[PATCH 28/28] drm/xe/pf: Refactor strlcat() to seq_buf in sched_group_engines_read()

Similar to control_read(), sched_group_engines_read() constructs a
space-separated list of hardware engine names in a stack buffer using
repeated strlcat() calls inside a loop.

In preparation for removing the deprecated strlcat() API[1], refactor
sched_group_engines_read() to use struct seq_buf and seq_buf_printf().

Link: https://github.com/KSPP/linux/issues/370 [1]
Cc: codemender-patching+linux@google.com
Assisted-by: Developer:Gemini [editor_update_file, make_kernel_build_single_file, shell_command_run]
Signed-off-by: Bill Wendling <morbo@google.com>
---
Cc: Russell King <linux@armlinux.org.uk>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: WANG Xuerui <kernel@xen0n.name>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: Helge Deller <deller@gmx.de>
Cc: Thomas Gleixner <tglx@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: x86@kernel.org
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ian Abbott <abbotti@mev.co.uk>
Cc: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: David Airlie <airlied@gmail.com>
Cc: Simona Vetter <simona@ffwll.ch>
Cc: Matthew Brost <matthew.brost@intel.com>
Cc: "Thomas Hellström" <thomas.hellstrom@linux.intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: Matthias Schwarzott <zzam@gentoo.org>
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Cc: Tony Nguyen <anthony.l.nguyen@intel.com>
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Cc: Andrew Lunn <andrew+netdev@lunn.ch>
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Cc: "Mike Rapoport (Microsoft)" <rppt@kernel.org>
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Cc: Tiezhu Yang <yangtiezhu@loongson.cn>
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---
 drivers/gpu/drm/xe/xe_gt_sriov_pf_debugfs.c | 15 ++++++++-------
 1 file changed, 8 insertions(+), 7 deletions(-)

diff --git a/drivers/gpu/drm/xe/xe_gt_sriov_pf_debugfs.c b/drivers/gpu/drm/xe/xe_gt_sriov_pf_debugfs.c
index 5db7fc067c4d..548a50f74422 100644
--- a/drivers/gpu/drm/xe/xe_gt_sriov_pf_debugfs.c
+++ b/drivers/gpu/drm/xe/xe_gt_sriov_pf_debugfs.c

@@ -377,8 +377,10 @@ static ssize_t sched_group_engines_read(struct file *file, char __user *buf,
 	struct xe_hw_engine *hwe;
 	enum xe_hw_engine_id id;
 	char engines[128];
+	struct seq_buf s;
+	const char *s_str;
 
-	engines[0] = '\0';
+	seq_buf_init(&s, engines, sizeof(engines));
 
 	if (group < num_groups) {
 		for_each_hw_engine(hwe, gt, id) {

@@ -386,15 +388,14 @@ static ssize_t sched_group_engines_read(struct file *file, char __user *buf,
 			u16 guc_logical_instance = xe_hwe_guc_logical_instance(hwe);
 			u32 mask = groups[group].engines[guc_class];
 
-			if (mask & BIT(guc_logical_instance)) {
-				strlcat(engines, hwe->name, sizeof(engines));
-				strlcat(engines, " ", sizeof(engines));
-			}
+			if (mask & BIT(guc_logical_instance))
+				seq_buf_printf(&s, "%s ", hwe->name);
 		}
-		strlcat(engines, "\n", sizeof(engines));
+		seq_buf_puts(&s, "\n");
 	}
 
-	return simple_read_from_buffer(buf, count, ppos, engines, strlen(engines));
+	s_str = seq_buf_str(&s);
+	return simple_read_from_buffer(buf, count, ppos, s_str, strlen(s_str));
 }
 
 static const struct file_operations sched_group_engines_fops = {

-- 
2.55.0.1032.g73a4cd73de-goog