FAILED: patch "[PATCH] qed: fix LL2 RX buffer allocation" failed to apply to 4.19-stable tree

The patch below does not apply to the 4.19-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-4.19.y
git checkout FETCH_HEAD
git cherry-pick -x 2f3389c73832ad90b63208c0fc281ad080114c7a
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2023102029-display-provolone-fab2@gregkh' --subject-prefix 'PATCH 4.19.y' HEAD^..

Possible dependencies:

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 2f3389c73832ad90b63208c0fc281ad080114c7a Mon Sep 17 00:00:00 2001
From: Manish Chopra <[email protected]>
Date: Fri, 13 Oct 2023 18:48:12 +0530
Subject: [PATCH] qed: fix LL2 RX buffer allocation
MIME-Version: 1.0
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Driver allocates the LL2 rx buffers from kmalloc() area to construct the skb using slab_build_skb()

The required size allocation seems to have overlooked for accounting both skb_shared_info size and device placement padding bytes which results into the below panic when doing skb_put() for a standard MTU sized frame.

skbuff: skb_over_panic: text:ffffffffc0b0225f len:1514 put:1514 head:ff3dabceaf39c000 data:ff3dabceaf39c042 tail:0x62c end:0x566 dev:<NULL>
…

skb_panic+0x48/0x4a
skb_put.cold+0x10/0x10
qed_ll2b_complete_rx_packet+0x14f/0x260 [qed]
qed_ll2_rxq_handle_completion.constprop.0+0x169/0x200 [qed]
qed_ll2_rxq_completion+0xba/0x320 [qed]
qed_int_sp_dpc+0x1a7/0x1e0 [qed]

This patch fixes this by accouting skb_shared_info and device placement padding size bytes when allocating the buffers.

index 717a0b3f89bd..ab5ef254a748 100644
@@ -113,7 +113,10 @@ static void qed_ll2b_complete_tx_packet(void *cxt,
 static int qed_ll2_alloc_buffer(struct qed_dev *cdev,
 				u8 **data, dma_addr_t *phys_addr)
 {
-	*data = kmalloc(cdev->ll2->rx_size, GFP_ATOMIC);
+	size_t size = cdev->ll2->rx_size + NET_SKB_PAD +
+		      SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
+
+	*data = kmalloc(size, GFP_ATOMIC);
 	if (!(*data)) {
 		DP_INFO(cdev, "Failed to allocate LL2 buffer data\n");
 		return -ENOMEM;

@@ -2589,7 +2592,7 @@ static int qed_ll2_start(struct qed_dev *cdev, struct qed_ll2_params *params)
 	INIT_LIST_HEAD(&cdev->ll2->list);
 	spin_lock_init(&cdev->ll2->lock);
 
-	cdev->ll2->rx_size = NET_SKB_PAD + ETH_HLEN +
+	cdev->ll2->rx_size = PRM_DMA_PAD_BYTES_NUM + ETH_HLEN +
 			     L1_CACHE_BYTES + params->mtu;
 
 	/* Allocate memory for LL2.