faff0ee 100644 (file)
--- a/fs/backing-file.c
+++ b/fs/backing-file.c
@@ -176,7 +176,7 @@ ssize_t backing_file_read_iter(struct file *file, struct iov_iter *iter,
            !(file->f_mode & FMODE_CAN_ODIRECT))
                return -EINVAL;
 
-       old_cred = override_creds(ctx->cred);
+       old_cred = override_creds_light(ctx->cred);
        if (is_sync_kiocb(iocb)) {
                rwf_t rwf = iocb_to_rw_flags(flags);
 
@@ -197,7 +197,7 @@ ssize_t backing_file_read_iter(struct file *file, struct iov_iter *iter,
                        backing_aio_cleanup(aio, ret);
        }
 out:
-       revert_creds(old_cred);
+       revert_creds_light(old_cred);
 
        if (ctx->accessed)
                ctx->accessed(iocb->ki_filp);
@@ -233,7 +233,7 @@ ssize_t backing_file_write_iter(struct file *file, struct iov_iter *iter,
         */
        flags &= ~IOCB_DIO_CALLER_COMP;
 
-       old_cred = override_creds(ctx->cred);
+       old_cred = override_creds_light(ctx->cred);
        if (is_sync_kiocb(iocb)) {
                rwf_t rwf = iocb_to_rw_flags(flags);
 
@@ -264,7 +264,7 @@ ssize_t backing_file_write_iter(struct file *file, struct iov_iter *iter,
                        backing_aio_cleanup(aio, ret);
        }
 out:
-       revert_creds(old_cred);
+       revert_creds_light(old_cred);
 
        return ret;
 }
@@ -281,9 +281,9 @@ ssize_t backing_file_splice_read(struct file *in, struct kiocb *iocb,
        if (WARN_ON_ONCE(!(in->f_mode & FMODE_BACKING)))
                return -EIO;
 
-       old_cred = override_creds(ctx->cred);
+       old_cred = override_creds_light(ctx->cred);
        ret = vfs_splice_read(in, &iocb->ki_pos, pipe, len, flags);
-       revert_creds(old_cred);
+       revert_creds_light(old_cred);
 
        if (ctx->accessed)
                ctx->accessed(iocb->ki_filp);
@@ -310,11 +310,11 @@ ssize_t backing_file_splice_write(struct pipe_inode_info *pipe,
        if (ret)
                return ret;
 
-       old_cred = override_creds(ctx->cred);
+       old_cred = override_creds_light(ctx->cred);
        file_start_write(out);
        ret = out->f_op->splice_write(pipe, out, &iocb->ki_pos, len, flags);
        file_end_write(out);
-       revert_creds(old_cred);
+       revert_creds_light(old_cred);
 
        if (ctx->end_write)
                ctx->end_write(iocb, ret);
@@ -337,9 +337,9 @@ int backing_file_mmap(struct file *file, struct vm_area_struct *vma,
 
        vma_set_file(vma, file);
 
-       old_cred = override_creds(ctx->cred);
+       old_cred = override_creds_light(ctx->cred);
        ret = call_mmap(vma->vm_file, vma);
-       revert_creds(old_cred);
+       revert_creds_light(old_cred);
 
        if (ctx->accessed)
                ctx->accessed(vma->vm_file);