linux-kernel - [PATCH v4 1/6] staging: vchiq_core: Locally cache cache_line

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Message-ID: <20241013112128.397249-2-umang.jain@ideasonboard.com>
Date: Sun, 13 Oct 2024 16:51:23 +0530
From: Umang Jain <umang.jain@...asonboard.com>
To: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Broadcom internal kernel review list <bcm-kernel-feedback-list@...adcom.com>
Cc: linux-rpi-kernel@...ts.infradead.org,
	linux-arm-kernel@...ts.infradead.org,
	linux-staging@...ts.linux.dev,
	linux-kernel@...r.kernel.org,
	Kieran Bingham <kieran.bingham@...asonboard.com>,
	Dan Carpenter <dan.carpenter@...aro.org>,
	Laurent Pinchart <laurent.pinchart@...asonboard.com>,
	kernel-list@...pberrypi.com,
	Stefan Wahren <wahrenst@....net>,
	Umang Jain <umang.jain@...asonboard.com>
Subject: [PATCH v4 1/6] staging: vchiq_core: Locally cache cache_line_size information

Locally cache 'cache_line_size' information in a variable instead of
repeatedly accessing it from drv_mgmt->info. This helps to reflow lines
under 80 columns.

No functional change intended in this patch.

Signed-off-by: Umang Jain <umang.jain@...asonboard.com>
Reviewed-by: Stefan Wahren <wahrenst@....net>
---
 .../interface/vchiq_arm/vchiq_core.c          | 19 +++++++++++--------
 1 file changed, 11 insertions(+), 8 deletions(-)

diff --git a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_core.c b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_core.c
index 1e4b2978c186..e9b60dd8d419 100644
--- a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_core.c
+++ b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_core.c
@@ -1490,6 +1490,7 @@ create_pagelist(struct vchiq_instance *instance, char *buf, char __user *ubuf,
 	size_t pagelist_size;
 	struct scatterlist *scatterlist, *sg;
 	int dma_buffers;
+	unsigned int cache_line_size;
 	dma_addr_t dma_addr;
 
 	if (count >= INT_MAX - PAGE_SIZE)
@@ -1638,10 +1639,10 @@ create_pagelist(struct vchiq_instance *instance, char *buf, char __user *ubuf,
 	}
 
 	/* Partial cache lines (fragments) require special measures */
+	cache_line_size = drv_mgmt->info->cache_line_size;
 	if ((type == PAGELIST_READ) &&
-	    ((pagelist->offset & (drv_mgmt->info->cache_line_size - 1)) ||
-	    ((pagelist->offset + pagelist->length) &
-	    (drv_mgmt->info->cache_line_size - 1)))) {
+	    ((pagelist->offset & (cache_line_size - 1)) ||
+	    ((pagelist->offset + pagelist->length) & (cache_line_size - 1)))) {
 		char *fragments;
 
 		if (down_interruptible(&drv_mgmt->free_fragments_sema)) {
@@ -1671,6 +1672,7 @@ free_pagelist(struct vchiq_instance *instance, struct vchiq_pagelist_info *pagel
 	struct pagelist *pagelist = pagelistinfo->pagelist;
 	struct page **pages = pagelistinfo->pages;
 	unsigned int num_pages = pagelistinfo->num_pages;
+	unsigned int cache_line_size;
 
 	dev_dbg(instance->state->dev, "arm: %pK, %d\n", pagelistinfo->pagelist, actual);
 
@@ -1685,16 +1687,17 @@ free_pagelist(struct vchiq_instance *instance, struct vchiq_pagelist_info *pagel
 	pagelistinfo->scatterlist_mapped = 0;
 
 	/* Deal with any partial cache lines (fragments) */
+	cache_line_size = drv_mgmt->info->cache_line_size;
 	if (pagelist->type >= PAGELIST_READ_WITH_FRAGMENTS && drv_mgmt->fragments_base) {
 		char *fragments = drv_mgmt->fragments_base +
 			(pagelist->type - PAGELIST_READ_WITH_FRAGMENTS) *
 			drv_mgmt->fragments_size;
 		int head_bytes, tail_bytes;
 
-		head_bytes = (drv_mgmt->info->cache_line_size - pagelist->offset) &
-			(drv_mgmt->info->cache_line_size - 1);
+		head_bytes = (cache_line_size - pagelist->offset) &
+			     (cache_line_size - 1);
 		tail_bytes = (pagelist->offset + actual) &
-			(drv_mgmt->info->cache_line_size - 1);
+			     (cache_line_size - 1);
 
 		if ((actual >= 0) && (head_bytes != 0)) {
 			if (head_bytes > actual)
@@ -1707,8 +1710,8 @@ free_pagelist(struct vchiq_instance *instance, struct vchiq_pagelist_info *pagel
 		    (tail_bytes != 0))
 			memcpy_to_page(pages[num_pages - 1],
 				       (pagelist->offset + actual) &
-				       (PAGE_SIZE - 1) & ~(drv_mgmt->info->cache_line_size - 1),
-				       fragments + drv_mgmt->info->cache_line_size,
+				       (PAGE_SIZE - 1) & ~(cache_line_size - 1),
+				       fragments + cache_line_size,
 				       tail_bytes);
 
 		down(&drv_mgmt->free_fragments_mutex);
-- 
2.45.2