[PATCH RESEND v1] fuse: remove redundant buffer size checks for interrupt and forget requests

[Joanne Koong <joannelkoong@gmail.com>]

In fuse_dev_do_read(), there is already logic that ensures the buffer is
a minimum of at least FUSE_MIN_READ_BUFFER (8k) bytes.

This makes the buffer size checks for interrupt and forget requests
redundant as sizeof(struct fuse_in_header) + sizeof(struct
fuse_interrupt_in) and sizeof(struct fuse_in_header) + sizeof(struct
fuse_forget_in) are both less than FUSE_MIN_READ_BUFFER.

We can get rid of these checks.

Signed-off-by: Joanne Koong <joannelkoong@gmail.com>
---
 fs/fuse/dev.c | 18 ++++--------------
 1 file changed, 4 insertions(+), 14 deletions(-)

diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c
index 6fe0d8c263df..be4e66ed633c 100644
--- a/fs/fuse/dev.c
+++ b/fs/fuse/dev.c
@@ -1377,7 +1377,7 @@ static int request_pending(struct fuse_iqueue *fiq)
  */
 static int fuse_read_interrupt(struct fuse_iqueue *fiq,
 			       struct fuse_copy_state *cs,
-			       size_t nbytes, struct fuse_req *req)
+			       struct fuse_req *req)
 __releases(fiq->lock)
 {
 	struct fuse_in_header ih;
@@ -1394,8 +1394,6 @@ __releases(fiq->lock)
 	arg.unique = req->in.h.unique;
 
 	spin_unlock(&fiq->lock);
-	if (nbytes < reqsize)
-		return -EINVAL;
 
 	err = fuse_copy_one(cs, &ih, sizeof(ih));
 	if (!err)
@@ -1428,8 +1426,7 @@ static struct fuse_forget_link *fuse_dequeue_forget(struct fuse_iqueue *fiq,
 }
 
 static int fuse_read_single_forget(struct fuse_iqueue *fiq,
-				   struct fuse_copy_state *cs,
-				   size_t nbytes)
+				   struct fuse_copy_state *cs)
 __releases(fiq->lock)
 {
 	int err;
@@ -1446,8 +1443,6 @@ __releases(fiq->lock)
 
 	spin_unlock(&fiq->lock);
 	kfree(forget);
-	if (nbytes < ih.len)
-		return -EINVAL;
 
 	err = fuse_copy_one(cs, &ih, sizeof(ih));
 	if (!err)
@@ -1475,11 +1470,6 @@ __releases(fiq->lock)
 		.len = sizeof(ih) + sizeof(arg),
 	};
 
-	if (nbytes < ih.len) {
-		spin_unlock(&fiq->lock);
-		return -EINVAL;
-	}
-
 	max_forgets = (nbytes - ih.len) / sizeof(struct fuse_forget_one);
 	head = fuse_dequeue_forget(fiq, max_forgets, &count);
 	spin_unlock(&fiq->lock);
@@ -1515,7 +1505,7 @@ static int fuse_read_forget(struct fuse_chan *fch, struct fuse_iqueue *fiq,
 __releases(fiq->lock)
 {
 	if (fch->minor < 16 || fiq->forget_list_head.next->next == NULL)
-		return fuse_read_single_forget(fiq, cs, nbytes);
+		return fuse_read_single_forget(fiq, cs);
 	else
 		return fuse_read_batch_forget(fiq, cs, nbytes);
 }
@@ -1582,7 +1572,7 @@ static ssize_t fuse_dev_do_read(struct fuse_dev *fud, struct file *file,
 	if (!list_empty(&fiq->interrupts)) {
 		req = list_entry(fiq->interrupts.next, struct fuse_req,
 				 intr_entry);
-		return fuse_read_interrupt(fiq, cs, nbytes, req);
+		return fuse_read_interrupt(fiq, cs, req);
 	}
 
 	if (forget_pending(fiq)) {
-- 
2.52.0