FAILED: patch "[PATCH] s390/cio: Restore GFP_DMA for CHSC allocation" failed to apply to 6.18-stable tree

FAILED: patch "[PATCH] s390/cio: Restore GFP_DMA for CHSC allocation" failed to apply to 6.18-stable tree

[gregkh]

The patch below does not apply to the 6.18-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 <stable@vger.kernel.org>.

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-6.18.y
git checkout FETCH_HEAD
git cherry-pick -x ea34567db0a6b3a7ce78ba421592344315c8f90e
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2026052823-pavement-affirm-22a2@gregkh' --subject-prefix 'PATCH 6.18.y' HEAD^..

Possible dependencies:



thanks,

greg k-h

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

From ea34567db0a6b3a7ce78ba421592344315c8f90e Mon Sep 17 00:00:00 2001
From: Peter Oberparleiter <oberpar@linux.ibm.com>
Date: Thu, 7 May 2026 16:27:08 +0200
Subject: [PATCH] s390/cio: Restore GFP_DMA for CHSC allocation

Re-add GFP_DMA when allocating memory for CHSC control blocks.
On some supported machines, CHSC cannot access memory outside
the DMA zone, causing CHSC command failures.

Cc: stable@vger.kernel.org
Fixes: a3a64a4def8d ("s390/cio: remove unneeded DMA zone allocation")
Signed-off-by: Peter Oberparleiter <oberpar@linux.ibm.com>
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>

diff --git a/drivers/s390/cio/chsc.c b/drivers/s390/cio/chsc.c
index fbb58edd6274..9689f722c863 100644
--- a/drivers/s390/cio/chsc.c
+++ b/drivers/s390/cio/chsc.c
@@ -1142,8 +1142,8 @@ int __init chsc_init(void)
 {
 	int ret;
 
-	sei_page = (void *)get_zeroed_page(GFP_KERNEL);
-	chsc_page = (void *)get_zeroed_page(GFP_KERNEL);
+	sei_page = (void *)get_zeroed_page(GFP_KERNEL | GFP_DMA);
+	chsc_page = (void *)get_zeroed_page(GFP_KERNEL | GFP_DMA);
 	if (!sei_page || !chsc_page) {
 		ret = -ENOMEM;
 		goto out_err;
diff --git a/drivers/s390/cio/chsc_sch.c b/drivers/s390/cio/chsc_sch.c
index 73413417a2ce..b6cb8bb8bcc4 100644
--- a/drivers/s390/cio/chsc_sch.c
+++ b/drivers/s390/cio/chsc_sch.c
@@ -292,7 +292,7 @@ static int chsc_ioctl_start(void __user *user_area)
 	if (!css_general_characteristics.dynio)
 		/* It makes no sense to try. */
 		return -EOPNOTSUPP;
-	chsc_area = (void *)get_zeroed_page(GFP_KERNEL);
+	chsc_area = (void *)get_zeroed_page(GFP_DMA | GFP_KERNEL);
 	if (!chsc_area)
 		return -ENOMEM;
 	request = kzalloc_obj(*request);
@@ -340,7 +340,7 @@ static int chsc_ioctl_on_close_set(void __user *user_area)
 		ret = -ENOMEM;
 		goto out_unlock;
 	}
-	on_close_chsc_area = (void *)get_zeroed_page(GFP_KERNEL);
+	on_close_chsc_area = (void *)get_zeroed_page(GFP_DMA | GFP_KERNEL);
 	if (!on_close_chsc_area) {
 		ret = -ENOMEM;
 		goto out_free_request;
@@ -392,7 +392,7 @@ static int chsc_ioctl_start_sync(void __user *user_area)
 	struct chsc_sync_area *chsc_area;
 	int ret, ccode;
 
-	chsc_area = (void *)get_zeroed_page(GFP_KERNEL);
+	chsc_area = (void *)get_zeroed_page(GFP_KERNEL | GFP_DMA);
 	if (!chsc_area)
 		return -ENOMEM;
 	if (copy_from_user(chsc_area, user_area, PAGE_SIZE)) {
@@ -438,7 +438,7 @@ static int chsc_ioctl_info_channel_path(void __user *user_cd)
 		u8 data[PAGE_SIZE - 20];
 	} __attribute__ ((packed)) *scpcd_area;
 
