Patch "ubd: refactor the interrupt handler" has been added to the 6.10-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    ubd: refactor the interrupt handler

to the 6.10-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     ubd-refactor-the-interrupt-handler.patch
and it can be found in the queue-6.10 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit f4983914a37fa71fc8e32e6ee154897542aaac72
Author: Christoph Hellwig <hch@xxxxxx>
Date:   Fri May 31 09:47:56 2024 +0200

    ubd: refactor the interrupt handler
    
    [ Upstream commit 5db755fbb1a0de4a4cfd5d5edfaa19853b9c56e6 ]
    
    Instead of a separate handler function that leaves no work in the
    interrupt hanler itself, split out a per-request end I/O helper and
    clean up the coding style and variable naming while we're at it.
    
    Signed-off-by: Christoph Hellwig <hch@xxxxxx>
    Reviewed-by: Martin K. Petersen <martin.petersen@xxxxxxxxxx>
    Acked-By: Anton Ivanov <anton.ivanov@xxxxxxxxxxxxxxxxxx>
    Link: https://lore.kernel.org/r/20240531074837.1648501-2-hch@xxxxxx
    Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
    Stable-dep-of: 31ade7d4fdcf ("ubd: untagle discard vs write zeroes not support handling")
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/arch/um/drivers/ubd_kern.c b/arch/um/drivers/ubd_kern.c
index ef805eaa9e013..0c9542d58c01b 100644
--- a/arch/um/drivers/ubd_kern.c
+++ b/arch/um/drivers/ubd_kern.c
@@ -447,43 +447,30 @@ static int bulk_req_safe_read(
 	return n;
 }
 
-/* Called without dev->lock held, and only in interrupt context. */
-static void ubd_handler(void)
+static void ubd_end_request(struct io_thread_req *io_req)
 {
-	int n;
-	int count;
-
-	while(1){
-		n = bulk_req_safe_read(
-			thread_fd,
-			irq_req_buffer,
-			&irq_remainder,
-			&irq_remainder_size,
-			UBD_REQ_BUFFER_SIZE
-		);
-		if (n < 0) {
-			if(n == -EAGAIN)
-				break;
-			printk(KERN_ERR "spurious interrupt in ubd_handler, "
-			       "err = %d\n", -n);
-			return;
-		}
-		for (count = 0; count < n/sizeof(struct io_thread_req *); count++) {
-			struct io_thread_req *io_req = (*irq_req_buffer)[count];
-
-			if ((io_req->error == BLK_STS_NOTSUPP) && (req_op(io_req->req) == REQ_OP_DISCARD)) {
-				blk_queue_max_discard_sectors(io_req->req->q, 0);
-				blk_queue_max_write_zeroes_sectors(io_req->req->q, 0);
-			}
-			blk_mq_end_request(io_req->req, io_req->error);
-			kfree(io_req);
-		}
+	if (io_req->error == BLK_STS_NOTSUPP &&
+	    req_op(io_req->req) == REQ_OP_DISCARD) {
+		blk_queue_max_discard_sectors(io_req->req->q, 0);
+		blk_queue_max_write_zeroes_sectors(io_req->req->q, 0);
 	}
+	blk_mq_end_request(io_req->req, io_req->error);
+	kfree(io_req);
 }
 
 static irqreturn_t ubd_intr(int irq, void *dev)
 {
-	ubd_handler();
+	int len, i;
+
+	while ((len = bulk_req_safe_read(thread_fd, irq_req_buffer,
+			&irq_remainder, &irq_remainder_size,
+			UBD_REQ_BUFFER_SIZE)) >= 0) {
+		for (i = 0; i < len / sizeof(struct io_thread_req *); i++)
+			ubd_end_request((*irq_req_buffer)[i]);
+	}
+
+	if (len < 0 && len != -EAGAIN)
+		pr_err("spurious interrupt in %s, err = %d\n", __func__, len);
 	return IRQ_HANDLED;
 }