Patch "net: wwan: iosm: Properly check for valid exec stage in ipc_mmio_init()" has been added to the 5.15-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

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

    net: wwan: iosm: Properly check for valid exec stage in ipc_mmio_init()

to the 5.15-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:
     net-wwan-iosm-properly-check-for-valid-exec-stage-in.patch
and it can be found in the queue-5.15 subdirectory.

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



commit 5a4271bdeb9ccc8308f6ee63e87407716420d10f
Author: Maciej S. Szmigiero <mail@xxxxxxxxxxxxxxxxxxxxx>
Date:   Sun Dec 29 17:46:58 2024 +0100

    net: wwan: iosm: Properly check for valid exec stage in ipc_mmio_init()
    
    [ Upstream commit a7af435df0e04cfb4a4004136d597c42639a2ae7 ]
    
    ipc_mmio_init() used the post-decrement operator in its loop continuing
    condition of "retries" counter being "> 0", which meant that when this
    condition caused loop exit "retries" counter reached -1.
    
    But the later valid exec stage failure check only tests for "retries"
    counter being exactly zero, so it didn't trigger in this case (but
    would wrongly trigger if the code reaches a valid exec stage in the
    very last loop iteration).
    
    Fix this by using the pre-decrement operator instead, so the loop counter
    is exactly zero on valid exec stage failure.
    
    Fixes: dc0514f5d828 ("net: iosm: mmio scratchpad")
    Signed-off-by: Maciej S. Szmigiero <mail@xxxxxxxxxxxxxxxxxxxxx>
    Link: https://patch.msgid.link/8b19125a825f9dcdd81c667c1e5c48ba28d505a6.1735490770.git.mail@xxxxxxxxxxxxxxxxxxxxx
    Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/net/wwan/iosm/iosm_ipc_mmio.c b/drivers/net/wwan/iosm/iosm_ipc_mmio.c
index 09f94c123531..b452ddf9ef06 100644
--- a/drivers/net/wwan/iosm/iosm_ipc_mmio.c
+++ b/drivers/net/wwan/iosm/iosm_ipc_mmio.c
@@ -102,7 +102,7 @@ struct iosm_mmio *ipc_mmio_init(void __iomem *mmio, struct device *dev)
 			break;
 
 		msleep(20);
-	} while (retries-- > 0);
+	} while (--retries > 0);
 
 	if (!retries) {
 		dev_err(ipc_mmio->dev, "invalid exec stage %X", stage);