-	scpcd_area = (void *)get_zeroed_page(GFP_KERNEL);
+	scpcd_area = (void *)get_zeroed_page(GFP_KERNEL | GFP_DMA);
 	if (!scpcd_area)
 		return -ENOMEM;
 	cd = kzalloc_obj(*cd);
@@ -500,7 +500,7 @@ static int chsc_ioctl_info_cu(void __user *user_cd)
 		u8 data[PAGE_SIZE - 20];
 	} __attribute__ ((packed)) *scucd_area;
 
-	scucd_area = (void *)get_zeroed_page(GFP_KERNEL);
+	scucd_area = (void *)get_zeroed_page(GFP_KERNEL | GFP_DMA);
 	if (!scucd_area)
 		return -ENOMEM;
 	cd = kzalloc_obj(*cd);
@@ -563,7 +563,7 @@ static int chsc_ioctl_info_sch_cu(void __user *user_cud)
 		u8 data[PAGE_SIZE - 20];
 	} __attribute__ ((packed)) *sscud_area;
 
-	sscud_area = (void *)get_zeroed_page(GFP_KERNEL);
+	sscud_area = (void *)get_zeroed_page(GFP_KERNEL | GFP_DMA);
 	if (!sscud_area)
 		return -ENOMEM;
 	cud = kzalloc_obj(*cud);
@@ -625,7 +625,7 @@ static int chsc_ioctl_conf_info(void __user *user_ci)
 		u8 data[PAGE_SIZE - 20];
 	} __attribute__ ((packed)) *sci_area;
 
-	sci_area = (void *)get_zeroed_page(GFP_KERNEL);
+	sci_area = (void *)get_zeroed_page(GFP_KERNEL | GFP_DMA);
 	if (!sci_area)
 		return -ENOMEM;
 	ci = kzalloc_obj(*ci);
@@ -696,7 +696,7 @@ static int chsc_ioctl_conf_comp_list(void __user *user_ccl)
 		u32 res;
 	} __attribute__ ((packed)) *cssids_parm;
 
-	sccl_area = (void *)get_zeroed_page(GFP_KERNEL);
+	sccl_area = (void *)get_zeroed_page(GFP_KERNEL | GFP_DMA);
 	if (!sccl_area)
 		return -ENOMEM;
 	ccl = kzalloc_obj(*ccl);
@@ -756,7 +756,7 @@ static int chsc_ioctl_chpd(void __user *user_chpd)
 	int ret;
 
 	chpd = kzalloc_obj(*chpd);
-	scpd_area = (void *)get_zeroed_page(GFP_KERNEL);
+	scpd_area = (void *)get_zeroed_page(GFP_KERNEL | GFP_DMA);
 	if (!scpd_area || !chpd) {
 		ret = -ENOMEM;
 		goto out_free;
@@ -796,7 +796,7 @@ static int chsc_ioctl_dcal(void __user *user_dcal)
 		u8 data[PAGE_SIZE - 36];
 	} __attribute__ ((packed)) *sdcal_area;
 
-	sdcal_area = (void *)get_zeroed_page(GFP_KERNEL);
+	sdcal_area = (void *)get_zeroed_page(GFP_KERNEL | GFP_DMA);
 	if (!sdcal_area)
 		return -ENOMEM;
 	dcal = kzalloc_obj(*dcal);
diff --git a/drivers/s390/cio/scm.c b/drivers/s390/cio/scm.c
index d13ed1011c03..171212a6d2d9 100644
--- a/drivers/s390/cio/scm.c
+++ b/drivers/s390/cio/scm.c
@@ -229,7 +229,7 @@ int scm_update_information(void)
 	size_t num;
 	int ret;
 
-	scm_info = (void *)__get_free_page(GFP_KERNEL);
+	scm_info = (void *)__get_free_page(GFP_KERNEL | GFP_DMA);
 	if (!scm_info)
 		return -ENOMEM;